Evidence of cell-mediated antitumor immunity in rats bearing syngeneic tumors by the leukocyte adherence inhibition test.

A modified form of the leukocyte adherence inhibition (LAI) test has been used to follow cell-mediated immunity (CMI) in rats of the Lewis inbred strain (LW), F1 hybrids inbred strains LW x AVN with transplanted syngeneic tumors B77, MC-1, and the random-bred Sprague Dawley strain with spontaneous REF tumor. Peripheral blood leukocytes of animals incubated witha specific tumor extract showed an adherence capacity by 30--40% lower than the same cell population cultured without this specific extract, or with a foreign nonspecific extract. The results are commented in connection with a possible application of this modified form of LAI test in studies of the immunological state of patients with a malignant disorder.