Clonal selection hypothesis

Question 1

principles of clonal selection hypthesis

Answer 1

1. each lymphocycte bears a single type of receptor of a unique specificity
2. interaction between a foreign molecule and a lymphocyte receptor capable of binding that molecule with high affinity leads to lymphocyte activation
3. the differentiates effector cells derived from an activated lymphocyte will have receptors of identical specificity to those of the parental cell from which they were derived
4. Lymphocytes bearing receptors which recognise self molecules are deleted at an early stage of lymphocyte development

Question 2

the clonal selection hyphothesis stages

Answer 2

during development each lymphocyte precursor able to give rise to a number of lymphocytes.
lymphocytes with receptors that bind self antigens are eliminated early in development assuring self tolerance.
antigen interacts with receptor on mature lymphocyte .cell activated(lymphoblast) and starts to divide
produces clones of itself whose receptors bind the same antigen
cell proliferates and differentiate to produce effector and memory cells
once antigen is eliminated by effector cells the immune response ceases. (Memory cells remain)

Question 3

steps of b cell activation

Answer 3

1. surface Ig receptor binds to antigen
2. antigen is internalised by receptor mediated endocytosis
3. peptide antigen is presented on surface with MHC class II molecules
4. Antigen is presented to helper T cell
5. T cell gets activated expressed CD40L and secretes cytokines
6. Activation of B cell by cytokines and CD40 ligation

Question 4

whats an Ig

Answer 4

An antibody (Ab), also known as an immunoglobulin (Ig),[1] is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen

Question 5

T cell independent mechanism

Answer 5

much more rare as in most instances it is the action of t cells that causes b cells to proliferate and differentiate. typically activated by non protein antigen. they are not presented on the MHC and have no involvement of helper T cells. not fully understood why and how it works

Question 6

what is the course of a typical antibody response

Answer 6

(google typical antigen response-

Question 7

difference between primary and secondary antibody responce

Answer 7

secondary response is more rapid and intense and produces a higher amount of antibody as there is more memory cells.