Listeriosis in beige mice and their heterozygous littermates.

The ability to resist the facultative intracellular bacterium Listeria monocytogenes was not impaired in the beige mutants of C57BL/6J mice which are known to be deficient in a number of immune functions. The intravenous LD₅₀ of Listeria in beige (bg/bg) mice and their normal heterozygous (bg+) littermates was approximately 5 × 10⁵. Growth of Listeria in the spleen and liver during primary and secondary infections was similar in the two groups of mice, and each was able to act efficiently in adoptive transfer of immunity. Histological examination showed a normal accumulation of polymorphonuclear and mononuclear cells at foci of infection in the liver, while in the spleen the previously described depletion of T cells 2-4 days after infection was observed in both groups. In-vitro 18-hr cytotoxicity of peritoneal cells for P815 targets, a function usually attributed to macrophages, was increased 2 days after infection in both bg/bg and bg/+ mice. In contrast, 4 hr cytotoxicity of spleen cells for YAC-1 targets, considered typical of natural killer (NK) cells, was depressed in uninfected bg/bg mice and only slightly raised during infection. This compared with a normal NK activity in uninfected bg/+ mice which was markedly increased during infection. [ABSTRACT FROM AUTHOR]