Previous Article | Next Article ![]()
Journal of Virology, May 2000, p. 4139-4145, Vol. 74, No. 9
Department of
Virology1 and Department of
Bacteriology,2 Graduate School of Medical
Sciences, Kyushu University, Fukuoka 812-8582, and Department
of Virology II, National Institute of Infectious Diseases, Tokyo
162-8640,3 Japan
Received 6 December 1999/Accepted 4 February 2000
The Edmonston strain of measles virus (MV) that utilizes the human
CD46 as the cellular receptor produced cytopathic effects (CPE) in all
of the primate cell lines examined. In contrast, the wild-type MV
strains isolated in a marmoset B-cell line B95a (the KA and Ichinose
strains) replicated and produced CPE in some but not all of the primate
lymphoid cell lines. To determine the mechanism underlying this
difference in cell tropism, we used a recently developed recombinant
vesicular stomatitis virus (VSV) containing as a reporter the green
fluorescent protein gene in lieu of the VSV G protein gene (VSV Measles continues to be a major
childhood killer and is currently estimated to cause almost 1 million
deaths a year (8). Measles virus (MV) is an enveloped
negative-strand RNA virus that is a member of the
Morbillivirus genus in the Paramyxoviridae family. MV has two envelope glycoproteins, the hemagglutinin (H) and
fusion (F) proteins, mediating receptor binding and membrane fusion,
respectively (8).
MV was first isolated in tissue culture by inoculating primary human
kidney cells with the blood of a child with measles (6). Since then, continuous monkey kidney cell lines (e.g., Vero) have been
commonly used to isolate MV strains from clinical samples. However,
several blind passages were generally required in these cell lines
before virus propagation and development of cytopathic effects (CPE).
Recently, Kobune et al. reported that MV strains could be isolated much
more rapidly and efficiently in the Epstein-Barr virus
(EBV)-transformed marmoset B-cell line B95-8 and its adherent subline
B95a than in monkey kidney cell lines, and that MV strains isolated in
B95a cells, but not Vero cell-adapted strains, retained pathogenicity
for monkeys (12, 13). These studies suggested that MV
strains grown in B95a cells may be more representative of MV
circulating in humans than are MV strains selected in Vero cells.
Subsequently, other human B-cell lines were also used to isolate
wild-type MV strains (14, 25).
Several years ago, CD46 (also called membrane cofactor protein) was
identified as the cellular receptor for the Edmonston and Halle strains
of MV (4, 15, 17). The H protein was found to induce
downregulation of CD46 from the surface of MV-infected cells
(18). However, many recent wild-type MV strains isolated in
B-cell lines were found not to grow in other CD46-positive cell lines
(9, 12, 14, 24, 25, 30). Furthermore, Schneider-Schaulies et
al. showed that wild-type strains can be classified into
CD46-downregulating and -non-downregulating groups (24).
Two amino acid residues of the H protein (at positions 451 and 481)
were shown to be critical for determining the ability of MV strains to
cause hemadsorption, HeLa cell fusion, and CD46 downregulation (1,
14). More recently, using a direct binding assay with insect
cells expressing the H protein, Hsu et al. demonstrated that a single
amino acid change at position 481 determines the ability of the H
protein to bind CD46 (9). We showed that the H gene of the
wild-type MV isolates induced cell fusion in B95a cells, but not in
other CD46-positive cell lines, when coexpressed with the F gene
(30). All of these observations led to the proposal that the
H protein of the Edmonston strain, but not of many wild-type strains
isolated in B-cell lines, interacts with CD46, and that there is
another cellular receptor for these wild-type MV strains (2, 3, 9,
14, 30).
On the other hand, by analyzing differences in the growth properties
and nucleotide sequences of B95a-grown strains and their Vero
cell-adapted strains, Takeda et al. concluded that the changes in the H
protein were not important for MV adaptation to Vero cells
(29). Further, Johnston et al. generated a recombinant Edmonston MV expressing wild-type WTF strain envelope proteins and
showed that the recombinant virus expressing the WTF H protein spread
in Vero cells although the parental WTF virus did not, suggesting that
cell-specific factors other than receptor usage are also important in
determining MV cell tropism (11).
In this study, we first examined cell tropism of the Edmonston strain
and the KA strain, a CD46-non-downregulating wild-type MV isolate, in a
large number of cell lines. We then used a recombinant vesicular
stomatitis virus (VSV) to produce pseudotypes bearing MV envelope
proteins and showed unequivocally that virus entry is a major
determinant of cell tropism of the Edmonston and KA strains.
Cells.
293T is derived from the human kidney cell line 293 and contains the simian virus 40 large T antigen (5). The
other cell lines used in this study and their derivations are listed in
Table 1. BJAB and BJAB-B95-8 were kindly
provided by Kenzo Takada. CHO/CD46 and CHO/pME18S are CHO-derived cell
lines in which the expression vector pME18S with and without the human
CD46 gene, respectively, was transfected and were kindly provided by
Yusuke Murakami (10). All adherent cell lines except B95a
and CHO-derived cell lines were grown in Dulbecco modified Eagle medium
supplemented with 7% heat-inactivated fetal bovine serum (FBS), 0.15%
sodium bicarbonate, and 50 µg of gentamicin per ml. L.Neo and
L.CD46.1 (32) were grown in the medium supplemented with 0.5 mg of G418 per ml. B95a, CHO-derived cell lines, and all cell lines in
suspension were grown in RPMI 1640 supplemented with 10%
heat-inactivated FBS, 0.15% sodium bicarbonate, and 50 µg of
gentamicin per ml. CHO/CD46 and CHO/pME18S were grown in medium
supplemented with 0.7 mg of hygromycin B per ml.
0022-538X/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Virus Entry Is a Major Determinant of Cell Tropism
of Edmonston and Wild-Type Strains of Measles Virus as Revealed by
Vesicular Stomatitis Virus Pseudotypes Bearing Their Envelope
Proteins
![]()
ABSTRACT
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
G*).
MV glycoproteins were efficiently incorporated into VSV
G*, producing
the VSV pseudotypes. VSV
G* complemented with VSV G protein
efficiently infected all of the cell lines tested. The VSV pseudotype
bearing the Edmonston hemagglutinin (H) and fusion (F) protein
(VSV
G*-EdHF) infected all cell lines in which the Edmonston strain
caused CPE, including the rodent cell lines to which the human CD46
gene was stably transfected. The pseudotype bearing the wild-type KA H
protein and Edmonston F protein (VSV
G*-KAHF) infected all lymphoid
cell lines in which the wild-type MV strains caused CPE as efficiently as VSV
G*-EdHF, but it did not infect any of the cell lines resistant to infection with the KA strain. The results indicate that the difference in cell tropism between these MV strains was largely determined by virus entry, in which the H proteins of respective MV
strains play a decisive role.
![]()
INTRODUCTION
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
![]()
MATERIALS AND METHODS
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
TABLE 1.
Susceptibility of cell lines to different strains of MV
Viruses.
The Edmonston strain of MV was obtained from
American Type Culture Collection and grown on Vero cells. The wild-type
MV strains, KA and Ichinose, were isolated from patients with measles
by using B95a cells and were grown on B95a cells (generous gifts of
Fumio Kobune) (30). (In this report, the term
"wild-type" refers to MV strains that have been isolated and
propagated in marmoset or human B-cell lines and usually do not grow
well in Vero cells.) The Edmonston strain was titrated on Vero cells,
and the KA and Ichinose strains were titrated on B95a cells. VSV
G*-G
is the recombinant VSV derived from a full-length cDNA clone of VSV
genome (Indiana serotype) in which the coding region of the G protein was replaced by the coding region of a modified version of the green
fluorescent protein (GFP) gene and the G protein was expressed in
trans by pCVSVG (28). VSV
G*-G, kindly provided
by Michael A. Whitt, was grown and harvested by infecting 293T cells
which had been transfected with pCVSVG.
Plasmids. cDNA clones of the Edmonston H and F genes were obtained from M. A. Billeter (23) and subcloned into the expression vector pCXN2 (19). They were designated pCXN2H and pCXN2F. A cDNA clone of the KA H gene was obtained by reverse transcriptase-PCR and cloned into pCXN2, yielding pCXN2KAH (30). pCVSVG is the expression plasmid in which cDNA encoding the VSV G protein was cloned into the expression vector pCAGGS (19).
Virus growth in cell lines. Each cell line (2.5 × 105 cells) was infected with the Edmonston (titrated on Vero cells) or KA (titrated on B95a cells) strain at a multiplicity of infection (MOI) of 0.25. After 1 h of infection, cells were washed with phosphate-buffered saline three times, replenished with 1 ml of fresh medium, and incubated in 24-well plate at 37°C in a 5% CO2 incubator. Cells and medium were recovered at various times after infection and then treated by one cycle of freezing-thawing and low-speed centrifugation. The suspensions containing the Edmonston strain were titrated on Vero cells, and those containing the KA strains were titrated on B95a cells.
Preparation of pseudotype viruses.
293T cells were
transfected with pCVSVG, pCXN2H plus pCXN2F, pCXN2KAH plus pCXN2F, or
pCXN2 by using Lipofectamine (GIBCO/BRL). Thirty-two hours after
transfection, cells were infected with VSV
G*-G at an MOI of 1 (titrated on 293T cells) for 1 h at 37°C. They were then washed
with Dulbecco modified Eagle medium without FBS seven times, and
culture medium was added. After 21 h of incubation at 37°C in a
CO2 incubator, culture fluid and scraped cell debris were
collected, treated by one cycle of freezing-thawing, and sonicated. The suspensions containing pseudotype viruses were clarified
by low-speed centrifugation and stored at
80°C. They were
designated VSV
G*-G, VSV
G*-EdHF, VSV
G*-KAHF, and VSV
G*. When
VSV
G*-EdHF was prepared, culture medium was supplemented with the
fusion block peptide (Z-D-Phe-Phe-Gly) (21) from
5 h after lipofection to immediately before infection with
VSV
G*-G, in order to prevent 293T cells from fusing each other upon
transfection with pCXN2H plus pCXN2F.
Titration of pseudotype viruses in various cell lines. For adherent cell lines, 2 × 104 cells (5 × 104 cells for B95a) in 100 µl of fresh culture medium were sedimented in the well of 96-well flat-bottom plate. After overnight incubation, 50 µl of serially diluted virus stock was added to each well, followed by incubation at 37°C in a CO2 incubator. At 24 h after infection, infectious units of pseudotype virus stocks were determined by counting the number of GFP-expressing cells under a fluorescence microscope. Since infected cells may divide during 24 h of incubation, a doublet of GFP-expressing cells, when observed, was counted as 1 infectious unit. For cell lines in suspension, 5 × 104 cells in 100 µl of fresh culture medium were infected in a similar manner. At 24 h after infection, cells in each well were treated by pipetting to break cell clumps and left to settle for 30 to 90 min; then GFP-expressing cells were counted. Since single infected cells may produce GFP-expressing progeny cells during 24 h of incubation, we may overestimate infectious units for cell lines in suspension, depending on the doubling time of the cell lines. This may become a problem when we compare infectious units between different cell lines. However, as long as we compare infectious units of four pseudotype viruses within a single cell line, the proportional difference in infectivity is not affected. The same preparations of virus stocks were used for all titrations, and each cell line was simultaneously prepared for the titration of four types of pseudotype viruses.
Electron microscopy. Virus samples were prepared as described above except that only culture supernatant containing pseudotype viruses (not cell debris) was used. They were partially purified by centrifugation through 20% sucrose and labeled with serum from a patient with subacute sclerosing panencephalitis (SSPE) (31) and protein G conjugated with gold. Virus samples were negatively stained with uranyl formate and examined in an electron microscope.
| |
RESULTS |
|---|
|
|
|---|
Cell tropism of the wild-type KA strain of MV.
To examine the
difference in cell tropism between the Edmonston strain and the
wild-type KA strain of MV, we infected various cell lines and observed
the development of CPE (Fig. 1 and Table 1). The Edmonston strain caused CPE in all human and monkey cell lines
tested. CPE was weaker in Daudi cells than in other human cell lines,
probably because the F protein is not effectively processed in Daudi
cells (7). Interestingly, even the rodent and rabbit cell
lines developed focal small syncytia when infected at a high MOI
(>10). On the other hand, the KA strain produced CPE only in B95a,
B95-8, Raji, Ramos, BJAB-B95-8, MT-2, and C91/PL cells, which are all
lymphoid cell lines (Fig. 1).
|
|
CD3
CD4+ CD8
CD25+. These cells were also strongly stained by serum from
a patient with human T-cell leukemia virus type 1 (HTLV-1)-associated
myelopathy, confirming that they are HTLV-1-infected cell lines. To
determine whether the observed tropism was peculiar to the KA strain,
another wild-type strain isolated in B95a cells, Ichinose, was also
used to infect the cell lines examined in Fig. 1, and exactly the same tropism was observed (data not shown).
Incorporation of MV envelope proteins into VSV
pseudotypes.
To determine whether virus entry or subsequent
intracellular replication is responsible for the difference in cell
tropism between the Edmonston and wild-type MV strains, we used the
recently developed recombinant VSV
G*, which contains the GFP
gene instead of the VSV G protein gene and thus is not infectious
unless the envelope proteins mediating receptor binding and membrane
fusion are provided in trans (28). VSV
G*
complemented with the VSV G gene (VSV
G*-G) can infect the
majority of cell lines (28). To confirm the incorporation of
MV envelope proteins into VSV particles, 293T cells were transfected
with the KA H protein and the Edmonston F protein, followed by
infection with VSV
G*-G, producing VSV
G*-KAHF. VSV
G*-G
and VSV
G*-KAHF were partially purified by centrifugation and
stained with SSPE serum containing high levels of anti-MV antibodies
and protein G conjugated with gold, followed by negative staining.
Electron microscopic analysis revealed that VSV
G*-G and
VSV
G*-KAHF virions had almost the same sizes, presumably reflecting
the similar composition of nucleocapsids, and that the majority of
VSV
G*-KAHF virions, but no VSV
G*-G virions, were labeled with
SSPE serum (Fig. 3). Thus, MV envelope proteins were successfully incorporated into VSV particles, consistent with a previous report (26).
|
Susceptibility of cell lines to VSV pseudotypes.
We prepared
four types of pseudotype viruses: VSV
G*-G, VSV
G*-EdHF
bearing the Edmonston H and F proteins, VSV
G*-KAHF, and VSV
G* bearing no envelope protein. The Edmonston F gene was used to
generate both VSV
G*-EdHF and VSV
G*-KAHF, and thus any difference in infectivity between these two pseudotypes should be due to the H
protein on their envelopes. VSV
G* was prepared without supplying
envelope proteins, so that the cell's susceptibility to VSV
G* will
reflect virus entry independent of VSV or MV envelope proteins.
G*-G infected all of
the cell lines tested, with titers ranging from 106.0 to
108.7 infectious units/ml (as measured by counting the
number of GFP-expressing cells). On B95a, Vero, and HeLa cells,
VSV
G*-EdHF had higher infectivity titers than VSV
G* by over 3 logs, whereas these two pseudotype viruses showed similar levels of
titers on BHK21 and RK13 cells. CHO/CD46 and L.CD46.1, the rodent cell
lines to which the human CD46 gene was stably transfected, were more
susceptible to VSV
G*-EdHF than their parental cell lines to which
only the control plasmid was transfected. The VSV
G*-KAHF titer was
over 4 logs higher than the VSV
G* titer on B95a cells but not
significantly higher on the other adherent cell lines tested. Thus,
each adherent cell line showed susceptibility to VSV
G*-EdHF and
VSV
G*-KAHF, in a manner consistent with its susceptibility to the
Edmonston strain and KA strain.
|
G*-EdHF, while neither of the mouse cell lines
was. VSV
G*-KAHF titers were 2 to 3 logs higher than VSV
G* titers
on B95-8, Raji, Ramos, BJAB-B95-8, and MT-2. VSV
G* showed a high
infectivity titer on C91/PL, making it impossible to evaluate virus
entry into this cell line dependent on the MV envelope proteins. Again,
each cell line in suspension showed susceptibility to VSV
G*-EdHF and
VSV
G*-KAHF, in a manner consistent with its susceptibility to the
Edmonston and KA strains.
| |
DISCUSSION |
|---|
|
|
|---|
In this study, we first showed the clear difference in cell tropism between the Edmonston strain and the wild-type KA strain, using a large number of various cell lines. The Edmonston strain caused CPE in all human and monkey cell lines tested and in rodent cell lines expressing human CD46, whereas the KA strain caused CPE only in a restricted number of human and marmoset lymphoid cell lines. It was also confirmed in several cell lines that the development of CPE paralleled virus replication. Thus, the KA strain neither produced CPE nor replicated well in BJAB and Jurkat cells. Another wild-type strain (Ichinose) isolated in B95a cells showed the same tropism as the KA strain.
Since both marmoset B95-8 cells and human Raji cells, which are highly susceptible to wild-type MV strains, have been infected with EBV, the relationship between EBV infection and susceptibility to wild-type MV strains has been discussed elsewhere (3). In fact, we showed that the KA and Ichinose strains caused CPE in BJAB-B95-8, an EBV-infected line of BJAB cells, whereas they did not in BJAB. On the other hand, these wild-type strains caused CPE in Ramos, an EBV-negative B-cell line. Furthermore, although our wild-type MV strains did not grow in BJAB, another group used this cell line to isolate and propagate the wild-type MV strains (24, 25). These results suggest that EBV infection per se is not a prerequisite for the cell's susceptibility to wild-type MV. EBV infection may, however, make the cells more susceptible to wild-type MV by upregulating certain proteins that serve either as the cellular receptor or as certain host factors.
We also showed that the KA and Ichinose strains caused CPE in two human T-cell lines, MT-2 and C91/PL, which are HTLV-1-transformed cell lines derived from human cord blood mononuclear cells (16, 20). Though MT-2 and C91/PL cells were originally identified as T cells, they did not express CD3 but were still HTLV-1 positive. We found that wild-type MV strains propagated on these cell lines did not infect Vero cells, indicating that they retained the wild-type phenotype (data not shown). Although we have previously reported that the KA and Ichinose strains produced CPE in phytohemagglutinin-stimulated human peripheral blood mononuclear cells (30), this is the first description of T-cell lines susceptible to wild-type MV strains.
Which step of virus growth determines the difference in cell tropism
between MV strains? To evaluate virus entry, we prepared VSV
pseudotypes bearing MV envelope proteins. It had been reported that the
H and F proteins of MV were efficiently incorporated into VSV virions
(26). In this study, we used a recombinant VSV (VSV
G*)
lacking the G protein gene. Thus, the pseudotype viruses enter cells
using envelope proteins provided in trans, and then
subsequent intracellular steps progress as part of the VSV replication
cycle. As a result, the difference in the infectivity between
pseudotype viruses reflects the difference in the efficiency of entry
using the envelope proteins provided. The infectivity titration of
pseudotype viruses on various cell lines showed that the difference in
cell tropism between the Edmonston and KA strains could be explained by
the efficiency of virus entry, in which the H proteins of the involved
MV strains play a decisive role.
This pseudotype virus system contains two factors which may cause a
false infectivity. First, VSV
G*-G used to prepare pseudotypes may
contaminate virus stocks, producing a background infectivity. Second,
virus entry independent of VSV or MV envelope glycoproteins may occur.
To evaluate these two factors, we included VSV
G* in our experiments.
The infectivity titers of VSV
G* on most cell lines were negligible,
indicating that neither residual VSV
G*-G in pseudotype virus stocks
nor envelope protein-independent virus entry was significant in our
system. VSV
G* showed a high infectivity titer on C91/PL cells, which
was presumably caused by the second factor described above. We
hypothesize that VSV
G* bears the HTLV-1 receptor molecule derived
from 293T cells, which might facilitate the interaction of the
pseudotype with HTLV-1 envelope proteins expressed on C91/PL cells,
although we have not explored this further. We have previously reported
that the H gene of wild-type MV strains induced cell fusion in B95a
cells, but not in other CD46-positive human and monkey cell lines, when
transfected together with the F gene (30). The pseudotype
virus system used in this study has advantages over the transfection
experiment, as it can quantitatively determine the entry of cell-free
virus, rather than cell-cell fusion, in adherent cells as well as in
cells in suspension.
However, our pseudotype assay may not perfectly reflect MV entry for
the following reasons. First, the amount of MV envelope proteins on VSV
pseudotype virus may be lower than that on MV virion, which will make
the pseudotype bearing MV envelope proteins enter only highly
susceptible cells. Second, VSV pseudotype viruses do not have
quasispecies as regards envelope proteins because they are expressed
from the plasmids. This may explain why rodent cells developed focal
small syncytia when infected with the Edmonston strain at a high MOI,
but VSV
G*-EdHF showed no infectious titers on them.
Recently, Takeda et al. reported that changes in the polymerase and accessory proteins, not in envelope proteins, were responsible for the growth difference between a B95a-grown MV strain and its Vero-adapted strain (29). Johnston et al. generated a recombinant Edmonston MV expressing envelope proteins of the wild-type WTF strain and showed that the recombinant virus expressing the WTF H protein spread in Vero cells although the parental WTF virus did not (11). These studies indicate that cellular factors other than virus entry play an important role in determining MV cell tropism. How are these studies reconciled with our results? One interpretation is that although Vero cells do not have the authentic receptor for wild-type MV strains, they may still enter Vero cells with a low efficiency and thereafter replicate and produce CPE to a certain extent. The adaptation to the intracellular environment may increase such viral growth in Vero cells, thus affecting MV cell tropism. However, our results clearly showed that there exist large differences in the efficiencies of virus entry between susceptible and nonsusceptible cell lines, accounting for the major part of the tropism. Furthermore, Takeda et al. (29), reported that the Vero-adapted virus had a serine-to-glycine change at position 546 of the H protein, which may also allow this virus to efficiently infect Vero cells (22, 27). In the study by Johnston et al. (11), the WTF strain did not spread in Vero cells, but transfection of the WTF H protein gene and the Edmonston F gene caused cell fusion in Vero cells, suggesting that the WTF strain is able to fuse with Vero cells at a higher efficiency than the KA and Ichinose strains. Thus, even in these studies, virus entry seems to be a major determinant of MV cell tropism, although other cell-specific factors and/or other viral proteins (e.g., polymerase) apparently influence subsequent viral replication, contributing to tropism.
In summary, we newly identified several cell lines, including T-cell lines, that can support the efficient replication of wild-type MV strains. We successfully generated the VSV pseudotype expressing MV envelope proteins in the absence of the VSV G protein. Using this pseudotype virus system, we showed that the infectivity of a MV strain for the cell was perfectly correlated with the efficiency of entry into that cell by the VSV pseudotype bearing the corresponding MV H protein, indicating that virus entry is a major determinant of cell tropism of MV strains. We are now using this VSV pseudotype system to identify the molecule that enables wild-type MV strains to enter cells.
| |
ACKNOWLEDGMENTS |
|---|
We thank M. A. Whitt for allowing us to use the VSV
G*-GFP
system. We also thank F. Kobune, K. Takada, and Y. Murakami for providing the wild-type MV strains, BJAB and BJAB-B95-8 cell lines, and
CHO-derived cell lines, respectively.
This work was supported by grants from the Ministry of Education, Science and Culture of Japan and from the Program for Promotion of Fundamental Studies in Health Sciences of the Organization for Drug ADR Relief, R&D Promotion and Product Review of Japan.
| |
FOOTNOTES |
|---|
* Corresponding author. Mailing address: Department of Virology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan. Phone: 81-92-642-6135. Fax: 81-92-642-6140. E-mail: yyanagi{at}virology.med.kyushu-u.ac.jp.
| |
REFERENCES |
|---|
|
|
|---|
| 1. | Bartz, R., U. Brinckmann, L. M. Dunster, B. Rima, V. ter Meulen, and J. Schneider-Schaulies. 1996. Mapping amino acids of the measles virus hemagglutinin responsible for receptor (CD46) downregulation. Virology 224:334-337[CrossRef][Medline]. |
| 2. | Bartz, R., R. Firsching, B. Rima, V. ter Meulen, and J. Schneider-Schaulies. 1998. Differential receptor usage by measles virus strains. J. Gen. Virol. 79:1015-1025[Abstract]. |
| 3. | Buckland, R., and T. F. Wild. 1997. Is CD46 the receptor for measles virus? Virus Res. 48:1-9. |
| 4. | Dorig, R. E., A. Marcil, A. Chopra, and C. D. Richardson. 1993. The human CD46 molecule is a receptor for measles virus (Edmonston strain). Cell 75:295-305[CrossRef][Medline]. |
| 5. |
DuBridge, R. B.,
P. Tang,
H. C. Hsia,
P.-M. Leong,
J. H. Miller, and M. P. Calos.
1987.
Analysis of mutation in human cells by using an Epstein-Barr virus shuttle system.
Mol. Cell. Biol.
7:379-387 |
| 6. | Enders, J. F., and T. C. Peebles. 1954. Propagation in tissue cultures of cytopathic agents from patients with measles. Proc. Soc. Exp. Biol. Med. 86:277-286. |
| 7. |
Fujinami, R. S., and M. B. A. Oldstone.
1981.
Failure to cleave measles virus fusion protein in lymphoid cells: a possible mechanism for viral persistence in lymphocytes.
J. Exp. Med.
154:1489-1499 |
| 8. | Griffin, D. E., and W. J. Bellini. 1996. Measles virus, p. 1267-1312. In B. N. Fields, D. M. Knipe, P. M. Howley, R. M. Chanock, J. L. Melnick, T. P. Monath, B. Roizman, and S. E. Straus (ed.), Fields virology, 3rd ed. Lippincott-Raven, Philadelphia, Pa. |
| 9. |
Hsu, E. C.,
F. Sarangi,
C. Iorio,
M. S. Sidhu,
S. A. Udem,
D. L. Dillehay,
W. Xu,
P. A. Rota,
W. J. Bellini, and C. D. Richardson.
1998.
A single amino acid change in the hemagglutinin protein of measles virus determines its ability to bind CD46 and reveals another receptor on marmoset B cells.
J. Virol.
72:2905-2916 |
| 10. | Iwata, K., T. Seya, H. Ariga, and S. Nagasawa. 1994. Expression of a hybrid complement regulatory protein, membrane cofactor protein decay accelerating factor on Chinese hamster ovary: comparison of its regulatory effect with those of decay accelerating factor and membrane cofactor protein. J. Immunol. 152:3436-3444[Abstract]. |
| 11. |
Johnston, I. C. D.,
V. ter Meulen,
J. Schneider-Schaulies, and S. Schneider-Schaulies.
1999.
A recombinant measles vaccine virus expressing wild-type glycoproteins: consequences for viral spread and cell tropism.
J. Virol.
73:6903-6915 |
| 12. |
Kobune, F.,
H. Sakata, and A. Sugiura.
1990.
Marmoset lymphoblastoid cells as a sensitive host for isolation of measles virus.
J. Virol.
64:700-705 |
| 13. | Kobune, F., H. Takahashi, K. Terao, T. Ohkawa, Y. Ami, Y. Suzaki, N. Nagata, H. Sakata, K. Yamanouchi, and C. Kai. 1996. Nonhuman primate models of measles. Lab. Anim. Sci. 46:315-320[Medline]. |
| 14. | Lecouturier, V., J. Fayolle, M. Caballero, J. Carabana, M. L. Celma, R. Fernandez-Munoz, T. F. Wild, and R. Buckland. 1996. Identification of two amino acids in the hemagglutinin glycoprotein of measles virus (MV) that govern hemadsorption, HeLa cell fusion, and CD46 downregulation: phenotypic markers that differentiate vaccine and wild-type MV strains. J. Virol. 70:4200-4204[Abstract]. |
| 15. |
Manchester, M.,
M. K. Liszewski,
J. P. Atkinson, and M. B. A. Oldstone.
1994.
Multiple isoforms of CD46 (membrane cofactor protein) serve as receptors for measles virus.
Proc. Natl. Acad. Sci. USA
91:2161-2165 |
| 16. | Miyoshi, I., I. Kubonishi, S. Yoshimoto, T. Akagi, Y. Ohtsuki, Y. Shiraishi, K. Nagata, and Y. Hinuma. 1981. Type C virus particles in a cord T-cell line derived by co-cultivating normal human cord leukocytes and human leukaemic T cells. Nature 294:770-771[CrossRef][Medline]. |
| 17. |
Naniche, D.,
G. Varior-Krishnan,
F. Cervoni,
T. F. Wild,
B. Rossi,
C. Rabourdin-Combe, and D. Gerlier.
1993.
Human membrane cofactor protein (CD46) acts as a cellular receptor for measles virus.
J. Virol.
67:6025-6032 |
| 18. |
Naniche, D.,
T. F. Wild,
C. Rabourdin-Combe, and D. Gerlier.
1993.
Measles virus haemagglutinin induces down-regulation of gp57/67, a molecule involved in virus binding.
J. Gen. Virol.
74:1073-1079 |
| 19. | Niwa, H., K. Yamamura, and J. Miyazaki. 1991. Efficient selection for high-expression transfectants by a novel eukaryotic vector. Gene 108:193-200[CrossRef][Medline]. |
| 20. |
Popovic, M.,
P. S. Sarin,
M. Robert-Gurroff,
V. S. Kalyanaraman,
D. Mann,
J. Minowada, and R. C. Gallo.
1983.
Isolation and transmission of human retrovirus (human T-cell leukemia virus).
Science
219:856-859 |
| 21. | Richardson, C. D., A. Scheid, and P. W. Choppin. 1980. Specific inhibition of paramyxovirus and myxovirus replication by oligopeptides with amino acid sequences similar to those at the N-termini of the F1 or HA2 viral polypeptides. Virology 105:205-222[CrossRef][Medline]. |
| 22. | Rima, B. K., J. A. P. Earle, K. Baczko, V. ter Meulen, U. G. Liebert, C. Carstens, J. Carabana, M. Caballero, M. L. Celma, and R. Fernandez-Munoz. 1997. Sequence divergence of measles virus haemagglutinin during natural evolution and adaptation to cell culture. J. Gen. Virol. 78:97-106[Abstract]. |
| 23. | Schmid, A., C. R., and M. A. Billeter. 1987. A procedure for selective full length cDNA cloning of specific RNA species. Nucleic Acids Res. 15:3987-3996. |
| 24. | Schneider-Schaulies, J., L. M. Dunster, F. Kobune, B. Rima, and V. ter Meulen. 1995. Differential downregulation of CD46 by measles virus strains. J. Virol. 69:7257-7259[Abstract]. |
| 25. |
Schneider-Schaulies, J.,
J.-J. Schnorr,
U. Brinckmann,
L. M. Dunster,
K. Baczko,
U. G. Liebert,
S. Schneider-Schaulies, and V. ter Meulen.
1995.
Receptor usage and differential downregulation of CD46 by measles virus wild-type and vaccine strains.
Proc. Natl. Acad. Sci. USA
92:3943-3947 |
| 26. |
Schnell, M. J.,
L. Buonocore,
E. Kretzschmar,
E. Johnson, and J. K. Rose.
1996.
Foreign glycoproteins expressed from recombinant vesicular stomatitis viruses are incorporated efficiently into virus particles.
Proc. Natl. Acad. Sci. USA
93:11359-11365 |
| 27. |
Shibahara, K.,
H. Hotta,
Y. Katayama, and M. Homma.
1994.
Increased binding activity of measles virus to monkey red blood cells after long-term passage in Vero cell cultures.
J. Gen. Virol.
75:3511-3516 |
| 28. |
Takada, A.,
C. Robinson,
H. Goto,
A. Sanchez,
K. G. Murti,
M. A. Whitt, and Y. Kawaoka.
1997.
A system for functional analysis of Ebola virus glycoprotein.
Proc. Natl. Acad. Sci. USA
94:14764-14769 |
| 29. |
Takeda, M.,
A. Kato,
F. Kobune,
H. Sakata,
Y. Li,
T. Shioda,
Y. Sakai,
M. Asakawa, and Y. Nagai.
1998.
Measles virus attenuation associated with transcriptional impediment and a few amino acid changes in the polymerase and accessory proteins.
J. Virol.
72:8690-8696 |
| 30. | Tanaka, K., M. Xie, and Y. Yanagi. 1998. The hemagglutinin of recent measles virus isolates induces cell fusion in a marmoset cell line, but not in other CD46-positive human and monkey cell lines, when expressed together with the F protein. Arch. Virol. 143:213-225[CrossRef][Medline]. |
| 31. | Yanagi, Y., B. A. Cubitt, and M. B. A. Oldstone. 1992. Measles virus inhibits mitogen-induced T cell proliferation but does not directly perturb the T cell activation process inside the cell. Virology 187:280-289[CrossRef][Medline]. |
| 32. | Yanagi, Y., H.-L. Hu, T. Seya, and H. Yoshikura. 1994. Measles virus infects mouse fibroblast cell lines, but its multiplication is severely restricted in the absence of CD46. Arch. Virol. 138:39-53[CrossRef][Medline]. |
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»