Increased cell-mediated lysis of chicken erythrocytes following the addition of metabolic inhibitors.

The effect of a variety of metabolic inhibitors on the cell-mediated lysis of chicken erythrocytes by immune spleen cells was investigated using the Cr-release assay. The addition of cycloheximide, puromycin, emetine, pactamycin, actinomycin D or EDTA during the early stages of the reaction (0-2 h) produced partial to complete inhibition of the cytotoxic reaction, while the addition of these compounds at later time periods (2-4 h) resulted in the progressive loss of inhibitory effects. Later additions (4-6 h) of all compounds, except EDTA, resulted in a significant increase in target cell lysis. The ability of these compounds to induce increased cytotoxicity required complete inhibition of protein synthesis and the presence of reactive effector cells. It did not appear to be due to an increase in the rate of 51Cr release from previously damaged target cells, or inhibition of a target-cell repair mechanism dependent on protein synthesis. At least a portion of the increased reactivity was due to effector cell-target cell adhesions which formed after the addition of the inhibitor. The data suggests that the addition of metabolic inhibitors during the later stages of the reaction induced an increase in the efficiency or number of cytotoxic attacks.