Molecular Features of the V1-V4 Coding Region of Sexually Transmitted Human Immunodeficiency Virus Type 1.

Background.: Investigations into which human immunodeficiency virus type 1 (HIV-1) sequence features may be selected for transmission during sexual exposure have been hampered by the small number of characterized transmission pairs in individual studies.

Methods.: To boost statistical power to detect differences in glycosylation, length, and electrical charge in the HIV-1 V1-V4 coding region, we reanalyzed all available 2485 env sequences derived from 114 subjects representing 58 transmission pairs from previous studies using mixed-effects linear regression and an approach to approximate the unobserved transmitted virus.

Results.: The recipient partner had a shorter V1-V4 region and fewer potential N-linked glycosylation sites (PNGS) than sequences from the source partner. We also detected a trend toward more PNGS and lower isoelectric points in transmitted sequences with source partner and the evolutionary tendency to shorten V1-V4 sequences, reduce the number of PNGS, and lower isoelectric points in the recipient following transmission.

Conclusions.: By using all available well-characterized env sequences from transmission pairs via sexual exposure, we were able to identify several important virologic factors that may be important in the development of biomedical preventive interventions.