The B cell is the initiating antigen-presenting cell in peripheral lymph nodes.

Abstract

We have examined the role of B cells in antigen presentation in lymph nodes in several ways. We found that mice depleted of B lymphocytes via chronic injection of anti-mu-chain antibody do not mount peripheral lymph node T cell proliferative responses to normally immunogenic doses of antigen. Depletion of B cells by passage of immune lymph node cells over anti-immunoglobulin columns early after immunization depletes antigen-presenting function from draining lymph nodes, and this function can be restored by using B cells or splenic adherent cells to allow the remaining T cells to proliferate. Lymph node B cells present antigen very effectively to lines of antigen-specific T cells. However, unfractionated lymph node cells from anti-mu-treated mice present very poorly, if at all, whereas unfractionated spleen cells from the same mice do present antigen. This is in keeping with our previous finding that helper T cell function in the spleen is normal in B cell-deprived mice. Finally, when mice homozygous for the lymphoproliferative gene lpr are treated chronically with anti-mu-chain antibody, lymphadenopathy is greatly retarded, suggesting a role for B cells in the massive proliferation of T cells in this syndrome. From this analysis, it would appear that the initiating antigen-presenting cell in the lymph node is a B lymphocyte, and that B lymphocytes in lymph nodes may be distinct from those in the spleen. It is of interest that these results also suggest that the lymph node lacks an antigen-presenting cell that is found in the spleen, perhaps the dendritic cell.

Tumor-Infiltrating B Lymphocytes: Promising Immunotherapeutic Targets for Primary Liver Cancer Treatment

“…The B-cell subsets, once mature and terminally differentiated into plasma and effector cells, are mainly involved in circulating antibodies secretion, thymic-independent IgM antibody responses and antigen presentation [ 40 , 41 ]. B lymphocytes are required for the initiation of T-cell immune responses, and recent studies have demonstrated that their absence impairs CD4+ T-cell priming [ 42 ]. The differential activation and expansion of CD4+ T cells by B lymphocytes could be associated with immune responses, making this a critical area for future studies of host defense and autoimmunity.…”

B cell depletion therapy in autoimmune diseases

“…Priming and clonal expansion of naïve CD4 + T cells. Although naïve T-cell responses are normally primed by dendritic cells, B cells are also very efficient antigenpresenting cells (APC) and have been postulated to play important roles in the initial T cell priming (45)(46)(47)(48)(49)(50). While not fully understood, B cells are also likely to play important roles in the reactivation of memory responses, and the continued stimulation and expansion of primary responses may be assisted by activated B cells (50)(51)(52)(53)(54).…”