SEROTYPING OF HIV TYPE-1 INFECTIONS - DEFINITION, RELATIONSHIP TO VIRAL GENETIC SUBTYPES, AND ASSAY EVALUATION

V3 serotyping refers to a system based on binding of antibody in patie nt sera to V3-loop peptides derived from HIV-1 env genetic subtypes, T he V3(X) serotype represents reactivity of serum from an HIV-1-infecte d patient (regardless of viral genetic subtype), which reacts preferen tially to a V3 peptide derived from the X subtype sequence, We have cl assified HIV-1 serotypes, determined the relationship between the HIV- 1 V3 serotypes and viral genetic subtypes in a large study (n = 125), and evaluated the performance of three different V3 peptide-binding as says, Seven HIV-1 V3 serotypes mere identified: A, B, B-Br, B-Th, C, D , and E, Serotypes B-Br and B-Th represent sera that react specificall y to peptides derived from Brazilian B (B-Br, GWGR) and Thai B (B-Th, GPGQ) Strains, The HIV-1 V3 B, C, and E serotypes correlated Closely w ith their viral env genetic subtypes; 19-26 of 32 B sera (59-79%), 3-4 of 4 C sera (75-100%), and 19-22 of 23 E sera (83-96%) mere identifie d as serotypes B, C, and E, respectively, In contrast, two major V3 se rotypes were classified in A sera: A (14-18 of 36 [40-50%]) and C (12- 19 of 36 [33-54%]), Similarly, two major V3 serotypes were classified in D sera: B (6-10 of 20 [30-50%]) and D (9-12 of 20 [45-60%]), Seroty ping of subtype E sera showed the best concordance with genetic subtyp es by all assays, Overall, HIV-1 V3 serotyping produced consistent res ults among three laboratories, However, HIV-1 V3 serotypes do not dist inguish all HIV-1 genetic subtypes, The relative biological significan ce of the V3 serotypes remains to be elucidated.