Immunological functions of splenic B-lymphocytes

Abstract

The spleen is a key lymphoid organ for generating B-lymphocyte (B cell)-mediated humoral immunity. This review examines the key features and functions of splenic B cells. Splenic B cell subsets, including virgin, memory, and CD5+ B cells, are characterized by their phenotypic markers and functions. Structural aspects of the spleen, including red pulp, follicles, periarterial lymphoid sheaths (PALS), and germinal centers, are related to the B cells localized in these areas. The migratory behavior of B cells in these splenic compartments is considered in the context of antigen exposure, adhesion molecules, and migratory stimuli. Antigen-specific B cells in the spleen are examined with an emphasis on their in situ characteristics assessed by immunocytochemical methods. This includes the detection of antigen-binding antibody-forming cells (AFC), idiotype-producing AFC, and the application of computer-aided imaging to analyze these cells. Interactions between splenic B cells and other cell types, such as T-lymphocytes (T cells) and antigen-processing/presenting cells like macrophages and dendritic cells, are briefly examined. Cytokines that influence splenic B cells are reviewed. Interactions between B cells and the neuroendocrine system are discussed briefly. The functions of splenic B cells are considered. Antibody production, cytokine synthesis, and potential immunoregulatory activities are considered.