Inhibition of cytolytic activity by Meth A cells cannot be neutralized by anti-TGF-beta antibody. A cold target inhibition assay was carried out with H-2^d anti-H-2^b CTLs and EL-4 target cells. Cold target cells, antibody, and the buffer control are listed. The diamond indicates CTL killing in the absence of cold target (effector to target ratio 10).