![[Feedback]](/icons/banner/feedbackACT.gif)
![[For Subscribers]](/icons/banner/subscriberACT.gif)
![[Archive]](/icons/banner/archiveACT.gif)
![[Search]](/icons/banner/searchACT.gif)
![[Contents]](/icons/banner/tocACT.gif)
Previous Article | Next Article 
Journal of Virology, May 1999, p. 4465-4469, Vol. 73, No. 5
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Molecular Cloning and Expression of Major
Structural Protein VP1 of the Human Polyomavirus JC Virus: Formation
of Virus-Like Particles Useful for Immunological and
Therapeutic Studies
Claudia
Goldmann,1
Harald
Petry,1
Stephan
Frye,1,2
Oliver
Ast,1
Susanne
Ebitsch,1
Klaus-Dieter
Jentsch,1
Franz-Josef
Kaup,3
Frank
Weber,2
Corinna
Trebst,2
Thomas
Nisslein,1
Gerhard
Hunsmann,1
Thomas
Weber,2,
and
Wolfgang
Lüke1,*
Department of Virology and
Immunology1 and Department of
Experimental Pathology,3 German Primate Centre,
and Department of Neurology, University of
Göttingen,2 D-37077 Göttingen,
Germany
Received 23 April 1997/Accepted 1 February 1999
 |
ABSTRACT |
The major structural viral protein, VP1, of the human polyomavirus
JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), was expressed by using recombinant baculoviruses. Recombinant VP1 formed virus-like particles (VLP) with
the typical morphology of empty JCV capsids. Purified VP1 VLP bind to
SVG, B, and T cells, as well as to monkey kidney cells. After binding,
VP1 VLP were also internalized with high efficiency and transported to
the nucleus. Immunization studies revealed these particles as highly
immunogenic when administered with adjuvant, while immunization without
adjuvant induced no immune response. VP1 VLP hyperimmune serum inhibits
binding to SVG cells and neutralizes natural JCV. Furthermore, the
potential of VP1 VLP as an efficient transporter system for gene
therapy was demonstrated. Exogenous DNA could be efficiently packaged
into VP1 VLP, and the packaged DNA was transferred into COS-7 cells as
shown by the expression of a marker gene. Thus, VP1 VLP are useful for
PML vaccine development and represent a potential new transporter
system for human gene therapy.
| |
TEXT |
The human polyomavirus JC virus
(JCV) is the etiological agent of progressive multifocal
leukoencephalopathy (PML), the only known viral demyelinating disease
of humans (14). Owing to the worldwide AIDS pandemic, PML is
becoming increasingly more frequent (3). Immunodeficiency in
AIDS patients leads to reactivation of JCV, causing PML
(14). About 7% of all patients with AIDS ultimately develop
PML, and at least 85% of all PML cases occur in these patients
(4). PML can be specifically correlated to the appearance of
JCV DNA in the cerebrospinal fluid (22, 23). Moreover, the
immune response to JCV in the course of infection and the development
of PML has been recently investigated, and elevated VP1-specific
antibody synthesis can be quite reliably used to diagnose PML
(24). Clinically, no attempts are currently being made to
use gene therapy or boost the immunological state of patients,
especially of human immunodeficiency virus type 1-infected but
asymptomatic individuals, to protect against JCV reactivation and the
development of PML.
For the development of such new approaches, we describe in the present
study the expression of the major structural protein VP1 of JCV as
recombinant virus-like particles (VLP) and their usefulness for
PML-specific vaccine development. Furthermore, the potential of VP1 VLP
as a new transporter system for gene therapy was demonstrated.
Expression, purification, and characterization of VP1 VLP.
With the help of recombinant baculoviruses, the major structural
protein VP1 of JCV could be successfully expressed in the insect cell
line Sf158. VP1 was detected in the cell extract and the cell culture
supernatant, and the highest expression was obtained 5 days after
infection. Therefore, recombinant VP1 VLP were purified from cell
culture supernatants and cell extracts 5 days after infection by a
simple and rapid two-step procedure including sedimentation through a
40% sucrose cushion, followed by a second centrifugation through a
step gradient of 40% sucrose and 50% metrizamide. VP1 VLP were
obtained in the pellet after the final centrifugation step and
consisted of two major proteins with molecular masses of 42 and 40 kDa
and a third minor protein of about 38 kDa. By Western blot (WB)
analysis with anti-simian virus 40 (SV40) hyperimmune serum
(23), the VP1-specific 42-kDa protein was identified as the
major immunoreactive component. Minor reactivities were also obtained
with the 40- and 38-kDa proteins, as well as with a protein of about 27 kDa.
For further characterization of the purified VP1 VLP, electron
microscopy was performed. The electron micrograph (Fig.
1) demonstrated that most of the VP1 VLP
exhibits the typical morphology of empty JCV capsids having a mean
diameter of 55 to 60 nm (closed triangle). A very small minority of
full particles was also identified (open triangle). This result was
confirmed by further analysis of the VP1 VLP in a CsCl density
gradient. As shown in Fig. 2A, two bands
were visible: a major band in the middle of the gradient with a density
of about 1.32 g/ml (closed triangle; empty particles) and a minor band
at a density of about 1.34 g/ml (open triangle; full particles).
Analysis of the gradient fractions by enzyme-linked immunosorbent assay
revealed a major immunoreactive peak in the density range of 1.31 to
1.33 g/ml (Fig. 2B, fractions 11 to 16; empty particles) and a minor
immunoreactive shoulder in the density range of 1.33 to 1.35 g/ml (Fig.
2B, fractions 7 to 10; full particles). WB analysis of each gradient
fraction with VP1-specific hyperimmune serum (see below) defined the
VP1-specific 42-kDa protein as the major reactive component in the
density range of empty particles (1.31 to 1.33 g/ml; fractions 11 to
16) (Fig. 2C). A similar strong VP1-specific reactivity was obtained
with the 40-kDa protein, whereas the reactivity with the 27-kDa protein
was somewhat reduced. In contrast, in the density range of the full
particles (1.33 to 1.35 g/ml; fractions 7 to 10), the major and only
reactive components were identified as the VP1-specific 42- and 40-kDa proteins. These results were confirmed by WB analysis of identical amounts of empty and full particles. Again, in empty particles, the
VP1-specific 42- and 40-kDa proteins were identified as the major
reactive components, whereas the reactivity with the 27-kDa protein was
reduced (Fig. 2D, lane 1). The major reactive components comprised by
the full particles were identified as the VP1-specific 42-kDa protein
and, at a somewhat lower intensity, the 40-kDa protein (Fig. 2D, lane
2).
View larger version (169K):
[in this window]
[in a new window]
|
FIG. 1.
Electron micrograph of purified VP1 VLP. Empty particles
are marked with a closed triangle, and a full particle is marked with
an open triangle.
|
|
View larger version (26K):
[in this window]
[in a new window]
|
FIG. 2.
Distribution of VP1 VLP in a CsCl density gradient. (A)
Picture of the tube after gradient centrifugation. The band
representing empty particles is marked with a closed triangle, and the
band representing full particles is marked with an open triangle. After
gradient fractionation, immunoreactive fractions were identified by
enzyme-linked immunosorbent assay (B) and WB (C) with VP1-specific
hyperimmune serum. (D) WB analysis of empty (lane 1) and full (lane 2)
particles using identical amounts of protein with VP1-specific
hyperimmune serum.
|
|
Immunological characterization and reactivity of VP1 VLP.
To
characterize the immunogenicity of VP1 VLP, immunization studies were
performed with rabbits by using different application routes. To
produce VP1-specific hyperimmune serum, purified VP1 VLP were dialyzed
overnight against reassociation buffer. For immunization, 100 µg of
VP1 VLP was mixed with 300 µg of keyhole limpet hemocyanin and
emulsified in complete Freund's adjuvant (CFA) and a rabbit was
immunized intramuscularly. One booster immunization was given 4 weeks
later with incomplete Freund's adjuvant (ICFA). Alternatively, VP1 VLP
were administered intravenously without CFA or ICFA. Whereas the
intravenous administration induced no VP1-specific immune response,
intramuscular administration with CFA or ICFA resulted in strong immune
reactivity. Twenty-five weeks after the last booster immunization, the
VP1-specific hyperimmune serum exhibited an endpoint titer of more than
105 and the major reactive component was the VP1-specific
42-kDa protein as shown by WB analysis. Strong VP1-specific reactivity was also obtained with the 40-kDa protein, whereas only minor reactivity was shown with the 27-kDa protein. The hyperimmune serum
cross-reacts with the VP1 present in natural JCV and SV40 particles.
Furthermore, the VP1-specific hyperimmune serum was able to neutralize
the infection of SVG cells (14) with natural JCV (Fig.
3). SVG-cell binding inhibition
experiments with this immune serum revealed that the binding of
125I-labelled VP1 VLP, which were iodinated as previously
described (17), was inhibited to about 90% at serum
dilutions of 1:10 and 1:20. At serum dilutions of 1:40 and 1:80,
binding inhibition levels of about 70 and 35% were obtained, whereas
at serum dilutions of 1:160 and 1:320, no binding inhibition was
measured. No binding inhibition was also obtained with preimmune serum
at a dilution of 1:20 or without serum.
View larger version (54K):
[in this window]
[in a new window]
|
FIG. 3.
Neutralization of JCV by VP1 specific hyperimmune serum.
For neutralization, the JCV infection stock was diluted 1:80 (row a) or
1:160 (row b) and incubated for 1 h with VP1-specific hyperimmune
serum at endpoint dilutions of 1:40 (lane 1), 1:80 (lane 2), 1:160
(lane 3), and 1:320 (lane 4) and with preimmune serum at a dilution of
1:40 (lane 5). Thereafter, JCV-antibody complexes were incubated with
SVG cells for 3 days and intracellular VP1 was detected by WB analysis
with anti-SV40 hyperimmune serum.
|
|
To investigate if the 40- and 27-kDa proteins represent VP1-specific
proteolytic cleavage products, the 42-kDa VP1-specific protein was
purified by three rounds of sodium dodecyl sulfate-polyacrylamide gel
electrophoresis. The finally electroeluted protein exhibited a
molecular mass of 42 kDa, and immunization studies were performed as
described for intact VP1 VLP with CFA and ICFA. WB analysis demonstrated that the resulting immune serum recognized only the 42-kDa
protein in the electroeluted fraction with high specificity. However,
when purified VP1 VLP were used as the antigen, the immune serum also
detected, in addition to the 42-kDa protein, the 40- and 27-kDa
components. These results suggested that the 40- and 27-kDa proteins
are proteolytic-cleavage products of the VP1-specific 42-kDa protein.
VP1 VLP as a transporter system for gene therapy.
For this
reason, the capacity of VP1 VLP to bind to different cell lines was
investigated. Saturating SVG-cell-binding conditions were obtained with
2 × 106 cpm of 125I-labelled VP1 VLP
(specific activity, 5 × 106 cpm of VP1 VLP per µg)
and 105 SVG cells within 80 min. The binding component was
identified as the VP1-specific 42-kDa protein. In a competition assay
with natural JCV, VP1 VLP binding could be competed in a
concentration-dependent manner (Table 1).
Under these conditions, VP1 VLP were able to bind to the monkey kidney
cell lines COS-7 (10) and TC7 (19), showing more
than 50% better binding than to SVG cells. Binding to the human B-cell
line Raji (4) was 25% more efficient, whereas equal binding
efficiency was obtained with the human T-cell line CEM (5).
VP1 VLP not only bound to these cell lines but were also internalized
and transported to the nucleus as demonstrated by immunofluorescence
analysis.
To explore the potential of VP1 VLP for packaging of foreign DNA, we
investigated if VP1 VLP are dissociable like natural JCV (6)
and if a reassociation reaction can be initiated to reconstitute intact
VP1 VLP. The principle of the dissociation reaction is removal of
Ca2+ ions and reduction of disulfide bonds. Optimal
dissociation conditions were examined in pilot experiments. Compared to
VP1 VLP before dissociation (Fig. 4A)
with a specific dissociation buffer (10 mM Tris/HCl [pH 8.5], 150 mM
NaCl, 10 mM EGTA, 5 mM dithiothreitol), VP1 VLP were completely
dissociable to VP1 pentamers during incubation for 1 h at 4°C
(Fig. 4B). Intact VP1 VLP could then be reconstituted during a
reassociation reaction, started by the addition of 1 mM
CaCl2, followed by dialysis overnight against reassociation buffer (10 mM Tris/HCl [pH 7.5], 150 mM NaCl2, 1 mM
CaCl2). The reassociation resulted in the formation of VP1
VLP having nearly the same morphology as the VP1 VLP before
dissociation (Fig. 4C). Thereafter, we investigated if foreign DNA can
be packaged into VP1 VLP during this dissociation-reassociation cycle.
For comparison with the dissociation-reassociation cycle, two more
packaging procedures were tested, namely, osmotic shock (2)
and dissociation of VP1 VLP in double-distilled H2O before
reassociation. Packaging data are given in Fig.
5. As can be seen, all of the packaging procedures result in VP1 VLP association of the pCMV-
-Gal plasmid (4.5 kb), where the expression of the reporter gene is driven by a
cytomegalovirus promotor. The packaged plasmid DNA was demonstrated to
be resistant to DNase I digestion, indicating uptake into the VP1 VLP.
From the results, it could be assumed that a package procedure using
the dissociation-reassociation cycle (Fig. 5A, lanes 2, 5, and 6; e.g.,
suspension of VP1 VLP in dissociation buffer or double-distilled
H2O) was superior. As quantitated by competitive PCR, a
plateau was reached around 1012 added plasmid molecules,
resulting in about 108 to 109 packaged plasmid
molecules (Fig. 5B). The calculated packaging efficiency was 1:3. This
means, for example, that about 3 × 106 VP1 VLP are
able to package 106 plasmid molecules.
View larger version (86K):
[in this window]
[in a new window]
|
FIG. 4.
Electron micrographs of purified, intact VP1 VLP before
(A) and after (B) dissociation and intact VP1 VLP after reassociation
(C). Bars, 50 nm.
|
|
View larger version (35K):
[in this window]
[in a new window]
|
FIG. 5.
Packaging of foreign plasmid DNA by VP1 VLP. (A)
Packaging of foreign plasmid DNA was performed with ratios of DNA to
VP1 VLP of 1:10 (lanes 1 to 3) and 1:20 (lanes 4 to 6) by osmotic shock
(lanes 1 and 4), as well as particle dissociation in dissociation
buffer (lanes 2 and 5) and double-distilled H2O (lanes 3 and 6). After reassociation and DNase I digestion, particles were
pelleted through a 40% sucrose cushion and packaged DNA was extracted
and analyzed. As a control, unpackaged DNA was digested with DNase I
(lane 7) or not digested (lane 8). (B) Quantification of packaged DNA
by quantitative competitive PCR. VP1 VLP (3 × 1011)
were dissociated and incubated with increasing amounts of plasmid
molecules for 1 h at 37°C and then subjected to dialysis
overnight against reassociation buffer. Packaged VP1 VLP were digested
with DNase I and pelleted through a 40% sucrose cushion. DNA was
extracted and quantified by quantitative competitive PCR. (C) Analysis
of -galactosidase expression. The reporter plasmid was packaged in
VP1 VLP, and COS-7 cells were exposed for 2 days. Cells were stained
with 5-bromo-4-chloro-3-indolyl--D-galactopyranoside
(X-Gal) and then examined microscopically and photographed.
|
|
Transfer efficiency was investigated in COS-7 cells. As is shown in
Fig. 5C, VP1 VLP can efficiently transduce packaged plasmid DNA into
COS-7 cells, resulting in the expression of a functional -galactosidase, as demonstrated by the presence of blue cells. Transfer efficiency was clearly reduced when an equal amount of plasmid
molecules was transfected using liposomes. If a multiplicity of
infection (MOI) in relation to the packaged plasmid molecules of 50 was
selected (MOI of VP1 VLP, 150) and 500,000 cells were used for
transduction, about 100,000 COS-7 cells efficiently expressed the
-galactosidase (Table 2). In
comparison to transfection experiments with identical plasmid molecules
packaged in liposomes, transduction with VP1 VLP was about 200 times
more efficient.
VP1 VLP as a tool for vaccine development and gene therapy.
Antiviral therapy to combat JCV reactivation and the development of PML
has been attempted, as has enhancement of cellular immunity (for a
review, see reference 15). However, the efficacy of
these treatments remains inconclusive owing to the fact that only case
reports and small controlled trials have been reported. Furthermore,
new strategies for the development of a vaccine or gene therapy have
not been reported.
Here we show the successful expression of the major structural protein,
VP1, of JCV, resulting in the formation of VLP with a predominant
morphology of empty JCV capsids. Purified VP1 VLP exhibited high
immunogenicity when administered intramuscularly with an adjuvant,
whereas no immune response was obtained after intravenous application
without an adjuvant. VP1-specific hyperimmune serum neutralized VP1 VLP
binding to and JCV infection of SVG cells. Therefore, VP1 VLP appear to
exhibit neutralizing and cell-binding epitopes like natural JCV and
offer an opportunity to develop prophylactic or therapeutic candidate
vaccines to prevent PML by interfering with primary infection or
reactivation of JCV. Similar recombinant VLP has been described for
human papillomaviruses, and such HPV VLP will now be applied as a
prophylactic or therapeutic vaccine to combat, for example, cervical
cancer (for reviews, see references 11, 13, 20 and
21).
VP1 VLP could also be demonstrated as a potential new transporter
system for gene therapy. They not only showed efficient binding to B
and T cells, as well as to kidney cells, but were also internalized and
transported to the nucleus. All of these cell lines are derived from
body compartments which either represent a major site of JCV
persistence, such as the kidneys (16), or may function as a
ferry for JCV to enter the brain, such as B cells (1, 18).
Recently, we have shown that T cells may also be a site of JCV latency
(unpublished observation). Furthermore, a number of problems and
drawbacks of other gene transfer systems (for a review, see reference
12) could be circumvented with VP1 VLP. For example,
adenovirus-derived systems induce a strong immune response irrespective
of the application route, not allowing repeated administration
(7-9). However, when VP1 VLP were administered intravenously, no immune response was obtained. Furthermore, gene therapeutic approaches based on viral vectors suffer from the drawback
of introducing unwanted additional viral genetic information into the
recipient host alongside the gene of interest, and a packaging cell
line is needed (for a review, see reference 12). VP1
VLP, however, were able to package foreign DNA in a manner that
protected it from the action of an external nuclease during a
dissociation-reassociation cycle. Unwanted additional viral information
is not necessary alongside the gene of interest, and a packaging cell
line is also not needed. It could further be shown that the transfer of
the packaged DNA by VP1 VLP was clearly superior to DNA transfer by
liposomes. However, quantitative comparisons to other gene transfer
systems could not be performed. Titers are commonly not given as MOIs,
which is, to our knowledge, a basic prerequisite for estimation of the
potential of any gene therapy transporter system. VP1 VLP may now open
up ways not only to combat JCV reactivation and the development of PML
but also to develop new human gene therapy approaches.
| |
ACKNOWLEDGMENTS |
We thank E. O. Major, Laboratory of Molecular Medicine and
Neuroscience, NINDS, Bethesda, Md., for generously providing SVG cells.
T.W. and S.F. were supported by grants from the Graduiertenkolleg
Molekularbiologische Analyse pathophysiologischer Prozesse. This work
was further supported by a grant from the Stiftung zur Bekämpfung
neuroviraler Erkrankungen to T.W. (MSC/2738.rhe 27 33641). W.L. was
supported by a grant of the Verbundantrag HIV/SIV Immunpathogenese
und Immunprävention. Furthermore, W.L. and T.W. were supported by
a grant from the Deutsche Forschungsgemeinschaft (Lu 397/5-1, We
1297/3-1).
| |
FOOTNOTES |
*
Corresponding author. Mailing address: Department of
Virology and Immunology, German Primate Centre, Kellnerweg 4, D-37077 Göttingen, Germany. Phone: 49-551-3851152. Fax: 49-551-3851184. E-mail: WLUEKE{at}WWW.DPZ.GWDG.DE.
Present address: Neurological Clinic, Marienkrankenhaus, 22087 Hamburg, Germany.
| |
REFERENCES |
| 1.
|
Atwood, W.,
K. Ameyami,
R. Traub,
J. Harms, and E. Major.
1992.
Interaction of the human polyomavirus JCV with human B-lymphocytes.
Virology
190:716-723[Medline].
|
| 2.
|
Barr, M.,
K. Keck, and H. Aposhian.
1979.
Cell-free assembly of a polyoma-like particle from empty capsids and DNA.
Virology
96:656-659[Medline].
|
| 3.
|
Berger, J., and M. Concha.
1995.
Progressive multifocal leukoencephalopathy: the evolution of a disease once considered rare.
J. Neurovirol.
1:5-18[Medline].
|
| 4.
|
Epstein, M.,
Y. Achong,
Y. Barr,
B. Zajac,
G. Henle, and W. Henle.
1966.
Morphological and virological investigations on cultured Burkitt tumor lymphoblasts (strain Raji).
J. Natl. Cancer Inst.
37:547-559.
|
| 5.
|
Foley, G.,
H. Lazarus,
S. Farber,
G. Uzman,
B. Boone, and R. McCarty.
1965.
Continuous culture of human lymphoblasts from peripheral blood of a child with acute leukemia.
Cancer
18:522-528[Medline].
|
| 6.
|
Frye, S.,
C. Trebst,
U. Dittmer,
H. Petry,
M. Bodemer,
G. Hunsmann,
T. Weber, and W. Lüke.
1997.
Efficient production of JCV in SVG cells and the use of purified viral antigens for analysis of specific humoral and cellular immune response.
J. Virol. Methods
63:81-92[Medline].
|
| 7.
|
Gahéry-Ségard, H.,
V. Juillard,
J. Gaston,
R. Lengagne,
A. Pavirani,
P. Boulanger, and J.-G. Guillet.
1997.
Humoral immune response to the capsid components of recombinant adenoviruses: routes of immunization modulate virus-induced Ig subclass shifts.
Eur. J. Immunol.
27:653-659[Medline].
|
| 8.
|
Gahéry-Ségard, H.,
V. Molinier-Frenkel,
C. LeBoulaire,
P. Saulnier,
P. Opolon,
R. Lengagne,
E. Gautier,
A. LeCesne,
L. Zitvogel,
A. Venet,
C. Schatz,
M. Courtney,
T. LeChevalier,
T. Tursz,
J.-G. Guillet, and F. Farace.
1997.
Phase I trial of recombinant adenovirus gene transfer in lung cancer: longitudinal study of the immune responses to transgene and viral products.
J. Clin. Investig.
100:2218-2226[Medline].
|
| 9.
|
Gahéry-Ségard, H.,
F. Farace,
D. Godfrin,
J. Gaston,
R. Lengagne,
T. Tursz,
P. Boulanger, and J.-G. Guillet.
1998.
Immune response to recombinant capsid proteins of adenovirus in humans: antifiber and anti-penton base antibodies have a synergistic effect on neutralizing activity.
J. Virol.
72:2388-2397[Abstract/Free Full Text].
|
| 10.
|
Gluzman, Y.
1981.
SV40-transformed simian cells support the replication of early SV40 mutants.
Cell
23:175-182[Medline].
|
| 11.
|
Jarrett, W.,
K. Smith,
B. O'Neil,
J. Gaukroger,
L. Chandrachud,
G. Grindlay,
G. McGarvie, and M. Campo.
1991.
Studies on vaccination against papillomaviruses: prophylactic and therapeutic vaccination with recombinant structural proteins.
Virology
184:33-42[Medline].
|
| 12.
|
Jolly, D.
1994.
Viral vector systems for gene therapy.
Cancer Gene Ther.
1:51-64[Medline].
|
| 13.
|
Kirnbauer, R.
1996.
Papillomavirus-like particles for serology and vaccine development.
Intervirology
39:54-61[Medline].
|
| 14.
|
Major, E.,
A. Miller,
P. Mourrain,
R. Traub,
E. DeWidt, and J. Sever.
1985.
Establishment of a line of human fetal glial cells that supports JCV multiplication.
Proc. Natl. Acad. Sci. USA
82:1257-1261[Abstract/Free Full Text].
|
| 15.
|
Major, E. O.,
K. Amemiya,
C. S. Tornatore,
S. A. Houff, and J. R. Berger.
1992.
Pathogenesis and molecular biology of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain.
Clin. Microbiol. Rev.
5:49-73[Abstract/Free Full Text].
|
| 16.
|
McCance, D.
1983.
Persistence of animal and human papovavirus in renal and nervous tissues.
Prog. Clin. Biol. Res.
105:343-357[Medline].
|
| 17.
|
Polzien, F.,
J. Scharf,
W. Lüke, and G. Hunsmann.
1992.
CD4-binding of gp130 micelles isolated from SIVagmTYO-7.
AIDS Res. Hum. Retroviruses
8:1171-1177[Medline].
|
| 18.
|
Rieckmann, P.,
U. Michel, and J. H. Kehrl.
1994.
Regulation of JC virus expression in B lymphocytes.
J. Virol.
68:217-222[Abstract/Free Full Text].
|
| 19.
|
Robb, J., and K. Huebner.
1973.
Effect of cell chromosome number on simian virus 40 replication.
Exp. Cell Res.
81:120-126[Medline].
|
| 20.
|
Sapp, M.,
C. Volpers, and R. Streeck.
1996.
Synthesis, properties and applications of papillomavirus-like particles.
Intervirology
39:49-53[Medline].
|
| 21.
|
Van Driel, W.,
M. Ressing,
R. Brandt,
R. Toes,
G. Fleuren,
J. Trimbos,
W. Kast, and C. Melief.
1996.
The current status of therapeutic HPV vaccine.
Ann. Med.
28:471-477[Medline].
|
| 22.
|
Weber, T.,
R. Turner,
S. Frye,
B. Ruf,
J. Haas,
E. Schielke,
H. Pohle,
W. Lüke,
W. Lüer,
K. Felgenhauer, and G. Hunsmann.
1994.
Specific diagnosis of progressive multifocal leukoencephalopathy by polymerase chain reaction.
J. Infect. Dis.
169:1138-1141[Medline].
|
| 23.
|
Weber, T.,
R. Turner,
S. Frye,
W. Lüke,
H. Kretzschmar,
W. Lüer, and G. Hunsmann.
1994.
Progressive multifocal leukoencephalopathy diagnosed by amplification of JC virus-specific DNA from cerebrospinal fluid.
AIDS
8:49-57[Medline].
|
| 24.
|
Weber, T.,
C. Trebst,
S. Frye,
P. Cinque,
L. Vago,
C. Sindic,
W. Schulz-Schaeffer,
H. Kretzschmar,
W. Enzensberger,
G. Hunsmann, and W. Lüke.
1997.
Analysis of the systemic and intrathecal humoral immune response in progressive multifocal leukoencephalopathy.
J. Infect. Dis.
176:250-254[Medline].
|
Journal of Virology, May 1999, p. 4465-4469, Vol. 73, No. 5
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Kawano, M.-a., Inoue, T., Tsukamoto, H., Takaya, T., Enomoto, T., Takahashi, R.-u, Yokoyama, N., Yamamoto, N., Nakanishi, A., Imai, T., Wada, T., Kataoka, K., Handa, H.
(2006). The VP2/VP3 Minor Capsid Protein of Simian Virus 40 Promotes the in Vitro Assembly of the Major Capsid Protein VP1 into Particles. J. Biol. Chem.
281: 10164-10173
[Abstract]
[Full Text]
-
Wong, S. B. J., Siliciano, R. F.
(2005). Contribution of Virus-Like Particles to the Immunogenicity of Human Immunodeficiency Virus Type 1 Gag-Derived Vaccines in Mice. J. Virol.
79: 1701-1712
[Abstract]
[Full Text]
-
Qu, Q., Sawa, H., Suzuki, T., Semba, S., Henmi, C., Okada, Y., Tsuda, M., Tanaka, S., Atwood, W. J., Nagashima, K.
(2004). Nuclear Entry Mechanism of the Human Polyomavirus JC Virus-like Particle: ROLE OF IMPORTINS AND THE NUCLEAR PORE COMPLEX. J. Biol. Chem.
279: 27735-27742
[Abstract]
[Full Text]
-
Johne, R., Muller, H.
(2004). Nuclear Localization of Avian Polyomavirus Structural Protein VP1 Is a Prerequisite for the Formation of Virus-Like Particles. J. Virol.
78: 930-937
[Abstract]
[Full Text]
-
Tegerstedt, K., Andreasson, K., Vlastos, A., Hedlund, K. O., Dalianis, T., Ramqvist, T.
(2003). Murine pneumotropic virus VP1 virus-like particles (VLPs) bind to several cell types independent of sialic acid residues and do not serologically cross react with murine polyomavirus VP1 VLPs. J. Gen. Virol.
84: 3443-3452
[Abstract]
[Full Text]
-
Viscidi, R. P., Rollison, D. E. M., Viscidi, E., Clayman, B., Rubalcaba, E., Daniel, R., Major, E. O., Shah, K. V.
(2003). Serological Cross-Reactivities between Antibodies to Simian Virus 40, BK Virus, and JC Virus Assessed by Virus-Like-Particle-Based Enzyme Immunoassays. CVI
10: 278-285
[Abstract]
[Full Text]
-
Chackerian, B., Lenz, P., Lowy, D. R., Schiller, J. T.
(2002). Determinants of Autoantibody Induction by Conjugated Papillomavirus Virus-Like Particles. J. Immunol.
169: 6120-6126
[Abstract]
[Full Text]
-
Komagome, R., Sawa, H., Suzuki, T., Suzuki, Y., Tanaka, S., Atwood, W. J., Nagashima, K.
(2002). Oligosaccharides as Receptors for JC Virus. J. Virol.
76: 12992-13000
[Abstract]
[Full Text]
-
Triyatni, M., Saunier, B., Maruvada, P., Davis, A. R., Ulianich, L., Heller, T., Patel, A., Kohn, L. D., Liang, T. J.
(2002). Interaction of Hepatitis C Virus-Like Particles and Cells: a Model System for Studying Viral Binding and Entry. J. Virol.
76: 9335-9344
[Abstract]
[Full Text]
-
Harrington, P. R., Yount, B., Johnston, R. E., Davis, N., Moe, C., Baric, R. S.
(2002). Systemic, Mucosal, and Heterotypic Immune Induction in Mice Inoculated with Venezuelan Equine Encephalitis Replicons Expressing Norwalk Virus-Like Particles. J. Virol.
76: 730-742
[Abstract]
[Full Text]
-
Touze, A., Bousarghin, L., Ster, C., Combita, A.-L., Roingeard, P., Coursaget, P.
(2001). Gene transfer using human polyomavirus BK virus-like particles expressed in insect cells. J. Gen. Virol.
82: 3005-3009
[Abstract]
[Full Text]
-
Clark, B., Caparros-Wanderley, W., Musselwhite, G., Kotecha, M., Griffin, B. E.
(2001). Immunity against both polyomavirus VP1 and a transgene product induced following intranasal delivery of VP1 pseudocapsid-DNA complexes. J. Gen. Virol.
82: 2791-2797
[Abstract]
[Full Text]
-
Ishizu, K.-I., Watanabe, H., Han, S.-I., Kanesashi, S.-N., Hoque, M., Yajima, H., Kataoka, K., Handa, H.
(2001). Roles of Disulfide Linkage and Calcium Ion-Mediated Interactions in Assembly and Disassembly of Virus-Like Particles Composed of Simian Virus 40 VP1 Capsid Protein. J. Virol.
75: 61-72
[Abstract]
[Full Text]
Top
Abstract
Text
