Cyclosporin receptor on mouse lymphocytes.

Specific binding of [3H]-cyclosporin C (3H-CS-C), an immunosuppressive oligopeptide, was characterized on different mouse lymphocytes. The binding was saturable, time-dependent and reversible; and KD of 1.5 x 10(-7) M and maximum binding capacity Bmax of 35 pmol/4 x 10(6) cells was found for thymocytes. A computerized analysis of the data confirmed a single population of high affinity binding sites. Lymphocytes of different organs differed in their Bmax: thymus greater than spleen greater than mesenteric lymph node (pure T cells) greater than mesenteric lymph node (pure B cells). Erythrocytes did not show a specific binding.