HIV-1 genomic RNA diversification following sexual and parenteral virus transmission.

Human immunodeficiency virus type 1 (HIV-1) genomic RNA variation was studied in seven presumed donor-recipient pairs directly following sexual (6/7) or parenteral (1/7) transmission. The first RNA-positive serum sample of each recipient and the serum sample of the virus transmitter, identified by epidemiological history and taken within a time bracket of three months of the recipient seroconversion, were analyzed by polymerase chain reaction amplification followed by sequencing of eight cDNA clones of 276 bp, including the V3 coding region. The sequence populations of the recipients were without exception homogeneous, while the sequence populations of the transmitters showed varying degrees of heterogeneity. Nucleotide distance between consensus sequences of unrelated individuals from the Amsterdam population (interpatient variation) averaged 11% (range 7-15%). The largest distance between two clonal sequences of one individual (intrapatient variation) was also 11%. Consensus sequences of five recipients differed by only 0-1% from the consensus sequence of the presumed transmitter, including two pairs of which the transmission was either proven or highly probable. This contrasted with a difference of 10-12% in two pairs, casting doubt on the epidemiological relatedness. Antibody reactivity to a panel of V3 peptides with varying degrees of similarity to the V3 sequences obtained did not augment the discriminatory power of sequence analysis. Results of the sequential sequencing of samples of one transmitter suggest that this was due to an anamnestic antibody response of the transmitter to early variants. From the loss of sequence heterogeneity following transmission and the consensus sequence similarities observed within five transmitter-recipient pairs, we conclude that HIV-1 transmission results in the selection of a limited number of genomes carrying on the infection in the new host, but does not generally lead to a shift in the sequence population as defined by the consensus sequence.