Immunoglobulin heavy variable 3-64D
1_MEFWL 6_ SWVLL 11_ VAILK 16_ DVQCE 21_ VQLVE 26_ SGGGL 31_ VQPGG 36_ SLRLS 41_ CSASG 46_ FTFSS 51_ YAMHW 56_ VRQAP 61_ GKGLE 66_ YVSAI 71_ SSNGG 76_ STYYA 81_ DSVKG 86_ RFTIS 91_ RDNSK 96_ NTLYL 101_ QMSSL 106_ RAEDT 111_AVYYC
1: V region of the variable domain of immunoglobulin heavy chains that participates in the antigen recognition (PubMed:24600447). Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:20176268, PubMed:22158414). The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen (PubMed:17576170, PubMed:20176268)