The provocation of latent lymphocytic choriomeningitis virus infections in mice by treatment with antilymphocytic serum.

The hypothesis that treatment with antilymphocytic serum (ALS) can provoke latent virus infections has been investigated. In adult mice infections with sublethal doses of LCM virus usually result in the development of immunity to the virus and at the same time to a prolonged latent infection. In the experiments described an intensive treatment with large doses of ALS was given to mice which had recovered from LCM virus infection. At the beginning of the treatment the mice had high titers of complement-fixing antibodies in their blood and no detectable virus. The data presented show that in spite of the immunity the ALS treatment provoked the occult virus and led to the development of viremia in all the treated mice. In some, very high virus titers were demonstrable. When the ALS treatment was discontinued the viremia disappeard again. In most of the mice the ALS did not suppress the complement-fixing antibody titers and in some there was even a considerable increase in titer. In such cases the increases in virus titers and in antibody titers were closely related to one another. These results demonstrate once again that the complement-fixing antibodies to the LCM virus in mice probably do not influence the virus.