Complement-mediated anti-HIV-1 effect induced by human IgM monoclonal antibody against ganglioside GM2

HIV-infected cells aberrantly express a high level of antigenic glycosidic structures such as GM2 and Gg4, Some normal sera containing natural IgM Abs to GM2 and/or Gg4 cause C-mediated cytolysis of HIV-infected cells. In the present study we demonstrated that a human IgM anti-GM2 mAb (L55 Ab) can i nduce cytolysis of HIV-infected cells. Increased GM2 expression by HIV-1 in fection of a human T cell line (MOLT4), a human monocyte cell line (U937), and human lymphoblastoid cells was confirmed by immunofluorescence staining with L55 Ab. These infected cells were readily lysed by L55 Ab in the pres ence of fresh human serum as a C source that alone did not cause cytolysis. L55 Ab also had the ability to destroy HIV-1 particles via C-mediated lysi s. By adding L55 Ab together,vith human C to mixed culture of HIV-infected cells and naive cells, HIV-1 replication was significantly suppressed, and this effect was synergistic when L55 Ab was combined,vith a reverse transcr iptase inhibitor and a proteinase inhibitor, Therefore, a human IgM anti-GM 2 mAb may be effective in treating HIV-infected patients, especially when u sed together with chemotherapeutic agents.