Non-specific resistance to virulent infection with Salmonella enteritidis was studied in the mice previously infected with BCG, and the following results were obtained.
1) In CFl, DKl and dd mice, the non-specific resistance was found to be induced at the 3rd and 5th week of BCG-infection but not within one week. In DKl mice, which have been inbred in our Department as an extremely susceptible mouse strain against the infection with S. enteritidis, the non-specific resistance was induced in a low degree by BCG infection.
2) Intravenous infection with BCG was the most effective route for induction of the non-specific resistance.
3) The non-specific resistance started to be effective about 10 days after the infection with BCG and remained effective even after 13 week of the infection.
4) In BCG-infected mice growth of the infected S. enteritidis in the liver, spleen, lungs, peritoneal cavity and blood was found to be inhibited already 6 hours after the infection with Salmonella, and the growth of S. enteitidis was also found to be retarded thereafter as compared with the growth in control mice.
5) Immunization with killed BCG bacilli mixed with adjuvant could not confer the non-specific resistance on mice.
