Fc gamma RI and Fc gamma RII on monocytes and granulocytes are cytotoxic trigger molecules for tumor cells.

摘要: As part of an effort to define the cytotoxic trigger molecules on human myeloid cells, ability different Fc receptors for IgG (Fc gamma R) mediate killing tumor cell lines by monocytes and granulocytes was examined. This accomplished studying cytolysis hybridoma (HC) targets bearing surface antibody directed toward R. The HC line, IV.3A, which bears Ig low affinity R RII) neutrophils lysed monocytes. extent lysis IV.3A approximately equal that anti-Fc RI (the high monocytes) (HC 32.2A 62A) not augmented treatment with interferon-gamma (IFN-gamma). In contrast, only after activation IFN-gamma. Since is detectable untreated induced IFN-gamma these IFN-gamma-activated correlated receptor induction. On other hand, RII present at levels IFN-gamma-treated neutrophils, but mediated cytotoxicity via RII. this case, enhanced appeared be due events than increase in number. Neither nor RIII 3G8A. Thus, binding target does lead may initiate signals distinct from those triggered through or Surprisingly, amounts mouse IgG1 irrelevant specificity were also blocked soluble IV.3 thus portion Furthermore, donors a form incapable aggregated did lyse HC, displayed normal IV.3, demonstrating structurally remained functional molecule. Overall, studies have demonstrated triggering monocyte- granulocyte-mediated antibody-dependent begun dissect similarities differences among three defined cells.