The immunological relationship between filtrable agent, Salmonella and murine leukosis.

Salmonella typhimurium was invariably isolated from our J strain murine leukosis. Immunization of D103 mice with either inactivated Salmonella typhimurium or the cell-free extract of leukosis inhibited the transplantation of leukosis. The adoptive immunization of D103 mice with spleen cells of Strong A mice immunized with either Salmonella or the cell-free extract of leukosis inhibited the transplantation of leukosis. The addition of either Salmonella or the cell-free extract of leukosis inhibited the migration of macrophages of leukosis spleen in tissue culture. Strong A mice is non-susceptible to J strain leukosis. However, inoculation of neonatal Strong A mice with the cell-free extract of leukosis produced a susceptibility to the transplantation of leukosis. These results suggest that both a filtrable agent and Salmonella typhimurium are present in cells of this leukosis and might be etiologically related to the leukosis.