Biochem and Immunology Insights

  CELL-MEDIATED IMMUNITY —   CMI is an immune response that involves activation of:   Cells —   Cytotoxic T-lymphocytes —   Macrophage —   Natural killer cell, —     Release of various cytokines in response to an antigen.   Cytotoxic T-cell —   It is most effective in removing virus-infected cells, tumour cells, and intracellular bacteria. —   It also plays a major role in transplant rejection. —   In periphery, when cytotoxic T-cell is required Pre-CTL is activated by T-helper cell —   T-helper cell is primed to respond to viral peptides after viral particles have been ingested and presented by MQ cells at the site of infection. —   . —   Antigens inside a cell are brought to the surface of the APC by the class II MHC molecule, where they can be recognized by the T helper cell https://www.vectorstock.com/royalty-free-vector/cytotoxic-t-cell-vector-23523146 —   In turn t...

  THE COMPLEMENT SYSTEM Class III region ¢   Between class I and II regions is class III –contain genes coding for complement components ¢   Complement is a protein cascade composed of more than 40 proteins including factors ¢   Components are made from the liver, though some local production at sites of inflammation maybe undertaken by macrophages Complement has 3 pathways ¢   Alternative pathway ¢   Classical pathway ¢   Lectin pathway ¢   Membrane attack pathway/common pathway ¢   The majority of complement proteins are soluble,   some are membrane bound ¢   The soluble proteins circulate in an inactive state, and each must be activated sequentially for the reaction to proceed ¢   Each activated molecules can catalyze the conversion   of several molecules of the next component in the sequence, this leads to amplification Complement activation ¢   In complement activation, classical and a...

  MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) MHC describes a collection of genes that in human represents about 0.1% of the whole genome   MHC LOCATION ¢   Situated on the short arm of chromosome 6. ¢    Many of the genes in MHC are involved in immune function ¢   In human MHC -human leukocyte antigen (HLA system) ¢   HLA molecules are designated with greek letters α and  β  to describe the structure of polypeptide chain , Structure of HLA HLA consists of 3 major classes ¢   Class I ¢   Class II ¢   Class III ¢   Genes in HLA are designated using capital italic letters (A, B, C and D).                                                                     MHC Class I molecules inc...