In-vitro effects of Mycobacterium bovis BCG-lysate and its derived heat shock proteins on cytokines secretion by blood mononuclear cells of rheumatoid arthritis patients in comparison with healthy controls.

Abstract Background Several studies have shown that heat shock protein (HSP)-reactive T cells have an immunoregulatory phenotype indicating that HSPs are able to trigger immunoregulatory pathways, which can suppress immune responses that occur in human inflammatory diseases, such as rheumatoid arthritis (RA). Mycobacterium bovis strain Bacillus Calmette-Guerin (BCG) is rich of HSPs which could be good resources of these regulatory proteins for modulation of immune response. Purposes To study the effects of BCG-lysate and BCG-derived HSPs on secretion of T regulatory cytokines by PBMCs of RA patients in comparison with healthy controls. Methods BCG was heat killed and sonicated to have BCG-lysate. BCG-derived HSP65/HSP70 were detected by immunoblotting and purified by preparative SDS-PAGE. PBMCs of 18 RA patients/16 controls collected by Ficoll-paque were stimulated with BCG-lysate/BCG-derived HSP-65/HSP-70. Supernatant of stimulated PBMCs was aspirated for measuring TGF-β, IL-10, IL-4 and IFN-γ with sandwich ELISA. Results BCG-lysate augmented the amounts of all the mentioned cytokines as dose dependent significantly. The level of TGF-β in controls was higher than patients ( P  P  Conclusion Although BCG is able to provoke T helper 1 cell mediated immunity, its HSP proteins are able to trigger T regulatory cytokines. Healthy controls were under stronger immune regulations.