Induction of immunity to chemically-induced rat tumours by cellular or soluble antigens

Abstract

Summary. Radiation-attenuated, aminoazo

Modification of the immunogenicity and antigenicity of rat hepatoma cells. II. Mild heat treatment

“…This concl-usion cannot be generally applied directly to the immunogenic capacity of cellular antigen preparations or chemically inactivated (e.g. iodoacetamide-treated) tumours in the mouse, Thymidine rat or guinea-pig, since in several instances immunoprotection may be afforded using such materials (reviewed by Law & Appella, 1975;Baldwin & Price, 1975 Price et al, 1978). Thus, it is reasonable to conclude that although retention of tumour-specific antigen in the immunogen is a necessary condition to elicit specific tumour-transplantation immunity, it is insufficient for the induction of an effective, or optimal, rejection response against antigenic tumours.…”

“…However, subcellular fractions, including plasma membranes and solubilized antigen preparations, are markedly ineffective in inducing resistance to tumour-cell challenge (Price & Baldwin, 1974;Price et al, 1978) even though these preparations retain serologically defined tumour-specific antigen and may elicit specific antibody production. Clearly then, there is a major difference between tumour-specific antigens expressed on an intact cell membrane of an attenuated cell and antigens present in cell-free extracts.…”

Tumour-associated antigens reacting with cytotoxic antibodies in serum of hepatoma-bearing rats

“…Whether these effects are caused by the same antigens is not known. However, the antigens described by these authors have been reported to comprise tumour-specific as well as embryonic tumour-associated components (Zoller et al, 1976(Zoller et al, , 1977Price et al, 1978). Although we obtained good inhibition of cytotoxicity with both D23 hepatoma extracts and with hepatoma cell-sap fractions (Lando et al, 1979) known to contain embryonic antigens the involvement of such antigens in our systems seems of minor significance, since cytotoxicity was efficiently abrogated by absorption with KCI extracts of normal adult rat tissues.…”

“…Such extracts of many tumours (Meltzer et al, 1971;Leonard et al, 1975;Barra et al, 1977) and particularly of the chemically induced rat hepatomas, have been shown to contain antigens that inhibit the cell-mediated cytotoxicity to the tumour (Zoller et al, 1976;, antigens that react with circulating antibodies in serum from tumour-bearing animals (Zoller et al, 1976) and antigens that can induce immunoprotection against the tumour (Price et al, 1978). Whether these effects are caused by the same antigens is not known.…”

Modification of the immunogenicity and antigenicity of rat hepatoma cells. I. Cell-surface stabilization with glutaraldehyde

“…This tumour is characterized by the expression of a tumour-specific rejection antigen against which it is possible to induce moderate levels of immunoprotection when y-irradiated tumour cells are used as immunogen (Baldwin & Barker, 1967a;Price et al, 1978). Subeellular preparations or soluble antigen isolated from this hepatoma are generally ineffective in inducing resistance to tumour challenge except when administered within a restricted dose range (Price & Baldwin, 1974;Price et al, 1978). The initial hypothesis considered was to explore whether stabilization of the cell surface with glutaraldehyde as a cross-linking reagent increased or modified the immunogenicity of the tumour, the view being that such treated cells would represent a more persistent immunogen.…”