Sex, alloimmunisation, and susceptibility to HIV infection.

Presents a commentary on a report in this issue concerning how women who have unprotected sexual intercourse with the same man over a year generate a significant alloimmune response against their partner's leucocytes as compared to third-party leucocytes. Contention that this "immunisation" probably arises via repeated exposure to HLA antigens expressed on leucocytes and epithelial cells in semen and female genital secretions; Additional finding that T cells isolated from the test subjects were resistant to both CCR5 and CXCR4 binding strains of HIV-1 in vitro; Thought by study authors that the concept of mucosal alloimmunisation may be a vaccine strategy to induce protection against HIV-1; Belief that the study raises more questions than it offers clinical applications.