Previous Article | Next Article 
Journal of Virology, August 2004, p. 8753-8760, Vol. 78, No. 16
0022-538X/04/$08.00+0 DOI: 10.1128/JVI.78.16.8753-8760.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.
Vß14+ T Cells Mediate the Vaccine-Enhanced Disease Induced by Immunization with Respiratory Syncytial Virus (RSV) G Glycoprotein but Not with Formalin-Inactivated RSV
Teresa R. Johnson,1* Steven M. Varga,2,
Thomas J. Braciale,2 and Barney S. Graham1
Viral Pathogenesis Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892,1
Bernie B. Carter Center for Immunology Research, University of Virginia Health Sciences Center, Charlottesville, Virginia 229082
Received 16 December 2003/
Accepted 12 April 2004

ABSTRACT
Mice immunized with respiratory syncytial virus (RSV) G glycoprotein
or with formalin-inactivated RSV (FI-RSV) exhibit severe disease
following RSV challenge. This results in type 2 cytokine production
and pulmonary eosinophilia, both hallmarks of vaccine-enhanced
disease. RSV G-induced T-cell responses were shown to be restricted
to CD4
+ T cells expressing Vß14 in the T-cell receptor
(TCR), and the deletion of these T cells resulted in less severe
disease. We therefore examined the role of Vß14
+ T
cells in FI-RSV-induced disease. BALB/c mice were immunized
with vaccinia virus expressing secreted RSV G (vvGs) or with
FI-RSV. At the time of challenge with live RSV, mice were injected
with antibody to the Vß14 component of the TCR. vvGs-immunized
mice treated with anti-Vß14 had reduced cytokine levels
in the lung. Eosinophil recruitment to the lung was also significantly
reduced. In contrast, depletion of Vß14
+ T cells in
FI-RSV-immunized mice had little impact on cytokine production
or pulmonary eosinophilia. An analysis of TCR Vß chain
usage confirmed a bias toward Vß14 expression on CD4
+ T cells from vvGs-immunized mice, whereas the CD4
+ T cells in
FI-RSV-immunized mice expressed a diverse array of Vß
chains. These data show that although FI-RSV and vvGs induce
responses resulting in similar immunopathology, the T-cell repertoire
mediating the response is different for each immunogen and suggest
that the immune responses elicited by RSV G are not the basis
for FI-RSV vaccine-enhanced disease.

INTRODUCTION
Respiratory syncytial virus (RSV) is a member of the
Paramyxoviridae family of viruses. The negative-sense single-stranded RNA genome
contains 10 genes that encode 11 proteins (
16). The G glycoprotein,
the putative attachment protein of RSV, is expressed on both
the surface of the virus and on virally infected cells. The
G glycoprotein is naturally produced as both membrane-anchored
and secreted forms due to the presence of a second methionine
codon in the transmembrane region of the protein (
18,
42). The
secreted form of RSV G can be detected in culture supernatants
soon after infection (at 6 h postinfection), while the detection
of all membrane-anchored proteins occurs later (18 to 20 h postinfection).
Thus, secreted RSV G is available to modulate early innate immune
responses to RSV. Two antigenic strains of virus, A and B, exist
and cocirculate each year, and much of the antigenic diversity
between and within RSV strains is due to variations in the RSV
G glycoprotein, with as little as 35% homology between G glycoproteins
of strain A and strain B isolates (
20,
21,
33). Therefore, as
the attachment protein, the first viral protein expressed, and
the source of most of the antigenic diversity, the G glycoprotein
is a potentially important target of protective antiviral immune
responses and should be considered for inclusion in any vaccine
product. RSV G also has features that suggest it should not
be included as a vaccine antigen. It is heavily glycosylated
(
30) and does not induce antibody well in young infants (
34).
Additionally, it is not stable as a purified protein even when
stored at 70°C (E. Walsh, personal communication).
Also, G-specific cytolytic CD8
+-T-cell responses are very rare
(
2,
3,
7,
10,
45). Finally, RSV G-specific CD4
+-T-cell responses
have been associated with severe disease (
1,
38,
54).
RSV is the major cause of respiratory disease in infants and young children, resulting in more than 130,000 hospitalizations in the United States each year (43). While RSV infection normally results in mild upper respiratory tract symptoms, a subset of infants progress to a more severe lower respiratory tract disease. Children who experience these severe acute lower respiratory tract symptoms caused by RSV infection have an increased incidence of childhood asthma (reviewed in reference 39). Therefore, development of an RSV vaccine is of high priority.
In the early 1960s, a trial of formalin-inactivated alum-precipitated RSV (FI-RSV) was conducted. However, rather than protecting vaccinees against infection, children immunized with the FI-RSV preparation experienced more severe disease following subsequent natural exposure to the virus, resulting in the hospitalization of 80% of FI-RSV-immunized infants and two deaths, compared to 5% hospitalization and no deaths in children immunized with a similar preparation of parainfluenza virus (26, 28). Subsequent analyses of blood from these children demonstrated significant titers of nonneutralizing serum antibody (28) and heightened lymphoproliferative responses (29). Histopathologic examination of lung tissue from one of the infants that died revealed a prominent eosinophilic infiltrate (15, 28). Animal models of RSV pathogenesis have similarly demonstrated enhanced disease in FI-RSV-immunized animals following challenge with live RSV (9, 13, 35, 41). This vaccine-enhanced disease is typified by pulmonary eosinophilia and the production of type 2 cytokines, especially interleukin-4 (IL-4), IL-5, and pulmonary eosinophilia. Interference with the function of these cytokines decreases disease severity (9, 23, 25, 48-50), underscoring the importance of cytokines in FI-RSV vaccine-enhanced immunopathogenesis.
Recombinant vaccinia viruses expressing RSV G induce CD4+ T cells that secrete IL-4, IL-5, and IL-13 and result in pulmonary eosinophilia upon RSV challenge of vaccinated mice (4, 17, 24, 38, 45, 46). Mice immunized with vaccinia virus expressing only the secreted form of RSV G (vvGs) exhibit more severe disease after challenge than do mice immunized with vaccinia expressing wild-type (vvGwt) or only membrane-anchored (vvGr) G glycoprotein (4, 24). These similar disease patterns of type 2 cytokine production and pulmonary eosinophilia following RSV challenge of FI-RSV- or G-immunized mice have led to the proposal that it is the presence of the G glycoprotein in FI-RSV that predisposes for the vaccine-enhanced illness observed. However, we have demonstrated that while similar endpoints of pulmonary eosinophilia and severe illness occur in FI-RSV- and G-immunized mice, the cytokine requirements of these two immunogens are significantly different. Vaccine-enhanced disease in FI-RSV-immunized mice, in which IL-4 expression predominates, may be modulated by the inhibition of IL-4 or IL-13 alone (23, 25, 48) or by the addition of exogenous IL-12 during priming (49). In contrast, IL-13 expression is greater in vvGs-immunized mice, and disease is reduced only when both IL-4 and IL-13 function is blocked (23, 25). Furthermore, the presence of gamma interferon (IFN-
) (22) or IL-12 (unpublished data) during vvGs priming has minimal impact on vaccinia virus replication or disease following live RSV challenge.
In vitro analyses have shown that CD4+ T cells from BALB/c mice immunized with RSV G respond to a single peptide spanning amino acids (aa) 183 to 198 (47, 51) or aa 193 to 203 (44) of the G glycoprotein and produce both type 1 and type 2 cytokines following peptide stimulation. Immunization of BALB/c mice with only this immunodominant epitope of RSV G is sufficient to induce those immune responses that result in enhanced disease following RSV challenge (51). Subsequent work demonstrated the presence of a single immunodominant CD4-T-cell-restricted epitope spanning aa 183 to 195 that elicited both Th1 and Th2 CD4+ T cells (55). Further examination of the CD4+ memory T-cell response to the immunodominant epitope spanning aa 183 to 195 demonstrated that this population is highly skewed with Vß14-T-cell-receptor (TCR)-expressing cells that exhibit striking conservation within the complement determining region 3 (54). When these Vß14+ T cells were depleted in G-immunized mice prior to RSV challenge, eosinophilia and type 2 cytokine production were reduced. We therefore examined the contribution of Vß14+ T cells to vaccine-enhanced disease in FI-RSV-immunized mice.

MATERIALS AND METHODS
Viruses and vaccine formulations.
RSV A2 was grown in HEp-2 cells (American Type Culture Collection)
in Eagle's modified essential medium supplemented with 10% fetal
calf serum, glutamine, and antibiotics (10% EMEM). FI-RSV was
prepared as previously described (
13). An RSV challenge stock
was grown in HEp-2 cells as previously described (
14). vvGs
and vvGwt were gifts from Gail Wertz (University of Alabama
at Birmingham). The viruses were grown in BSC40 cells in 10%
EMEM and purified on discontinuous potassium tartrate gradients
as described previously (
24). PCR showed all virus stocks to
be free of mycoplasma and adenovirus contamination.
Immunization, antibody treatment, and RSV challenge of mice.
Six-week-old pathogen-free BALB/c mice were purchased from Charles River Laboratories. Mice were immunized intramuscularly with 0.1 ml of FI-RSV diluted 1:10 in 1x phosphate-buffered saline (PBS) or with vvGs or vvGwt (5 x 105 PFU in 0.05 ml) intradermally at the base of the tail. Six weeks later, all mice were challenged intranasally with 107 PFU of live RSV in 0.1 ml.
To deplete Vß14+ T cells, subsets of FI-RSV- and vvGs-immunized mice were injected intraperitoneally with 0.1 mg of anti-Vß14 in 0.2 ml of PBS. Additional immunized mice were injected with 0.1 mg of immunoglobulin M (IgM) isotype-matched control antibody. The mice were injected on days 1, 2, and 5 around RSV challenge. The anti-Vß14 antibody and the IgM control were purchased from BD Pharmingen.
RSV titers.
Subsets of mice were euthanized 4 and 7 days postchallenge for determination of virus titers. The lungs were removed and transferred to 10% EMEM and quick-frozen. The lungs were stored at 80°C until assayed. RSV titers were measured by plaque assay on subconfluent HEp-2 monolayers as previously described (24). The data are expressed as the log10 PFU per gram of lung tissue.
Cytokine protein levels in the lung.
IL-4, IL-5, IL-13, IFN-
, eotaxin, MIP-1
, and MIP-1ß protein levels were measured by cytokine-specific sandwich enzyme-linked immunosorbent assays (ELISAs; R&D Systems, Minneapolis, Minn.) using the lung supernatants after viral plaque assays were completed. The data are expressed as picograms per milliliter.
BAL.
Seven days after challenge, a subset of mice were euthanized. A tracheotomy was performed, and the large airways were washed with 0.5 ml PBS-1% bovine serum albumin. The bronchoalveolar lavage (BAL) wash was centrifuged, and the supernatant was removed. The BAL pellet was resuspended, total cell counts of the BAL cell pellet were made by trypan blue exclusion, and cytospins were made with the remaining sample. The cytospins were differentially stained with HemaStain, and differential cell counts were determined by counting at least 300 total cells. The data are expressed as the percentage of eosinophils and as the total number of eosinophils present.
Lung histopathology.
Seven days after challenge, mice were euthanized. The left lungs were inflated with 10% formalin and removed and transferred to formalin. The tissue was paraffin embedded, and thin sections were cut. Sections were stained with hematoxylin and eosin and with Giemsa stain.
Analysis of TCR expression.
Mice were immunized with vvGs or FI-RSV and challenged with live RSV. Five days after challenge, lung lymphocytes were isolated from immunized and challenged mice as described previously (55). The cells (2 x 106) were stained with phycoerythrin (PE)-conjugated anti-CD4 and fluorescein isothiocyanate-labeled anti-TCR monoclonal antibodies in staining buffer (PBS containing 2% fetal bovine serum and 0.02% NaN3). All antibodies were purchased from BD Pharmingen, with the exception of anti-TCR Vß8.2/3, which was purchased from CalTag. Stained cells were fixed and erythrocytes were lysed with fluorescence-activated cell sorter lysing solution (BD Pharmingen), washed, resuspended in staining buffer, and analyzed on a FACSCalibur flow cytometer.
Peptide stimulation and intracellular cytokine production.
Mice were immunized with vac-lac (recombinant vaccinia virus encoding ß-galactosidase), vvGs, or FI-RSV and were challenged with live RSV. Lung mononuclear cells were isolated as described previously (55) 5 days after RSV challenge. Lung mononuclear cells (2 x 106) were then stimulated for 5 h in the presence or absence of 1 µM RSV peptides (Table 1) and in the presence of 1 µg of brefeldin A (Sigma)/ml. The cells were then washed in staining buffer and fixed with fluorescence-activated cell sorter lysing solution. After fixation, the cells were washed twice in permeabilization buffer (staining buffer containing 0.5% saponin) and blocked with purified anti-Fc
RII/III (clone 2.4G2; BD Pharmingen). The cells were then stained with PerCp/Cy5.5-conjugated anti-CD4 and a combination of either PE-labeled anti-IL-4 (clone 11B11) and allophycocyanin (APC)-labeled anti-IL-5 (clone TRFK5) or PE-labeled anti-IL-6 (clone MP5-20F3) and APC-labeled anti-IFN-
(clone XMG1.2). PE- and APC-conjugated rat IgG1 (clone R3-34) were used as isotype-matched control antibodies. All antibodies were purchased from BD Pharmingen. Stained cells were washed, resuspended in staining buffer, and analyzed on a FACSCalibur flow cytometer.
Statistical analysis.
Data were maintained in a Paradox database. Comparisons between
immunization groups were made with a Kruskal-Wallis test by
using SAS software.
P < 0.05 was defined as a significant
difference. For statistical analysis of eosinophil and cytokine
data, a Student's
t test was performed by using the SigmaStat
software package (Jandel Scientific, San Rafael, Calif.) to
compare two groups, or one-way analysis of variance was used
to compare more than two groups. If the data did not distribute
normally, a rank sum test was used to compare two groups.

RESULTS
Depletion of Vß14+ T cells at the time of RSV challenge reduces pulmonary eosinophilia and type 2 cytokine production in both vvGwt- and vvGs-immunized mice.
It was previously demonstrated that while immunization with
vaccinia virus expressing either vvGwt or only vvGs results
in pulmonary eosinophilia and type 2 cytokine production following
RSV challenge, the magnitude of the response in vvGs-immunized
mice is more similar to that of FI-RSV-immunized mice (
24).
Prior to Vß14 depletion studies in parallel with FI-RSV-immunized
mice, we compared the relative effects of Vß14 antibody
treatment during immunization with either vvGwt or vvGs. Mice
were immunized with vvGwt or vvGs, and 6 weeks later, the mice
were challenged with live RSV. At days 1, 2, and 5 of
challenge, anti-Vß14 antibody was administered to
deplete mice of Vß14
+ CD4
+ T cells. Seven days after
RSV challenge, mice were euthanized and BAL was performed. When
evaluated as the percentage of cells present in the BAL, depletion
of Vß14
+ T cells at the time of RSV challenge reduced
eosinophil recruitment to the large airways by 42.7 and 50.6%
in mice immunized with vvGwt and vvGs, respectively (Fig.
1A).
Similarly, the reduction in total number of eosinophils recruited
to the BAL compartment was 30.0 and 58.7% in vvGwt- and vvGs-immunized
mice, respectively (Fig.
1B). Thus, as previously reported (
54),
anti-Vß14 treatment of vvGwt-primed mice reduced pulmonary
eosinophilia to nearly background levels of <5% eosinophils
during primary RSV infection, as reported by numerous groups
(
4,
24,
38,
45,
53). However, with the greater inflammatory
response induced in vvGs-immunized mice, administration of Vß14-specific
antibody significantly reduces pulmonary eosinophilia but does
not completely abolish the eosinophil-recruiting immune responses.
In a similar manner, depletion of Vß14
+ T cells in
vvGwt- and vvGs-immunized mice reduced the production of type
2 cytokines and chemokines following RSV challenge (Fig.
1C)
but did not completely eliminate production of these cytokines,
in agreement with findings of previous work (
54). These data
demonstrate that RSV-specific immune responses are mediated
by Vß14
+ T cells in both vvGwt- and vvGs-immunized
mice. Thus, since an impact on disease severity was observed
in anti-Vß14-treated vvGs-immunized mice, comparative
studies with FI-RSV immunization utilized vvGs-primed mice,
where the magnitude of responses are more similar to those of
FI-RSV-immunized mice (
23,
24).
Depletion of Vß14+ T cells does not reduce pulmonary eosinophilia following RSV challenge in FI-RSV-immunized mice but does so in vvGs-immunized mice.
Immunization with FI-RSV (
13,
35), with vaccinia virus expressing
the entire RSV G (
17,
38,
45,
46), or with vaccinia virus expressing
only secreted RSV G (
4,
23-
25) results in profound pulmonary
eosinophilia following challenge with live RSV. We sought to
determine whether Vß14
+ T cells contribute to eosinophil
infiltration in FI-RSV-immunized mice as has been shown for
G-immunized mice (
54) in mice with similar magnitudes of disease
severity upon RSV challenge. In our model of the pathogenesis
of RSV vaccine-enhanced disease, the magnitude of disease severity
is most similar in FI-RSV- and vvGs-immunized mice, while vvGwt-primed
mice typically exhibit less severe disease following RSV challenge
(
23,
24). Therefore, to fairly evaluate the contribution of
Vß14
+ T cells to disease, we chose to compare FI-RSV-immunized
mice with vvGs-immunized mice rather than with vvGwt-primed
animals. Mice were immunized with FI-RSV or with vvGs, and 6
weeks later, the mice were challenged with live RSV. At days
1, 2, and 5 of challenge, anti-Vß14 antibody
was administered to deplete mice of Vß14
+ CD4
+ T cells.
Seven days after challenge of mice immunized with the FI-RSV
or vvGs and depleted of Vß14
+ T cells, mice were euthanized
and BAL was performed. Differential staining of the BAL cells
demonstrated profound eosinophilia in mice primed with FI-RSV
or with vvGs and treated with IgM (Fig.
2). Depletion of Vß14
+ T cells significantly reduced the degree of eosinophils in the
BAL of vvGs-immunized mice as evaluated by either the percentage
(Fig.
2A) or the number of eosinophils present (Fig.
2B) in
vvGs-immunized mice (
P < 0.01, comparing mice treated with
anti-Vß14 to those treated with IgM isotype control
antibody). In contrast, depletion of Vß14
+ T cells
in FI-RSV-immunized mice resulted in an increase in the percentage
of eosinophils in the BAL compartment (Fig.
2A), although the
difference was not statistically significant (
P = 0.18). However,
the total number of eosinophils (Fig.
2B) was similar between
the two treatment groups of FI-RSV-immunized mice. Similar patterns
were observed upon histopathologic examination of the lung tissue.
Specifically, in vvGs-immunized mice, but not in FI-RSV-primed
mice, depletion of Vß14
+ T cells decreased the number
of eosinophils recruited to the lung after RSV challenge (data
not shown). These data demonstrate that Vß14
+ T cells
are involved in the recruitment of eosinophils to the lungs
of RSV-challenged vvGs-immunized mice while this subset of T
cells plays no significant role in pulmonary eosinophilia of
FI-RSV-immunized mice.
Significant levels of type 2 cytokines and chemokines are produced in FI-RSV-immunized mice following RSV challenge.
Protein levels of cytokines and chemokines in the lungs were
measured by ELISA 4 and 7 days after challenge of immunized
mice. IL-4, IL-5, IL-13, IFN-

, eotaxin, MIP-1

, and MIP-1ß
production were examined in lung supernatants (Tables
2 and
3, respectively). At day 4 postchallenge (Table
2), all cytokines
and chemokines but IL-4 and IL-5 were significantly reduced
in vvGs-immunized mice by the depletion of Vß14
+ T
cells, whereas only MIP-1ß levels were reduced in
FI-RSV-immunized mice by anti-Vß14 treatment. In contrast,
at day 7 postchallenge, the levels of nearly all cytokines in
anti-Vß14-treated and IgM-treated control mice were
similar in both vvGs- and FI-RSV-immunized groups (Table
3).
Only MIP-1ß levels in vvGs-immunized mice were significantly
altered by the depletion of Vß14
+ T cells. Thus, Vß14
+ T cells contribute to the production of type 2 cytokines and
chemokines in vvGs-immunized mice but appear to play no significant
role in cytokine production following RSV challenge in FI-RSV-immunized
mice.
Deletion of Vß14+ T cells significantly decreases viral titers following RSV challenge in vvGs-primed mice.
Peak viral replication occurs 4 days after primary RSV infection,
and virus clearance occurs between days 7 and 9 in the BALB/c
mouse model of RSV (
14). To assess the contribution of Vß14
+ T cells to viral clearance, RSV titers in the lung were measured
at days 4 and 7 postchallenge. Anti-Vß14-treated vvGs-immunized
mice had lower RSV titers than did IgM-treated mice at both
days 4 and 7 after challenge (Fig.
3). While the difference
at day 4 postchallenge was statistically significant, high titers
of RSV were still present in the lung. In contrast, FI-RSV-immunized
mice depleted of Vß14
+ T cells had higher RSV titers
at day 4 postchallenge than did IgM-treated controls, although
the difference was not significant. All FI-RSV-immunized mice
cleared the virus by day 7 postchallenge. These data demonstrate
a minimal role for Vß14
+ T cells in RSV clearance
in either vvGs- or FI-RSV-immunized mice.
FI-RSV-immunized mice exhibit diverse TCR Vß receptor usage and do not respond to any single RSV peptide, in contrast to the restricted Vß14 TCR expression and peptide specificity in vvGs-immunized mice.
Immunization of BALB/c mice with vvGs induces immune responses
mediated by an expanded oligoclonal CD4
+-T-cell subset that
predominantly express the Vß14 TCR (
54). Since immunization
with FI-RSV or with vvGs results in very similar patterns of
disease, we examined the Vß TCR diversity of CD4
+ T cells from FI-RSV- and vvGs-immunized mice. While a predominance
of CD4
+ T cells in vvGs-immunized mice were positive for the
Vß14 chain of the TCR, the cells in FI-RSV-immunized
mice expressed a balanced array of Vß chains (Fig.
4).
An I-E
d-restricted epitope has been identified in RSV G, and
this peptide stimulates both type 1 and type 2 cytokine production
(
47,
55). Therefore, we examined the ability of a panel of I-E
d-restricted
RSV-derived peptides (Table
1) to stimulate cytokine production
in FI-RSV- and vvGs-immunized mice. While the majority of the
CD4
+ T cells in vvGs-immunized mice responded only to the G
peptide at aa 183 to 195, CD4
+ T cells from FI-RSV-immunized
mice responded with a different pattern (Fig.
5). No single
peptide used in these studies elicited cytokine production that
was greater than that observed during primary RSV infection
of vac-lac-immunized and RSV-challenged mice (Fig.
5). Similar
patterns of production were observed for IL-4, IL-5, and IL-6.
Together, these data demonstrate that vvGs immunization elicits
a restricted subset of T cells specific for aa 183 to 195 of
RSV G that mediate disease, whereas FI-RSV disease is the result
of a diverse set of T cells with unidentified and potentially
diverse peptide specificities.

DISCUSSION
With an increasing incidence of severe disease and increased
rates of hospitalization in both infants and the elderly, the
development of a safe and effective vaccine against RSV is of
tremendous importance. However, an incomplete understanding
of RSV pathogenesis and the failed vaccine trials of the 1960s
hinder the accomplishment of this goal. With its role as the
viral attachment protein (
31) and as the source of much of the
sequence variation between virus strains (
20,
21), it is desirable
to include the G glycoprotein as a component of any RSV immunogen.
However, the similar patterns of severe disease induced by immunization
with FI-RSV or with RSV G complicate the question of the safety
of a vaccine construct containing RSV G. While disease in FI-RSV-
and G-immunized animals may appear to be analogous, there are
several indications that they have distinct pathogenic mechanisms
that lead to a common final pathway resulting in enhanced disease.
It has been clearly demonstrated that both immunization with FI-RSV (9, 13, 35, 41, 50) and immunization with RSV G (4, 17, 24, 38, 45, 46) predispose for severe disease typified by severe illness, pulmonary eosinophilia, and type 2 cytokine production. However, although the endpoints may be similar, it is apparent that the cytokine requirements for these two immunogens are distinct. While illness and type 2 cytokine production are reduced in RSV-challenged FI-RSV-immunized mice with IL-4 depletion (23, 48), the enhanced disease is unaltered in G-primed mice when IL-4 function is inhibited either by antibody depletion or in IL-4-deficient mice (23, 25). Furthermore, inhibition of IL-13 alone modulates disease only in FI-RSV-primed mice (25). Both IL-4 and IL-13 function must be blocked to modulate disease in mice immunized with RSV G (25). Additionally, when RSV glycoprotein F is administered as a purified protein in the context of alum, immune responses that result in eosinophilia and IL-4 and IL-5 production following RSV challenge are induced (8, 17, 35). However, in contrast to G-specific responses, F-specific immune responses may be modified by Th1-modulating adjuvants such as monophosphoryl lipid A or QS-21 (17, 35). Thus, the ability to induce disease-enhancing immune responses is not restricted to RSV G but appears to be a consequence of parenteral administration of RSV antigen and presentation to the immune system as a soluble protein that cannot be processed via the major histocompatibility complex class I pathway.
Vaccine-enhanced disease was observed in approximately 80% of FI-RSV vaccinees in the 1960s trial (26, 28) and occurs in many animal models (5, 9, 24, 25, 40, 41, 50). In contrast, RSV G-induced immune responses associated with vaccine-enhanced illness exhibit some degree of genetic restriction, with pulmonary eosinophilia being absent (19, 47) or dramatically reduced (23) in vvGs-immunized mouse strains other than BALB/c. The peptide at aa 183 to 198 of the RSV G glycoprotein is sufficient to elicit pulmonary eosinophilia and both type 1 and type 2 cytokine production in BALB/c mice (44, 47, 51) and is largely restricted to a subset of CD4+ T cells expressing the Vß14 TCR (54). The existence of this immunodominant epitope that alone is sufficient to induce those immune responses associated with vaccine-enhanced disease underscores the phenomenon of genetically restricted RSV G immunogenicity, which is not consistent with the nearly universal induction of vaccine-enhanced illness by the FI-RSV vaccine in children less than 6 months of age (28).
These observations, together with the distinct cytokine requirements in FI-RSV- and vvGs-immunized mice, led us to hypothesize that while Vß14+ CD4+ T cells mediate much of the eosinophil recruitment and cytokine production in vvGs-primed RSV-challenged mice, such an oligoclonal T-cell subset would not be expanded and would not significantly contribute to vaccine-enhanced disease in FI-RSV-immunized mice. As reported previously (54), these data confirm that the depletion of Vß14+ T cells at the time of challenge of vvGs-immunized mice decreases the degree of pulmonary eosinophilia and type 2 cytokine production. In marked contrast, however, anti-Vß14 treatment of FI-RSV-immunized mice has little impact on any aspect of disease examined in these studies. Furthermore, analyses of TCR expression and T-cell specificity underscore the distinct differences in T-cell subsets. Whereas vvGs-immunized mice show a prevalence of Vß14+ CD4+ T cells that are specific for a single immunodominant epitope encompassing aa 183 to 195 of RSV G, RSV challenge of FI-RSV-immunized mice amplifies CD4+ T cells expressing a diverse Vß TCR repertoire with no predominance for an individual peptide apparent. This finding suggests that T cells induced by FI-RSV immunization are specific for an as-yet-unidentified RSV peptide or that they are specific for a diverse array of peptides.
It is not necessarily unexpected to see a selected expansion of a particular Vß-restricted T-cell subset upon exposure to RSV G. Pathogenic roles for specific T-cell subsets in several models of infection and in various autoimmune diseases, including a disease-causing population of Vß14+ CD8+ T cells in a mouse model of ulcerative colitis (36), have been described (6, 11, 12, 32, 36, 37). Several of those studies describe a protective effect of selected depletion of the particular T-cell subset associated with disease without any toxicity or observable effect in normal populations (6, 11). In fact, the deletion of the disease-causing T-cell subsets is an effective treatment for at least two autoimmune syndromes in humans (6, 37). Thus, while studies have not described the effects of Vß14+-T-cell depletion in normal uninfected mice, these studies and the data reported here (for RSV-challenged mice primed with vac-lac or FI-RSV) would suggest that the elimination of this T-cell subset does not adversely affect the general immune status of mice.
These data demonstrate that distinct immune responses mediated by discrete T-cell subsets result in pulmonary eosinophilia and type 2 cytokine production in vvGs- and FI-RSV-immunized mice. Thus, the induction of a single oligoclonal G-specific CD4+-T-cell subset is not the basis for vaccine-enhanced disease induced by FI-RSV immunization. Therefore, these data suggest that RSV G may be safely included in a vaccine product if the potential vaccine is properly formulated to target RSV antigens to endogenous antigen-processing and presentation pathways. Furthermore, these data confirm that a restricted T-cell subset mediates RSV G-specific immune responses in BALB/c mice. In contrast, within the parameters utilized in this study, these data do not support the hypothesis that FI-RSV immunization induces oligoclonal T-cell subsets with restricted peptide specificities and suggest that either the peptide specificity in FI-RSV-immunized mice has yet to be identified or that FI-RSV-induced responses have diverse specificities. These observations may suggest that FI-RSV vaccine-enhanced disease will be produced in nearly all populations with diverse genetic backgrounds. In contrast, the severe disease of RSV G-immunized RSV-challenged mice, which is clearly genetically restricted, may be comparable to the severe disease of children during primary infection. Information gained from an investigation into the pathogenic mechanisms of RSV G-induced disease may provide insights into the immunologic basis for severe primary RSV disease in humans, while further research is necessary to understand the underlying mechanisms of FI-RSV vaccine-enhanced disease and to aid in the proper formulation of a safe vaccine product.

ACKNOWLEDGMENTS
This work was funded in part by National Institutes of Health
grants AI-37293 (TJB) and HL-33391 (TJB) and by a grant from
the Parker B. Francis Foundation (SMV).

FOOTNOTES
* Corresponding author. Mailing address: VRC NIAID NIH, Bldg. 40, Room 2614, 40 Convent Dr., MSC 3017, Bethesda, MD 20892-3017. Phone: (301) 594-8570. Fax: (301) 480-2771. E-mail:
teresaj{at}nih.gov.

Present address: Department of Microbiology, University of Iowa, Iowa City, IA 52242. 

REFERENCES
1 - Alwan, W. H., W. J. Kozlowska, and P. J. M. Openshaw. 1994. Distinct types of lung disease caused by functional subsets of antiviral T cells. J. Exp. Med. 179:81-89.[Abstract/Free Full Text]
2 - Bangham, C. R. M., M. J. Cannon, D. T. Karzon, and B. A. Askonas. 1985. Cytotoxic T-cell response to respiratory syncytial virus in mice. J. Virol. 56:55-59.[Abstract/Free Full Text]
3 - Bangham, C. R. M., P. J. M. Openshaw, A. Ball, A. M. Q. King, G. W. Wertz, and B. A. Askonas. 1986. Human and murine cytotoxic T cells specific to respiratory syncytial virus recognize the viral nucleoprotien (N), but not the major glycoprotein (G), expressed by vaccinia virus recombinants. J. Immunol. 137:3973-3977.[Abstract]
4 - Bembridge, G. P., R. Garcia-Beato, J. A. Lopez, J. A. Melero, and G. Taylor. 1998. Subcellular site of expression and route of vaccination influence pulmonary eosinophilia following respiratory syncytial virus challenge in BALB/c mice sensitized to the attachment G protein. J. Immunol. 161:2473-2480.[Abstract/Free Full Text]
5 - Cannon, M. J., P. J. M. Openshaw, and B. A. Askonas. 1988. Cytotoxic T cells clear virus but augment lung pathology in mice infected with respiratory syncytial virus. J. Exp. Med. 168:1163-1168.[Abstract/Free Full Text]
6 - Carrion, F., M. Fernandez, M. Iruretagoyena, L. E. Coelho Andrade, M. Odete-Hilario, and F. Figueroa. 2003. Selective depletion of Vß2+CD8+ T cells in peripheral blood from rheumatic heart disease patients. J. Autoimmun. 20:183-190.[CrossRef][Medline]
7 - Cherrie, A. H., K. Anderson, G. W. Wertz, and P. J. M. Openshaw. 1992. Human cytotoxic T cells stimulated by antigen on dendritic cells recognize the N, SH, F, M, 22K, and 1b proteins of respiratory syncytial virus. J. Virol. 66:2102-2110.[Abstract/Free Full Text]
8 - Connors, M., P. L. Collins, C.-Y. Firestone, A. V. Sotnikov, A. Waitze, A. R. Davis, P. P. Hung, R. M. Chanock, and B. R. Murphy. 1992. Cotton rats previously immunized with a chimeric RSV FG glycoprotein develop enhanced pulmonary pathology when infected with RSV, a phenomenon not encountered following immunization with vaccinia-RSV recombinants or RSV. Vaccine 10:475-484.[CrossRef][Medline]
9 - Connors, M., N. A. Giese, A. B. Kulkarni, C.-Y. Firestone, I. Morse, and B. R. Murphy. 1994. Enhanced pulmonary histopathology induced by respiratory syncytial virus (RSV) challenge of formalin-inactivated RSV-immunized BALB/c mice is abrogated by depletion of interleukin-4 (IL-4) and IL-10. J. Virol. 68:5321-5325.[Abstract/Free Full Text]
10 - Gaddum, R. M., R. S. Cook, J. M. Furze, S. A. Ellis, and G. Taylor. 2003. Recognition of bovine respiratory syncytial virus proteins by bovine CD8+ T lymphocytes. Immunology 108:220-229.[CrossRef][Medline]
11 - Gomez, F. J., J. A. Cain, R. S. Gibbons, R. Allendoerfer, and G. S. Deepe, Jr. 1998. Vbeta4(+) T cells promote clearance of infection in murine pulmonary histoplasmosis. J. Clin. Investig. 102:984-995.[Medline]
12 - Gomez, F. J., E. O. Woodward, R. Pilcher-Roberts, R. S. Gibbons, and G. S. Deepe, Jr. 2001. Vß6+ and Vß4+ T cells exert cooperative activity in clearance of secondary infection with Histoplasma capsulatum. J. Immunol. 166:2855-2862.[Abstract/Free Full Text]
13 - Graham, B. S., G. S. Henderson, Y.-W. Tang, X. Lu, K. M. Neuzil, and D. G. Colley. 1993. Priming immunization determines T helper cytokine mRNA expression patterns in lungs of mice challenged with respiratory syncytial virus. J. Immunol. 151:2032-2040.[Abstract]
14 - Graham, B. S., M. D. Perkins, P. F. Wright, and D. T. Karzon. 1988. Primary respiratory syncytial virus infection in mice. J. Med. Virol. 26:153-162.[Medline]
15 - Graham, B. S., J. A. Rutigliano, and T. R. Johnson. 2002. Respiratory syncytial virus immunobiology and pathogenesis. Virology 297:1-7.[CrossRef][Medline]
16 - Hall, C. B. 2001. Respiratory syncytial virus and parainfluenza virus. N. Engl. J. Med. 344:1917-1928.[Free Full Text]
17 - Hancock, G. E., D. J. Speelman, K. Heers, E. Bortell, J. Smith, and C. Cosco. 1996. Generation of atypical pulmonary inflammatory responses in BALB/c mice after immunization with the native attachment (G) glycoprotein of respiratory syncytial virus. J. Virol. 70:7783-7791.[Abstract]
18 - Hendricks, D. A., K. Baradaran, K. McIntosh, and J. L. Patterson. 1987. Appearance of a soluble form of the G protein of respiratory syncytial virus in fluids of infected cells. J. Gen. Virol. 68:1705-1714.[Abstract/Free Full Text]
19 - Hussell, T., A. Georgiou, T. E. Sparer, S. Matthews, P. Pala, and P. J. M. Openshaw. 1998. Host genetic determinants of vaccine-induced eosinophilia during respiratory syncytial virus infection. J. Immunol. 161:6215-6222.[Abstract/Free Full Text]
20 - Johnson, P. R., R. A. Olmsted, G. A. Prince, B. R. Murphy, D. W. Alling, E. E. Walsh, and P. L. Collins. 1987. Antigenic relatedness between glycoproteins of human respiratory syncytial virus subgroups A and B: evaluation of the contributions of F and G glycoproteins to immunity. J. Virol. 61:3163-3166.[Abstract/Free Full Text]
21 - Johnson, P. R., M. K. Spriggs, R. A. Olmsted, and P. L. Collins. 1987. The G glycoprotein of human respiratory syncytial viruses of subgroups A and B: extensive sequence divergence between antigenically related proteins. Proc. Natl. Acad. Sci. USA 84:5625-5629.[Abstract/Free Full Text]
22 - Johnson, T. R., J. E. Fischer, and B. S. Graham. 2001. Construction and characterization of recombinant vaccinia viruses co-expressing a respiratory syncytial virus protein and a cytokine. J. Gen. Virol. 82:2107-2116.[Abstract/Free Full Text]
23 - Johnson, T. R., and B. S. Graham. 1999. Secreted respiratory syncytial virus G glycoprotein induces interleukin-5 (IL-5), IL-13, and eosinophilia by an IL-4-independent mechanism. J. Virol. 73:8485-8495.[Abstract/Free Full Text]
24 - Johnson, T. R., J. E. Johnson, S. R. Roberts, G. W. Wertz, R. A. Parker, and B. S. Graham. 1998. Priming with secreted glycoprotein G of respiratory syncytial virus (RSV) augments interleukin-5 production and tissue eosinophilia after RSV challenge. J. Virol. 72:2871-2880.[Abstract/Free Full Text]
25 - Johnson, T. R., R. A. Parker, J. E. Johnson, and B. S. Graham. 2003. IL-13 is sufficient for respiratory syncytial virus G glycoprotein-induced eosinophilia after respiratory syncytial virus challenge. J. Immunol. 170:2037-2045.[Abstract/Free Full Text]
26 - Kapikian, A. Z., R. H. Mitchell, R. M. Chanock, R. A. Shvedoff, and C. E. Stewart. 1969. An epidemiologic study of altered clinical reactivity to respiratory syncytial (RS) virus infection in children previously vaccinated with an inactivated RS virus vaccine. Am. J. Epidemiol. 89:405-421.[Abstract/Free Full Text]
27 - Katz, M. E., R. M. Maizels, L. Wicker, A. Miller, and E. E. Sercarz. 1982. Immunological focusing by the mouse major histocompatibility complex: mouse strains confronted with distantly related lysozymes confine their attention to very few epitopes. Eur. J. Immunol. 12:535-540.[Medline]
28 - Kim, H. W., J. G. Canchola, C. D. Brandt, G. Pyles, R. M. Chanock, K. Jensen, and R. H. Parrott. 1969. Respiratory syncytial virus disease in infants despite prior administration of antigenic inactivated vaccine. Am. J. Epidemiol. 89:422-434.[Abstract/Free Full Text]
29 - Kim, H. W., S. L. Leikin, J. Aerobic, C. D. Brandt, R. M. Chanock, and R. H. Parrott. 1976. Cell-mediated immunity to respiratory syncytial virus induced by inactivated vaccine or by infection. Pediatr. Res. 10:75-78.[Medline]
30 - Lambert, D. M. 1988. Role of oligosaccharides in the structure and function of respiratory syncytial virus glycoproteins. Virology 16:458-466.
31 - Levine, S., R. Franco-Klaiber, and P. R. Paradiso. 1987. Demonstration that glycoprotein G is the attachment protein of respiratory syncytial virus. J. Gen. Virol. 68:2521-2524.[Abstract/Free Full Text]
32 - Mendes-da-Cruz, D. A., J. de Meis, V. Cotta-de-Almeida, and W. Savino. 2003. Experimental Trypanosoma cruzi infection alters the shaping of the central and peripheral T-cell repertoire. Microb. Infect. 5:825-832.[CrossRef][Medline]
33 - Morgan, L. A., E. G. Routledge, M. M. Willcocks, A. C. R. Samson, R. Scott, and G. L. Toms. 1987. Strain variation of respiratory syncytial virus. J. Gen. Virol. 68:2781-2788.[Abstract/Free Full Text]
34 - Murphy, B. R., D. W. Alling, M. H. Snyder, E. E. Walsh, G. A. Prince, R. M. Chanock, V. G. Hemming, W. J. Rodriguez, H. W. Kim, B. S. Graham, and P. F. Wright. 1986. Effect of age and preexisting antibody on serum antibody response of infants and children to the F and G glycoproteins during respiratory syncytial virus infection. J. Clin. Microbiol. 24:894-898.[Abstract/Free Full Text]
35 - Neuzil, K. M., J. E. Johnson, Y.-W. Tang, J.-P. Prieels, M. Slaoui, N. Gar, and B. S. Graham. 1997. Adjuvants influence the quantitative and qualitative immune response in BALB/c mice immunized with respiratory syncytial virus FG subunit vaccine. Vaccine 15:525-532.[CrossRef][Medline]
36 - Nitta, T., H. Iwata, Y. Mori, H. Takagi, K. Kanetake, Y. Iida, K. Sakamoto, T. Yamada, M. Saio, and H. Hirose. 2003. Specific CTL activity of CD8+ TCR Vbeta14+ T cell in mouse 2,4,6-trinitrobenzene sulfonic acid-induced colitis. Dig. Dis. Sci. 48:2095-2103.[CrossRef][Medline]
37 - Olsson, T., C. Edenius, M. Ferm, P. Samuelson, A. Torrang, E. Wallstrom, M. Khademi, M. Andersson, and L. Arfors. 2002. Depletion of Vbeta5.2/5.3 T cells with a humanized antibody in patients with multiple sclerosis. Eur. J. Neurol. 9:153-164.[CrossRef][Medline]
38 - Openshaw, P. J. M., S. L. Clarke, and F. M. Record. 1992. Pulmonary eosinophilic response to respiratory syncytial virus infection in mice sensitized to the major surface glycoprotein G. Int. Immunol. 4:493-500.[Abstract/Free Full Text]
39 - Peebles, R. S. J., K. Hashimoto, and B. S. Graham. 2003. The complex relationship between respiratory syncytial virus and allergy in lung disease. Viral Immunol. 16:25-34.[CrossRef][Medline]
40 - Piedra, P. A., H. S. Faden, G. Cammussi, D. T. Wong, and P. L. Ogra. 1989. Mechanism of lung injury in cotton rats immunized with formalin-inactivated respiratory syncytial virus. Vaccine 124:34-38.
41 - Prince, G. A., A. B. Jenson, V. G. Hemming, B. R. Murphy, E. E. Walsh, R. L. Horswood, and R. M. Chanock. 1986. Enhancement of respiratory syncytial virus pulmonary pathology in cotton rats by prior intramuscular inoculation of formalin-inactivated virus. J. Virol. 57:721-728.[Abstract/Free Full Text]
42 - Roberts, S. R., D. L. Lichtenstein, L. A. Ball, and G. W. Wertz. 1994. The membrane-associated and secreted forms of the respiratory syncytial virus attachment glycoprotein G are synthesized from alternative initiation codons. J. Virol. 68:4538-4546.[Abstract/Free Full Text]
43 - Shay, D. K., R. C. Holman, R. D. Newman, L. L. Liu, J. W. Stout, and L. J. Anderson. 1999. Bronchiolitis-associated hospitalizations among US children, 1980-1996. JAMA 282:1440-1446.[Abstract/Free Full Text]
44 - Sparer, T. E., S. Matthews, T. Hussell, A. J. Rae, B. Garcia-Barreno, J. A. Melero, and P. J. M. Openshaw. 1998. Eliminating a region of respiratory syncytial virus attachment protein allows induction of protective immunity without vaccine-enhanced lung eosinophilia. J. Exp. Med. 187:1921-1926.[Abstract/Free Full Text]
45 - Srikiatkhachorn, A., and T. J. Braciale. 1997. Virus-specific memory and effector T lymphocytes exhibit different cytokine responses to antigens during experimental murine respiratory syncytial virus infection. J. Virol. 71:678-685.[Abstract]
46 - Srikiatkhachorn, A., and T. J. Braciale. 1997. Virus-specific CD8+ T lymphocytes downregulate T helper cell type 2 cytokine secretion and pulmonary eosinophilia during experimental murine respiratory syncytial virus infection. J. Exp. Med. 186:421-432.[Abstract/Free Full Text]
47 - Srikiatkhachorn, A., W. Chang, and T. J. Braciale. 1999. Induction of Th-1 and Th-2 responses by respiratory syncytial virus attachment glycoprotein is epitope and major histocompatibility complex independent. J. Virol. 73:6590-6597.[Abstract/Free Full Text]
48 - Tang, Y.-W., and B. S. Graham. 1994. Anti-IL-4 treatment at immunization modulates cytokine expression, reduces illness, and increases cytotoxic T lymphocyte activity in mice challenged with respiratory syncytial virus. J. Clin. Investig. 94:1953-1958.
49 - Tang, Y.-W., and B. S. Graham. 1997. T cell source of Type 1 cytokines determines illness patterns in respiratory syncytial virus-infected mice. J. Clin. Investig. 99:2183-2191.[Medline]
50 - Tang, Y.-W., K. M. Neuzil, J. E. Fischer, F. W. Robinson, R. A. Parker, and B. S. Graham. 1997. Determinants and kinetics of cytokine expression patterns in lungs of vaccinated mice challenged with respiratory syncytial virus. Vaccine 15:597-602.[CrossRef][Medline]
51 - Tebbey, P. W., M. Hagen, and G. E. Hancock. 1998. Atypical pulmonary eosinophilia is mediated by a specific amino acid sequence of the attachment (G) protein of respiratory syncytial virus. J. Exp. Med. 188:1967-1972.[Abstract/Free Full Text]
52 - Tripp, R. A., S. Hou, N. Etchart, A. Prinz, D. Moore, J. Winter, and L. J. Anderson. 2001. CD4+ T cell frequencies and Th1/Th2 cytokine patterns expressed in the acute and memory response to respiratory syncytial virus I-Ed-restricted peptides. Cell. Immunol. 207:59-71.[CrossRef][Medline]
53 - Tripp, R. A., D. Moore, L. Jones, W. M. Sullender, J. Winter, and L. J. Anderson. 1999. Respiratory syncytial virus G and/or SH protein alters Th1 cytokines, natural killer cells, and neutrophils responding to pulmonary infection in BALB/c mice. J. Virol. 73:7099-7107.[Abstract/Free Full Text]
54 - Varga, S. M., X. Wang, R. M. Welsh, and T. J. Braciale. 2001. Immunopathology in RSV infection is mediated by a discrete oligoclonal subset of antigen-specific CD4+ T cells. Immunity 15:637-646.[CrossRef][Medline]
55 - Varga, S. M., E. L. Wissinger, and T. J. Braciale. 2000. The attachment (G) glycoprotein of respiratory syncytial virus contains a single immunodominant epitope that elicits both Th1 and Th2 CD4+ T cell responses. J. Immunol. 165:6487-6495.[Abstract/Free Full Text]
Journal of Virology, August 2004, p. 8753-8760, Vol. 78, No. 16
0022-538X/04/$08.00+0 DOI: 10.1128/JVI.78.16.8753-8760.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Percopo, C. M., Qiu, Z., Phipps, S., Foster, P. S., Domachowske, J. B., Rosenberg, H. F.
(2009). Pulmonary Eosinophils and Their Role in Immunopathologic Responses to Formalin-Inactivated Pneumonia Virus of Mice. J. Immunol.
183: 604-612
[Abstract]
[Full Text]
-
Olson, M. R., Varga, S. M.
(2009). Fas Ligand Is Required for the Development of Respiratory Syncytial Virus Vaccine-Enhanced Disease. J. Immunol.
182: 3024-3031
[Abstract]
[Full Text]
-
Olson, M. R., Hartwig, S. M., Varga, S. M.
(2008). The Number of Respiratory Syncytial Virus (RSV)-Specific Memory CD8 T Cells in the Lung Is Critical for Their Ability to Inhibit RSV Vaccine-Enhanced Pulmonary Eosinophilia. J. Immunol.
181: 7958-7968
[Abstract]
[Full Text]
-
Meyerholz, D. K., Edsen-Moore, M., McGill, J., Coleman, R. A., Cook, R. T., Legge, K. L.
(2008). Chronic Alcohol Consumption Increases the Severity of Murine Influenza Virus Infections. J. Immunol.
181: 641-648
[Abstract]
[Full Text]
-
Yu, J.-R., Kim, S., Lee, J.-B., Chang, J.
(2008). Single Intranasal Immunization with Recombinant Adenovirus-Based Vaccine Induces Protective Immunity against Respiratory Syncytial Virus Infection. J. Virol.
82: 2350-2357
[Abstract]
[Full Text]
-
Castilow, E. M., Olson, M. R., Meyerholz, D. K., Varga, S. M.
(2008). Differential Role of Gamma Interferon in Inhibiting Pulmonary Eosinophilia and Exacerbating Systemic Disease in Fusion Protein-Immunized Mice Undergoing Challenge Infection with Respiratory Syncytial Virus. J. Virol.
82: 2196-2207
[Abstract]
[Full Text]
-
Castilow, E. M., Meyerholz, D. K., Varga, S. M.
(2008). IL-13 Is Required for Eosinophil Entry into the Lung during Respiratory Syncytial Virus Vaccine-Enhanced Disease. J. Immunol.
180: 2376-2384
[Abstract]
[Full Text]
-
Olson, M. R., Varga, S. M.
(2007). CD8 T Cells Inhibit Respiratory Syncytial Virus (RSV) Vaccine-Enhanced Disease. J. Immunol.
179: 5415-5424
[Abstract]
[Full Text]
-
Melendi, G. A., Laham, F. R., Monsalvo, A. C., Casellas, J. M., Israele, V., Polack, N. R., Kleeberger, S. R., Polack, F. P.
(2007). Cytokine Profiles in the Respiratory Tract During Primary Infection With Human Metapneumovirus, Respiratory Syncytial Virus, or Influenza Virus in Infants. Pediatrics
120: e410-e415
[Abstract]
[Full Text]
-
Peebles, R. S. Jr., Graham, B. S.
(2005). Pathogenesis of Respiratory Syncytial Virus Infection in the Murine Model. Proc Am Thorac Soc
2: 110-115
[Abstract]
[Full Text]