CELLS

B cells, also known as B lymphocytes, are part of the humoral immunity component of the adaptive immune system.¹ Antibodies, collectively known as immunoglobulins, are exclusively produced by B cells and all antibodies made by an individual B cell possess the same antigen-binding site. During the development of B cells within the bone marrow, antibody molecules are inserted into the plasma membrane, which serve as antigen receptors. Binding of antigens to these receptors in the peripheral lymphoid organs causes B-cell activation and further differentiation into either memory cells or antibody-secreting effector cells.²

Distinct cell surface proteins, including CD40, CD19, and B-cell receptor, are expressed throughout different stages of B-cell development and maturation and are used to identify subsets of B cells, including plasma cells and memory B cells. Upon activation, B cells can differentiate into plasma cells that secrete antibodies, present antigens, and secrete cytokines (IFN-γ, IL-6, and IL-10) that regulate the immune response.^1,3 Regulation of normal B-cell activation and longevity is maintained through a delicate balance between the activating and inhibitory processes. Disruption or disturbance of this balance can predispose towards pathogenic autoantibody production and autoimmunity.¹

Abnormal B-cell recognition of self-antigen followed by the production of autoantibodies may cause autoimmune diseases. Additionally, B cells also play important roles in modulating inflammation.^1,3

​​CD: cluster of differentiation; IFN-γ: interferon gamma; IL: interleukin.