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k Hel*
*
Basic Research Laboratory and
Biostatistics and Data Management Section, National Cancer Institute, Bethesda, MD 20892;
Emory University Vaccine Center at Yerkes, Atlanta, GA 30329;
Wisconsin Regional Primate Research Center, Madison, WI 53715;
¶ National Cancer Institute, Frederick, MD 21702; and
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Aventis-Pasteur, Toronto, Ontario, Canada
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Effective cytolytic activity of CD8+ T cells depends on help provided by CD4+ T lymphocytes. Indeed, virus-specific CD4+ lymphoproliferative responses (LPR)2 are associated with CD8+ T cell responses in HIV-1 infection (5, 19, 20). Control of viral rebound following the suspension of antiretroviral therapy in primary HIV-1 or SIV infection of humans or monkeys is associated with both CD4+ and CD8+ T cell responses to HIV or SIV Ags (21, 22, 23, 24). Altogether, these results indicate an important role for cell-mediated immunity in control of HIV/SIV replication and suggest that an important feature of effective HIV vaccine must be its ability to induce high frequency of virus-specific CD4+ and CD8+ T cells.
Highly attenuated live recombinant poxviruses, such as the modified
virus Ankara (MVA) (26, 27, 28, 29), the genetically attenuated
vaccinia-based vector NYVAC (21, 25, 30, 31), or the
canarypox-based vector designated ALVAC (32, 70)
have proven to be safe and immunogenic vaccine vehicles in
monkeys. However, immunizations with various strains of
recombinant poxvirus-based vaccines have demonstrated limited
protective efficacy against highly pathogenic
SIVmac251 challenge (25, 26, 27, 33, 70). Potential limitation of the use of poxvirus-based
vectors as immunization vehicles is related to the expression of
vector-specific gene products present in the inoculum or derived de
novo in the recipient, which could lead to immunogen
competition with the transgene product and/or vector-specific immune
responses. The latter is known to impair the reuse of vectors, such as
adenovirus or poxvirus-based vaccine candidates (34, 35, 36, 37, 38, 39).
One potential strategy to overcome these hurdles has been suggested by
studies using the murine model of malaria whereby the use of DNA-based
immunogen before administration of the poxvirus-based vaccine appeared
to focus the immune response to the desired Ag expressed by the DNA
(40, 41, 42). A combination of DNA priming followed by MVA or
NYVAC boost induced higher CD8+ T cell responses
than any of the individual vaccines alone and resulted
in protection against malaria. DNA-based HIV and SIV vaccines were
shown to be immunogenic in chimpanzees (43, 44) and rhesus
macaques (45, 46, 47), but failed to protect the latter
against a vigorous SIVmac251 challenge (46, 47) or SIV 
b670 (45). DNA priming followed by
MVA boost induced cell-mediated immune responses in nonhuman primates
(26, 45, 48) and decreased viremia following exposure to a
nonpathogenic SHIV-IIIB virus (44), pathogenic SHIV-89.6P
(49), or HIV-1 (50).
In a previous study we demonstrated that immunization with the highly attenuated NYVAC-SIV-gag-pol-env (NYVAC-SIV-gpe) resulted in a significant reduction of viremia in about one-third of macaques exposed i.v. to the highly pathogenic SIVmac251 (25). In the same study, 5 of 11 immunized macaques exposed intrarectally to SIVmac251 experienced transient low-level viremia at 1 wk postinfection and contained the virus below the limit of detection for several years thereafter (Ref. 25 and our unpublished observations). Importantly, i.v. or intrarectal challenge exposure was performed 6 or 9 mo following the last immunization, respectively, suggesting that the NYVAC-SIV-gpe vaccine candidate induced long-lasting virus-specific memory responses. In this study, we investigated whether the immunogenicity of NYVAC-SIV-gpe vaccine might be further enhanced by prior immunization with DNA-based immunogens expressing both the gag and env proteins of SIV239 in a Rev-independent manner. We demonstrate that DNA priming and subsequent boosting with NYVAC-SIV-gpe resulted in an enhancement of SIV-specific LPR and in an increase in the frequency and durability of CD8+ T cell responses to the immunodominant gag181 epitope. In addition, several of the immunized animals recognized a number of subdominant gag-, env-, and pol-specific epitopes in a cytolytic assay. Thus, the combination of these vaccine modalities deserves further evaluation in human trials of preventive and therapeutic HIV vaccine.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The backbone of both plasmid vectors was derived from the kanamycin-expressing pVR1332 (provided by Vical, San Diego, CA) (51). The SIV gag expression vector contained the CMV promoter (without introns), the RNA-optimized SIV p57 gag coding region, and the bovine growth hormone polyadenylation site. To optimize for RNA expression, the previously identified gag inhibitory sequences (INS) were mutated by introducing multiple silent point mutations not affecting the encoded protein precursor, as previously described for HIV-1 gag (52, 53, 54). The RNA-optimized SIV gp160 env gene contains 29 point mutations eliminating the Rev-responsive elements (55) and is conjugated at the 3' untranslated region to the constitutive transport element of simian retrovirus type 1, which further promotes mRNA export (56, 57). DNA plasmid preparations of a clinical-grade quality were produced by Qiagen (Hilden, Germany).
Animals and immunizations
All animals were colony-bred rhesus macaques (Macaca mulatta) obtained from Covance Research Products (Alice, TX). The animals were housed and handled in accordance with the standards of the Association for the Assessment and Accreditation of Laboratory Animal Care International. All rhesus macaques were seronegative for SIV-1, simian T cell leukemia virus type 1, and herpesvirus B before the study. All macaques were screened for the presence of the Mamu-A*01 allele by PCR (58) and the amplified DNA was sequenced to confirm the Mamu-A*01 status. The animals were immunized i.m. with 108 PFU of mock NYVAC or NYVAC-SIV-gpe vaccine. For DNA immunization, 4 mg of each plasmid (CMV/kan-SIVenv and CMV/kan-SIVgag) were administered. Four doses of 0.75 mg of each plasmid were injected i.m. into two sites on each leg; five doses of 0.2 mg of each plasmid were injected intradermally at five different sites in the abdominal area.
Lymphocyte proliferation assay
Ag-specific proliferation was measured using fresh PBMC isolated by density gradient centrifugation on Ficoll lymphocyte separation medium (ICN Pharmaceuticals, Aurora, Ohio). The cells were resuspended in RPMI 1640 medium (Life Technologies, Gaithersburg, MD) containing 5% inactivated human A/B serum (Sigma-Aldrich, St. Louis, MO), and cultured at 105 cells per well in triplicates for 3 days in the absence or presence of native HPLC-purified SIV p27 gag or gp120 Env proteins (Advanced BioScience Laboratories, Rockville, MD) or Con A as a positive control. The cells were then pulsed overnight with 1 µCi of [3H]thymidine before harvest. The relative rate of lymphoproliferation was calculated as fold of thymidine incorporation into cellular DNA over medium control (stimulation index (SI)).
Detection of epitope-specific CD3+CD8+ T lymphocytes by flow cytometry
Fresh PBMC were stained with anti-human CD3 Ab (PerCP
labeled, clone SP34; BD PharMingen, San Diego, CA), anti-human
CD8
Ab (FITC labeled, BD Biosciences, San Jose, CA), and
Mamu-A*01 tetrameric complexes refolded in the presence of a
specific peptide as described (59) and conjugated to
PE-labeled streptavidin (Molecular Probes, Eugene, OR). Samples were
analyzed on a FACSCalibur (BD Biosciences) and the data are presented
as percentage of tetramer-positive cells of all
CD3+CD8+ lymphocytes. To
amplify the peptide-specific CD8+ lymphocytes in
vitro, 3 x 106 cells in 1 ml of medium were
incubated with specific peptide at a final concentration of 10 µg/ml
for 3 days. rIL-2 (Roche, Indianapolis, IN) was added at 40 IU/ml and
the cells were cultured for an additional 4 days and stained as
described for fresh PBMCs.
ELISPOT assay
Monkey IFN-
-specific ELISPOT kits manufactured by U-Cytech
(Utrecht, The Netherlands) were used to detect the number of cells
producing IFN- upon in vitro stimulation. Ninety-six-well
flat-bottom plates were coated with anti-IFN- mAb MD-1 overnight
at 4°C and blocked with 2% BSA in PBS for 1 h at 37°C. Cells
(105 per well) were loaded in quadruplicates in
RPMI 1640 containing 5% human serum and 10 µg/ml of a specific
peptide or 5 µg/ml Con A as a positive control. The plates were
incubated overnight at 37°C, 5% CO2, and
developed according to the manufacturer’s guidelines (U-Cytech).
CTL assay
PBMC (5 x 106) were cultured with 10 µg/ml specific peptide for 3 days, IL-2 (Roche) was added at 40 IU/ml, and the cells were cultured for another 4 days. Twelve hours before the killing assay a second dose of IL-2 at 100 IU/ml was added. The cells were then incubated for 6 h in various E:T cell ratios with Mamu-A*01-positive 51Cr-labeled transformed B cells pulsed overnight with 10 µg/ml of a specific peptide. The killing of cells pulsed with an unrelated peptide in a control experiment was equal to the killing observed in the absence of any peptide.
Detection of anti-SIVmac251 binding Abs by ELISA
Serial dilutions of plasma were incubated with the lysate of SIVmac251 spiked with native purified gp120 env protein of SIVmac251 bound to microtiter plates as described elsewhere (60). End-point titers were defined as the reciprocal of the highest sera dilution that gave an optical absorbency at 450 nm, at least two SDs greater than average values obtained with negative control sera.
Statistical analysis
Tests of p27 Gag and gp120 Env lymphoproliferation were performed using repeated measures ANOVA on the log-transformed SI. This procedure combines the t tests at each time point while making the necessary correction for the correlation among the multiple values from each animal. Comparisons between groups at a single time point were done using the nonparametric Mann-Whitney rank sum test. The percentages of tetramer-positive cells of CD3+CD8+ lymphocytes were analyzed using repeated measures ANOVA after the arcsine transformation of the square root of each percentage. This transformation is commonly used with percentage data to bring closer to equality the unequal variances of a range of percentages. All p values reported are two-tailed. The Number Cruncher Statistical System (NCSS, Kaysville, UT) and Sigmastat (version 2.0; SPSS, Chicago, IL) statistical software packages were used for the analyses.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The expression of HIV and SIV genes in infected cells is regulated post-transcriptionally by the Rev protein that binds to the Rev-responsive elements and mediates the export of spliced retroviral mRNA. The expression of these genes in eukaryotic cells in the absence of Rev protein is hampered by the presence of INS that regulate the export of viral RNA from the nucleus. To overcome this problem, the previously identified INS sequences within the gag and env genes were mutagenized without changing the amino acid sequence of the p57 Gag and gp160 Env proteins, as previously described for HIV-1 gag (52, 53, 54). In the case of the SIV env gene, the constitutive transport element of simian retrovirus type 1, which further promotes mRNA export, was inserted in its 3' untranslated sequence (55). The introduction of these changes resulted in an efficient expression of both viral proteins in murine and human cells (52). The NYVAC-SIV-gpe vaccine was previously described (25).
Three groups of eight macaques were used in this study (Fig. 1
). At wk 0, 4, 24, and 52, animals in
group A (Fig. 1, controls) received i.m. inoculation of
108 PFU of mock NYVAC vaccine, while animals in
group B were immunized i.m. with the same dose of
NYVAC-SIV-gpe. Animals in group C were first immunized at 0,
4, and 12 wk by simultaneous i.m. and intradermal inoculations of
DNA-SIV-gag-env (DNA-ge), followed by
two boosts with 108 PFU of
NYVAC-SIV-gpe given i.m. at wk 24 and 52.
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The first immunization with either
NYVAC-SIV-gpe or DNA-ge did not induce any
detectable LPR to p27 or gp120 Ags in the immunized macaques (Fig. 2, A and
B). Following the second immunization,
positive (SI > 3) proliferative responses to both Ags were
detected in only some of the immunized macaques, with no clear
difference between groups B and C. However, an additional immunization
with DNA-ge of the animals in group C induced a significant
expansion of both p27 Gag and gp120 LPR (Fig. 2, C and
D). Thus, three inoculations of DNA-ge induced
significantly higher Gag-specific LPR than two NYVAC-SIV-gpe
inoculations.
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C). In contrast, boosting
of the DNA-primed macaques of group C with a single inoculation of
NYVAC-SIV-gpe greatly increased LPR to both p27 Gag and
gp120 Env to mean SI values of 62 and 42, respectively (Fig. 2C). The expansion of SIV-specific LPR was significantly
greater in macaques primed with DNA than in those primed with
NYVAC-SIV-gpe (p = 0.00006 for p27
and p = 0.028 for gp120) as summarized in Fig. 2D. The last immunization with NYVAC-SIV-gpe at
wk 52 significantly increased the level of LPR to both Ags in macaques
from both groups. The LPR to p27 Gag was higher and more durable in
animals of group C than those of group B, although at wk 64 the
response to gp120 Env was equivalent between the two groups (Fig. 2, C and D). Prior DNA immunization potentiates the CD8+ T cell response to the immunodominant epitope gag181
To assess the CD8+ T cell
responses to several Mamu-A*01-restricted SIV CTL
epitopes (61), two, four, and five
Mamu-A*01-positive macaques were included in groups A, B,
and C, respectively. The SIV-specific immune responses to the
immunodominant SIV gag epitope gag181 (also referred to as
p11C, C
M epitope; Refs. 62 and 63) was
enumerated in the blood of the vaccinated animals using
Mamu-A*01 tetrameric complex conjugated with the gag181
peptide. Two administrations of NYVAC-SIV-gpe to animals in
group B led to gag181-specific
CD3+CD8+ T cell response in
the blood of Mamu-A*01 macaques that ranged between 0.28 and
3% of total CD3+CD8+
T cells (Fig. 3, group B).
Culture of PBMC following stimulation with the gag181 peptide
expanded this population up to 27% (data not shown). The overall
frequency of the gag181-specific CD8+ T cells was
lower in the blood of macaques in group C immunized with
DNA-ge (ranging from 0.3 to 0.9%), and these cells
could be expanded following the in vitro peptide stimulation up to
5.1% (Fig. 3, and data not shown).
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B). In contrast, boosting with
NYVAC-SIV-gpe of DNA-SIV-ge-primed macaques
expanded the number of gag181-specific cells in most macaques (peak
response 1.5–5.5%; Fig. 3C). The frequency of
gag181-staining cells persisted at a higher level in the blood of
macaques in group C than in the blood of those in group B (wk 53–64,
p = 0.035). In fact, the gag181-specific T cells were
still detectable in the fresh blood of vaccinated animals 23 wk
following the last immunization (Fig. 4).
The levels of gag181-specific T cells at wk 76 correlated with the peak
response at wk 53 and were generally higher in
DNA-SIV-ge-primed macaques of group C than in animals of
group B.
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Because the IFN- ELISPOT assay is generally regarded as a
functional assay of specific CD8+ T cell
responses, we measured the ability of PBMC to produce IFN- following
overnight stimulation with the gag181 peptide. Consistent with the
higher frequency of gag181 tetramer-staining-positive
CD8+ T cells in blood of animals from group C the
numbers of IFN- spot-forming cells in response to gag181 peptide
stimulation were higher in animals of group C than in those of B (Fig. 5). Analysis of the cytolytic activity of
PBMC expanded in vitro in the presence of gag181 peptide demonstrated
that three of four Mamu-A*01 animals in group B vs all
Mamu-A*01 macaques in group C lysed target cells pulsed with
gag181 in a 51Cr-release assay (Fig. 6). Consistent with the results of
tetramer staining and ELISPOT assays, the gag181-specific CTL activity
was generally higher in DNA-primed animals of group C than in animals
of group B.
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To assess the breadth of the CD8+ T cell responses induced by vaccination in Mamu-A*01 animals (61), tetrameric complexes conjugated with the subdominant SIV-specific peptides gag254, env235, and env622 were used to stain fresh PBMC of the Mamu-A*01-positive animals at several time points. With this assay, no significant responses to env622 or env235 epitopes were detected at any time after immunization. In the case of the gag254 epitope, positive tetramer-staining cells were detected only following in vitro stimulation of cells from macaque 679 at wk 13 (3.3%) and 26 (1.5%) (data not shown).
To further assess CD8+ T cell responses to
subdominant epitopes, a panel of 14 different
Mamu-A*01-restricted peptides was used in an IFN- ELISPOT
assay. Six of these peptides (gag181, gag254, env133, env235, env622,
and pol151) induced IFN- production in the blood cells of immunized
animals (Fig. 6). No significant difference in the frequency of
recognition of subdominant epitopes in ELISPOT assay between the
NYVAC-primed vs DNA-primed macaques could be discerned (Table I). To assess whether the IFN-
production paralleled the cytolytic activity,
51Cr-release assays were performed following in
vitro 7-day stimulation of cells with specific peptides at wk 53 and 56
(Fig. 6 and Table I). Cumulatively, cytolytic activity to
subdominant SIV CTL epitopes was more frequent in the macaques in group
C than in those in group B (five positive of nine assays vs one of 14
assays, p = 0.018 by Fisher’s exact test). Thus, the
DNA-ge-primed NYVAC-SIV-gpe-boosted animals
appeared to recognize a broader array of subdominant SIV epitopes in
the cytolytic assay.
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The humoral response induced by the two vaccine regimens was
assessed in an ELISA using disrupted SIVmac
virions enriched with purified native SIVmac251
env protein. Immunization of group C animals with three doses of
DNA-SIV-ge induced detectable anti-SIV Abs in only one
animal. Two weeks following the boost with NYVAC-SIV-gpe (wk
26), the titers of SIV-specific binding Abs were
significantly higher in the group that received three immunizations
with NYVAC-SIV-gpe than in the DNA-SIV-ge-primed
NYVAC-SIV-gpe-boosted group (p =
0.002), whereas at wk 56 and 76 there was no significant difference
between groups B and C (Fig. 7).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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A combination of these vaccine modalities has been previously
investigated by others (26, 48, 49, 50, 64). However, none
of the previous studies in macaques directly compared the
immunogenicity of poxvirus-based vaccine to a regimen of DNA priming
and poxvirus boost. In this study we demonstrate vigorous SIV-specific
LPR elicited by DNA priming and subsequent poxvirus boost in non-human
primates. In addition, the prime-boost regimen induced durable CTL
responses superior to those induced by immunization with a
poxvirus-based recombinant vector alone. The animals in the DNA-primed
group recognized a broader array of subdominant SIV epitopes in the
cytolytic, but not the IFN- ELISPOT assay, suggesting different
levels of sensitivity of these functional assays.
The NYVAC-SIV-gpe-induced proliferative responses were up to 10-fold higher in DNA-SIV-ge-primed animals than in animals receiving NYVAC-SIV-gpe alone. Interestingly, the level of these responses induced by NYVAC-SIV-gpe immunization in DNA-primed macaques was similar to that induced by NYVAC-SIV-gpe vaccination of SIVmac251-infected macaques treated with antiretroviral therapy (21), suggesting that pharmacologically controlled viral replication may prime similarly to a DNA vaccine.
Regarding the expansion of virus-specific CD8+ T
cells, our findings parallel the observation of others, in that the
boost with NYVAC-SIV-gpe of DNA-primed animals resulted in
an induction of a high frequency of gag181-specific
CD8+ T cells in most
Mamu-A*01-positive macaques. In fact, in our study, the DNA
priming strategy resulted in an induction in blood of 1.5–5.5%
gag181-specific cells, and the response was more durable than in
NYVAC-SIV-gpe-only immunized group (Fig. 4). In contrast,
only one of four NYVAC-SIV-gpe-immunized macaques mounted a
similar response (no. 674). A possible explanation could be that animal
674 is homozygous for the Mamu-A*01 allele, a hypothesis
that at present cannot be tested because the PCR-based assay does not
discriminate for homozygosity. Hanke et al. (26) have
shown that a DNA prime, MVA boost regimen presenting a multiepitope
gene construct induced 1–5% of circulating CD8+
lymphocytes specific for epitope gag181. In a study by Allen et al.
(48), the use of a single epitope-based vaccine combined
with hepatitis B core Ag vector to provide T cell responses resulted in
induction of 0.8–20% of epitope-specific cells after the first MVA
boost; however, three of six animals displayed levels lower than 1.6%.
In our study, all five DNA-primed animals (group C) had from 1.5 to
5.5% of epitope-specific cells at 1 wk after the first
NYVAC-SIV-gpe boost. Therefore, our multiepitope vaccine
regimen expressing the whole Gag and Env proteins induced
CD8+ T cell responses comparable to those induced
by vaccine candidates designed for high expression of only a single or
a few CTL epitopes. The frequency of gag181 tetramer-staining cells
induced by DNA prime, NYVAC-SIV-gpe boost is equal to or
higher than those found in the blood of acutely and chronically
infected animals (33, 65, 66, 71 and B. R. Mothé, H.
Horton, D. K. Carter, M. E. Liebl, S. Fuenger, P. Skinner, T. M. Allen,
T. U. Vogel, W. Rehrauer, N. Wilson, G. Franchini, J. D. Altman, A.
Haase, L. J. Picker, D. Allison, and D. I. Watkins; unpublished
observations).
Likely, the repeated immunizations with recombinant poxvirus vectors may induce sufficient vector immunity to interfere with the presentation of the transgene upon subsequent boosts (35, 36, 37, 39). In fact, the CTL response to SIV gag was not further enhanced by the fourth immunization with NYVAC- (25) or MVA- (29, 33) based vaccine candidates. In this study, we show that both LPR and CTL responses were enhanced following the fourth immunization with NYVAC-SIV-gpe alone (group B). However, the level of these responses was not as high as that observed following a single NYVAC-SIV-gpe immunization of DNA-primed macaques (group C). Therefore, three or fewer inoculations with DNA combined with a single recombinant poxvirus-based vaccine boost might be sufficient to reach appropriate immune responses.
DNA priming may augment the overall immune response by focusing the response to the desired Ag; the recombinant poxvirus boost may then amplify the pool of existent Ag-specific cells by presenting the Ag in the context of local induction of cytokines and/or chemokines. Therefore, this strategy could be particularly useful in individuals with a pre-existing immunity to vaccinia virus. Alternatively, DNA priming might induce immune responses qualitatively different from those induced by immunization with recombinant poxviruses or other vaccine delivery vehicles, and the phenotypical difference of the T cell response may be maintained during subsequent booster immunizations or challenge infections (67). The ability of the prime-boost regimen to induce higher proliferative responses than NYVAC-SIV-gpe alone may relate to the ability of vaccinia viruses to interfere with the maturation of infected dendritic cells, decreasing their ability to present Ag to CD4 T cells, while preserving efficient Ag presentation to CD8 T cells (68, 69).
In conclusion, the combination of DNA priming and
NYVAC-SIV-gpe boost increases the extent and durability of
both the CD4+ and CD8+ T
cell responses. In addition, DNA priming broadens the array of
subdominant SIV epitopes recognized in the cytolytic, but not the
IFN-, ELISPOT assay. Because the correlates of protection have not
been fully defined, it remains to be ascertained whether these
responses may be of sufficient breadth and quantity to afford
protection from infection.
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Acknowledgments |
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Footnotes |
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2 Abbreviations used in this paper: LPR, lymphoproliferative response; MVA, modified virus Ankara; INS, inhibitory sequence; NYVAC-SIV-gpe, NYVAC-SIV-gag-pol-env; DNA-ge, DNA-SIV-gag-env; SI, stimulation index.
Received for publication July 27, 2001. Accepted for publication October 9, 2001.
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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J. Nacsa, Y. Edghill-Smith, W.-P. Tsai, D. Venzon, E. Tryniszewska, A. Hryniewicz, M. Moniuszko, A. Kinter, K. A. Smith, and G. Franchini Contrasting Effects of Low-Dose IL-2 on Vaccine-Boosted Simian Immunodeficiency Virus (SIV)-Specific CD4+ and CD8+ T Cells in Macaques Chronically Infected with SIVmac251 J. Immunol., February 15, 2005; 174(4): 1913 - 1921. [Abstract] [Full Text] [PDF]
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C. Devito, B. Zuber, U. Schroder, R. Benthin, K. Okuda, K. Broliden, B. Wahren, and J. Hinkula Intranasal HIV-1-gp160-DNA/gp41 Peptide Prime-Boost Immunization Regimen in Mice Results in Long-Term HIV-1 Neutralizing Humoral Mucosal and Systemic Immunity J. Immunol., December 1, 2004; 173(11): 7078 - 7089. [Abstract] [Full Text] [PDF]
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B. Garulli, Y. Kawaoka, and M. R. Castrucci Mucosal and Systemic Immune Responses to a Human Immunodeficiency Virus Type 1 Epitope Induced upon Vaginal Infection with a Recombinant Influenza A Virus J. Virol., January 15, 2004; 78(2): 1020 - 1025. [Abstract] [Full Text] [PDF]
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M. Moniuszko, C. Brown, R. Pal, E. Tryniszewska, W.-P. Tsai, V. M. Hirsch, and G. Franchini High Frequency of Virus-Specific CD8+ T Cells in the Central Nervous System of Macaques Chronically Infected with Simian Immunodeficiency Virus SIVmac251 J. Virol., November 15, 2003; 77(22): 12346 - 12351. [Abstract] [Full Text] [PDF]
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J. R. Mascola, M. G. Lewis, T. C. VanCott, G. Stiegler, H. Katinger, M. Seaman, K. Beaudry, D. H. Barouch, B. Korioth-Schmitz, G. Krivulka, et al. Cellular Immunity Elicited by Human Immunodeficiency Virus Type 1/ Simian Immunodeficiency Virus DNA Vaccination Does Not Augment the Sterile Protection Afforded by Passive Infusion of Neutralizing Antibodies J. Virol., October 1, 2003; 77(19): 10348 - 10356. [Abstract] [Full Text] [PDF]
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M. Tritel, A. M. Stoddard, B. J. Flynn, P. A. Darrah, C.-y. Wu, U. Wille, J. A. Shah, Y. Huang, L. Xu, M. R. Betts, et al. Prime-Boost Vaccination with HIV-1 Gag Protein and Cytosine Phosphate Guanosine Oligodeoxynucleotide, Followed by Adenovirus, Induces Sustained and Robust Humoral and Cellular Immune Responses J. Immunol., September 1, 2003; 171(5): 2538 - 2547. [Abstract] [Full Text] [PDF]
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N. Malkevitch, L. J. Patterson, K. Aldrich, E. Richardson, W. G. Alvord, and M. Robert-Guroff A Replication Competent Adenovirus 5 Host Range Mutant-Simian Immunodeficiency Virus (SIV) Recombinant Priming/Subunit Protein Boosting Vaccine Regimen Induces Broad, Persistent SIV-Specific Cellular Immunity to Dominant and Subdominant Epitopes in Mamu-A*01 Rhesus Macaques J. Immunol., April 15, 2003; 170(8): 4281 - 4289. [Abstract] [Full Text] [PDF]
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N. Himoudi, J.-D. Abraham, A. Fournillier, Y. C. Lone, A. Joubert, A. O. De Beeck, D. Freida, F. Lemonnier, M. P. Kieny, and G. Inchauspe Comparative Vaccine Studies in HLA-A2.1-Transgenic Mice Reveal a Clustered Organization of Epitopes Presented in Hepatitis C Virus Natural Infection J. Virol., November 13, 2002; 76(24): 12735 - 12746. [Abstract] [Full Text] [PDF]
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Z. Hel, J. Nacsa, E. Tryniszewska, W.-P. Tsai, R. W. Parks, D. C. Montefiori, B. K. Felber, J. Tartaglia, G. N. Pavlakis, and G. Franchini Containment of Simian Immunodeficiency Virus Infection in Vaccinated Macaques: Correlation with the Magnitude of Virus-Specific Pre- and Postchallenge CD4+ and CD8+ T Cell Responses J. Immunol., November 1, 2002; 169(9): 4778 - 4787. [Abstract] [Full Text] [PDF]
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E. Tryniszewska, J. Nacsa, M. G. Lewis, P. Silvera, D. Montefiori, D. Venzon, Z. Hel, R. W. Parks, M. Moniuszko, J. Tartaglia, et al. Vaccination of Macaques with Long-Standing SIVmac251 Infection Lowers the Viral Set Point After Cessation of Antiretroviral Therapy J. Immunol., November 1, 2002; 169(9): 5347 - 5357. [Abstract] [Full Text] [PDF]
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L. Stevceva, X. Alvarez, A. A. Lackner, E. Tryniszewska, B. Kelsall, J. Nacsa, J. Tartaglia, W. Strober, and G. Franchini Both Mucosal and Systemic Routes of Immunization with the Live, Attenuated NYVAC/Simian Immunodeficiency Virus SIVgpe Recombinant Vaccine Result in Gag-Specific CD8+ T-Cell Responses in Mucosal Tissues of Macaques J. Virol., October 11, 2002; 76(22): 11659 - 11676. [Abstract] [Full Text] [PDF]
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S. Santra, J. E. Schmitz, M. J. Kuroda, M. A. Lifton, C. E. Nickerson, C. I. Lord, R. Pal, G. Franchini, and N. L. Letvin Recombinant Canarypox Vaccine-Elicited CTL Specific for Dominant and Subdominant Simian Immunodeficiency Virus Epitopes in Rhesus Monkeys J. Immunol., February 15, 2002; 168(4): 1847 - 1853. [Abstract] [Full Text] [PDF]
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