Tumor-Specific and Allospecific Immunogenicity of Soluble Extracts from Chemically Induced Murine Sarcomas

Abstract

Abstract Chemically induced tumors possess vastly polymorphic tumor-specific transplantation antigens (TSTA)2 on their cell surfaces (1–4). Elucidation of the nature of tumor immunity will require detailed analysis of these antigenic markers. One step in such an endeavor is the solubilization of the marker from the cell membrane. There are several techniques to release cell surface antigens, namely, treatment with detergents or organic solvents, enzymatic hydrolysis, exposure to sonic energy, and salt extraction (5). Tumor-specific activity of the solubilized materials has been demonstrated by two types of immunologic assays: 1) in vivo immunogenicity, which is the capacity to protect syngeneic hosts against subsequent tumor challenge, and 2) elicitation of specific immune performances by sensitized cells, such as delayed-type cutaneous reactions, antigen-specific lymphocyte proliferation in vitro, and inhibition of the spontaneous migration of macrophages from sensitized hosts. Materials obtained from chemically induced guinea pig hepatomas by 3 M KCl extraction displayed tumor-specific antigenicity by the latter criteria (6, 7).