Biological activities and endotoxic activities of protective antigens (PAgs) of Leptospira interrogans.
The biological and endotoxic activities of protective antigens (PAgs) prepared by the chloroform-methanol-water method from Leptospira interrogans serovars lai, copenhageni and canicola were examined. The PAg preparations did not show a local Shwartzman reaction in the rabbits at doses of 100 micrograms and 50 micrograms/site and lethal toxicity to galactosamine-sensitized mice at the dose of 12.5 micrograms to 50 micrograms/mouse. PAgs exhibited a weak cytotoxic action on peritoneal exudate macrophages of C3H/HeJ and C3H/HeN mice at the dose of 500 micrograms/ml in vitro, but did not show cytotoxicity for BHK-21 cells kidney cells of the Syrian hamster, CHO-K1, ovary cells of the Chinese hamster, and CHL, lung cells of the Chinese hamster, at doses of 5 and 500 micrograms/ml. Gelation activity in the Limulus test was only observed at PAg concentrations over 100 ng/ml, which dose was 10,000 times that of lipopolysaccharide (LPS) of Escherichia coli O55:B5. Furthermore, an adjuvant activity of PAgs was not observed in the production of anti-sheep red blood cell antibody in mice. Mitotic conversion of spleen cells from C3H/HeJ and C3H/HeN mice was observed by the addition of PAgs in vitro. These results indicated that the biological properties of PAgs were different from those of LPS prepared from gram-negative enterobacteria, that PAgs had no endotoxic activity and that the biological safety of PAgs as vaccine was proved.
Masuzawa
T
T
Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Nakamura
R
R
Shimizu
T
T
Yanagihara
Y
Y
D000818:Animals; D000942:Antigens, Bacterial / Q000633:toxicity*; D001681:Biological Assay; D002460:Cell Line; D002478:Cells, Cultured; D003603:Cytotoxins / Q000633:toxicity; D004731:Endotoxins / Q000633:toxicity*; D007921:Leptospira interrogans / Q000276:immunology*; D008033:Limulus Test; D051379:Mice; D008809:Mice, Inbred C3H; D008934:Mitogens / Q000633:toxicity; D011817:Rabbits
D000942:Antigens, Bacterial; D003603:Cytotoxins; D004731:Endotoxins; D008934:Mitogens