QL9 (QLSPFPFDL) is a high-affinity alloantigen for the 2C T cell receptor (TCR).

Mouse T cell clone 2C recognizes two different major histocompatibility (MHC) ligands, the self MHC K^b and the allogeneic MHC L^d. Two distinct peptides, SIY (SIYRYYGL) and QL9 (QLSPFPFDL), act as strong and specific agonists when bind to K^b and L^d, respectively. QL9 binding to MHC L^d is influenced by the majority of peptide side chains, distributed across the entire length of the peptide. Findings with both systems, but QL9-L^d in particular, suggest that many single-residue substitutions, introduced into peptides to improve their binding to MHC and thus their vaccine potential, could impair T cell reactivity due to their dual impact on TCR binding. T cell activation assays are performed to measure effects of peptide SIY and QL9 residues on T cell function.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

• . Speir JA, et al. Structural basis of 2C TCR allorecognition of H-2Ld peptide complexes. Immunity. 1998 May;8(5):553-62.  [Content Brief]

  . Bowerman NA, et al. Different strategies adopted by K(b) and L(d) to generate T cell specificity directed against their respective bound peptides. J Biol Chem. 2009 Nov 20;284(47):32551-61.  [Content Brief]