EFFECT OF AMINO-ACID CHANGES IN THE GP120 V3 LOOP ON SEROLOGICAL CROSS-REACTIVITY OF HIV-1 SUBTYPES

Interaction of 148 sera from HIV-1-infected Russian patients with thre e synthetic peptides that mimic various V3 loop sequences of the South Russia subtype G and eight peptides with point substitutions was stud ied by ELISA. A sizable portion of the sera, especially those of subty pe C, interacted with the peptides. The central tetrapeptide GPGQ was found to be crucial for binding to the subtype C sera. The V3 epitope antigenicity of most subtype B variants was largely determined by glyc ine in the first position of the central motif and the flanking residu es.