Suppressor cells detected in murine bone marrow chimeras.

Bone marrow cells from BALB/c mice were transplanted into lethally X-irradiated C3H/He mice, either intravenously (i.v.) or intrasplenically (i.s.). Chimeras created by intrasplenic transplantation (designated i.s. chimeras) showed a higher survival rate than chimeras created by intravenous transplantation (designated i.v. chimeras). During the course of the study on the mechanisms which caused such a difference, suppressor cells were detected in the spleen of i.s. chimeras by means of MLR co-culture assay and CTL assay. Although these cells were also detected in i.v. chimeras, time course study of the suppressor activity against donor anti-host MLR in i.v. and i.s. chimeras showed some difference. Namely, the suppressor activity in the i.s. chimeras was more constant than that in the i.v. chimeras. This difference may induce a beneficial effect of i.s. bone marrow transplantation.