Resistance against Ehrlich Ascites Tumor Induced by DEPC-treated Ehrlich Cells

Abstract

The proliferating activity of Ehrlich ascites tumor cells decreased with the increase of the concentration of DEPC per 3 x 10 7 cells and disappeared at more than 200 f(g. Sixty per cent of the mice immunized with 200 flg DEPC-treated Ehrlich cells twice survived the challenge inoculation. And employment of Freund's complete adjuvant on the immunization increased the survival ratio up to 90~100%. Respiratory activity, trypan blue stainability and agglutination by concanavalin A were investigated. These results and the electronmicroscopical observation suggest that the specific structure of the cell surface must be maintained in the DEPC-treatment in order to display immunogenicity.

Antigenicity and Immunogenicity of Cell Surface Fraction of Ehrlich Ascites Tumor Cells

“…After centrifuging the mixture at 2500 x g for 5 min, the remaining antibody activity in the supernatant was measured by the immune adherence test. 3 ,12) Target cell suspension (Ehrlich cells, 10 6 /ml) was added to the supernatant in 0.1 ml portions. The suspension was shaken at 37"C for 30 min and allowed to stand at O°C for 60 min.…”

“…Moreover, when the Ehrlich tumor resistant mice were hyperimmunized by repeating the challenge inoculation of Ehrlich cells, antisera taken from such mice displayed immune cytotoxicity for Ehrlich cells, as well as immune adherence reactivity with human erythrocytes. 3 ) It is known that there are some tumor-specific antigens on tumor cell surface,4) from the agglutination of tumor cells caused by concanavalin A (Con A)5) and the immune adherence reaction of tumor cells with human erythrocytes in the presence of tumor-specific antisera. 6 ) These results suggest that the immunogenicity displayed in the specific structure of the Ehrlich cell surface might be related to antigenicity inducing tumor-specific antisera in hyperimmunized • mIce.…”