What are Immunoglobulins?
Antibodies, also known as immunoglobulins (Igs), are Y-shaped glycoproteins critical in the immune system’s defense against infection. Following B cell recognition of a foreign antigen by its B-cell receptor, B cells differentiate into plasma cells that produce and secrete antibodies, which have the same specificity as the receptor. Antibodies bind to antigens with high specificity and affinity, resulting in several effector functions, such as complement activation, enhanced phagocytosis (opsonization), and mast cell activation. Immunoglobulins are indispensable tools for research, diagnostics, and therapies.
Classes of Immunoglobulins
Antibodies are classified into five isotypes based on these heavy chains as IgM, IgG, IgA, IgE, and IgD, respectively. Each isotype is unique in its structure, localization, and biological functions.
Schroeder HW Jr, Cavacini L. Structure and function of immunoglobulins. J Allergy Clin Immunol. 2010;125(2 Suppl 2):S41-S52. doi:10.1016/j.jaci.2009.09.046
Murphy, K., Weaver, C., & Janeway, C. (2017). Janeway’s immunobiology