The Mouse mammary tumour virus (MMTV) is a retrovirus from the genus betaretroviruses. Several mouse strains carry the virus endogenously, but it is also trasmitted horizontally via milk from mother to pup. In the gut, the virus is taken up in Peyer's patches and infects B lymphocytes. MMTV codes for the retroviral structural genes and additionally for a superantigen. This stimulated T lymphocytes with a certain type of V beta chain in their T cell receptor, which in turn stimulates B cell proliferation increasing the population of cells that can be infected. During puberty, the virus enters the mammmary glands with migrating lymphocytes and infects proliferating mammary gland epithelial cells. MMTV can cause mammary carcinomas and also t cell lymphomas. It does not encode for an oncogene. The "LTR" contains a glucocorticoid hormone response element.

Retroviruses

Maus-Mammatumorvirus