Cells which are components of allergic inflammation bear on their surfaces or contain proteins which subserve specific functions, and understanding these functions wlil permit control of the allergic process. Three overlapping themes are identified: (1) the function of receptors on neutrophils, including the IgG Fc-gamma receptors (subproject 1, Dr. Ruddy) and the F-met-leu-phe receptor (subproject 2, Dr. Freer); (2) mechanisms of induction, regulation and maintenance of IgE synthesis, including the roles of follicular dendritic cells and antibody feedback (subproject 3, Dr. Tew) and the role of IgE and/or IgE immune complexes in lymphocyte activation (subproject 5, Dr. Schwartz) and the regulation of mast cell genesis (Dr. Huff).