Question

Which of the following processes: T cell development, T cell activation, B cell development, B cell activation would be disrupted by a deficiency in the indicated protein. Your answer should include all processes that would be disrupted.  If none of these processes is disrupted, state NONE.

Part 2: Justify your answers (a-d) by describing the cell type(s) that express the molecule and the function of the molecule in the processes you indicated would be disrupted.  

a. CD3 zeta chain

b. TLR4

c. B7

d. Artemis

Answer 1

Answer: (a) CD 3 zeta chain: It is located on T cell surface. CD3 zeta chain is a glycoprotein present on plasma membrane as an integral membrane protein.

Function: zeta chain form heterodimer with alpha, beta or gamma receptor to form t cell receptor which help in recognition of antigen and coupling this process with intracellular signalling pathways.

Deficiency of zeta : deficiency of zeta chain affect the t cell activation.

TLR4 :toll like receptors are the transmembrane protein. It is located on T cells, B cells, macrophages and dendritic cells.

Function: it helps in molecular pattern recognition associated with the the pathogen.

Deficiency of TLR4 : as it is present on both B and T cells. It's deficiency affects the pathogen molecular recognition by the cells and further signalling for B and T Cell activation.

B7= it is a peripheral membrane protein found on antigen presenting cells like B cells, macrophages and dendritic cells.

Function: it helps in activation of T cells by providing co-stimulatory action.

Deficiency of B7 it affect the T cell activation.

Artemis: it is a nucleus protein involved in V, DJ recombination and DNA repair process.

Function: it has endonucleus activity and help in DNA repair and V, DJ gene recombination. By this process b cell antibodies and t cell receptor genes combine.

Deficiency : it affects b and t cell development. deficiency in artemis causeayhabascan-type severe combined immunodeficiency.