Major peptide complex

Group of transmembrane proteins engaged in the presentation of small peptide fragments to T-cells. Two classes of Major histocompatibility complex (MHC) molecules exist both of which are encoded by a highly polymorphic gene cluster. MHC class I and class II proteins present peptide fragments to CD8+ and CD4+ T-cells, respectively. The human MHC is also known as HLA, the murine MHC as H-2 complex. 

F. F. Major histocompatibility complex class 11 binding characteristics of peptoid-peptide hybrids. Bioorg. Med. Chem. 

S, Reis e Sousa C, Germain RN, Mellman I, Steinman 48 RM The formation of immunogenic major histocompatibility complex class Il-peptide ligands in lysosomal compartments of dendritic cells is regulated by inflammatory stimuli. J Exp Med 2000 191 927-936. 49... 

Fig. 1. A model for functional migration of DCs and T cells. DCs are classified into naive, primed, and effector DCs, DCpre, and DC precursor. pMHC, peptide-major histocompatibility complex.

Santos, S.G., Campbell, E.C., Lynch, S., Wong, V., Antoniou, A.N., and Powis, S.J. (2007) Major histocompatibility complex class I-ERp57-tapasin interactions within the peptide-loading complex. /. Biol. Cbem. 282(24), 17587-17593. 

Tsomides, T.J., Walker, B.D., and Eisen, H.N. (1991) An optimal viral peptide recognized by CD8+T cells binds very tightly to the restricting class I major histocompatibility complex protein on intact cells but not to the purified class I protein. Proc. Natl. Acad. Sci. USA 88, 11276-11280. 

Fig. 8. Lck SH2 domain-peptide complex (Ac-cmF-Glu-Glu-Ile-OH, 12) revealing the twopronged plug engaging a two-holed socket 1 binding mode, reminiscent of the majority of SH2 domains (Protein Databank entry code 1BHF.PDB [118]). The protein is depicted in a Connolly surface mode, the ligand is given in a ball-and-stick representation. The cmF residue is deeply buried in its binding pocket (left)...

Spehr, M., Kelliher, K., Li, X.-H., Boehm, T., Leinders-Zufall, T. and Zufall, F. (2006) Essential role of the main olfactory system in social recognition of major histocompatibility complex peptide ligands. J. Neurosci 26, 1961-1970. 

T. H. Watts, H. E. Gaub, and H. M. McConnell, T-cell-mediated association of peptide antigen and major histocompatibility complex protein detected by energy transfer in an evanescent wave-field, Nature 320, 176-179 (1986). 

Haselden BM, Kay AB, Larche M Immunoglobulin E-independent major histocompatibility complex-restricted T cell peptide epitope-induced late asthmatic reactions. J Exp Med 1999 189 1885-1894. 

During the last decade the MHC class 1 antigen processing machinery (APM) has been well defined and appears to be more complex than initially expected. It consists of four major steps (i) peptide generation and peptide trimming, (ii) peptide transport, (iii) MHC class 1 assembly and (iv) presentation of the trimeric MHC class 1 heavy chain/p2-m/peptide complex on the cell surface (Eigure 1). 

Formation of antigens from the intracellular degradation of pathogens The proteolytic system hydrolyses proteins of pathogens that are present within the host cell (e.g. a virus), to produce a short peptide which forms a complex with a specific protein, known as the major histocompatibility complex (MHC) protein. The peptide is, in fact, the antigen. At the plasma membrane, the MHC protein locates within the membrane and the small peptide sits on the outside of the membrane, where it can interact with the receptor on a cytotoxic T-lymphocyte to kill the host cell and the virus (Chapter 17). 

They recognise small peptide antigens that mnst be bound to a specific protein, the major histocompatibility complex protein (MHC) (see below). 

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