A convenient and sensitive cytotoxicity assay for macrophage activating factor.
A convenient procedure is described for assaying macrophage activating factor (MAF) in lymphokine preparations. This procedure utilizes thioglycollate-elicited peritoneal macrophages from C57BL/6J mice as effector cells and [3H]thymidine-labeled L929 target cells. A novel component of the cytotoxicity assay is the inclusion of a 20 min terminal incubation of the cultures with 10 micrograms/ml pancreatic deoxyribonuclease to facilitate the release of radioactivity from killed target cells. This method routinely gives a 10-20-fold greater release of [3H]thymidine from cultures containing MAF than from cultures containing macrophages and target cells alone. Additional advantages of this procedure are that it is relatively rapid, killing can be monitored microscopically, and MAF assays can be performed using macrophage concentrations as low as 1 X 10(5)/cm2, using effector to target cell ratios as low as 1:1, and using lymphokine dilutions of 10(-3) - 10(-4).
D000818:Animals; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D003851:Deoxyribonucleases / Q000494:pharmacology; D005260:Female; D007739:L Cells / Q000276:immunology; D008222:Lymphokines / Q000032:analysis*; D008262:Macrophage Activation; D016215:Macrophage-Activating Factors; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013936:Thymidine / Q000378:metabolism
D008222:Lymphokines; D016215:Macrophage-Activating Factors; D003851:Deoxyribonucleases; D013936:Thymidine