It appears the B cells secrete IL-10, which is known as an anti-inflammatory. IL-10 has many different effects, but it's main role is regulating antigen presenting cells and T lymphocytes. In antigen presenting cells, IL-10 inhibits the secretion of pro-inflammatory cytokines, TNF alpha and IL-1(beta). IL-10 affects differentiated CD4+ T cells; more specifically, it showed that it reduced proliferation of Th1 and Th2. Th17 and cytotoxic T cells are unaffected by IL-10 so many believe these T cells are regulated by T regulatory and other cytokines.
Multiple Mechanisms of Immune Suppression by B Lymphocytes.
Klinker MW, Lundy SK.
Mol Med. 2011 Oct 24. doi: 10.2119/molmed.2011.00333.
Another interesting study of note by Sindhava et al showed that some B cells have been shown to produce high levels of IL-10 upon stimulation via TLRs that then suppressed proliferation and differentiation of those same B cells. This implies a possible function of B cells in autoimmunity and infection.
ReplyDelete1. Sindhava V, Woodman ME, Stevenson B, Bondada S (2010) Interleukin-10 Mediated Autoregulation of Murine B-1 B-Cells and Its Role in Borrelia hermsii Infection. PLoS ONE 5(7): e11445. doi:10.1371/journal.pone.0011445
This B cell ability to secrete IL-10 appears to be a another of the "checks and balances" that are build into the immune system. Everything in the immune system is about "relative amounts" of one thing when compared to another. I believe that this IL-10 secretion could be overcome by the Treg cells if a pro inflammatory response showed promise in dealing with the affliction.
ReplyDeleteRecent studies show that B lymphocytes have a remarkable effect on the pathogenesis of autoimmune diseases. B-cell depletion treatments improve these diseases. However, mouse models indicate disparate evidence wherein some subsets of B cells have pathogenic effects and others have regulatory functions. There are different types of B cells: autoreactive B cells, marginal zone B cells, transitional type 2-like B cells, or CD5(+) B cells. B cell receptor activation induces regulatory activity, which are then mediated through IL10 or direct cell-cell contact via CD40 or B7 costimulation. Bregs may participate differentially in a complex network that varies from disease to disease. B cells as an alternative therapy for autoimmune diseases would therefore require clearly elucidated mechanisms prior to therapeutic use.
ReplyDeleteLemoine S, Morva A, Youinou P, Jamin C.Ann Regulatory B cells in autoimmune diseases: how do they work? N Y Acad Sci. 2009, 1173:260-7.
Hello,
ReplyDeleteThis is the perfect blog for anyone who wants to know about this topic. Immune system protects the body from potentially harmful substances by recognizing and responding to antigens. These are molecules on the surface of cells, viruses and substances that appear foreign and harmful...