The structure and function of B cell receptors (BCRs), including how they specifically recognize antigens and initiate an immune response.
Basic Immunology: A foundational understanding of the immune system is essential in studying B cell receptors (BCRs). This includes concepts like innate and adaptive immunity, antigen presentation, and lymphocyte development.
Antibody Structure: BCRs are antibodies produced by B cells. Understanding the basic structure of antibodies, including the variable and constant domains, is crucial for comprehending how BCRs function.
Immunoglobulin Gene Rearrangement: To generate a diverse repertoire of BCRs, B cells undergo gene rearrangement. This process involves the recombination of variable (V), diversity (D), and joining (J) gene segments to create unique BCRs.
Allelic Exclusion: B cells only express one copy of immunoglobulin genes to prevent the expression of multiple BCRs on a single B cell.
Isotype Switching: Changes in the constant domain of the antibody molecule can result in the generation of different isotypes (e.g., IgA, IgE, etc.) with unique functions.
Enzymatic Mechanisms: The deletion and insertion of nucleotides at the junctions of V, D, and J gene segments are catalyzed by enzymes such as RAG1/2 and TdT.
B Cell Development: B cells undergo a series of stages, each with distinct gene expression patterns, before becoming mature B cells capable of producing functional BCRs.
B Cell Activation: B cells become activated upon encountering a specific antigen, leading to the production and secretion of BCRs that can bind to and neutralize the antigen.
BCR Signaling Pathways: Upon antigen binding, BCRs activate signaling pathways that ultimately lead to the proliferation and differentiation of B cells.
BCR Diversity: The diversity of BCRs is essential for recognition and neutralization of a wide variety of antigens. Understanding how BCR diversity is generated and maintained is critical in developing immunotherapeutic approaches.
Membrane-bound immunoglobulins (mIg): Membrane-bound immunoglobulins (mIg) are specialized B cell receptors found on the surface of B cells that recognize and bind specific antigens to initiate an immune response.
Soluble immunoglobulins (sIg): Soluble immunoglobulins (sIg) are secreted forms of B cell receptors that play a critical role in the immune response by binding to specific antigens and facilitating the recognition and elimination of pathogens.
IgM: IgM is the first antibody produced during an immune response and is primarily involved in the initial defense against pathogens.
IgD: IgD is a type of B cell receptor expressed on the surface of B cells, playing a role in initiating the immune response.
IgG: IgG is a type of antibody produced by B cells that plays a crucial role in immune responses, providing long-term protection against pathogens and toxins.
IgA: IgA is an antibody isotype that provides immune protection at mucosal surfaces.
IgE: IgE is a type of antibody produced by B cells that plays a key role in allergic reactions and defense against parasites.