Envelope V3 Region Sequences of Cuban HIV-1 Isolates:

Virologists used healthy donor peripheral blood mononuclear cells to isolate HIV-1 from 15 HIV-1 seropositive persons from different parts of Cuba. They used the polymerase chain reaction (PCR) to amplify the V3 region of purified HIV-1 DNA. They used dsDNA Cycle Sequencing System (Gibco BRL Life Technologies) to sequence the specific PCR fragment (about 330 bp). The 15 subjects fell into 3 distinct groups. Group A consisted of 3 subjects whose V3 sequences were related to the MN strain of HIV-1. All 3 had been infected with HIV-1 in Angola. Six young subjects from the same province in Cuba who had all practiced high risk sexual activities comprised Group B. They all became infected around the same period and had a short incubation period before developing AIDS. They may have been infected by a common source. Their V3 sequences had the same QR dipeptide in the V3 loop tip a distinct characteristic of LAI isolates in the Chicago area in 1984. The 6 remaining subjects were part of a well-characterized transmission chain (a male who had infected 13 of 17 female sexual contacts > 70% transmissibility) who comprised Group C. In the man and 2 of the women in the group a new change occurred from isoleucine to phenylalanine at position 12 with the subtype B consensus sequence. Researchers are now studying the relationship between this amino acid change and viral transmissibility. These results indicate that the HIV epidemic in Cuba has different origins.