Analysis of antibody specificity against the third variable region of the envelope glycoprotein gp120 of HIV-1 in plasma from HIV-1-positive individuals residing in Brazil

1. Antibody specificity for the principal neutralization domain (PND) of the human immunodeficiency virus type 1 (HIV-1) was studied in plasma from 122 HIV-1-infected individuals residing in Brazil. 2. Using 8 overlapping sequential pentadecapeptides corresponding to the third variable region (V3) of 5 different HIV-1 isolates in an enzyme-linked immunosorbent assay (ELISA), a preferential recognition of the peptides with amino acid sequences corresponding to the HIV-1 isolates IIIB and MN (maximal reactivities of 60-70) compared to the isolates SC, WMJ-2 or RF (maximal reactivities below 60) was observed. 3. A difference was observed in the overall reactivity pattern to HIV-1 SC peptides of plasma collected from individuals residing in the Brazilian states of Rio de Janeiro and Bahia. However, a statistically significant increased recognition by Bahian plasma was only observed for the HIV-1 SC C55 peptide. 4. The mean CD4/CD8 ratio of the group of plasma with an isolate-restricted recognition of peptides (0.522 +/- 0.074) was significantly lower than that of the total group of plasma (1.00 +/- 0.18).

Production of human monoclonal antibodies against HIV-1 peptides

Protocols were evaluated in an attempt to produce human monoclonal antibodies (HumAb) specific for the human immunodeficiency virus type 1 (HIV-1). The first series of experimentls involved in vitro immunization of normal human peripheral blood lymphocytes (PBL) with peptide C57 (HIV-1 strain IIIB clone BH10 gp 120 amino acids 324-338: GNMRQAHCNISRAKW) followed by either fusion to mouse/human heterolhybrids or transformation with Epstein Barr virus (EBV). Using the hybridoma technology, three IgM class (alfa light chain) Human Ab were obtained. In a parallel study, PBL from two HIV-1 infected patients were immortalized after in vitro stimulation with fragments of the HIV-1 envelope glycoprotein (recombinant gp120 fragment of gp 120, amino acids 295-473, or the penv9 fragment of gp160, amino acids 474-757). Five IgG class Human b (three IgG2m alfa; one IgG1, K; one IgG3, alfa) reactive with the antigens used in the in vitro stimulations were obtained