Mouse mammary tumor virus (MMTV) is a retrovirus that causes breast cancer in mice. MMTV-induced breast cancers represent a well-established model for human breast cancer research. ... if exogenous MMTVs infect germline cells, the viral genome becomes a stable part of the mouse genome and may be inherited from either parent (endogenous MMTV). In this report, the authors demonstrate that mice carrying endogenous MMTV in their genomes are more susceptible to disparate infectious agents, such as exogenous MMTV and the cholera-producing bacteria, Vibrio cholerae. However, this effect was selective since disease induced by another related bacteria, Salmonella typhimurium, was not affected. Genetic evidence suggests that a viral protein produced by endogenous MMTVs enhances pathogen-induced disease and death. Further, the human genome contains many human endogenous virus type Ks, which highly resemble MMTVs and also may influence disease. Therefore, this study suggests that endogenous retroviruses found in the mouse and human genomes alter the course of disease induced by multiple pathogenic organisms.
... mice that lack all endogenous Mtvs were resistant to mammary tumors induced by MMTV, lymphomas induced by TBLV, and mortality due to V. cholerae
... To our knowledge, our data represent the first report that a retroviral susceptibility mechanism may extend to bacteria. ... The dynamic compromise for mutual survival of both MMTV and the mouse will be influenced by complex interactions between the MMTV-modulated murine immune system and numerous environmental pathogens.
