Novel in vitro effects of bucillamine - Inhibitory effects on proinflammatory cytokine production and transendothelial migration of T cells

Objective, To investigate the novel antiinflammatory mechanism of a disease-modifying antirheumatic drug, bucillamine, on activated T cells, specifically its effect on T cell proliferation, cytokine production, and migration of T cells, Methods. T cells were cultured in wells coated with anti-CD3 monoclonal antibodies (mAb) plus anti-CD26 mAb or anti-CD3 plus anti-CD28 mAb, with or without bucillamine. Proliferative responses and the production of interleukin-2 (IL-2), interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), IL-6, IL-4, and IL-5 were measured under these costimulatory conditions. Phytohemagglutinin (PHA)-activated T cells were cultured on human umbilical vein endothelial cell-coated transwells in the presence or absence of bucillamine, and T cells migrating through the endothelial cell layer were counted. Immunofluorescence analysis was also performed to analyze the effect of bucillamine on the surface expression of adhesion molecules on T cells. Results. Bucillamine (64 mu M) significantly inhibited T cell proliferation and the production of IL-2, IFN gamma, TNF alpha, and IL-6, whereas it had no inhibitory effects on the production of IL-1 and IL-5 in the cultures with anti-CD3 plus anti-CD26 mAb, In contrast, bucillamine had no effects on T cell proliferation or any cytokine production in the cultures with anti-CD3 plus anti-CD28 mAb, Furthermore, the same concentration of bucillamine inhibited transendothelial migration of PHA-activated T cells, and reduced the expression level of CD44 on T cells, Conclusion. This study demonstrated the novel effects of bucillamine in vitro, showing inhibition of type 1 T helper-type cytokine production and proinflammatory cytokine production induced by certain costimulatory conditions, and inhibition of transendothelial migration of T cells, The inhibition of T cell migration appeared to be mediated partly through the reduced expression of CD44, an adhesion molecule on the T cell surface.