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Matching: The diagram in Figure Q6.1 shows a pathogen (in red) that is present i

ID: 149820 • Letter: M

Question

Matching: The diagram in Figure Q6.1 shows a pathogen (in red) that is present in different cellular compartments of each of the cell types shown. Pathogens that are endocytosed are indicated in red circles surrounded by the beige endosome. In each case, a specific T cell subset will recognize peptides of that pathogen presented on MHC molecules on the surface of the cell, and will execute its effector function. From the list below, match the appropriate T cell effector response to the cell type and location of the pathogen (5).

i.   CD8 T cell killing of target cell

ii.  CD4 T cell activation of target cell’s antibody production

iii.  CD8 T cell activation of target cell’s antibody production

iv.  CD4 T cell activation of target cell’s ability to kill intracellular pathogen

v.  CD8 T cell activation of target cell’s ability to kill intracellular pathogen

Any cell Macrophage B cell

Explanation / Answer

1. In any cell pathogen or antigen are processed via proteosome and causes activation of Tc cells which contain perforein and Granzyme B and causes apoptosis in cell. Option (i) is correct.

2. In 2nd macrophage process antigen via lysosomal endosomal pathway and presented at MHC II and causes helper T cell (CD4+) activation and causes activation of different cells of immune system via releasing cytokines. Option (iv) is correct.

3. B-cell also process soluble native antigens via endosomal lysosomal pathway and activated via produced cytokines from helper T cell (CD4+) and causes antibody production. Option ii is correct.