AB0020 B-lymphocyte function is altered by protease activated receptor-1

Background Protease-activated receptors (PARs) play an important role in most inflammatory and immune cell types, however, they have not been studied in B-lymphocytes. Objectives We sought to determine whether PAR1 or PAR2 were expressed by B-lymphocytes and if so, to determine their effect on cell proliferation, cytokine and antibody production. Methods Human “immature” B-cell lines Ramos and Raji, and “mature” EBV-LCL1 cells, and murine wildtype, PAR1 or PAR2 knock-out (KO) splenic B-lymphocytes were used. Cells were treated with 10 µM PAR antagonists or NFkB, ERK and p38 inhibitors, and assessed for cell proliferation by MTT assay and protein expression by ELISA, western blot and flow cytometry. Results Both PAR1 and PAR2 were expressed by all three cell lines. PAR1 antagonist increased IL-6, IL-10 and IgG in centroblast-like Ramos cells (p Conclusions PAR1 and PAR2 are expressed by B-lymphocytes and, exert differential effects on cell proliferation and cytokine and antibody secretion. Disclosure of Interest None Declared