Increased LAK activity against HIV-infected cell lines in HIV-1+ individuals.

The role of natural killer (NK) cells and their inducible counterparts, lymphokine-activated killer (LAK) cells in AIDS with regard to HIV-1 viral immunosurveillance and the control of secondary opportunistic disease has yet to be established. In this study, we have demonstrated that LAK cells derived from all HIV-1+ groups showed striking increases in their capacity to lyse HIV-1-infected U-937 cells relative to their uninfected U-937 counterparts. Surprisingly, similarly derived LAK cells from healthy seronegative controls showed no differences in their lysis of HIV-1-infected versus uninfected U-937 cells. The differential ability of LAK effectors from seropositive donors to lyse HIV-1-infected targets was demonstrable using a number of U-937 subclones and their HIV-1-infected counterparts. Again, no differences in LAK cell-mediated lysis of HIV-1-infected and uninfected U-937 subclones were observed in seronegative individuals. Our findings that HIV-1+ individuals show selective expansion of non-MHC restricted, HIV-1-directed cytotoxic LAK cells indicate that natural immunity may indeed play a role in HIV-1 viral immunosurveillance.