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Upregulation of Fcγ RI (CD64) and Fcγ RII (CD32) by neutrophil secretion products enhances bacterial phagocytosis in macrophages
Author(s) -
Soehnlein Oliver,
Lindbom Lennart
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a768-a
Subject(s) - phagocytosis , secretion , cd64 , microbiology and biotechnology , opsonin , biology , antibody , chemistry , immunology , biochemistry
In acute inflammation infiltrating neutrophils (PMN) release preformed granule proteins that functionally influence the close environment. Here, we present a role for neutrophil‐derived proteins in bacterial phagocytosis by macrophages (Mø). Granule exocytosis in PMN was induced through antibody cross‐linking of β 2 ‐integrins. The PMN secretion was then used to stimulate murine or human Mø for 2–24 h. The Mø were subsequently incubated with fluorescent Staphylococcus aureus and the number of phagocytosed bacteria per cell was quantified. Pre‐treatment of Mø with PMN secretion caused a several fold increase in phagocytosis of IgG‐opsonised but not of complement‐opsonised S. aureus . The PMN secretion evoked a rapid activation of Mø and caused upregulation of maturation markers such as CD86, HLA II, CD40 and CD25. Increased expression of CD64 and CD32 on Mø in response to treatment with PMN secretion likely serves as an effectuating link to the enhanced phagocytosis, since anti‐CD64 and anti‐CD32 antibodies blocked the enhanced phagocytosis. In line with these observations we found that intraperitoneal injection of PMN secretion enhanced phagocytosis of bacteria by peritoneal Mø in animals that were made neutropenic. Thus, secretion of PMN granule proteins activates Mø to phagocytose bacteria, which may contribute to host defense and could be of potential use in antimicrobial therapy.