Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

12th World AIDS Conference

Abstracts 21201-21205 279

munized with the NYVAC-SIV vaccine alone. At the end of the immunization
regimen, half of the animals were challenged with SIVmac251 by the intravenous
route, and the other half were exposed to SlVmac251 intrarectally. Significantly, five
of the eleven vaccinees exposed mucosally to SlVmac251 showed a transient peak
of viremia one week after viral challenge and subsequently appeared to clear
viral infection. In contrast, all twelve animals inoculated intravenously became
infected, but after 5-6 months from viral challenge, four animals were able to
control viral expression and appeared to progress to disease more slowly than
control animals. Protection did not appear to be associated with any of the measured immunological parameters. Further modulation of immune responses by
coadministration of NYVAC-cytokine recombinants did not appear to influence the
outcome of viral challenge. The fact that the NYVAC-SIV recombinant vaccine
appears to be effective, per se, in an animal model that best mirrors human
acquired immune deficiency syndrome (AIDS) supports the idea that a highly
attenuated poxvirus-based vaccine candidate can be a valuable approach to halt
the spread of human immunodeficiency virus (HIV) infection by the mucosal route.
497*/21201 HIV-1 cross-clade lymphoproliferative responses
following immunization with recombinant gp120
SF2
Thippawan Chuenchitra', S. Ratto-Kim6, M. De Souza4, K. Rungruengthanakit2,
S. Nitayaphan5, C. Khamboonruang2, C. Chuenchitra3, R.A. Michael7,
F. Sinangil8, A.M. Duliege8, J.G. McNeil7, D.L. Birx7. 1AFRIMS 315/6 Rajvithi
Rd. Bangkok 10401; 2RIHES, Chiang-Mai, Nitayaphan; 3RTAMC-AFRIMS,
Bangkok; 4HMJF/USAMC- AFRIMS, Bangkok; SRTAMC-AFRIMS, Bangkok,
Thailand; 6HMJF/USAMC- Wrair, Rockville; 7USAMC-WRAIR, Rockville; 8Chiron
Company, Emeryville, Duliege, USA
Objective: To determine whether recombinant HIV vaccine, Chiron vaccine'"
rgpl20 SF2 (clade B) in MF59 adjuvant induced cross-clade antigen-specific
lymphoproliferative responses.
Methods: Twenty-six HIV-negative healthy volunteers were enrolled in
Bangkok, Thailand in double-blind study and randomized to 2 groups - Group A
received the vaccine at 0, 1 and 4 months and Group B at 0, 1 and 6 months. Six
volunteers received placebo (MF59). Lymphoproliferative responses to rgp 120
SF2 (clade B) and Chiang-Mai gp 160 (clade E) were measured at baseline and
post-third immunization from cryopreserved PBMC. Results were expressed as
stimulation indices (Sl) and SI of - 3 were considered positive.
Results: Lymphoproliferative responses to rgp 120 SF2 were induced in 85%
of vaccinees at both 1 and 4 months post-third immunization (Group A = 80%,
Group B = 90%). Lymphoproliferative responses to Chiang-Mai gp160 (clade
E) were seen in 53% of vaccinees tested at 1 month post-third immunization,
declining to 39% at 4 months post-third immunization. However, the magnitude
of SI to rgp 120 SF2 was significantly greater than to Chiang-Mai gp160 (p <
0.01) - SI = 8.3 and 3.6 respectively at 1 month post-third immunization. Both the
frequency of positive SI and the magnitude of SI to the envelope antigens were
not significantly different between immunization regimens.
Conclusion: Immunization with HIV-1 clade B envelope protein induced crossreactive lymphoproliferative responses to clade E.
21202 HIV-protective effect of HLA-A28 in Africans exists also in
Caucasians: Analysis of the HLA-A28 antigen encoding
alleles by sequence based typing (SBT)
Rudolf Wank1, Barbara Laumbacher2. Goethestrasse 31 80336 Munchen;
2lnst. F. Immunologie Universitit Mjnchen, Germany
Hypothesis: The increased frequency of HLA-A28 in highly HIV exposed but not
infected African prostitutes should show an inverted correlation, i.e., a decreased
frequency of HLA-A28 in HIV positive individuals.
Methods: Frequencies of the antigen HLA-A28 and the encoding alleles were
compared in 265 HIV positive individuals and in 341 HIV negative controls. Antigen typing was done by the conventional HLA microdroplet assay, the encoding
alleles HLA-A-68011, A-68012, A*6802, A*6901 were assessed by sequence
based typing (SBT).
Results: The antigen frequency of A28 in HIV positive individuals was significantly decreased based on the decrease of the frequencies of HLA-A*68012 and
Ar6802 (Table 1). HLA-AS-6901 was found neither in HIV positive individuals nor
in the control panel.
Table 1: Frequencies of the HLA-A28 antigen and the encoding alleles in HIV infected and
controls
HLA-A28 HIV pos. N = 265% expected 15 0.058 p = 0.0221
A.*68011 found 6 0.022 expected 4 0.014 p not significant
A 68012 found 3 0.011 expected 9 0.035 p = 0.0498
A.+6802 found 3 0.011 expected 2 0.008 p not significant
A-68012 + A:6802: expected 11, found 2, p = 0.0123, pcorr = 0.0492
Conclusion: HIV resistance in Nairobi prostitutes remaining HIV negative was

associated with HLA-A28. In Caucasians we also found the A28 alleles A*68012
and A*6802 associated with resistance against HIV. Identification of peptides
presented by these alleles would mean to identify the most immunogenic HIV
peptides. The HIV peptides presented by A*68012 and A*6802 have already
shown efficiency in vivo and offer a diretissima for rapid development of an HIV
vaccine.

_212031 Tissue distribution and fate of HIV-1 DNA vaccine in
BALB/c mice
Kenji Okuda1, S.K. Kawamoto1, J.F. Fukushima1, Y.K. Koizumi2, B.W. Wahren3,
K.H. Hamajima1, K.N. Nishiokat. 1Dept. Bacteriology Yokohama City Univ.,
Yokohama; 2Dept. Internal Med. Yokohama City Univ., Yokohama, Japan; 3Dept.
Clin. Virology Karolinska, Stockholm, Sweden
Objectives and Design: We studied the tissue distribution of DNA vaccines when
they administered intranasally (i.n.) or intramuscularly (i.m.). Clinical importance
of mucosal immunization, especially i.n. immunization with DNA vaccines is increasing. We at first observed strong immune responses by i.n. administration,
we next investigated the tissue distribution and expression kinetics of HIV-1 env
and rev DNA plasmids (HIV plasmid) which were i.n. administered.
Methods and Results: Fluorescence in situ hybridization (FISH) examination
revealed that the localization was noticed in lung, liver, testis, spleen, and
regional lymph nodes, as well as brain and fetus. We observed the HIV plasmid
in liver and spleen even 5 minutes after i.n. administration. HIV plasmids were
strongly detected after 30 minutes in lung, liver, spleen, and kidney, and these
plasmids were detected in spleen, lung, and liver also after 2 weeks. The tissue
distribution of HIV plasmids by i.m. immunization was rather restricted when we
compared with the i.n. administration. The tissue localization of DNA plasmids
was also confirmed by radio-labeled plasmids. On day 3, strong gene expression
of HIV env was observed in lung and liver, and slightly in spleen, respectively,
using both immunofluorescent and RT-PCR methods. Furthermore, the gene
expression of DNA plasmids was observed also in fetus or brain.
Conclusion: I.n. administration of HIV env plasmids was shown to spread to in
the various tissue and successfully to induce systemic protein expression in the
whole body, and gave strong immunities to immunized individuals.
21204 1Antigenicity of HIV-1-like Gag-V3 chimeric particles
expressed by a recombinant vaccinia virus system
Asato Kojima1, Atsushi Yasuda2, E. Moriishi1, T. Kurata. iDept. Pathol., Natl.
Inst. Infect. Disease Toyama 1-23-1, Shinjuku-ku, Tokyo 162; 2Nippon Zeon Co.
Ltd. Kawasaki, Japan
Objective: In terms of intrinsic adjuvant properties of particulate antigens, the
Gag particels might be a suitable candidate as antigen-presenting carrier for the
development of HIV vaccine. In this work, we inserted third variable (V3) domain
of HIV-1 Env into Gag and studied abilities of chimeric Gag-V3 proteins to form
HIV-1-like particles and to present the V3 epitope.
Methods: Six deletion mutants and four substitution mutants were constructed
with the gag gene from HIV-1 clone pNL4-3. The DNA fragment of V3 region
of JR-FL was inserted into the mutagenated sites. These 10 gag mutant and
10 gag-V3 fusion genes were expressed by a vaccinia virus system. Expression
and release of chimeric Gag proteins were analysed by sucrose density gradient
ultracentrifugation, ELISA, western blot, and scanning electron microscopy. AntiGag antibodies and human anti-V3 monoclonal antibody with neutralizing activity
were used to detect Gag protein and the neutralizing V3 epitope.
Results: Western blot analysis of cell lysates infected with gag-V3 recombinants
revealed that Gag-V3 fusion proteins were expressed in the recombinant-infected
cells. The levels of expression within cells were similar in these recombinants.
Sucrose density gradient ultracentrifugation and western blot analysis of culture
medium of cells infected with wild type gag gene recombinant indicated that Gag
protein was efficiently released from the recombinant-infected cells and assembled into virus-like particles (VLPs). Eight out of ten Gag mutants and seven of ten
Gag-V3 chimeras provided the VLPs. No difference of equilibrium density was observed in four Gag-V3-chimeras. Two Gag-V3 chimeras showed reduced density
probably due to insertion of V3 sequence. An electromicroscopic analysis of the
peak fractions of sucrose density gradients revealed that 110- to 150-nm particles
produced from recombinant-infected cells exhibited morphorogies similar to those
of the wild-type Gag particles. Mice infected with Gag-V3 recombinants induced
both anti-Gag and anti-V3 antibody responses.
Conclusions: Gag proteins containing the V3 major neutralizing epitope at
different insertion sites produced and released efficiently HIV-1-like Gag-V3 fusion particles when expressed in mammalian cells with recombinant vaccinia
viruses. These results suggest that the particulate antigen system of Gag-V3
fusion protein is useful for the development multivalent AIDS vaccine.
21205 Improvement of nucleic acid vaccination against HIV-1
toward strong systemic and mucosal immunity
Shin Sasaki1, K.H. Hamajimal, J.F. Fukushima', N.I. Ishii2, H.M. Mohri3,
K.O. Okuda4. 1Department of Bacteriology, Yokohama City University,
Yokohama; 2Dept. of Dermatology Yokohama City Univ. Yokohama; 3Dept. of
Internal Med. Yokohama City Univ.; 4Dept. of Bacteriology Yokohama City Univ.,
Japan
Background: Nucleic acid vaccination has been preferentially used to generate
HIV-1 specific immunity and has demonstrated respectable results in some animal

models by using naked DNA administration. There has been few studies, however, which employ immunologic adjuvants in DNA vaccine formulations to obtain
stronger HIV-1 specific immunity. We therefore tried to enhance DNA-derived
immunity by using several immunologic adjuvants.
Methods: Mice were inoculated with pCMV160IIIB and pcREV which encode env and rev gene of HIV-1 strain IIIB through intramuscular or intranasal
route. Evaluated adjuvants were monophosphoryl lipid A, QS-21, mannan-coated