Immunization with p30 Enhances the Growth of a Rat Moloney Sarcoma

Abstract

Abstract p30, a core polypeptide, and gp 70, an envelope glycoprotein of C-type RNA tumor viruses, are present on the surface membranes of tumors induced by C-type virus. They have also been implicated in the development of host immunologic resistance to tumor growth (1–5). We have immunized rats with homogeneous preparations of p30, gp 70, and intact tumor cells to study their role in the growth and progression of challenge with a rat Moloney sarcoma (MST).3 MST produces Moloney leukemia virus (MuLV) particles in vitro and in vivo (6). Cultures of rat Moloney sarcoma cells (MST) were prepared from tumors induced by injecting MSV extracted from tumors of BALB/c mice into newborn Brown Norway (BN) rats (6). Cultures of cells were also prepared from a sarcoma induced by injecting newborn BN rats with 3-methylcholanthrene (BC5). BC5 cells were free of virus by electron microscopic and antigenic analyses (see below).