Alternative complement pathway activation by HIV infected cells: C3 fixation does not lead to complement lysis but enhances NK sensitivity.
HIV infected T and monocytic cell lines could activate and fix C3 fragments when incubated in human serum under conditions allowing for activation of the alternative complement pathway. Normal T lymphocytes incubated with HIV could also activate and fix C3. This activity was, at least in part, the property of the virus itself since cell-free HIV could efficiently activate C3. The C3 activating HIV infected cells were resistant to complement-mediated lysis, even after prolonged incubation periods. However, their sensitivity to cell-mediated natural killing increased, presumably due to their interaction with complement receptor bearing NK lymphocytes. The results suggest that the alternative complement pathway may contribute to the depletion of CD4+ T lymphocytes during HIV infection in vivo.
Yefenof
E
E
Lautenberg Center for General & Tumor Immunology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Asjö
B
B
Klein
E
E
D002460:Cell Line; D003176:Complement C3 / Q000378:metabolism; D003170:Complement Pathway, Alternative; D003602:Cytotoxicity, Immunologic; D006678:HIV / Q000276:immunology; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D003176:Complement C3