[Superantigens and retroviral infections. Increase of mammary tumorigenicity due to recombination between exogenous and endogenous MMTV viruses].
A number of milk-borne exogenous mouse mammary tumor viruses (MMTV) infect mice shortly after birth and, when expressed, produce superantigens. Herein we describe the biological effects of new variants of exogenous MMTV: one of them (BALB14) present in BALB/c mice and showing a low ability to induce mammary tumors, and the other (MMTV-7) being the result of recombination between the BALB14 and the Mtv-7 endogenous provirus. The recombinant virus which has the SAg-specificity of Mtv-7 was amplified in BALB/c mice this fact correlating with a high incidence of mammary tumors. The role of strong SAgs in the mechanism by which the recombinant virus increases its title in a susceptible host is discussed. The results obtained suggest that the presence of non-productive endogenous proviruses--considered as conferring a selective advantage to the mouse population by protecting it from infection with exogenous MMTV--should also be advantageous to the pathogen by increasing its variability, thus broadening the host range and allowing the expansion of highly tumorigenic variants.
Nepomnaschy
I
I
División Medicina Experimental, Academia Nacional de Medicina, Buenos Aires.
Buggiano
V
V
Goldman
A
A
Deroche
A
A
Bekinschtein
P
P
Berguer
P
P
Piazzon
I
I
D000818:Animals; D015197:Carcinogenicity Tests; D008325:Mammary Neoplasms, Experimental / Q000276:immunology*; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011995:Recombination, Genetic; D012192:Retroviridae Infections / Q000276:immunology*; D018089:Superantigens; D014412:Tumor Virus Infections / Q000276:immunology*
D018089:Superantigens
Superantígenos e infecciones retrovirales. Aumento de la tumorigenicidad mamaria por recombinación entre virus MMTV exógenos y endógenos.