Objective: To study the molecular epidemiology of HIV-1 subtype B amongst heterosexually infected individuals in The Netherlands.
Design: The study population comprised 54 individuals infected by subtype B viruses through heterosexual contacts. Serum samples were collected between 1988 and 1996.
Methods: Sequences of the gp120 V3 region were obtained from serum samples and analysed by using the signature pattern and phylogenetic methods.
Results: In 22 (41%) out of 54 subtype B sequences from heterosexually infected individuals, the synonymous nucleotide substitution in the second glycine codon at the tip of the V3 loop (the GGC pattern), previously identified as specific for Dutch injecting drug users (IDU), was found. The other previously described IDU sequence patterns were observed significantly more often among GGC- than among non-GGC-containing sequences. In addition, we identified another amino-acid change specific for the GGC sequences. In the phylogenetic and principal coordinate analyses, the GGC sequences from heterosexually infected individuals clustered separately from the non-GGC sequences and together with the IDU consensus sequence. Both the nonsynonymous and particularly the synonymous distances amongst the GGC sequences were significantly lower than amongst the non-GGC sequences.
Conclusions: Our data provide evidence for a common origin of the viruses in Dutch IDU and the GGC viruses in heterosexuals. We suggest that a considerable proportion of the viruses in heterosexually infected individuals in The Netherlands may have originated from Dutch IDU.