Appearance of acceptor-bound C3b on HLA-DR positive macrophages and on stimulated U937 cells; Inhibition of Fcγ-receptors by the covalently fixed C3 fragments

Anna Erdei, Zsuzsanna Bajtay, Zsuzsanna Fábry, R. B. Sim, J. Gergely

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The appearance and the functional role of acceptor-bound C3b during differentiation of human monocytes into macrophages were studied. Acceptor-bound C3b could be detected by the immune adherence (IA) test parallel to the expression of antigenic determinants specific to mature cells-i.e. on days 4-5 of culture. Consequently, the capacity of these phagocytes to fix C3b covalently via C3b-acceptors (C3bAs) can be considered as one of the signs of their activation/differentiation. All the mature macrophages positive in the IA test were also found to express HLA-DR antigens on their membrane. Using solubilized extracts of stimulated, 35S-cysteine-labelled cells of the human monocytic cell line, U937, we demonstrate that C3 synthesized by these cells can bind to C3bAs of the same cells. Covalently fixed C3 fragments were found to inhibit Fc -receptor-mediated ingestion of immune complexes and also antibody-dependent cellular cytotoxieity of monocyte-derived macrophages.

Original languageEnglish
Pages (from-to)295-303
Number of pages9
JournalMolecular Immunology
Volume25
Issue number3
DOIs
Publication statusPublished - Mar 1988

ASJC Scopus subject areas

  • Immunology
  • Molecular Biology

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