Cell, stimulation agent chemotactic peptide

Figure 4.8. Hypothesis for the local generation of mast-cell-stimulating peptides by the action of neutrophil-derived enzymes on albumin. Initial stimulation of the mast cell by any of a variety of agents causes the release of preformed histamine (H) neutrophil and eosinophil chemotactic factors (NCF, ECF) and enzymes and the de novo synthesis of prostaglandins (PG) and leukotrienes (LT). These agents increase vascular permeability and vessel diameter. As a result, albumin and later neutrophils (PMN) enter the tissue space where the latter undergo phagocytosis and the secretion of proteolytic enzymes to the extracellular space where they act on albumin to generate NRP (neurotensin-related peptide) and HRP (histamine-releasing peptide). These newly formed peptides then act as a second stimulus to the mast cell. In addition NRP and HRP may affect other immunocompetent celt such as monocytes, macrophages or eosinophils.

Oxygen uptake, O5, H2O2, OH production, as well as chemiluminescence, are stimulated by many agents, particulate or soluble, which include bacteria, latex, and zymosan (Table 4) (C6, B3), PMA (Jl, G6, R2), ionophores (W4), complement peptide Cg (G3), fluoride ion (G9, H2), and a chemotactic factor iV-formylmethionyl peptide (S5). These events have been demonstrated to be independent of phagocytosis and even of degranulation they only require contact of the stimulus with the cell membrane (M2, R4, G3, H2, G9). 

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