THE PROTECTIVE EFFECT OF MATERIALS EXTRACTED FROM BACTERIAL CELLS AGAINST INFECTION IN EXPERIMENTAL SALMONELLOSIS1. PROTECTION WITH PHENOL EXTRACT

摘要

The protective effect of living as well as killed cells and phenol extracts obtained from an attenuated strain of Salmonella enteritidis against infection with a virulent strain in mice were studied. Results summarized as follows.1. Killed cells of an attenuated strain had no protective effect against infection with a virulent strain, though living cells were remarkably effective.2. Eight fractions were obtained from an attenuated strain by extraction with phenol. A large amount of RNA and a small amount of DNA with protein were contained in these fractions.3. It was shown that fraction I and 1V extracted with phenol pH 4 had some protective effects against infection, but the remaining fraction I-D, Ill and all of the fractions extracted with phenol pH 6 were ineffective.