Diversity of HIV-1 subtype E in semen and cervicovaginal secretion

OBJECTIVES: To characterize human immunodeficiency virus type 1 (HIV-1) subtype E variants in blood and genital fluid of infected Thai couples. STUDY DESIGN/METHODS: Blood and genital fluid were collected from 30 asymptomatic healthy HIV-1 subtype E infected couples from Bangkok, Thailand from 1995 to 1998. RESULTS: All 60 viruses in blood samples were identified as subtype E by heteroduplex mobility assay. The biotype of viruses founded in blood was syncytium-inducing (SI), whereas M-tropic and non-syncytium-inducing (NSI) isolates were predominantly detected in genital fluid. HIV-1 proviral DNA was detected in 43.33% and 56.67%, and viral RNA was detected in 93.33% and 56.67%, of semen (n = 30) and cervicovaginal secretion (n = 30) samples tested, respectively. A higher intersample genetic distance and more positive charge of the V3 loop were found in blood strains composed of genital fluid strains (22.30 +/- 5.92% and 17.96 +/- 6.3%), which was statistically significant (P = 0.003). The env V1-V4 intraperson variation of the HIV-1 subtype E in the blood and genital fluid of each individual was in the range 3.0%-5.7%. We also determined the intrasample variation of HIV-1 from blood and genital fluid by heteroduplex mobility assay. The mean heteroduplex mobility of the HIV-1, V1-V4 region of env gene, in blood (n = 8) and genital fluid (n = 8) was 0.59 +/- 0.06 and 0.74 +/- 0.11 (t test, p = 0.001), respectively. CONCLUSIONS: There was genetic and phenotypic compartmentalization of HIV-1 subtype E in blood and genital fluid with the presence of SI and NSI phenotypic variants as a common property of subtype E isolates from blood and genital fluid, respectively.