Immunity against the mouse mammary tumour virus : immunologic events during tumour growth and studies on vaccination in mice

Development of mouse mammary tumours is a complex phenomenon, to which environmental factors, genetic background and the presence of an oncovirus contribute. The mammary tumour virus (MTV) of the mouse, first discovered by Bittner (1936), is a so-called B-type particle (Bernhard, 1958) and is composed of two major distinguishable elements {Sarkar et al., 1971): a bilayer lipid membrane whose exterior surface is covered with knobbed projections and a viral core. The virus consists of at least 11 different polypeptides; two of the major proteins are glycoproteins with molecular weights of 45,000 to 55,000 and 34,000 to 36,000 Daltons (D); they are usually referred to as gp52 and gp36. The knobs of the viral projections are composed of gp52; the gp36 component is situated within the membrane from which the projections protrude. Three other major polypeptides with molecular weights of approximately 28,000 (p28), 18,000 (p18) and 12,000 (p12) D are associated with the viral core. The main group-specific antigens are gp52 and p28 (Sarkar and Dion, 1975; Sarkar et al., 1976).