,High affinity soluble ILT2 receptor: a potent inhibitor of CD8+ T cell activation

• 作 者: Ruth K.Moysey Yi Li Samantha J.Paston Emma E.Baston Malkit S.Sami Brian J.Cameron Jessie Gavarret Penio Todorov Annelise Vuidepot Steven M.Dunn Nicholas J.Pumphrey Katherine J.Adams Fang Yuan Rebecca
• 机 构: Immunocore Limited,57c Milton Park,Abingdon,Oxon,OX14 4RX,UK“,”Current address:Oxford Nanopore Techn
• 出 处: 蛋白质与细胞
• 发表日期: 2010年12期
• 关键词: CD8+ T cells cellular activation autoimmunity cell surface molecules binding aff

Using directed mutagenesis and phage display on a soluble fragment of the human immunoglobulin superfamily receptor ILT2(synonyms:LIR1,MIR7,CD85j),we have selected a range of mutants with binding affinities enhanced by up to 168,000-fold towards the conserved region of major histocompatibility complex(MHC)class I molecules.Produced in a dimeric form,either by chemical cross-linking with bivalent polyethylene glycol(PEG)derivatives or as a genetic fusion with human IgG Fc-fragment,the mutants exhibited a further increase in ligand-binding strength due to the avidity effect,with resident half-times(t1/2)on the surface of MHC l-positive cells of many hours.The novel compounds antagonized the interaction of CD8 co-receptor with MHC I in vitro without affecting the peptide-specific binding of T-cell receptors(TCRs).In both cytokine-release assays and cell-killing experiments the engineered receptors inhibited the activation of CD8+ cytotoxic T lymphocytes(CTLs)in the presence of their target cells,with subnanomolar potency and in a dose-dependent manner.As a selective inhibitor of CD8* CTL responses,the engineered high affinity ILT2 receptor presents a new tool for studying the activation mechanism of different subsets of CTLs and could have potential for the development of novel autoimmunity therapies.