SUPERANTIGENIC CHARACTERISTICS OF MOUSE MAMMARY-TUMOR VIRUSES PLAY A CRITICAL ROLE IN SUSCEPTIBILITY TO INFECTION IN MICE

Mouse mammary tumor viruses (MMTV) are retroviruses that induce mammar y carcinomas. An interesting feature of these viruses is the superanti gen (SAg) encoded in an open reading frame within the 3' long terminal repeat. The mechanism by which ingestion of milk-borne virus results in infection of the host mammary tissue remains incompletely understoo d. However, a working model has been proposed in which the interaction between viral SAg, T-cell receptor and MHC class III-E facilitates vi ral replication and hence infectivity. In this review we summarize cur rent studies demonstrating the role of SAg stimulation in susceptibili ty to MMTV infection.