Increased serum IgG2b and IgM & IgG1 Fc receptors expressed on tissue mast cells in experimental GVHR and HVGR rat models.

Abstract

Chronic graft-versus-host reaction (GVHR) due to male specific (H-Y) antigen was induced by the injection of syngeneic (DA x Lewis) F1 female cells into (DA x Lewis)F1 male rats. Chronic host-versus-graft reaction (HVGR) based on major histocompatibility complex (MHC) (RT1a) occurred when host Lewis (RT1(1)) rats were transplanted (DA x Lewis)F1 donor cells (RT1a & RT1I). Chronic GVHR and HVGR were activated at fixed periods. The first attacks of the GVHR and HVGR were recognized 50-80 days after cell transplantation, but the most intensive attacks of both responses were observed 120-175 days after cell transplantation. During the most intensive attacks, two rats died from either GVHR or HVGR. Rat immunoglobulin assays measured by radial immunodiffusion (RID) showed that serum IgG2b rose to 10.600-11.500 mg/ml in the rats that had the advanced GVHR or HVGR. The tissue mast cells derived from the loose lymphoid tissues of the medullary and subcapsular sinuses have proliferated in the mesenteric lymph nodes of the rats. IgM and IgG1 binding Fc receptors expressed on the mast cells were demonstrated indirectly using alkaline phosphatase conjugated ant-rat IgM and anti-rat IgG1.