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The B-cell receptor (BCR) is a transmembrane protein on the surface of a B cell. A B-cell receptor includes both CD79 and the immunoglobulin. The plasma membrane of a B cell is indicated by the green phospholipids. The B- cell receptor extends both outside the cell (above the plasma membrane) and inside the cell (below the membrane).
Class switching occurs after activation of a mature B cell via its membrane-bound antibody molecule (or B cell receptor) to generate the different classes of antibody, all with the same variable domains as the original antibody generated in the immature B cell during the process of V(D)J recombination, but possessing distinct constant domains in their heavy chains.
CD32B is an inhibitory surface receptor that is part of a large population of B cell co-receptors, which act to modulate signaling. [3] Activated CD32B has the ability to cross-link with B cell receptors (BCRs), which increases the threshold for B cell activation and downregulates antibody production in the presence of IgG. [5]
B cells, unlike the other two classes of lymphocytes, T cells and natural killer cells, express B cell receptors (BCRs) on their cell membrane. [1] BCRs allow the B cell to bind to a foreign antigen, against which it will initiate an antibody response. [1] B cell receptors are extremely specific, with all BCRs on a B cell recognizing the same ...
In humoral immune response, the naive B cells begin the maturation process in the bone marrow, gaining B-cell receptors (BCRs) along the cell surface. [6] These BCRs are membrane-bound protein complexes that have a high binding affinity for specific antigens ; this specificity is derived from the amino acid sequence of the heavy and light ...
Somatic hypermutation (or SHM) is a cellular mechanism by which the immune system adapts to the new foreign elements that confront it (e.g. microbes).A major component of the process of affinity maturation, SHM diversifies B cell receptors used to recognize foreign elements and allows the immune system to adapt its response to new threats during the lifetime of an organism. [1]
Class switching is mediated by the enzyme AID (activation-induced cytidine deaminase) and occurs after the B cell binds an antigen through its B cell receptor. Class-switching usually requires interaction with a T helper cell. [3] [4] In humans, there are five heavy chain isotypes α,δ,γ,ε,μ, corresponding to five antibody isotypes: α ...
FCGR2B regulates B cell activation by increasing the BCR activation threshold and suppressing B cell-mediated antigen presentation to T cells through the ITIM-dependent inhibitory mechanism. [9] Ligation of FCGR2B on B cells downregulates antibody production, prevents the membrane organization of BCR and CD19 and promotes apoptosis .