Relative immunologic capacity of leukemic and low-leukemic strains of mice to resist infection.

A comparative study was made to determine whether young mice predisposed to a high incidence of spontaneous leukemia displayed a distinctive response to infection which could be related to either a hyperactivity of their reticuloendothelial system (RES) or, conversely, some immunologic deficiency. The relative susceptibility to experimental infection of young mice (7-10 weeks old) of '"leukemic" strains (AKR and C58) was compared with "low-leukemic" strains (C57BL/6, Swiss, BALB). Test agents included: Candida albicans, Blastomyces dermatitidis, Histoplasrna capsulatum, Sporotrichum Schenckii, Streptococcus pyvgenes, and Salmonella typhosa Ty~. When the dose levels of mycotic agents were carefully adjusted, it was possible to demonstrate marked differences in the response of male and female mice of the same strain to infection. Relative differences in the susceptibility of diverse inbred strains to mycotic infection were pronounced. Generally, predisposition to leukemia failed to correlate with either resistance or susceptibility to mycotic infection. Results with the bacterial agents presented the same general pattern. Experimental findings were discussed in regard to relative differences in the immunologic competence of "leukemic" and "low-leukemic" mice to resist infection and its possible relationship to early detectable changes in the RES of hosts predestined to manifest spontaneous malignant neoplasms.