A radio (51Cr) micro-tube leukocyte adherence inhibition assay: specific tumor-associated immunity in 3 murine tumor systems.

A radio (51Cr) micro-tube leukocyte adherence inhibition assay is described. In this study, murine mononuclear cells were labeled with 51Cr, plated into tissue culture plates with different tumor extracts and counts/min (cpm) of the non-adherent cells were used as a parameter of adherence inhibition. This assay was used to measure anti-tumor immunity, in vitro, in 3 murine tumor systems: MCA-38 colon adenocarcinoma, L1210 lymphoma and P815 mastocytoma. Tumor immunity was detected using 3 doses (0.01-0.001 mg/ml) of tumor extract in the MCA-38 tumor model, and using 2 doses (0.1-0.05 mg/ml) of tumor extract in both the L1210 and P815 tumor models. It was observed that specific tumor-associated adherence inhibition could be measured in the MCA-38 tumor model between days 7 and 22 of tumor growth and in the L1210 and P815 tumor models between days 7 and 17 of tumor growth. The radio-LAI assay described is an easy, specific and reproducible way to measure tumor-associated adherence inhibition, in vitro.