Comparison of the ability of red cells sensitized with a bispecific anti-D × anti-FcγRIII Fab fragment to activate human K cells and peritoneal macrophages through FcγRIII

Tibor Bakács, Andrew G. Hadley, Belinda M. Kumpel, David M. Segal, Ferenc Banhidy

Research output: Contribution to journalArticle

Abstract

The functional activity of FcγRIII on human K cells from peripheral blood was compared with that of FcγRIII on peritoneal macrophages (PM) separated from the waste material of patients undergoing peritoneal dialysis. FcγR function was assessed in vitro using human monoclonal IgG1 anti-D (AB5) or a bispecific antibody comprising Fab fragments of AB5 chemically linked to Fab fragments of monoclonal anti-FcγRIII, 3G8 (AB5 × 3G8). In antibody-dependent cell-mediated cytotoxicity (ADCC) assays, K cells mediated the lysis of papainized red cells sensitized with the AB5 × 3G8 bispecific antibody but not with AB5. In contrast, red cell lysis by PM was not promoted by AB5 × 3G8 although AB5 was active. However, this lysis, being inhibited by monomeric IgG, was presumably mediated via FcγRI. AB5 × 3G8 also failed to promote the binding and phagocytosis of both papainized and native red cells by PM although 99% of red cells and over 90% of peritoneal cells bound the bispecific antibody. In marked contrast to K cells therefore, FcγRIII on PM was unable to mediate functional interactions with red cells sensitized with anti-D × anti-FcγRIII bispecific antibody.

Original languageEnglish
Pages (from-to)91-95
Number of pages5
JournalImmunology letters
Volume42
Issue number1-2
DOIs
Publication statusPublished - Sep 1994

Keywords

  • Anti-D
  • Bispecific antibody
  • FcγRIII
  • K cell
  • Macrophage

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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