Use of Cr⁵¹-labeled peritoneal macrophages grownin vitro as target cells for quantitative analysis of cytotoxic activity of immune T-lymphocytes

Abstract

The use of macrophages previously labeled with Cr⁵¹ in suspension and growing in a monolayer on coverslips treated with poly-L-lysine (PLL), as target cells provides a means of determining the cytotoxic effect (CE) of immune lymphocytes based on the liberation of Cr⁵¹, which in the control does not exceed 10–20% of the maximal. The method proved also to be suitable for determining the effectiveness of lymphocyte fractionation. By the use of 2% sodium dodecylsulfate solution, 100% solubilization of labeled macrophages growing on the surface of the corverslip could be achieved, and CE could also be determined by measuring the quantity of label left behind in the intact macrophages. Both methods were found to be accurate, reproducible, and sensitive and they correlated closely both with each other and with the method of direct cell counting.