Functional role of NK cells in generation of anti–BW-Sp3 CTLs.

Splenocytes from immunocompetent or α-ASGM-1–treated BW-Sp3 tumor-bearing AKR mice were restimulated in vitro with irradiated cancer cells. After 5 days, viable lymphocytes were collected. (A) Cytolytic activity of effector CTL was measured in a 4-hour¹¹¹In-release assay against MHC class I⁻ BW-O (■) or BW-Sp3(B7-1) (░) target cells. Effector-to-target ratio for the presented results is 100:1. (B) Percentage of CD8⁺ T cells in restimulated CTL cultures. ▪ represents the fraction of CTLA4⁺ subpopulations; ■, the fraction of CD69⁺. (C) Percentage of CD4⁺ T cells in restimulated CTL cultures. ■ represents the fraction of CD69⁺ subpopulations. ■ indicates CD4⁺CD69⁻. Base line represents control percentages in restimulated naive spleens. These experiments were repeated at least 3 times, and the averages of these independent experiments are represented with their standard deviations. The statistical difference between immunocompetent and NK-depleted CTL populations at each time point is P ≤ .0095.