Observations on immunological tolerance and “Immunity” in mice infected congenitally with the virus of lymphocytic choriomeningitis (LCM)

Summary and conclusions

In a comparative study of the distribution of viral antigen in the organs of tolerant mice infected congenitally with LCM virus and of non-tolerant mature animals infected experimentally the complement-fixation titer was used as an indicator of the intensity of the infection. Preliminary tests had shown that there is a rough parallelism between the complement-fixation and infectivity titers of murine organs.

The organs of congenitally infected mice, young or old, generally contained more antigen than those of mature mice infected artificially. The very high antigen content of the lymphatic system in tolerant animals has been correlated with the tolerance phenomenon and the possibility considered that their immunological apparatus may be blocked by specific antigen as in mice showing “immunological paralysis” following inoculation with large doses of pneumococcal polysaccharide.

Mice tolerant towards LCM virus were able to produce hemagglutinationinhibiting antibodies against EEE virus to the same extent as normal mice in spite of the fact that LCM infection interferes slightly with EEE infection in tolerant animals.

The results of interference tests with distinguishable strains of LCM virus favor the hypothesis that the strong “immunity” of tolerant mice in the absence of antibodies is due to the interference phenomenon.