Demonstration, properties and significance of neutralizing antibodies in mature mice immune to lymphocytic choriomeningitis (LCM)

Summary and conclusions

Neutralization of LCM virus by murine immune sera was intensified by prolonged incubation (24 hours at 37° C) of the mixtures of serum and virus prior to intraperitoneal inoculation into mice. The neutralizing capacity of the sera tested was very low compared with that of mice immune to other viruses.

With the improved technique neutralizing antibodies were regularly demonstrated in serum pools from mature mice infected experimentally or by contact but not in the brains of such animals or in mice infectedin utero.

In contrast to the progeny of mice immune to influenza or EEE viruses, litters from LCM-immune females showed very little passive immunity when challenged intracerebrally at the age of 4 to 14 days and, in general, reacted more severely to the infection than normal controls. This phenomenon has been correlated with the hypothesis (3) that the symptoms of mice infected with LCM virus by the cerebral route are primarily caused by an antigen-antibody reaction.

The results obtained favor the theory that the immunity resulting from experimental infection of adult mice with the virus under study is not exclusively due to the presence of neutralizing antibodies (11, 5).