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Journal of Virology, April 1999, p. 3438-3442, Vol. 73, No. 4
Respiratory Viruses
Section1 and Experimental Primate
Virology Section,3 Laboratory of Infectious
Diseases, National Institute of Allergy and Infectious Diseases,
Bethesda, Maryland 20892, and Bioqual, Inc., Rockville,
Maryland 208502
Received 13 November 1998/Accepted 7 January 1999
The NS2 and SH genes of respiratory syncytial virus (RSV) have been
separately deleted from a recombinant wild-type RSV strain, A2 (M. N. Teng and P. L. Collins, J. Virol. 73:466-473, 1998; A. Bukreyev et al., J. Virol. 71:8973-8982, 1997; and this study). The resulting viruses, designated rA2 Respiratory syncytial virus (RSV)
remains the leading cause of serious viral bronchiolitis and pneumonia
in infants and young children throughout the world and accounts for
approximately 90,000 hospitalizations in the United States each year
(6, 16, 22). RSV infection is also an important cause of
severe respiratory illness in elderly (11-13, 24) and
immunocompromised (17, 19, 31) populations. While the
significance of RSV as a respiratory pathogen has made development of
an effective RSV vaccine a public health priority, such a vaccine does
not exist. Toward this goal, our laboratory has sought to develop a
live, attenuated RSV vaccine since a live virus vaccine, which mimics
natural infection, should induce a balanced cellular and humoral immune
response without potentiating disease upon subsequent infection with
wild-type (wt) virus (6, 25).
A number of live attenuated RSV vaccine candidates have been evaluated
in animals and humans, and the most promising subgroup A vaccine
candidates, cpts248/404 and its recombinant counterpart rA2cp248/404, have been shown to possess both temperature-sensitive (ts) and non-ts mutations which contribute to the
attenuation of the virus (8, 14, 33, 34). Our approach
toward vaccine development is based on the observation that a
combination of ts and non-ts attenuating
mutations in a single virus yields effective vaccine candidates with
increased phenotypic stability, as has been seen for influenza virus
(26, 27, 30), parainfluenza virus (18), and
poliovirus (2, 28, 32). By evaluating several ts
virus lineages derived from cold-passaged (cp) RSV (15), we have identified a sufficient collection of
ts attenuating mutations (10, 14, 20, 21, 33) and
have recently focused our efforts on the identification of stable,
non-ts attenuating mutations suitable for inclusion in
candidate vaccine strains (3, 34).
As the prototype of the pneumovirus genus of the family
Paramyxoviridae, RSV is an enveloped, negative-sense,
single-stranded RNA virus with a genome that is 15,222 nucleotides in
length and that encodes 10 subgenomic mRNAs (6).
Transcription of viral genes is directed by short, conserved gene start
and gene end (GE) cis-acting signals that flank each gene
and are separated by intergenic regions of various nucleotide lengths.
These mRNAs are translated into 11 known proteins: four nucleocapsid
proteins, namely, nucleocapsid N protein, phosphoprotein P, large
polymerase subunit L, and transcription elongation factor M2-1; three
transmembrane envelope glycoproteins, namely, fusion F protein,
attachment G protein, and small hydrophobic SH protein; two
nonstructural proteins, NS1 and NS2; the matrix M protein; and the
putative negative regulatory factor M2-2. Although each of these
proteins has been identified, the specific functions of several
proteins, such as NS1, NS2, and SH, have not been determined, although
NS1 has been shown to inhibit RNA synthesis (1).
By using the previously described reverse genetics system
(5), a recombinant wt RSV, designated rA2, was
generated. It contains the previously described 4C leader mutation, a
set of four intergenic and noncoding region marker mutations, and a set of six L gene translationally silent restriction site markers, as well
as two F gene mutations required to bring the coding region of the
recombinant wt clone into agreement with that of the human embryonic kidney (HEK) cell-passaged wt RSV (5,
34). Mutant viruses in which either the NS2 or the SH gene (and
its respective transcription signal) was completely deleted from rA2
have been successfully engineered, thus demonstrating the dispensable
nature of either gene for replication in tissue culture. For deletion of the NS2 gene (
0022-538X/99
Recombinant Respiratory Syncytial Virus Bearing a
Deletion of either the NS2 or SH Gene Is Attenuated in
Chimpanzees
ABSTRACT
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Abstract
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References
NS2 and rA2SH, were
administered to chimpanzees to evaluate their levels of attenuation and
immunogenicity. Recombinant virus rA2NS2 replicated to moderate
levels in the upper respiratory tract, was highly attenuated in the
lower respiratory tract, and induced significant resistance to
challenge with wild-type RSV. The replication of rA2SH virus was
only moderately reduced in the lower, but not the upper, respiratory
tract. However, chimpanzees infected with either virus developed
significantly less rhinorrhea than those infected with wild-type RSV.
These findings demonstrate that a recombinant RSV mutant lacking either
the NS2 or SH gene is attenuated and indicate that these deletions may
be useful as attenuating mutations in new, live recombinant RSV vaccine candidates for both pediatric and elderly populations. The SH mutation was incorporated into a recombinant form of the
cpts248/404 vaccine candidate, was evaluated for safety in
seronegative chimpanzees, and can now be evaluated as a vaccine for humans.
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Abstract
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References
NS2), nucleotides 577 to 1098 were removed, which
segment joins the authentic NS1 GE sequence to the complete NS2-N
intergenic region (29). For deletion of the SH gene (SH), the ScaI-PacI restriction fragment containing the
SH gene was deleted and replaced with a short synthetic DNA, resulting
in the removal of nucleotides 4205 to 4623 (Fig.
1). This process introduced a single
nucleotide change in the M GE signal, making it identical to that of
the wt SH GE signals. It should be noted that the SH
virus described here (Fig. 1) is different from the one designated
D46/6368, which was described previously (3) and which lacks
the six silent L gene restriction sites and the two F gene mutations
noted above. In chimpanzees, neither the L gene restriction sites nor
the F gene mutations affected the replication of recombinant RSV
(34). Also, D46/6368 contains some incidental, heterologous
sequence and an unusually long intergenic region at the deletion point.
Like their wt recombinant parent, the rA2SH and rA2NS2
viruses contain only authentic transcription signals and intergenic
regions. Also, they have the same genetic background as previously
described biologically derived and recombinant cpts vaccine
candidates and thus can be compared directly with those vaccine
candidates.
View larger version (11K):
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FIG. 1.
Deletion of the SH gene to generate rA2 SH. The map of
the negative-sense wt RSV genome is shown (not to scale), as
is the sequence illustrating the deletion, which involved nucleotides
4205 to 4623 (arrows). To construct rA2SH, plasmid D50, containing
the left-hand end of the genome from the 3' leader region to the end of
the M2 gene, was digested with ScaI and PacI and
the resulting fragment was replaced with a short double-stranded DNA
constructed by hybridizing the two synthetic oligonucleotides
ACTCAAATAAGTTAAT and TAACTTATTTGAGT. In the final
construction, the deletion extended from the middle of the M GE signal
to the middle of the SH GE signal. In the SH genome, compared to its
wt recombinant parent, the M GE signal sustained a single
nucleotide change (AGTTAATAAAAAA to
AGTTAATTAAAAA, with the change underlined) to
become identical to that of the wt SH GE signal. The
modified D50 plasmid was then used to assemble a complete antigenome by
ligation with a cDNA containing the L gene and trailer region as
described previously (5, 33, 34). IG, intergenic region; GS,
gene start signal; GE, gene end signal.
The NS2 and SH deletion viruses have been characterized with regard to
their growth phenotypes in cell culture. On HEp-2 cell monolayers,
D46/6368 grew slightly better than wt RSV (up to 12.6-fold higher levels) and consistently produced plaques that were 70% larger
(reference 3 and data not shown), while the
rA2NS2 virus grew more slowly than wt RSV and produced
pinpoint plaques at a titer 5- to 50-fold lower than that of
wt RSV (29). When inoculated intranasally into
mice, the D46/6368 virus resembled wt RSV in its level of
replication in the lungs, whereas it replicated to a level 10-fold
lower in the upper respiratory tract (3). Also in mice,
D46/6368 and wt RSV were similar with respect to immunogenicity and efficacy in inducing resistance to RSV challenge (3). In addition, the SH gene was also deleted from the
D53cp248/404 cDNA, which encodes a recombinant version of the
cpts248/404 vaccine candidate. This deletion was made by
replacing the SpeI-StuI cassette of D53cp248/404,
which contains the SH gene, with the same cassette from the SH cDNA
(Fig. 1). The resulting virus, rA2cp248/404SH, maintained the same
level of temperature sensitivity as rA2cp248/404 and acquired a larger
plaque size at the permissive temperature (data not shown). If the
SH and NS2 mutant viruses exhibit an attenuation (att)
phenotype in chimpanzees, these mutants would be of special interest
for vaccine development, since it is expected that a high level of
genetic stability in vitro and in vivo would be afforded by complete
deletion of a viral gene. Satisfactorily attenuated and immunogenic
mutants of this type might be especially safe for use in
immunocompromised subjects.
The replication of the rA2NS2 and rA2SH deletion mutants was
evaluated in a separate study with young RSV-seronegative chimpanzees according to established procedures (9), and their levels of replication and reactogenicity were compared with those of rA2 and
rA2cp248/404. These findings were also compared to results from
previous studies with wt RSV, which was shown to produce acute respiratory tract disease in humans and chimpanzees (7, 9,
23). Chimpanzees are the only known nonhuman host in which RSV
replication and virulence approach that observed in seronegative humans. These features are indispensable for evaluation of a live attenuated RSV prior to administration to humans, particularly with
mutants containing novel gene deletions. Because of the very limited
number of RSV-seronegative chimpanzees available for study, the sizes
of the experimental groups were small. Animals were inoculated
simultaneously by the intranasal and intratracheal routes. Upper
respiratory tract (nasopharyngeal swab) and lower respiratory tract
(tracheal lavage) samples were collected over a period of 10 days, and
the chimpanzees were monitored daily for symptoms of rhinorrhea. To
compare the levels of virus replication in the animal groups, we
determined the mean peak titers of infectious virus in both the upper
and lower respiratory tracts. We considered differences in mean peak
titers greater than 10-fold to be significant, which was confirmed
statistically by the use of Duncan's Multiple Range test. Rhinorrhea
scores (see Table 1, footnote d, for a definition) were also
compared, and we considered scores greater than 1.0 to be significant
based on extensive prior experience with this experimental model of RSV
upper respiratory tract disease. The two wt viruses, RSV A2
and rA2, were comparable in their levels of virus replication and in
the extents of rhinorrhea that they caused in chimpanzees (Table
1), despite the 21 nucleotide differences between the two viruses, which represent the nucleotide changes engineered into rA2 (5, 34). Since rA2 replicates and
induces rhinorrhea in a manner similar to that of its biologically
derived counterpart, it is an appropriate virus to compare with the
rA2SH and rA2NS2 mutants, which are isogenic with it except for
deletion of an RSV gene.
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Mutant virus rA2NS2 was 12.5-fold reduced in replication in the
upper respiratory tract compared to rA2 (Table 1), whereas rA2SH
replicated to a level comparable to that of rA2. However, in the lower
respiratory tract, rA2NS2 and rA2SH showed 10,000-fold and
40-fold reductions in replication, respectively, compared to the level
of replication of rA2. In comparison with chimpanzees receiving either
wt RSV A2 or rA2, chimpanzees infected with rA2NS2 or
rA2SH exhibited less rhinorrhea. These findings demonstrate that
deletion of either the NS2 or the SH gene leads to attenuation of both
replication and disease symptoms in chimpanzees, with deletion of the
NS2 gene having a greater effect.
Immunization with either rA2NS2 or rA2SH induced a high level of
neutralizing antibodies that was comparable to that induced by
infection with either of the wt control viruses (Table 1). Immunization with rA2NS2, as with cpts248/404, induced
resistance to replication of wt RSV in both the upper and
lower respiratory tracts (Table 2). Taken
together, these results indicated that immunization with rA2NS2 was
nearly as effective as immunization with mutant cpts248/404,
even though cpts248/404 was administered at a fivefold
higher dose. Because the SH mutant D46/6368 was shown previously to
induce complete protection in mice against wt RSV challenge
(3), this analysis was not repeated with chimpanzees.
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Vaccine candidate cpts248/404 caused a significant level of
nasal congestion in a majority of vaccinees in the RSV vaccine target
population of one-month-old infants, which suggests that it is
incompletely attenuated for this age group (35). Therefore, more attenuated derivatives of cpts248/404 will be needed
for use in very young infants. Since neither rA2NS2 nor rA2SH is as attenuated in chimpanzees as the incompletely attenuated
rA2cp248/404 vaccine candidate, the NS2 and SH mutants are of
interest for use in conjunction with the mutations present in
rA2cp248/404. We have initiated studies designed to further attenuate
cpts248/404 by the deletion of the SH gene, the less
attenuating of the two deletion mutations, from rA2cp248/404. This
mutation was selected for study first since the clinical evaluation of
cpts248/404 in young infants indicated that only a slight
increase in attenuation would be necessary to produce a satisfactory
candidate vaccine and because the SH deletion was associated with a
significant reduction in rhinorrhea (Table 1). The SH gene was removed
from rA2cp248/404, and the resulting virus, rA2cp248/404SH, was
administered to chimpanzees (Table 1). Since cpts248/404 is
highly attenuated in chimpanzees at a dose of 4.0 log10
PFU/ml (8), its recombinant derivatives rA2cp248/404 and
rA2cp248/404SH were administered at an elevated dose of 5.0 log10 PFU/ml in an attempt to augment their levels of
replication to levels that would permit the detection of a difference
in growth capacity. As shown in Table 1, a significant difference in
levels of replication of the two viruses in the upper and lower
respiratory tracts was not observed and a difference in the levels of
rhinorrhea or in the neutralizing antibody responses in sera was not
observed. In rA2cp248/404SH, the attenuation conferred by deletion
of the SH gene may be masked by the cpts248/404 att mutations. An increase in attenuation of
rA2cp248/404SH may be apparent only in humans, where
cpts248/404 replicates to a 100-fold higher titer than in
chimpanzees (35), and such studies have been initiated.
Since the attenuating mutations identified in cpts248/404
are point mutations, it is hoped that the overall stability of the
attenuation phenotype of rA2cp248/404 will be increased by the complete
deletion of the SH gene.
Deletion of NS2 is the single most attenuating non-ts
mutation we have studied to date, significantly surpassing the
attenuation conferred by the cp and SH mutations in both
the upper and the lower respiratory tract (34). Mutant virus
rA2NS2 replicates slightly better than rA2cp248/404 in the upper
respiratory tracts of chimpanzees, and this property suggests a
possible role for it as a vaccine candidate for the elderly. To be
effective, a live attenuated vaccine for this group would need to be
capable of replicating and immunizing in the presence of RSV antibodies induced by prior infections and yet be sufficiently attenuated in the
lower respiratory tract so as to preclude any serious reactogenicity. Because the rA2NS2 virus was highly attenuated in the lower
respiratory tracts of chimpanzees yet remained relatively infectious
for the upper respiratory tracts, this virus may have potential use as a vaccine for a seropositive population. In addition, the feasibility of removing the NS2 gene from rA2cp248/404 and other attenuated recombinant viruses for use in the pediatric population is also under
investigation in our laboratory.
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ACKNOWLEDGMENTS |
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We thank Robert M. Chanock and Peter F. Wright for careful reviews of the manuscript.
This work is part of a continuing program of research and development with Wyeth-Lederle Vaccines and Pediatrics through CRADA no. AI-000030 and AI-000087.
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FOOTNOTES |
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* Corresponding author. Mailing address: LID, NIAID, 7 Center Dr., MSC 0720, Bethesda, MD 20892-0720. Phone: (301) 496-4205. Fax: (301) 496-8312. E-mail: sswhitehead{at}nih.gov.
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Journal of Virology, April 1999, p. 3438-3442, Vol. 73, No. 4
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89: 525-533
[Abstract] [Full Text] -
Krempl, C. D., Wnekowicz, A., Lamirande, E. W., Nayebagha, G., Collins, P. L., Buchholz, U. J.
(2007). Identification of a Novel Virulence Factor in Recombinant Pneumonia Virus of Mice. J. Virol.
81: 9490-9501
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Fuentes, S., Tran, K. C., Luthra, P., Teng, M. N., He, B.
(2007). Function of the Respiratory Syncytial Virus Small Hydrophobic Protein. J. Virol.
81: 8361-8366
[Abstract] [Full Text] -
Kotelkin, A., Belyakov, I. M., Yang, L., Berzofsky, J. A., Collins, P. L., Bukreyev, A.
(2006). The NS2 Protein of Human Respiratory Syncytial Virus Suppresses the Cytotoxic T-Cell Response as a Consequence of Suppressing the Type I Interferon Response.. J. Virol.
80: 5958-5967
[Abstract] [Full Text] -
Biacchesi, S., Pham, Q. N., Skiadopoulos, M. H., Murphy, B. R., Collins, P. L., Buchholz, U. J.
(2005). Infection of Nonhuman Primates with Recombinant Human Metapneumovirus Lacking the SH, G, or M2-2 Protein Categorizes Each as a Nonessential Accessory Protein and Identifies Vaccine Candidates. J. Virol.
79: 12608-12613
[Abstract] [Full Text] -
Collins, P. L., Murphy, B. R.
(2005). New Generation Live Vaccines against Human Respiratory Syncytial Virus Designed by Reverse Genetics. Proc Am Thorac Soc
2: 166-173
[Abstract] [Full Text] -
Wright, P. F., Ikizler, M. R., Gonzales, R. A., Carroll, K. N., Johnson, J. E., Werkhaven, J. A.
(2005). Growth of Respiratory Syncytial Virus in Primary Epithelial Cells from the Human Respiratory Tract. J. Virol.
79: 8651-8654
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Baron, M. D., Banyard, A. C., Parida, S., Barrett, T.
(2005). The Plowright vaccine strain of Rinderpest virus has attenuating mutations in most genes. J. Gen. Virol.
86: 1093-1101
[Abstract] [Full Text] -
Asenjo, A., Rodriguez, L., Villanueva, N.
(2005). Determination of phosphorylated residues from human respiratory syncytial virus P protein that are dynamically dephosphorylated by cellular phosphatases: a possible role for serine 54. J. Gen. Virol.
86: 1109-1120
[Abstract] [Full Text] -
Thorpe, L. C., Easton, A. J.
(2005). Genome sequence of the non-pathogenic strain 15 of pneumonia virus of mice and comparison with the genome of the pathogenic strain J3666. J. Gen. Virol.
86: 159-169
[Abstract] [Full Text] -
Biacchesi, S., Skiadopoulos, M. H., Yang, L., Lamirande, E. W., Tran, K. C., Murphy, B. R., Collins, P. L., Buchholz, U. J.
(2004). Recombinant Human Metapneumovirus Lacking the Small Hydrophobic SH and/or Attachment G Glycoprotein: Deletion of G Yields a Promising Vaccine Candidate. J. Virol.
78: 12877-12887
[Abstract] [Full Text] -
Naylor, C. J., Brown, P. A., Edworthy, N., Ling, R., Jones, R. C., Savage, C. E., Easton, A. J.
(2004). Development of a reverse-genetics system for Avian pneumovirus demonstrates that the small hydrophobic (SH) and attachment (G) genes are not essential for virus viability. J. Gen. Virol.
85: 3219-3227
[Abstract] [Full Text] -
Oomens, A. G. P., Wertz, G. W.
(2004). trans-Complementation Allows Recovery of Human Respiratory Syncytial Viruses That Are Infectious but Deficient in Cell-to-Cell Transmission. J. Virol.
78: 9064-9072
[Abstract] [Full Text] -
Elliott, M. B., Pryharski, K. S., Yu, Q., Boutilier, L. A., Campeol, N., Melville, K., Laughlin, T. S., Gupta, C. K., Lerch, R. A., Randolph, V. B., LaPierre, N. A., Dack, K. M. H., Hancock, G. E.
(2004). Characterization of Recombinant Respiratory Syncytial Viruses with the Region Responsible for Type 2 T-Cell Responses and Pulmonary Eosinophilia Deleted from the Attachment (G) Protein. J. Virol.
78: 8446-8454
[Abstract] [Full Text] -
Elliott, M. B., Pryharski, K. S., Yu, Q., Parks, C. L., Laughlin, T. S., Gupta, C. K., Lerch, R. A., Randolph, V. B., LaPierre, N. A., Dack, K. M. H., Hancock, G. E.
(2004). Recombinant Respiratory Syncytial Viruses Lacking the C-Terminal Third of the Attachment (G) Protein Are Immunogenic and Attenuated In Vivo and In Vitro. J. Virol.
78: 5773-5783
[Abstract] [Full Text] -
Johnson, T. R., Teng, M. N., Collins, P. L., Graham, B. S.
(2004). Respiratory Syncytial Virus (RSV) G Glycoprotein Is Not Necessary for Vaccine-Enhanced Disease Induced by Immunization with Formalin-Inactivated RSV. J. Virol.
78: 6024-6032
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Ramaswamy, M., Shi, L., Monick, M. M., Hunninghake, G. W., Look, D. C.
(2004). Specific Inhibition of Type I Interferon Signal Transduction by Respiratory Syncytial Virus. Am. J. Respir. Cell Mol. Bio.
30: 893-900
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Thoulouze, M.-I., Bouguyon, E., Carpentier, C., Bremont, M.
(2004). Essential Role of the NV Protein of Novirhabdovirus for Pathogenicity in Rainbow Trout. J. Virol.
78: 4098-4107
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Easton, A. J., Domachowske, J. B., Rosenberg, H. F.
(2004). Animal Pneumoviruses: Molecular Genetics and Pathogenesis. Clin. Microbiol. Rev.
17: 390-412
[Abstract] [Full Text] -
Tran, K. C., Collins, P. L., Teng, M. N.
(2004). Effects of Altering the Transcription Termination Signals of Respiratory Syncytial Virus on Viral Gene Expression and Growth In Vitro and In Vivo. J. Virol.
78: 692-699
[Abstract] [Full Text] -
Bossert, B., Marozin, S., Conzelmann, K.-K.
(2003). Nonstructural Proteins NS1 and NS2 of Bovine Respiratory Syncytial Virus Block Activation of Interferon Regulatory Factor 3. J. Virol.
77: 8661-8668
[Abstract] [Full Text] -
Valarcher, J.-F., Furze, J., Wyld, S., Cook, R., Conzelmann, K.-K., Taylor, G.
(2003). Role of Alpha/Beta Interferons in the Attenuation and Immunogenicity of Recombinant Bovine Respiratory Syncytial Viruses Lacking NS Proteins. J. Virol.
77: 8426-8439
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Schlender, J., Zimmer, G., Herrler, G., Conzelmann, K.-K.
(2003). Respiratory Syncytial Virus (RSV) Fusion Protein Subunit F2, Not Attachment Protein G, Determines the Specificity of RSV Infection. J. Virol.
77: 4609-4616
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Oomens, A. G. P., Megaw, A. G., Wertz, G. W.
(2003). Infectivity of a Human Respiratory Syncytial Virus Lacking the SH, G, and F Proteins Is Efficiently Mediated by the Vesicular Stomatitis Virus G Protein. J. Virol.
77: 3785-3798
[Abstract] [Full Text] -
Young, D. F., Andrejeva, L., Livingstone, A., Goodbourn, S., Lamb, R. A., Collins, P. L., Elliott, R. M., Randall, R. E.
(2003). Virus Replication in Engineered Human Cells That Do Not Respond to Interferons. J. Virol.
77: 2174-2181
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Neumann, G., Whitt, M. A., Kawaoka, Y.
(2002). A decade after the generation of a negative-sense RNA virus from cloned cDNA - what have we learned?. J. Gen. Virol.
83: 2635-2662
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Krempl, C., Murphy, B. R., Collins, P. L.
(2002). Recombinant Respiratory Syncytial Virus with the G and F Genes Shifted to the Promoter-Proximal Positions. J. Virol.
76: 11931-11942
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Zimmer, G., Conzelmann, K.-K., Herrler, G.
(2002). Cleavage at the Furin Consensus Sequence RAR/KR109 and Presence of the Intervening Peptide of the Respiratory Syncytial Virus Fusion Protein Are Dispensable for Virus Replication in Cell Culture. J. Virol.
76: 9218-9224
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Teng, M. N., Collins, P. L.
(2002). The Central Conserved Cystine Noose of the Attachment G Protein of Human Respiratory Syncytial Virus Is Not Required for Efficient Viral Infection In Vitro or In Vivo. J. Virol.
76: 6164-6171
[Abstract] [Full Text] -
Bossert, B., Conzelmann, K.-K.
(2002). Respiratory Syncytial Virus (RSV) Nonstructural (NS) Proteins as Host Range Determinants: a Chimeric Bovine RSV with NS Genes from Human RSV Is Attenuated in Interferon-Competent Bovine Cells. J. Virol.
76: 4287-4293
[Abstract] [Full Text] -
Schmidt, A. C., Wenzke, D. R., McAuliffe, J. M., St. Claire, M., Elkins, W. R., Murphy, B. R., Collins, P. L.
(2002). Mucosal Immunization of Rhesus Monkeys against Respiratory Syncytial Virus Subgroups A and B and Human Parainfluenza Virus Type 3 by Using a Live cDNA-Derived Vaccine Based on a Host Range-Attenuated Bovine Parainfluenza Virus Type 3 Vector Backbone. J. Virol.
76: 1089-1099
[Abstract] [Full Text] -
Techaarpornkul, S., Barretto, N., Peeples, M. E.
(2001). Functional Analysis of Recombinant Respiratory Syncytial Virus Deletion Mutants Lacking the Small Hydrophobic and/or Attachment Glycoprotein Gene. J. Virol.
75: 6825-6834
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Zimmer, G., Trotz, I., Herrler, G.
(2001). N-Glycans of F Protein Differentially Affect Fusion Activity of Human Respiratory Syncytial Virus. J. Virol.
75: 4744-4751
[Abstract] [Full Text] -
Karger, A., Schmidt, U., Buchholz, U. J.
(2001). Recombinant bovine respiratory syncytial virus with deletions of the G or SH genes: G and F proteins bind heparin. J. Gen. Virol.
82: 631-640
[Abstract] [Full Text] -
Bukreyev, A., Murphy, B. R., Collins, P. L.
(2000). Respiratory Syncytial Virus Can Tolerate an Intergenic Sequence of at Least 160 Nucleotides with Little Effect on Transcription or Replication In Vitro and In Vivo. J. Virol.
74: 11017-11026
[Abstract] [Full Text] -
Hallak, L. K., Spillmann, D., Collins, P. L., Peeples, M. E.
(2000). Glycosaminoglycan Sulfation Requirements for Respiratory Syncytial Virus Infection. J. Virol.
74: 10508-10513
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Cuesta, I., Geng, X., Asenjo, A., Villanueva, N.
(2000). Structural Phosphoprotein M2-1 of the Human Respiratory Syncytial Virus Is an RNA Binding Protein. J. Virol.
74: 9858-9867
[Abstract] [Full Text] -
Teng, M. N., Whitehead, S. S., Bermingham, A., St. Claire, M., Elkins, W. R., Murphy, B. R., Collins, P. L.
(2000). Recombinant Respiratory Syncytial Virus That Does Not Express the NS1 or M2-2 Protein Is Highly Attenuated and Immunogenic in Chimpanzees. J. Virol.
74: 9317-9321
[Abstract] [Full Text] -
Schlender, J., Bossert, B., Buchholz, U., Conzelmann, K.-K.
(2000). Bovine Respiratory Syncytial Virus Nonstructural Proteins NS1 and NS2 Cooperatively Antagonize Alpha/Beta Interferon-Induced Antiviral Response. J. Virol.
74: 8234-8242
[Abstract] [Full Text] -
Bukreyev, A., Whitehead, S. S., Prussin, C., Murphy, B. R., Collins, P. L.
(2000). Effect of Coexpression of Interleukin-2 by Recombinant Respiratory Syncytial Virus on Virus Replication, Immunogenicity, and Production of Other Cytokines. J. Virol.
74: 7151-7157
[Abstract] [Full Text] -
Tao, T., Skiadopoulos, M. H., Davoodi, F., Riggs, J. M., Collins, P. L., Murphy, B. R.
(2000). Replacement of the Ectodomains of the Hemagglutinin-Neuraminidase and Fusion Glycoproteins of Recombinant Parainfluenza Virus Type 3 (PIV3) with Their Counterparts from PIV2 Yields Attenuated PIV2 Vaccine Candidates. J. Virol.
74: 6448-6458
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Matthews, J. M., Young, T. F., Tucker, S. P., Mackay, J. P.
(2000). The Core of the Respiratory Syncytial Virus Fusion Protein Is a Trimeric Coiled Coil. J. Virol.
74: 5911-5920
[Abstract] [Full Text] -
Buchholz, U. J., Granzow, H., Schuldt, K., Whitehead, S. S., Murphy, B. R., Collins, P. L.
(2000). Chimeric Bovine Respiratory Syncytial Virus with Glycoprotein Gene Substitutions from Human Respiratory Syncytial Virus (HRSV): Effects on Host Range and Evaluation as a Live-Attenuated HRSV Vaccine. J. Virol.
74: 1187-1199
[Abstract] [Full Text] -
Jin, H., Cheng, X., Zhou, H. Z. Y., Li, S., Seddiqui, A.
(2000). Respiratory Syncytial Virus That Lacks Open Reading Frame 2 of the M2 Gene (M2-2) Has Altered Growth Characteristics and Is Attenuated in Rodents. J. Virol.
74: 74-82
[Abstract] [Full Text] -
Whitehead, S. S., Hill, M. G., Firestone, C. Y., St. Claire, M., Elkins, W. R., Murphy, B. R., Collins, P. L.
(1999). Replacement of the F and G Proteins of Respiratory Syncytial Virus (RSV) Subgroup A with Those of Subgroup B Generates Chimeric Live Attenuated RSV Subgroup B Vaccine Candidates. J. Virol.
73: 9773-9780
[Abstract] [Full Text] -
Bermingham, A., Collins, P. L.
(1999). The M2-2 protein of human respiratory syncytial virus is a regulatory factor involved in the balance between RNA replication and transcription. Proc. Natl. Acad. Sci. USA
96: 11259-11264
[Abstract] [Full Text] -
Zimmer, G., Budz, L., Herrler, G.
(2001). Proteolytic Activation of Respiratory Syncytial Virus Fusion Protein. CLEAVAGE AT TWO FURIN CONSENSUS SEQUENCES. J. Biol. Chem.
276: 31642-31650
[Abstract] [Full Text]
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