Gripp CB, Guimaraes ML, Neves I, Costa CI, Santos VG, Linhares de Carvalho MI, Galvao-Castro B, Bongertz V, Morgado MG; International Conference on AIDS.

Int Conf AIDS. 1996 Jul 7-12; 11: 61 (abstract no. We.A.3026).

Dept. of Immunology/IOC/FIOCRUZ, Rio de Janeiro, Brazil.

Objectives: The aim of this work is to assess whether the polymorphism in this region could also restrict T cell antigenic response to the synthetic peptides corresponding to the V3 loop of distinct subtype B isolates, including the Brazilian B'. Methods: We have evaluated the lymphoproliferative response (LR) of asymptomatic HIV-1 positive individuals, infected in Brazil, against 15mer synthetic peptides corresponding to the crown of the V3 loop of MN, SF-2, LAI and the Brazilian consensus B and B'. Briefly, triplicates of PBMC from HIV-1 positive individuals were cultivated at 2x106cells/ml in RPMI-1640 (Sigma Chem Co., USA) suplemented with 10% of heat-inactivated human AB serum (Sigma Chem Co. Mo. USA) for 5-6days in the presence of 10-20 micrograms/ml each peptide (Chyron Mimotopes, Au), or PHA mitogen (Sigma Chem Co., USA) at 5 micrograms/ml. One uCi of [3H]methylthymidine (Amersham, UK) with a specific activity of 20Ci./mmol was added to each well 16-18hr before harversting. Results: Only 10 out 29 individuals analysed up to now reacted with at least one of the peptides. PBMC from five out of the 10 reactive individuals did not react with the GWG peptide (B') while reacting with one or more peptide containing the GPG motif. Only one patient showed lymphoproliferative response exclusively to the GWG peptide, although with a quite low stimulation index. The other four individuals, who were also reactive to this peptide, showed lymphoproliferative response to at least one other peptide containing the GPG motif at the crown of the V3 loop. The stimulation indexes were, however, highly variable among them. All these individuals were infected with HIV-1 subtype B isolates, determined by Heteroduplex Mobility assay as described (EL Delwart et al. 1993 Science 262: 1257-1261). Nucleotide sequencing is being carried out to discriminate the V3 loop variations inside the subtype B. Conclusion: Despite interisolate peptide sequence heterogeneity, HIV-1 positive individuals reactive to the typical Brazilian HIV-1 B' peptide showed broad LP reaction with other peptides as MN, LAI, SF-2 or B consensus, suggesting conservative T cell epitopes in this region. Supported by UNDP/World Bank/Brazilian Ministry of Health and PIAF/FIOCRUZ.

Publication Types:

• Meeting Abstracts

Keywords:

• Amino Acid Sequence
• Antibodies
• Brazil
• HIV-1
• Humans
• Peptides
• T-Lymphocytes

Other ID:

• 96923388

UI: 102219287

From Meeting Abstracts