Improved survival mediated by Corynebacterium parvum following allogeneic bone marrow transplantation in rabbits

The effect of Corynebacterium parvum on survival was studied in aplastic rabbits transplanted with allogeneic bone marrow cells. Twenty four hours after receiving 1200 rad of total body irradiation, NZW males were reconstituted from unrelated R females using bone marrow combined with spleen cells or with marrow alone. The effects of treating donor, or both donor and recipient, with C parvum were contrasted. Rabbits in Group I were infused with a mixture of bone marrow and spleen cells. In control aminals (Group Ia) none of the 14 animals survived to 40 days. Similarly, there were no survivors among 17 animals in group Ib where only the donors were pretreated with C. parvum. When both donor and recipient received this agent (Group Ic) three of the 13 animals (23%) survived beyond 40 days. Animals in Group II were infused with marrow cells alone. Of the controls (Group IIa), 3 out of 24 animals (12.5%) survived to 40 days; pretreatment of the donor with C. parvum (Group IIb) resulted in survival of 8 of the 18 animals (44%); when both donor and recipient received this agent (Group IIc), 16 of 26 animals (62%) survived beyond 40 days. Both the incidence and the severity of histologically demonstrable graft-versus-host disease was markedly reduced in the surviving animals. These observations demonstrate a significant effect of parenteral C. parvum on the prolongation of survival in the irradiated rabbit following transplantation with allogeneic bone marrow cells, which is related to reduction in GVHD.