INCREASED ANTIBACTERIAL RESISTANCE AND IMMUNODEPRESSION DURING GRAFT-VERSUS-HOST REACTIONS IN MICE

Graft-versus-host (GVH) reactions were induced in adult C57BL/6J X A/J F1 hybrid mice by i.v. injection of parental (A/J) spleen cells. Eighteen days later, spleen weight was increased, but no other overt signs of GVH disease were present. At this time, various aspects of resistance to infection and immunological responsiveness were examined. Animals given parental cells were highly resistant to i.v. infection with an intracellular bacterial parasite, Listeria monocytogenes, when compared with control mice given isogeneic or allogeneic spleen cells, or nothing. There was marked depression of the growth of Listeria in the spleen and liver and increased survival after a large challenge dose. Furthermore, the mice undergoing GVH reactions possessed a peritoneal macrophage population with greatly increased capacity to inactivate Salmonella typhimurium, another intracellular parasite. The antibody response to sheep erythrocytes, as measured by direct plaque-forming spleen cells and serum hemolytic and hemagglutinin titres, was almost completely suppressed when sheep erythrocytes were injected i.v. 18 days after parental spleen cells. In addition, depression of the immune response to keyhole limpet hemocyanin given s.c. in Freund’s complete adjuvant was manifest in mice with GVH reactions by failure to develop immediate hypersensitivity reactions to subsequent injections of hemocyanin into the footpad. © 1969 by The Williams and Wilkins Co.