[Mutation of envelop protein V3 loop in HIV-1 epidemic in Liaoning province]

To study the characteristics of human immunodeficiency virus (HIV-1) V3 loop amino acid mutations among HIV-1 infected people in Liaoning province.

The whole blood samples of the HIV carriers and AIDS patients were collected in Liaoning province, China and were extracted PBMC genome DNA. HIV-1 V3 and flanking region sequences were amplified by nest-polymerase chain reaction (nest-PCR) with env specific primers: ED5/ED12 and ED31/ED33. Products were sequenced directly and sequences were aligned, translated and analyzed.

In AIDS group, some amino acid mutations at specific position of V3 loop: S to R at position 11, H to S, T and N at position 13, A to V at position 19, F to Y at position 20, Q or D to N at position 25 and 29, were found and all common mutations were associated with T tropic/SI phenotype. The frequency of such amino acid mutations in specific positions was higher in AIDS group than that of the asymptomatic infection group (P < 0.05). In addition, we found some unusual tetramer compositions on the tip of V3 loop: GQGR, APGR and RPGA, GLGR, RPGA in addition to some rare mutations, such as: N to H at position 5 and H to S, F at position 34.

The amino acid mutations on the V3 loop of HIV-1 epidemic in Liaoning province were in agreement with the results of subtype B, but we observed some rare mutations and unusual tetramer compositions on the tip of V3 loop.