Description:Lymphotoxin (LT) and LT are members of the TNF super...

Description:Lymphotoxin (LT) and LT are members of the TNF superfamily of ligands that function as essential elements in the organization of lymphoid tissue and initiation of innate and acquired immune responses. LT and LT genes reside in the major histocompatibility complex forming a tripartite locus with TNF. LT is secreted as a homolrimer, but also assembles with LT into a membrane-anchored heterotrimeric complex of a l2stoichiometry. LT3, like TNF, binds TNF receptor type I (55-60kD and TNFRII (75-80 kDa). whereas LT12 binds the LTR. The LTR also binds LIGHT, a related cytokine that signals via HVEM (HveA). and HVEM also binds LT. LT produced by activated . . and NK cells mediate inflammatory processes important for immune response to certain viral and bacterial pathogens. Mice deficient in LT or lack formation of lymph nodes. Peyers patches and have disorganized microarchitecture in the spleen leading to poor immunoglobulin production. The differentiation of natural killer (NK) cells and NK-T cells are impaired in LT-deficient mice leaving them unable to control certain tumors. Lymphotoxins have unique roles, but function in some cases with TNF and LIGHT cytokine systems as an integrated network that orchestrates multiple developmental processes and immune responses.



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