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Different Sensitivity of Complement to Salmonella typhimurium Accounts for the Difference in Natural Resistance to Murine Typhoid between A/J and C57BL/6 Mice
Author(s) -
Nakano Akira,
Kita Eiji,
Kashiba Shuzo
Publication year - 1995
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1995.tb02175.x
Subject(s) - opsonin , microbiology and biotechnology , biology , salmonella , lipopolysaccharide , spleen , antibody opsonization , in vitro , intracellular , c57bl/6 , incubation , in vivo , interferon gamma , phagocytosis , bacteria , immunology , biochemistry , genetics
The difference in natural resistance to Salmonella typhimurium between S. typhimurium‐ resistant A/J mice and S. typhimurium ‐susceptible C57BL/6 mice was analyzed. In both strains, the growth of S. typhimurium was controlled in the spleen until 48 hr of infection, while serum C3b levels were increased in A/J mice immediately after infection but not in C57BL/6 mice. Incubation of A/J mouse serum with S. typhimurium or its lipopolysaccharide (LPS) generated sufficient amounts of C3b, but that of C57BL/6 mouse serum with them did not. A/J macrophages had higher intracellular killing activity in vitro than did C57BL/6 cells against S. typhimurium pre‐opsonized with each corresponding fresh serum. However, the cells from both mice exhibited a similar level of killing activity against S. typhimurium pre‐opsonized with fresh A/J serum or rabbit complement. The resistance of C57BL/6 mice was significantly increased by opsonizing S. typhimurium with fresh A/J serum or rabbit complement before inoculation. The serum level of interferon‐γ (IFN‐γ) in A/J mice was 2.7 times as high as in C57BL/6 mice at 48 hr post‐infection. Recombinant murine IFN‐γ enhanced the intracellular killing activity of macrophages from both mice when S. typhimurium was pre‐opsonized with fresh A/J serum but not with fresh C57BL/6 serum. These findings suggest that A/J macrophages exhibit maximal killing activity against A/J serum‐opsonized S. typhimurium in vivo when the cells are activated with IFN‐γ. Therefore, the rapid and sufficient activation of complement by Salmonella LPS may render A/J mice more resistant against murine typhoid.