Complement-mediated cytolysis and azidothymidine are synergistic in HIV-1 suppression.

Some normal human sera contain a natural IgM antibody against gangliotetraose and GM2 which is capable of initiating complement-mediated cytolysis of HIV-1-infected cells. A potent cytolytic serum (lytic serum) harboring this antibody also caused lysis of HIV-1 virions. When lytic serum was added to a mixed culture of HIV-infected cells and naive cells at a ratio of 1:100, expansion of HIV-1 infection was postponed by 1 week. Furthermore, the co-presence of both the lytic serum and azidothymidine continued to significantly suppress infection, even after 4 weeks of cultivation.