MEMBRANE RECEPTOR FOR ANTIGEN

Kelompok : 4Ninda Sahriyani

(105090100111010)Ganys Tri S.

(115090107111020)Agatha Mia

(115090101111010)Vita Agustina

(115090100111011)Jurusan Biologi

Fakultas Matematika dan Ilmu pengetahuan Alam

Universitas Brawijaya2013

THREE LIMBS OF IMMUNE RESPONE

Fig 1. Three Limbs Immune Respone

• 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:Class I• Found in every

nucleated cell• Bound to cytotoxic T

cell (CD8)

Class II• Found in special cell

such as macrophage, dendritic cell, B cell, and thymus

• Bound to Helper T cell

Major Histocompatability Complex (MHC)

1.Determinate between the self and nonself antigens

2.Presenting antigen to T cells

3.Determinate interaction between B cells, T cells and other cells.

Function of MHC

There are 3 ways of processing and presentation antigens :

1. Protein from extracellular pathogen broken down and processed by exogen pathway

2. Protein from self-protein and virus protein processed by endogen pathway

3. Lipid and derivate processed like extracelular protein and endosom, with CD1, that similiar to MHC and presented to CD8 T cell.

Function of MHC

Degradation Process (Processing and Presentation) Antigen

Fig 2. MHC Structures

TABLE 1. DIFFERENCES BETWEEN CLASS I AND CLASS II MHC

Variable Class I MHC Class II MHCBound to CD8 T cell CD4 T cellEnzyme to form peptide

Cytosolic protease Endosome and lysosom protease

Peptide binding site in cell

Reticulum endoplasmic Vesicle specialized compartment

Peptide size 8-9 amino acid 13-17 amino acid

Expression and Presentation

• Expressed to hematopoietic cells• Presented by all nucleated cells.

• Expressed to hematopoietic cell and stromal cell at thymus• Presented by macrophage, dendritic cell, B cell

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

Fig 2. Class I MHC Antigen Presenting Pathway

Fig 3. Class II MHC Antigen Presenting Pathway

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 (TCR)

Fig 5. TCR-CD3 • TCR binding to MHC-antigen• The long cytoplasmic tail of the CD3 functions in signal transduction.

T Cell Receptor Complex: TCR-CD3

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.

Role of co-receptors in TCR binding affinity

THANK YOU FOR YOUR ATTENTION…ANY QUESTION???

VIDEO

Link : T Cell Dependent Antigenshttp://highered.mcgraw-hill.com/olc/dl/120110/micro33.swf

Cytotoxic T Cellhttp://highered.mcgraw-hill.com/olc/dl/

120110/micro34.swf