Effects of Salmonella infection on hemopoietic stem cells in mice immunized with Salmonella vaccines.

Effects of Salmonella enteritidis infection on hemopoietic stem cells were examined in mice immunized with killed bacteria and in those immunized with viable bacteria. The results are summarized as follows: i) Mice immunized with the killed salmonellae showed hemopoietic responses similar to those of normal, nonimmunized mice, i. e., increase in CFUs and CFUc in the spleen and decrease in these cells in the bone marrow. ii) Mice immunized with viable salmonellae were protected from such decreases in bone marrow stem cells, but showed a decrease in spleen CFUc, with a concomitant decrease in the peripheral granulocytes. iii) Hemopoietic responses to viable salmonellae of mice immunized with viable bacteria differed from the responses to killed salmonellae of normal, non-immunized mice. These results suggest that both LPS and cell-mediated immune responses affect hemopoietic stem cells in mice infected with salmonellae.