Inhibitors of Dipeptidyl Peptidase I (DPPI) As Mast Cell Stabilising Agents/ ghada mohamed abd elhaleem elfeki ; mohamed a. badawy , mohamed a. el-desouky , andrew f. walls.

Thesis (Ph.D)-Cairo University,2022.

Bibliography: p. 94-104.

Inhibitors of mast cell tryptase and chymase are potent inhibitors of mast cell activation. These abundant mast cell proteases may be converted into catalytically active forms by dipeptidyl peptidase 1 (DPPI), but the potential role of DPPI in degranulation is not known. Cells of the LAD2 human mast cell line and RBL rat mast cell line were sensitized with myeloma IgE and activated with anti-IgE antibody or calcium ionophore A23817. Concentrations of β-hexosaminidase were determined in supernatants and cell lysates, and also tryptase and DPPI using specific ELISA or chromogenic substrates. Cells were pre-incubated with the DPPI inhibitor Gly-Phe-CHN2 (GFCN) or with the small molecule of DPPI inhibitors PZ610, PZ709 or PZ889 for 0, 5 or 30 minutes Parallel studies were conducted with mast cells dispersed from human tonsil, in which histamine release was also determined.