Abstract
In order to bring light on the mechanism of the experimental typhoid infection and the accompanying secondary septicemia and the immunity to them, the mice which received pertussis vaccine intraperitoneally and preparatorily were challenged intraperitoneally with S. enteritidis of varying virulence.
As a result, it was found that this preparatory inoculation of pertussis vaccine exhibited ann evident defense action against the challenge with a moderately virulent strain of S, enteritidis andd the mice may could tolerate the experimental typhoid infection and the secondary septicemia, while this defense action could not clearly be seen against the challenge with a fully virulent strain of S. enteritidis.
The serologically nonspecific defense phenomenon observed by the author seems to be different in respect of the mechanism from the prevention by vaccination with attenuated living bacilli of homologous species, because in the former phenomenon the locus where the pertussis vaccine was inoculated exerts an important role in the effect on the challenge organisms and the effect originatedd by the inoculation of pertussis vaccine was demonstrated only for a limited period of time.
Basing on these observations, the preventive effect on the typhoid infection was analytically discussed from the view point of infection and immunity, and the mechanisms of the typhoid infection and of the immunity to it were revealed to some extent.
