Effects of adult F1 thymocytes on graft-versus-host splenomegaly and homing of parental normal and cortisone-resistant thymocytes in F1 neonates.

In Simonsen assays parental cortisone-resistant thymocytes (P-CRTs) accounted for all of the thymic graft-versus-host reactivity (GVHR) of 3- to 6-week-old BALB/c males in (C3H X BALB/c) (CBF1) neonatal recipients. In the course of these studies, it was observed that coinjection of P-CRTs with large numbers of normal CBF1 thymocytes (F1 NTs) significantly reduced the GVHR of the P-CRTs as measured in Simonsen splenomegaly and [3H]TdR splenic proliferation assays. Homing experiments indicate that one explanation for the reduction in GVHR was a specific decrease in the homing of P-CRTs to spleens of F1 neonatal hosts when P-CRTs were coinjected with F1 NTs.