Bacterial activation of mast cells.
Mast cells often are found in a perivascular location but especially in mucosae, where they may response to various stimuli. They typically associate with immediate hypersensitive responses and are likely to play a critical role in host defense. In this chapter, a common airway pathogen, Moraxella catarrhalis, and a commensal bacterium, Neiserria cinerea, are used to illustrate activation of human mast cells. A human mast cell line (HMC-1) derived from a patient with mast cell leukemia was activated with varying concentrations of heat-killed bacteria. Active aggregation of bacteria over mast cell surfaces was detected by scanning electron microscopy. The activation of mast cells was analyzed by nuclear factor-kappaB (NF-kappaB) activation and cytokine production in culture supernatants. Both M. catarrhalis and N. cinerea induce mast cell activation and the secretion of two key inflammatory cytokines, interleukin-6 and MCP-1. This is accompanied by NF-kappaB activation. Direct bacterial contact with mast cells appears to be essential for this activation because neither cell-free bacterial supernatants nor bacterial lipopolysaccharide induce cytokine secretion.
Chi
David S
DS
Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
Walker
Elaine S
ES
Hossler
Fred E
FE
Krishnaswamy
Guha
G
D002478:Cells, Cultured; D006358:Hot Temperature; D006801:Humans; D008407:Mast Cells / Q000276:immunology* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D001936:Moraxella catarrhalis / Q000276:immunology*; D042804:Neisseria cinerea / Q000276:immunology*