Utilizing peptides based on the V3 region of gp120, we undertook a serologic examination of human immunodeficiency virus type 1 (HIV-1)-infected individuals from Argentina to determine if prevalent HIV-1 isolates could be identified in this population. Our findings suggest that a similar pool of HIV-1 subgroup B isolates exists in both Argentina and the United States.
PIP: This study examined serum specimens from HIV-1 infected individuals from Argentina (n = 50) and the United States (n = 38) for antibody reactivity to a panel of V3-based synthetic peptides. Serum specimens were further analyzed for the ability to neutralize laboratory and clinical isolates of HIV-1 in vitro. Patterns of antibody reactivity to these V3 peptides, together with neutralizing activity, indicated that infected individuals from both Argentina and the US have been exposed to HIV-1 isolates belonging to subgroup B. Serum specimens from the United States (37 males and 1 female) were obtained from military personnel and their dependents. Of these patients, 35 were asymptomatic and 3 were symptomatic. Specimens from Argentina were obtained from HIV-1-infected individuals examined in Buenos Aires, Argentina (37 males and 13 females). Half of the infected individuals from Argentina were symptomatic. Serum specimens were screened for antibody reactivity to HIV-1 gp160 synthetic peptides by an enzyme-linked immunosorbent assay. Examination of V3 peptide recognition indicated that a higher percentage of Argentinean serum specimens reacted with peptide RP189 than serum specimens from the United States (34% and 5%, respectively). A higher percentage of serum specimens from the United States reacted with peptide RP135 (LAI) than was observed with serum specimens from Argentina (47% vs. 16%, respectively). Neutralization assays again indicated a similar pattern of antibody reactivity with serum specimens from infected individuals from Argentina and the United States. Nucleotide sequence analysis of clinical isolates has demonstrated that the HIV-1 subgroup B is predominant in the United States. Serologic reactivity to V3-based peptides in this study suggests that isolates commonly found in the US (i.e., MN, SF2, and NY-5) are also frequently observed in Argentina. These results suggest that there is similar distribution of HIV-1 subgroup B isolates among infected individuals from Argentina and the United States.