Definitions of M Locus
Genetic loci responsible for the encoding of minor lymphocyte stimulatory antigens. There are at least two unlinked loci ( in the mouse) and they appear to be separate from the major histocompatibility complex and minor histocompatibility loci. The mouse mammary tumor virus ( see MAMMARY TUMOR VIRUS, MOUSE) has the ability to integrate into these loci. The antigens induce strong T- cell proliferative responses in mixed lymphocyte reactions.