STRUCTURE AND FUNCTION OF HUMAN EFFUSION MACROPHAGES FROM PATIENTS WITH MALIGNANT AND BENIGN DISEASE

Abstract

Human effusion macrophages isolated from the pleural or ascitic effusions of 14 patients with malignant or benign disease usually inhibited methyl-3H-thymidine incorporation in an adherent human tumor cell line (NHIK 3025) when the macrophages were challenged with target cells immediately after isolation. The cytostatic activity disappeared when the macrophages were cultured for 18 h in vitro before target cell challenge. The presence of endotoxin or Corynebacterium parvum [Propionibacterium acnes] (Cp) during the macrophage-target cell interaction induced a small enhancement of the macrophage-mediated cytostatic activity. Preincubation of macrophages with Cp or Cp-induced lymphokine supernatants for 2-18 h before target cell challenge induced increased cytostatic activity in the macrophage cultures. Adherent (NHIK 3025) or non-adherent (K-562) human tumor cells prelabeled with methyl-3H-thymidine, when added to freshly isolated macrophages, were lysed in a slowly progressive manner. The cytolytic activity to K-562 cells was enhanced by increasing macrophage density in the cultures, and by incubating the macrophages for 2 h with lymphokine supernatants before target cell challenge. Morphological observations indicated that K-562 cells adhered to macrophage membranes with lysis proceeding extracellularily.