R. Schweitzer-stenner et al., Mast cell stimulation by co-clustering the type I Fc epsilon-receptors with mast cell function-associated antigens, IMMUNOL LET, 68(1), 1999, pp. 71-78
The secretory response of rat mucosal-type mast cells (line RBL 2H3) to sti
muli produced by clustering or co-clustering two of its membranal component
s; the type I Fee receptor and the mast cell function associated antigen (M
AFA) was investigated. The primary reagents employed for this purpose were
Fab fragments of the monoclonal antibodies J17 and G63 specific to the abov
e respective proteins. The Fabs were then aggregated by F(ab')(2) fragments
of mouse IgG specific goat antibodies. This reaction was assumed to yield
predominantly three different bivalent clustering reagents. Namely, dimers
of the Fc epsilon RI specific (J17-Fab)(2); dimers of the MAFA specific, (G
63-Fab)(2) and bispecific (J17-Fab-G63-Fab) dimers. The observed cellular s
ecretory response was analyzed by employing a model which accounts for the
clustering and co-clustering of Fc epsilon RIs and MAFAs by the above proto
cols. Results of this analysis provided evidence that at least some of the
MAFA molecules are physically associated with the Fc epsilon RT. As a conse
quence, clustering of MAFA and Fc epsilon RI by bispecific J17-Fab-G63-Fab
dimers induces secretion at comparatively low concentrations of these reage
nts, though with a significantly lower maximal response than that caused by
the respective monospecific reagent (J17-Fab)(2). This result most likely
reflects the inhibitory capacity of MAFA-Fc epsilon RI interaction. (C) 199
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