alloreactive lymphocytesLymphocytes responsible for the strong humoral and cellular responses to non-self antigens. Repeated exposure to the lymphocytes of another person, as occurs in unprotected sexual intercourse, promotes a significant immune response to that person's lymphocytes compared with other person's lymphocytes. This is probably due to exposure to HLA antigens on white cells and epithelial cells in semen. There is evidence that such mucosal alloimmunization may provide some protection against HIV infection.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005