Immunoglobulin lambda variable 3-19 (Ig lambda chain V-III region SH)
1_MAWTP 6_ LWLTL 11_ LTLCI 16_ GSVVS 21_ SELTQ 26_ DPAVS 31_ VALGQ 36_ TVRIT 41_ CQGDS 46_ LRSYY 51_ ASWYQ 56_ QKPGQ 61_ APVLV 66_ IYGKN 71_ NRPSG 76_ IPDRF 81_ SGSSS 86_ GNTAS 91_ LTITG 96_ AQAED 101_ EADYY 106_CNSRD
1: V region of the variable domain of immunoglobulin light 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)