MembraneReceptor for Antigen • Kelompok : 4 • NindaSahriyani (105090100111010) • GanysTri S. (115090107111020) • Agatha Mia (115090101111010) • Vita Agustina(115090100111011) • Jurusan Biologi • Fakultas Matematika dan Ilmu pengetahuan Alam • Universitas Brawijaya • 2013
Three Limbs of immune respone Fig 1. Three Limbs Immune Respone
Major Histocompatability Complex (MHC) • Group of genes that code for proteins that found on the surfaces of cells that help the immune system recognize foreign substances • Also known as HLA (Human Leukocyte Antigen) • Two types:
Function of MHC • Determinate between the self and nonself antigens • Presenting antigen to T cells • Determinate interaction between B cells, T cells and other cells.
Degradation Process (Processing and Presentation) Antigen There are 3 ways of processing and presentation antigens : • Protein from extracellular pathogen broken down and processed by exogen pathway • Protein from self-protein and virus protein processed by endogen pathway • Lipid and derivate processed like extracelular protein and endosom, with CD1, that similiar to MHC and presented to CD8 T cell. Function of MHC
Similarities of Antigen Presenting by MHC molecules • Presented to T cell on the surface of APC (Antigen Presenting Cell) • Every MHC can only bind to single antigen fragment at one time, at the peptide binding cleft • The presented antigen fragment is only amino acid chain • The binding is done intracellular
T Cell Receptor (TCR) T • Mature T cell have thousands identical receptor on the cell surface • 2 kinds of receptor: • Alpha/beta (αβ) chain T cell (95%) • Gamma/delta (γδ) chain T cell (5%) • Co-receptor : CD4 and CD8
T Cell Receptor Complex: TCR-CD3 Fig 5. TCR-CD3 TCR binding to MHC-antigen The long cytoplasmic tail of the CD3 functions in signal transduction.
Role of co-receptors in TCR binding affinity Fig. 6 Role of co- receptor CD 4 and CD8 : they may act as adhesion molecule helping the T cell bind to the APC during antigen presentation for duration that is sufficient for antigen recognition or act as signal transducers.
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VIDEO Link : T Cell Dependent Antigens http://highered.mcgraw-hill.com/olc/dl/120 110/micro33.swf Cytotoxic T Cell http://highered.mcgraw-hill.com/olc/dl/120110/micro34.swf