Cell-mediated immunity to tumor antigen in Marek's disease: susceptibility of effector cells to antithymocyte serum and enhancement of cytotoxic activity by Vibrio cholerae neuraminidase

Spleen cells from chickens inoculated 7 to 8 days previously with Marek's disease virus were cytotoxic for ⁵¹Cr-labeled cells of a Marek's disease lymphoblastoid cell line (MSB-1 line) in a 4-h in vitro cytotoxic assay. The cytotoxic activity of spleen cells was inhibited by pretreatment with antithymocyte serum and complement, but not with complement alone or in combination with antibursa cell serum or normal preimmune serum. The conclusion was that the effector cell in the above cytotoxic assay was a thymus-derived lymphocyte. Also, pretreatment of target cells with Vibrio cholerae neuraminidase enhanced in vitro cytotoxic activity of effector cells. Similar enzymatic treatment of effector cells had a negligible effect on cytotoxicity.