Investigation of population diversity of human immunodeficiency virus type 1 in vivo by nucleotide sequencing and length polymorphism analysis of the V1/V2 hypervariable region of env.

In this study we have analysed variability in the V1 and V2 regions of human immunodeficiency virus type 1 (HIV-1) proviral sequences amplified from lymphoid tissue, brain and other non-lymphoid tissue collected at autopsy from three HIV-1-infected individuals with giant cell encephalitis. We found no evidence for any tissue-specific grouping of variants in the V1/V2 regions, in contrast to previous comparisons of sequences in the V3 region, but consistent with the existence of evolutionarily distinct lineages previously observed in these study subjects by sequence comparisons of the p17gag gene. Examination of inferred amino acid sequences from V1 and V2 revealed no correlations between tissue origin with overall charge, length or number of glycosylation sites. Length polymorphism analysis is a rapid method to compare whole populations of HIV-1 variants within a sample, and provides information on the length and diversity of the V1 and V2 hypervariable regions. Based upon a comparison of 42 individuals with CD4 counts ranging from 802 to < 1 at time of death, we found no evidence for changes in the length of V2 with development of AIDS. Using the number of length variants in the V1 and V2 hypervariable region as a marker of the overall degree of variability within HIV populations, we found no evidence for an increase or a decrease in diversity between those with and without AIDS defining illness.