Abstract
When lymphoid cell suspensions from the spleen, lymph nodes, blood, and thoracic duct of parental strain adult rats were injected beneath the renal capsule of F(1) hybrid hosts, the transferred cells and/or their progeny invaded the underlying renal cortex and destroyed most of the tubules which they surrounded. The immunogenetic conditions under which this reaction was observed defined it as a graft vs. host reaction (GVHR). On the 7th day the GVHRs were histologically similar to primary renal homografts undergoing rejection. Lymphoid cells from donors tolerant to the other parental strain were inactive after transfer to the hybrid, whereas cells from either normal or sensitized donors consistently produced reactions of about equal severity. Lewis lymphoma cells displayed malignant, invasive activity but did not destroy either isologous or homologous tissue, showing that the presence of an infiltrate was not per se sufficient to damage the parenchyma. These observations indicate that the GVHRs were manifestations of the ability of the transferred lymphocytes to enter into a homograft reaction with consequent destruction of renal parenchyma, and support the hypothesis that at least some of the lymphocytes which are seen infiltrating primary homografts are the agents which effect their destruction.