EFFECT ON HUMAN MONOCYTE KILLING OF TUMOR-CELLS OF ANTIBODY RAISED AGAINST AN EXTRACELLULAR MONOCYTE CYTO-TOXIN

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 48  (2) , 321-327
Abstract
Human monocytes can kill or inhibit the growth of certain tumor cell lines. Among the possible mediators is a cytototoxin synthesized in readily detectable amounts by endotoxin-stimulated monocytes. A neutralizing antiserum to the cytotoxin was used to assess the cytotoxin''s contribution to monocyte killing of tumor cells. The antiserum was tested for possible inhibition of monocyte killing of 3 tumor cell lines, L929 [mouse liver fibroblast], K562 [human leukemia] and A549 [human adenocarcinoma]. Inhibition was complete with L929, partial with K562 and insignificant with A549. Thus, the contribution of the cytotoxin to monocyte killing of tumor cels depends on the tumor line under test. Antibody against endotoxin-induced cytotoxin also neutralized cytotoxin induced in monocytes by other agents, including BCG, Corynebacterium parvum [Propionibacterium acnes], pokeweed mitogen and zymosan. Cytotoxin could be quantitatively removed from monocyte supernatants by Sepharose-bound, anti-cytotoxin antibody. Recovery of the cytotoxin from the imunoadsorbent was difficult because of its lability in the solutions commonly used for desorption. The best recovery was achieved with 2 M urea, 2 M MgCl2 giving a 25% yield and a 40-fold increase in purity in a single step.