NK cells lacking CD158a, CD158b, and CD159a have greater ability to kill HIV-infected cells. HIV-1_SF162-infected T-cell blasts were used as target cells in a 4-hour cytotoxic assay. NK cells were depleted of CD158a⁺, CD158b⁺, and CD159a⁺ cells before their use as effector cells in the cytotoxic assay. NK cells not depleted of CD158a⁺, CD158b⁺, and CD159a⁺ cells were used as controls. Effector cell-target cell ratios of 1:1, 5:1, and 10:1 were used. All samples were performed in triplicate. Student t test was used to determine the statistical differences between percentage of specific lysis of HIV-infected cells by NK cells depleted of cells bearing CD158a, CD158b, and CD159a, with percentage of specific lysis of HIV-infected cells by unfractionated NK cells containing CD158⁺, CD158b⁺, and CD159a⁺ cells. ^*P < .05; ^**P < .01