Cytokine-stimulated human natural killer cytotoxicity: response to rotavirus-infected cells.

The ability of rotavirus-infected cells to stimulate leukocytes to release a cytokine which enhanced the subsequent leukocyte cytotoxicity to a second set of [51Cr] labeled rotavirus-infected cells was analyzed. Human interferon increased leukocyte cytotoxicity to Simian rotavirus (SA-11)-infected target cells. Similarly, 11 of 12 supernates of SA-11-stimulated peripheral blood leukocyte cultures increased the killing of SA-11-infected cells (P less than 0.005). This resulted in a calculated cytokine-dependent cellular cytotoxicity value of 9.6 +/- 1.9%. Three of five of the supernates tested contained measurable levels of interferon (12-48 unit/ml). In contrast, SA-11-stimulated colostral leukocyte culture supernates neither increased leukocyte cytotoxicity nor contained measurable levels of interferon.