The principal neutralizing domain (PND) of HIV-1, located within the third variable region (V3) of the gp120 envelope protein, is related to the humoral and cellular immune response. We studied the V3 PND-specific antibody response in 30 children with vertically acquired HIV-1 infection by determining the antibodies that bound synthetic peptides derived from the PND of the HIV-1(MN), HIV-1(SF-2), HIV-1(SC), HIV-1(IIIB), HIV-1(RF), HIV-1(ELI), and HIV-1(Z6) virus strains. At a standard antigen concentration, we found that most sera (90%) reacted against PND(MN) peptide, but 73.3% also cross-reacted against multiple PNDs. A search for high-affinity/avidity antibodies was conducted in an antigen-limited assay; at lower peptide concentrations, cross-reactivity was restricted to PND(MN) and PND(SC) in 12 of 22 broadly reactive sera. Sequence analysis of the V3 region of HIV-1 isolates indicated that patients with high-afffnity/avidity antibodies to PND(MN) and PND(SC) had a PND with an internal 12-amino acid sequence (serotype-specific domain, SSD) that was highly homologous (>90%) with the MN and SC SSD. Broadly reactive sera with low-affinity/avidity antibodies showed a lower degree of homology with the SSD sequence of all tested viral strains. The role of anti-PND antibodies in vertical transmission was further studied in 49 children born to HIV-1-seropositive mothers. No statistical correlation emerged between V3 antibodies and HIV-1 transmission, but we found that maternal V3 antibodies were lost soon after birth. This finding may be relevant to a new serological approach to the early diagnosis of vertically transmitted HIV-1 infection.
|Number of pages||8|
|Journal||AIDS Research and Human Retroviruses|
|Publication status||Published - 1993|
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