Effects of water-soluble cigarette smoke extracts upon the release of beta-hexosaminidase from RBL-2H3 basophilic leukaemia cells in response to substance P, compound 48/80, concanavalin A and antigen stimulation.

Abstract

To determine whether water-soluble constituents of cigarette smoke affect mast cell function using an in vitro model, RBL-2H3 basophilic leukaemia cells. RBL-2H3 cells were induced to degranulate in response to compound 48/80 and substance P, as assessed by monitoring the release of the granular enzyme beta-hexosaminidase, by treatment for 7 days with 20 microM quercetin. Responses to concanavalin A and antigen were determined by measuring the beta-hexosaminidase release from cells cultured on fibronectin-coated plates. The beta-hexosaminidase release response to compound 48/80 induced by quercetin treatment was accompanied by a release of lactate dehydrogenase, suggesting that degranulation is not the only process triggered by compound 48/80 under these conditions. Quercetin treatment reduced the beta-hexosaminidase release response to concanavalin A. Precoating of the culture wells with rat fibronectin enhanced the beta-hexosaminidase response to calcimycin, but not to concanavalin A. Under these conditions, concanavalin A did not induce a release of lactate dehydrogenase. The responses to c48/80, substance P, calcimycin, concanavalin A and antigen (after IgE pretreatment) were reduced by treatment with cigarette smoke solution obtained from standard and low-tar cigarettes (IR3 and IR5F). The effect of cigarette smoke solution from IR5F cigarettes upon the beta-hexosaminidase release elicited by compound 48/80 (in quercetin-treated cells) and by concanavalin A (in cells cultured on fibronectin-coated wells) could be prevented by N-acetyl-L-cysteine, but not with either hemoglobin, alpha-tocopherol, catalase or palmitoylethanolamide. N-acetyl-L-cysteine also reduced the effect of cigarette smoke solution upon the degranulation response to antigen. Under the conditions used, oxidants present in cigarette smoke solution from IR5F cigarettes reduce the ability of RBL-2H3 cells to degranulate in response to both immunological and non-immunological stimuli.