Immunological unresponsiveness of nude mice to LCM virus infection.

The acute LCM infection in nude mice runs a course which is clinically inapparent, and neither a humoral nor a cell-mediated immune response could be detected. Furthermore, during this infection the blood virus titers reached extremely high values. These observations are contrary to what is seen when ordinary normal mice are infected with the LCM virus but identical with the events following infection of ordinary but immune-deficient mice. Despite the absence of immune responses to the virus in the nude mice the very high virus titers obtained within the first few days of the infection declined somewhat during the following weeks. This and the other observations made are discussed briefly in the light of the current hypothesis concerning the immune status of the nude mice and the pathogenesis of the LCM virus infection in mice.