Morphologic and antigenic properties of mouse mammary tumor virus produced in a hormone-responsive fashion by C57Bl/10 mammary tumors of non-viral origin.
Bl-MaTU/A1 mouse mammary tumor cells, derived from a C57B1/10 mammary adenocarcinoma induced by dimethylbenzanthracene and mammotropic hormones, express virus particles and proteins related to mouse mammary tumor virus (MMTV). Immunocytochemical analysis by means of monospecific and monoclonal anti-gp52 sera revealed a different localization of the main structural proteins of MMTV in Bl-MaTU/A1 and GR cells (the latter used as a positive virus-producing control). Immunoelectron microscopy of B-type particles budding from the microvilli of dexamethasone-stimulated Bl-MaTU/A1 cells showed remarkably weak reactivity of the viral envelope with anti-gp52-protein A-gold complexes as compared with that of dexamethasone-stimulated GR cells. Since Bl-MaTU/A1-associated MMTV originates from the amplified unit II of endogenous MMTV, which is altered probably within the env gene, the observed antigenic difference in the Bl-MaTU/A1-associated MMTV may be due to altered synthesis of gp52 glycoprotein in these cells.
Marchetti
A
A
Institute of Pathologic Anatomy and Histology, University of Pisa, Italia.
Svec
J
J
Hlavay
E
E
Veselovska
Z
Z
Castagna
M
M
Squartini
F
F
D000230:Adenocarcinoma / Q000139:chemically induced / Q000382:microbiology*; D000818:Animals; D000957:Antigens, Viral, Tumor / Q000276:immunology*; D000939:Epitopes; D005455:Fluorescent Antibody Technique; D066298:In Vitro Techniques; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000382:microbiology*; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D014407:Tumor Cells, Cultured / Q000276:immunology; D014771:Virion / Q000276:immunology
D000957:Antigens, Viral, Tumor; D000939:Epitopes