Vitral assessment of mast cells degranulation mediated by IgG antibodies

BACKGROUND: Data on the potential for mast cell activation and degranulation under these IgG-containing immune complexes indicate the presence of another innovative pathway for mast cell activation and help explain the severe infection following vaccination.

AIM: The aim of the study was to evaluate the possibility of activation and degranulation of mast cells of peritoneal exudate in mice by binding Fcγ receptors.

MATERIALS AND METHODS: Influenza viruses A/Vietnam/1194/2004(H5N1) NIBRG-14 and A/New York/61/ 2015(H1N1)pdm09 were used in the work. Cells of the peritoneal exudate of CBA mice, containing an average of 7–10% mast cells, were used as a source of mast cells. The degranulation of mast cells 40 min after the introduction of IgG-containing immune complexes into cultures was assessed by the release of histamine into culture attachments. The histamine level was determined fluorimetrically after the formation of its complexes with orthophthalic aldehyde, and the histamine concentration was expressed in ng/ml.

RESULTS: In response to the binding of Fcγ receptors, a dose-dependent release of histamine from the mast cells occurs. Histamine production was noted both during the introduction of model immune complexes formed by thermally aggregated IgG, and during the formation of complexes including IgG and influenza viruses of different strains. A higher level of histamine secretion was noted during the formation of IgG complexes with the H5N1 influenza virus. The level of histamine mast cells production during Fcγ receptor binding was comparable to the response to Fcε receptor binding.

CONCLUSIONS: Binding of immune complexes containing IgG class immunoglobulins to receptors on the surface of peritoneal exudate mast cells leads to their activation and degranulation, which is accompanied by dose-dependent histamine secretion, the level of which also depends on the strain of influenza virus in the complex.