CD40L is transferred to antigen‐presenting B cells during delivery of T‐cell help. Issue 1 (28th November 2016)

• Record Type: Journal Article
• Authors: Gardell, Jennifer L.; Parker, David C.
• Is Part Of: European journal of immunology. Volume 47:Issue 1(2017)
• Page Start: 41
• Page End: 50
• Publication Date: 2016-11-28
• Subjects: CD154 -- CD40L -- CD40 ligand -- Immunological synapse -- Membrane transfer -- T‐cell help; Immunology -- Periodicals; 616.079
• DOI: 10.1002/eji.201646504
• Languages: English
• ISSNs: 0014-2980

Abstract

Abstract : CD40L (CD154) is the membrane‐associated cytokine essential for T‐cell help for B cells. Following TCR recognition of peptide‐MHC and immunological synapse formation, CD40L is deposited on the antigen‐presenting B cells (red) that become activated and proliferate, but not on the bystander B cells (blue) that are not presenting antigen. Abstract : The delivery of T‐cell help to B cells is antigen‐specific, MHC‐restricted, and CD40L (CD154) dependent. It has been thought that when a T cell recognizes an antigen‐presenting B cell, CD40L expressed on the T‐cell surface engages with CD40 on the surface of B cells as long as the cells remain conjugated. By adding fluorescently labeled anti‐CD40L antibody during overnight incubation of antigen‐presenting B cells with antigen‐specific T cells, we discovered that CD40L does not remain on the surface of the T cell, but it is transferred to and endocytosed by B cells receiving T‐cell help. In the presence of anti‐CD40L antibody, transferred CD40L is nearly absent on bystander B cells that are not presenting antigen, and the bystander cells do not become activated. Because transfer of CD40L to B cells correlates with B‐cell activation, we speculate that persistence of helper T‐cell‐derived CD40L on or in B cells could permit sustained CD40 signaling enabling survival and proliferation of antigen‐presenting B cells following brief interactions with helper T cells in vivo in germinal centers.