CHARACTERISTICS OF THE HISTAMINE-RELEASE FROM HAMSTER-CHEEK POUCH MAST-CELLS STIMULATED BY LECTINS FROM BRAZILIAN BEANS AND CONCANAVALIN-A

We have characterized the histamine releasing effects of lectins extra cted from Brazilian beans, in comparison to concanavalin A, in hamster cheek pouch cell suspensions containing mast cells, The lectins from Dioclea virgata, Canavalia brasiliensis, and Dioclea rostrata induce h istamine release in a similar manner to concanavalin A, but appear to differ in potency and efficacy. The effects depended on the temperatur e, pH, and metabolic energy; demonstrating the non-cytotoxic nature of the histamine release. at is suggested that the lectins studied act b y the same mechanism as concanavalin A (interacting with sugars in the antibodies bound to the mast cells), since high concentrations of glu cose inhibit the histamine release. The lectins at high concentrations quench the histamine release. This suppression is reversed by increas ing calcium concentration, suggesting that the lectins bind to the cal cium that is essential for the secretion, thereby confirming and exten ding our previous data using the lectin from Dioclea virgata in rat pe ritoneal mast cells.