Parameters determining the stimulatory capacity of the type I Fc epsilon-receptor

Several experiments and theoretical considerations aimed at obtaining the p arameters which determine the capacity of type I Fce-receptors to stimulate the secretion of mast cells are reviewed. Earlier studies have established that secretion requires Fc epsilon RI clustering at least two dimers. The roles of such clusters lifetimes and configuration requires a detailed and quantitative analysis of FceRI clustering and stimulus secretion. Different approaches to these issues are described and discussed. We especially addr ess the relevance of the general concept of kinetical proof reading (T.W. M cKeithan, Proc. Natl. Acad. Sci. USA 92 (1995) 5042) which is based on the assumption that the stimulating receptors must stay in an active state suff iciently long to bridge the time interval between initiation and terminatio n of cell activation. For mast cells which generally secrete upon clusterin g of type I Fc epsilon-receptors, this implies that effective stimulation r equires a sufficiently long lifetime of such clusters. This notion is corro borated by results obtained from several experiments performed in the last 20 years which are briefly described and compared in this review. (C) 1999 Elsevier Science B.V. All rights reserved.