Abstract
Peripheral blood lymphocytes, intraepithelial lymphocytes from the small intestine and lymphocytes from the thymus, spleen, mesenteric lymph nodes and Peyer's patches from 5 young adult pigs were used as effector cells in a spontaneous cell-mediated cytotoxicity chromium release assay against PK-15 cells persistently infected with transmissible gastroenteritis virus as targets. Both peripheral blood and intraepithelial lymphocytes caused marked specific chromium release, while the lymphocytes from the remaining tissues were inactive in spontaneous cell-mediated cytotoxicity.