HIV-1 in semen: an isolated virus reservoir

The reservoir of HIV-1 in semen is unknown. Semen is comprised of secretions and cells from seminal vesicles, prostate, testis, epididymis, and ejaculatory ducts; leucocytes are present in semen, although their source and their role in the semen viral burden is unclear. Reports that semen viral RNA concentrations do not correlate with those in plasma, that infectious virus in semen is independent of plasma viraemia and discordant with respect to syncytium-inducing properties or nucleoside resistance, and that the envelope sequences of sexually transmitted virus differ from those in the blood of the transmitter, suggest that semen HIV-1 does not arise from the same reservoir of infection as peripheral blood.