Lymphocyte cytotoxicity in x-irradiation-induced rat small bowel adenocarcinoma. III. Blocking by 3 M KCL extract
Stevens, R.H.; Brooks, G.P.; Osborne, J.W.; Hoffman, K.L.; Lawson, A.J.
Journal of Immunology 120(1): 335-339
1978
ISSN/ISBN: 0022-1767 PMID: 627724 Document Number: 124495
Hypertonic salt extracts (3 M KCl) of x-irradiation-induced Holtzman rat small bowel adenocarcinomas blocked the in vitro destruction of allogeneic cultured cells of this malignancy by sensitized lymphoid cells obtained from tumor-bearing animals. The protective effect were mediated by a blocking action at both the effector and the target cell level. The extracts were separated into 50% ammonium sulfate soluble and insoluble fractions with the soluble fraction being more effective in blocking the cytotoxic responses through interaction with the lymphoid cells whereas the insoluble one had a greater effect upon tumor target cells. Associated with both fractions was the oncofetal glycoprotein previously identified with the cellular membrane of this x-ray-induced malignancy. Immunoglobulins were identified with insoluble fraction; some were able to bind the oncofetal protein, thus clasifying it as a fetal antigen. The protective effects of the soluble fraction and this neoantigen were found to be citric acid labile, whereas the effects due to the insoluble fraction were unchanged.