BT302 GDB Solution

BT302 GDB Idea Solution 

Portray Antigen Processing and Presentation in detail. Clarify with the assistance of flowchart. 


Antigen handling and introduction is the procedure by which protein antigen is ingested by an antigen-exhibiting cell (APC), mostly processed into peptide sections and afterward showed on the outside of the APC related with an antigen-displaying atom, for example, MHC class I or MHC class II, for acknowledgment by specific lymphocytes, for example, T cells. 

Immune system microorganisms can possibly perceive antigens when they are shown on cell surfaces. This is done by Antigen-exhibiting cells (APCs), the most significant of which are dendritic cells, B cells and macrophages. APCs digest proteins they experience and show peptide pieces from them on their surfaces for another invulnerable cell to perceive. 

This procedure of antigen introduction permits T cells to "see" what proteins are available in the body and to shape a versatile invulnerable reaction against them. Right now will examine how antigens are handled, introduced, and the perceived by T cells. 

Antigen Presentation 

Antigens are conveyed to the outside of APCs by Major Histocompatibility Complex (MHC) atoms. Diverse MHC atoms can tie various peptides. The MHCs are exceptionally polygenic and polymorphic which prepares us to perceive a huge swath of various antigens we may experience. There are various classes of MHC, which have various capacities: 

MHC class I particles are found on completely nucleated cells (not simply proficient APCs) and commonly present intracellular antigens, for example, infections. 

MHC class II particles are just found on APCs and normally present extracellular antigens, for example, microscopic organisms. 

This is consistent in light of the fact that should an infection be inside a cell of any kind, the safe framework should have the option to react to it. This likewise clarifies why pathogens inside human red platelets (which are non-nucleated) can be hard for the insusceptible framework to discover, for example, in intestinal sickness. 

Antigen Processing 

Before antigen can be exhibited, it should initially be handled. Preparing changes proteins into antigenic peptides. 

MHC Class I Molecules 

Intracellular peptides for MHC class I introduction are made by proteases and the proteasome in the cytosol, at that point shipped into the endoplasmic reticulum by means of TAP (Transporter related with Antigen Processing) to be additionally handled. 

They are then amassed together with MHC I atoms and travel to the cell surface prepared for introduction. 

MCH Class II Molecules 

The course of preparing for exogenous antigens for MHC class II introduction starts with endocytosis of the antigen. Once inside the cell, they are encased inside endosomes that ferment and actuate proteases, to debase the antigen. 

MHC class II particles are moved into endocytic vesicles where they tie peptide antigen, and afterward travel to the cell surface. 

Antigen Recognition 

The antigen displayed on MHCs is perceived by T cells utilizing a T cell receptor (TCR). These are antigen-explicit. 

Immune system microorganism Receptors 

Every T cell has a great many TCRs, each with a one of a kind explicitness that on the whole permits our resistant framework to perceive a wide cluster of antigens. 

This decent variety in TCRs is accomplished through a procedure called V(D)J recombination during advancement in the thymus. TCR chains have a variable area where quality fragments are haphazardly revamped, utilizing the proteins RAG1 and RAG2 to start cleavage and non-homologous end joining to rejoin the chains. 

The decent variety of the TCRs can be additionally expanded by embeddings or erasing nucleotides at the intersections of quality fragments; together shaping the possibility to make up to 1015 special TCRs. 

TCRs are explicit for a specific antigen as well as for a particular MHC atom. White blood cells will possibly perceive an antigen if a particular antigen with a particular MHC particle is available: this wonder is called MHC limitation. 


Just as the TCR, another T cell particle is required for antigen acknowledgment and is known as a co-receptor. These are either a CD4 or CD8 particle: 

CD4 is available on T partner cells and just ties to antigen:MHC II edifices. 

CD8 is available on cytotoxic T cells and just ties to antigen:MHC I edifices. 

This hence prompts altogether different impacts. Antigens gave MHC II will enact T partner cells and antigens gave MHC I actuate cytotoxic T cells. Cytotoxic T cells will murder the cells that they perceive, though T assistant cells have a more extensive scope of consequences for the showing cell, for example, actuation to create antibodies (on account of B cells) or initiation of macrophages to execute their intracellular pathogens.

Click Here To Download

0/Post a Comment/Comments

Previous Post Next Post