AIDS 2006 - Effectiveness of Anti-HIV T Cell Immunity

Effectiveness of Anti-HIV T Cell Immunity

WEAA02

Type:

Oral abstract session

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Venue:

Session Room 9

Interpretation:

None

Time:

10:45 - 12:15

Code:

WEAA02

Co-Chairs:

Elly Katabira, Uganda
Guiseppe Pantaleo, Switzerland

Presentations in this session:
10:45
WEAA0201
Abstract
Powerpoint (286 KB) Designing a vaccine strategy: implications of viral escape and SHIV-specific CD8 T cells at transmission and during acute infection
Presented by Caroline Shamala Fernandez, Australia
C.S. Fernandez¹, M.Z. Smith¹, C.J. Batten¹, R. De Rose¹, J. Reece¹, E. Rollman¹, V. Venturi², M.P. Davenport², S.J. Kent¹
¹University of Melbourne, Department of Microbiology and Immunology, Parkville, Australia, ²University of NSW, Department of Haematology, Prince of Wales Hospital, and Centre for Vascular Research, Kensington, New South Wales, Australia

11:00
WEAA0202
Abstract
Powerpoint (1.11 MB) Incorporation of sequence diversity increases the rate of detection of HIV-specific T cell responses
Presented by Nicole Frahm, United States
N. Frahm¹, K. Yusim², W. Fisher², M. Muldoon³, C. Linde¹, H. Hewitt¹, K. Faircloth¹, B. Walker¹, C. Brander¹, B. Korber²
¹Massachusetts General Hospital, Harvard Medical School, Partners AIDS Research Center, Charlestown, MA, United States, ²Los Alamos National Laboratory, Theoretical Biology and Biophysics, Los Alamos, NM, United States, ³University of Manchester, School of Mathematics, Manchester, United Kingdom

11:15
WEAA0203
Abstract Dual selection pressure by drugs and HLA class I-restricted immune responses on HIV-1 protease
Presented by Sandra M. Mueller, Germany
S.M. Mueller¹, B. Schaetz¹, K. Eismann¹, S. Bergmann¹, M. Bauerle¹, M. Schmitt-Haendle¹, K. Maurer¹, M. Schmucker², H. Walter³, B. Schmidt³, K. Korn³, H. Sticht⁴, B. Spriewald⁵, E.G. Harrer¹, T. Harrer¹, HIV Competence Network HIV/AIDS
¹University of Erlangen-Nuremberg, Department of Medicine III - Immunology/HIV Competence Network HIV/AIDS, Erlangen, Germany, ²University of Erlangen-Nuremberg, Erlangen, Germany, ³University of Erlangen-Nuremberg, Institute of Clinical and Molecular Virology, Erlangen, Germany, ⁴University of Erlangen-Nuremberg, Institute of Biochemistry, Emil-Fischer-Center, Erlangen, Germany, ⁵University of Erlangen-Nuremberg, Department of Medicine III, Erlangen, Germany

11:30
WEAA0204
Abstract Vaccine induced T-cell responses in immunised rhesus macaques correlate with SIV replication kinetics in vitro but not in vivo
Presented by Washingtone Ochieng', Germany
W. Ochieng', C. Stahl-Hennig, Y.-S. Suh, S. Sopper, G. Hunsmann, U. Sauermann
German Primate Centre, Virology and Immunology, Goettingen, Germany

11:45
WEAA0205
Abstract Cross-clade recognition of Gag-p24 GPSHKARVL epitope restricted by HLA-B7 in a HIV-1 CRF15_01B infected individual
Presented by Erika Castro, Switzerland
E. Castro¹, A. Harari¹, C. Cellerai¹, P.A. Bart¹, J.P. Chave², G. Pantaleo¹
¹Laboratory of AIDS Immunopathogenesis, University Hospital, Division of Immunology and Allergy, Lausanne, Switzerland, ²University Hospital, Division of Infectious Diseases, Lausanne, Switzerland

Audio files:

English audio file (mp3 format, 23.4 MB)

Rapporteur report

Science Track A: Biology and Pathogenesis of HIV report by Dr. Nicole Bernard

Presentations in this session related to T cell immune responses to HIV and SIV that may be effective at controlling infection. Also included was a paper describing improved strategies for detecting responses to HIV that may encompass better detection of autologous virus at sequences that differ from consensus sequence.

WEAA0201

Dr. C.S. Fernandez

The presenter described a monkey model in which CD8+ T cells specific for an immunodominant peptide were induced by vaccination and reported on the impact of the pre-existing CTL on viral load set point after challenge with a SHIV isolate encoding an epitope variant with reduced fitness. In acute infection, in animals able to recognize the wild type variant reversion followed by reescape of the recognized epitope occurred. Pre-existing CTL were more beneficial to the host in terms of viral load set point than the fitness cost incurred by the escape mutation.

Dr. N Frahm

This report described a strategy for synthesizing toggled peptides (peptides tat contain alternate amino acid substitutions) at particular sequence locations.This can be done because HIV sequence diversity is limited to particular sequence positions and amino acids. These toggled peptide provide superior coverage to consensus clade B peptide sets for stimulating greater breadth and magniude of HIV-specific reponses

Dr. S.M. Muller

Correlations between expressed HLA alleles and sequence polymorphisms due to drug resistance mutations in HIV protease were identified. Upon screening 26 consensus clade B and variant sequence peptides containing HLA class I linked mutations for stimulatory capacity in subjects expressing HLA alleles restricting either one or both variants, stimulatory capacity of variants peptides often acted as escape mutations inducing lower responses. In some patients antigenicity was either maintained or enhanced.

Dr. W. Ochieng

A vaccine study of macaques immunized using a prime boost strategy involving DNA prime with adenovirus boosting.

Dr. E Castro

Presented was a case study of a patient infected with an A/E/B recombinant virus who has had a benign course of infection. Peptide specific responses in this individual recognized autologous HIV sequences better than consensus sequences with robust polyfuntional characteristics (IFN-gamma and IL-2).

The session generated further discussion on the inability of the data presented to resolve the cause and effect relationship between immune responses and control of viral replication versus virological factor contributing to destruction of immunity. The strategy for low cost synthesis of peptides better able to cover autologous sequences is of interest and availability of such peptide sets from the NIH reagent bank is eagerly anticipated.

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