T-cells, effector functions and MHCs

Question 1

What does MHC stand for?

Answer 1

Major histocompatibility complex

Question 2

What are the two types of MHC molecules?

Answer 2

MHC I and MHC II

MHC I is a monomer which associates with a Beta2 microglobulin, endogenous proteins displayed on all nucleated cells.

MHC II is an alpha-beta dimer, expressed on antigen presenting cells (monocytes, macrophages, dendritic cells and B-lymphocytes) showing exogenous proteins.

Question 3

Where are MHC I cells presented?

Answer 3

On the surface of all nucleated cells.

Question 4

Where are MHC II cells presented?

Answer 4

On antigen presenting cells (monocytes, macrophages, dendritic cells and B-lymphocytes)

Question 5

What is the structure of T cell receptors?

Answer 5

Membrane bound heterodimers with the 2 chains joined with disulfide bonds.

Question 6

What are the two signals needed to activate a T cell?

Answer 6

Signal 1: MHC + TCR meet (putting the plug into a socket)

Signal 2: Costimulation of CD28 and CD86 (switching it on)

Question 7

What are CD-8 T cells

Answer 7

Cytotoxic cells; finds virally infected cells and kills them.

Question 8

Describe a Th1 cell

Answer 8

Secretes interferon gamma (IFNgamma) and IL2 which promote proliferation and activation of CD8 cells and macrophages

Question 9

Describe a Th2 cell

Answer 9

Secretes IL-4 and IL13; helps B cells by increasing diffusion, class switching and affinity maturation and differentiation of B cells into plasma cells

Question 10

Describe a Th17 cell

Answer 10

Secretes IL-17, -21, -22, which helps secrete antimicrobial peptides.
Also helps maturation of neutrophils.

Question 11

Describe a Treg cell

Answer 11

Downregulates the other immune responses via cell-to-cell contact and via cytokines.