The major house-dust mite allergen, Der f 2, stimulates the phospholipase D (PLD) in T lymphocytes from Dermatophagoides farinae specific allergic individuals. PLD activity increased more than two-fold in T cells from allergic patients compared with those cells from normal controls with maximal responses within 30 min after exposure of Der f 2. A well-known PLD activator PKC-alpha was found to be translocated to membrane from cytosol in Der f 2-treated T cells from Dermatophagoides farinae specific allergic individuals. Down-regulation of PKC-alpha with phorbol myristate acetate pretreatment for 24 h abolished Der f 2-induced PLD activation. Ro 320432, PKC inhibitor also reduced the effects of Der f 2-induced PLD activation suggesting that PKC-alpha acts as upstream activator of PLD in Der f 2-treated T cells. Taken together, the present data suggest that Der f 2 can stimulate PLD activity through the PKC-alpha activation in T cells from Dermatophagoides farinae allergic individuals
Adolescent ; Adult ; Animals ; Antigens, Dermatophagoides/*immunology ; Dermatophagoides farinae/*immunology ; Female ; Humans ; Hypersensitivity, Immediate/*enzymology/*immunology ; Male ; Phospholipase D/*metabolism ; Protein Kinase C/antagonists & inhibitors/*physiology ; Research Support, Non-U.S. Gov't ; Skin Tests ; T-Lymphocytes/*enzymology/immunology ; Tetradecanoylphorbol Acetate/*analogs & derivatives/pharmacology ; Up-Regulation