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

280 Abstracts 21206-21210

12th World AIDS Conference

diC14-amidine, ubenimex; they were administered concurrently with the immunogenic DNA. HIV-1-specific serum IgG, IgG1, IgG2a, IgE and intestinal IgA antibody
production was measured by ELISA, specific delayed-type hypersensitivity reaction and cytolytic activity of the bulk splenic mononuclear cells were also
evaluated. Amount of IL-2, IL-4, and IFN-gamma was quantified in the culture
media of antigen-restimulated splenocytes.
Results: All of these adjuvants consistently enhanced HIV-1-specifc both humoral and cell-mediated immune responses. Analysis on serum immunoglobulin
subtype and cytokine secretion profile suggested that Thl subset was activated
by these adjuvants. Intranasal DNA administration elicited comparable systemic
immunity to that elicited by intramuscular injection. Furthermore, intranasal administration preferentially induced intestinal IgA production and cytolytic activity
of mesenteric lymphnodes.
Conclusion: The use of immunologic adjuvants is simple and economical,
so that adjuvanted DNA vaccination should be paid an attention in the disease
control strategies against HIV-1. Intranasal DNA application is also promising in
inducing mucosal immunity which plays an important role in the first line of host
defense against HIV-1.
21206 Construction and characterization of recombinant
BCG-vectored vaccine against HIV-1 clade E strain
Kazuhiro Matsuo, H. Yoshizaki, K. Someya, S. Naganawa, H. Yoshikura,
S. Yamazaki, M. Honda. AIDS Research Ctr., NIID 1-23-1 Toyama, Shinjuku-Ku,
Tokyo 162, Japan
Objectives: To construct and characterize the recombinant Mycobacterium bovis
BCG (rBCG) vector-based vaccine secreting the V3 principal neutralizing epitope
of HIV-1 clade E strain.
Methods: Synthetic DNAs encoding V3 sequences of clade E HIV-1 were
inserted into a mycobacterial secretion vector and then introduced into BCG
Tokyo substrain. The a antigen-V3 chimeric protein secretion from the rBCG
was analyzed by Western blot assay using an antiserum of HIV clade E carrier.
Antibody production was examined in guinea pigs immunized subcutanously and
peripheral blood mononuclear cell- based in vitro virus neutralizing assay was
carried out using WHO reference strains of clade E and B viruses.
Results: The V3 sequences of 19 amino acids (act) and 15aa fused with
mycobacterial a antigen were not secreted while 13aa and 11aa sequences were
successfully secreted from BCG cells. The 13aa construct which was named
rBCG-THA13 possessed higher antigenicity in the Western blot assay. From
a mutational experiment, it was suggested that the local charge valance and
conformational change near the inserted epitope may affect the ability to secrete
the chimeric protein. Serum IgG from a guinea pig immunized with rBCG-THA13
neutralized the reference strains of both T-cell- and macrophage-tropic clade E
viruses. Surprisingly, the serum IgG could also neutralize ThaiB (clade B) strains
which possessed a conserved GPGQ motif in their V3 sequences.
Conclusion: These data suggest that the rBCG-THA13 construct is implicated
in the development of a prophylactic vaccine in Thailand in which both clade E
and B viruses are prevalent.
S21207 Antigenicity of HIV-1 envelope glycoproteins from either
primary isolates or T-cell lines adapted strains expressed
using a Semliki forest virus vector
Denys Brand, F. Lemiale1, G. Thibault2, B. Verrier3, F. Barin2. Faculte De
Medecine, 1EP CNRS 117, 2 Bd Tonnelle, Tours; 2CHU Bretonneau, Tours;
3ENS, Lyon, France
Objective: To study the presentation of neutralizing epitopes on oligomeric glycoproteins derived from HIV-1 primary isolates or T-cell lines adapted (TCLA)
strains.
Methods: The Env-encoding gene from 2 TCLA strains (HXB2 and MN) and
3 primary viruses (BX08, CHA, LYO; all 3 of clade B) isolated early in infection (one during primary infection before appearance of HIV-1 antibodies, and
2 within 6 months after seroconversion) were cloned into the pCRII plasmid,
and then into the pSFV 1 plasmid. Four clones per isolate were selected for
further analysis. After in vitro transcription, electroporations were performed on
BHK-21 cells. Antigenicity was studied by radio-immunoprecipitation (RIPA) and
FACS analysis using anti-HIV-1 positive human sera and a panel of neutralizing
human monoclonal antibodies - hu-mAbs - (IgG1bl2 and F105, both directed to
conformational epitopes; 447-52D and 2F5, both directed to sequential epitopes).
Results: the results obtained by RIPA showed major differences in antigenicity
of the various envelopes. Envelopes from TCLA strains were clearly bound by all
the hu-mAbs whereas envelopes from CHA or LYO isolates were not recognized
by 447-52D and 2F5, or IgG1bl2, respectively. FACS analysis revealed the better
presentation of the envelopes derived from TCLA isolates. The envelopes from
CHA and LYO isolates were only weakly or not bound by the various hu-mAbs.
The BX08 envelope behaved as an intermediate since bound efficiently by most
of the hu-mAbs.
Conclusion: These results indicate that neutralizing epitopes are much more

accessible on envelopes derived from TCLA strains that on those derived from
primary isolates, and that these epitopes are differently accessible depending on
both the clone and the primary isolate itself.

21208 | Development of rationally designed vaccines for HIV-1
through the use of molecular adjuvants
Jong Joseph Kim, D.B. Weiner. 422 Curie Blvd. Room 505 Brb-1, Philadelphia,
PA; University of Pennsylvania Philadelphia PA, USA
Objectives: To engineer in vivo the enhancement of HIV-1 -specific immune
responses, the role of co-delivery of genes for Thl- and Th2-type cytokines along
with DNA vaccine formulations for HIV-1 antigen was investigated.
Design: DNA vaccination of mice and rhesus monkeys.
Methods: The genes for Thl cytokine (IL-2, IL-12, IL-15, and IL-18), and Th2
cytokine (IL-4, IL-5 and IL-10) genes were cloned into an expression vector. These
constructs were injected into mice along with DNA vaccine cassettes for HIV-1
envelope and gag/pol antigens. We analyzed the immunological effects of the
co-injection with these genetic adjuvant cassettes on the direction and magnitude
of antigen-specific immune responses by examining the magnitude of antigenspecific humoral and cellular immune responses after plasmid co-delivery. This
method was also extended to the immunization of rhesus macaques.
Results: We observed enhancement of antigen-specific humoral response
with the co-delivery of Th2 cytokine genes IL-4, IL-5, and IL-10 as well as that of
IL-2 and IL-18. A dramatic increase in antigen-specific T helper cell proliferation
was seen with IL-2 and IL-12 co-injections. In addition, we observed a significant
enhancement of the cytotoxic response with the co-administration of IL-12 and
IL-15 genes with HIV-1 DNA immunogens. These increases in CTL response
were both MHC class I-restricted and CD8+ T cell-dependent.
Conclusions: Together with earlier reports on the utility of co-immunizing
immunologically important molecules with DNA immunogens, we demonstrate
the potential of this strategy as an important tool for the development of more
rationally designed vaccines.
21209 Effects of a PPD-pentavalent V3 loop penta-peptide
conjugate vaccine on reduction of viral loads and HIV V3
sequence in HIV+ subjects
Arye Rubinstein1, Y. Mizrachi2, J. Lenz2, M. Pettoello-Mantovani2, G.Q. Liu2,
H. Goldstein2, I. Yust3, M. Burke3, N. Vardinon3, Z. Spirer3, S.J. Cryz4. 11300
Morris Park Avenue Bronx New York 10461; 2Albert Einstein College of Medicine
Bronx NY, USA; 3Sourasky Medical Center Univ Tel-Aviv Tel-Aviv, Israel; 4Swiss
Serum and Vaccine Institute Berne, Switzerland
Objective: To determine the utility of a therapeutic V3 loop peptide vaccine in
asymptomatic HIV+ subjects.
Method: Seven HIV+ PPD+ asymptomatic adult patients on no active antiretroviral therapy were immunized with a mixture of V3 loop derived peptides coupled
to PPD (PPD-pentapeptide-PND). Each peptide consisted of 13 aminoacid sequences corresponding to the primary neutralizing domain (PND) of five HIV-1
isolates prevalent in the USA. Immunological and virological parameters were
evaluated over a period of 33 months.
Results: All seven patients exhibited an increase in antibody titers to vaccine
peptides and to the V3 loop apex motif of GPGRAF. Over time there was a progressive increase in antibodies capable of neutralizing MN-primary isolates and
autologous virus in PBMCs. The emergence of high affinity/avidity antibodies with
neutralizing activity was accompanied by decreases in viral loads. Sequencing of
the V3 loop in patients on immunotherapy showed that no complete identity with
the vaccine peptide was required for responses to occur. During vaccination the
number of V3 loop sequence variations was decreased. Fifteen months post last
immunization there was a reemergence of numerous V3 mutations.
Conclusions: The PPD-pentapeptide-PND vaccine elicited in HIV+ PPD+ volunteers neutralizing antibodies to primary isolates accompanied by a decrease in
viral loads and in V3 loop sequence variations.
21210| HIV negative infants born to HIV-1 but not HIV-2 positive
mothers fail to develop a BCG scar
Martin Ota, D. O'Donovan, A. Marchant, S. Jaffar, K.P.W. Mcadam, T. Corrah,
H.C. Whittle. Medical Research Council Laboratories PO Box 273 Banjul,
Gambia
Objective: To evaluate the influence of maternal HIV infection on the response
to BCG vaccination in HIV-negative offspring.
Methods: At the age of 18 months 17 and 64 uninfected children born to HIV-1
and HIV-2 infected mothers respectively, and 114 children born to HIV uninfected
mothers were examined for presence of BCG scar and response to Mantoux test
using 10TU of Purified Protein Derivative (PPD). HIV infection in the children was
diagnosed by PCR and antibody serology assays at the age of 18 months.
Results: BCG scar was less prevalent in children born to HIV-1 infected mothers (18%) as compared to children born to HIV-2 infected (50%) or control mothers
(48%) (p = 0.04).
Parameters affecting BCG scar formation in controls included vaccination before age of 7 days and birth weight below 2.5 kg.
Conclusions: We conclude that maternal HIV-1 infection impairs the formation

of BCG scars in the offspring independently of HIV transmission, and the use of
BCG scar in vaccination surveys should be done with caution in places where
HIV-1 is endemic.