Question

EXPLAIN each of the following questions thorouhly.

1. What are the characteristics of NK (natural killer) cells and what role do they play in immunity? 2. Explain in detail, how antigenic specificity is determined in humoral immunity? 3. At the gene level beginning with germ line DNA, explain how mature (functional) mRNA for the heavy chain polypeptide of an immunoglobulin arises in B lymphocytes. 4. Compare and contrast the various molecular pattern recognition receptors found in innate immunity leukocytes.

Answer 1

Page 1 Biology Question Date tions. 6 What are the charaderistics kinee) cells and cohal role do they of NK (hatwal play in immun- > . Nk (Nautua Hillel cells commise to y ou OR peupheral blood mononuclear cells and have morphology of large granulu lymphocytes with the central role of killing the virw-infected. and malignantly transformed cells, coithout amor sensitization whe - Niscelts participate in hematopoiests régulation reproduction procese well eu în numeow immune system reactions in vivo a • Natural killer cells are a type of lymphocyte (a wbcs ) and a component of innate immune System. " NK cells play a major role in the host rejecton of both tumoud and virally infected cells. They serve to contain viral infections while the. I lada plive immune response is generating maqes. Specifre cytotoxic T-cells that can clear the infection 7 Explain in detall how antigenic specificity is determined in humoral immunity? • Antigenic specificity: the Property of mature B and I lymphocytes that enables them to respond to specific foreign antigen entering. the body ! • The exact process by conich B-lymphoutes. become capable of recognizing and respondin

page @ Page No. Date to antiqen i ansnown • Humoral immunity is aspect of immunity that - is mediated by macromolecules found in extrac. ellular fluids sinch cu secreted Ab; complement proteins and certain antimicrobial peptides Humoral immunity is so named because it involves substances found in humors body flude! Its aspect involving antibodiei are often called antibody mediated immunity ornith It refeld To Ab production and the accessory. Processes that accompany it includina : Th 2 actiun ! land cytokine producte terminoy center fomatn affinity matigation & memory cell geneation It also refers to the effector. Ion of antibodres cohich includes pathogen, pano Mechanism: In humoral immune response fit B.. cei mature in bone maszow -o. A macrophage enqulfs pathogen o Macrophage! than digest the bacterium & prevents pathogen's Aa OTH cell binda to macrophage f become activated Activated th cell bind to Bocell . When B ceh activated, tern into plauma cells & other into memory cells Ploumo & prauma cell seesete abi orth to IgG cell 57 Loc Cetus p.to

page 3 (Page No. Date T • At the gene level begining coith the germ line PNA - Explain how mature (functional mRNA PER the heavy chain polypeptide of an Ig aarses in B fymphocyte. Pe Immunoglobulin heavy chains are formed from 14 gene segments encoded on choomosome . Immunoglobulin heavy f eight chain cue encoded by a series of gene segments that undergoes rearrangement and joining pally D B-cell antogeny • B-cell exposure to Ag and speerfic - Teell. interaction result in induction of v-region. somatia mutation . An immunoglobulin alenes naturally acquire. frequent premature tominat a codones CDI •VD - VPS mechanism Đ Compare and controut voo lous molecular patteen recognition receptors found in innate immunity leukocytes: · PRPS - pray a crucial role in proper function of the innate immune system • PRPs are q ermline encoded host sensors conich. delect molecules typical for pathogen Mannose Receptor. Dectin I 6 Scavengen receptor (4 opsonin receptor O N-formy Met receptors *****