Helper T Cells

Question 1

What are the 2 options for helper T cells after they get activated in the lymph nodes by dendritic cells with costimulation?

Answer 1

Some can go into the germinal centers with B cells and activate B cells. Others will leave the lymph nodes and head to the infected tissue.

Question 2

how do CD4 helper T cells leave the blood vessel and go into the tissue?

Answer 2

The same mechanism at neutrophils

Question 3

What does a helper T cell do in the tissue?

Answer 3

The activated CD4 cells with respond to the antigen on MHC class 2 on another dendritic cell and then release cytokines. They cytokines will work on other types of cells to either do their job better or tell other cells to kill.

Question 4

TH1 cells

Answer 4

release INF gamma. Tell microbes to kill its intracellular microbes

Question 5

TH2 cells

Answer 5

release IL4, IL5 and IL13 and work on worms/intestinal parasites

Question 6

TH17

Answer 6

release IL17 and works on extracellular microbes and fungi.

Question 7

How do the cytokines (INF gamma) work when released by TH1 cells?

Answer 7

The TH1 is presented the antigen on MHC II by the macrophage. The cytokines (INF gamma) released by the TH1 will bind to a receptor on the macrophage. This activates the macrophage. The macrophage and TH1 cell will bind CD40 ligand and CD40 and this tells the cell to kill the microbe inside of it.

Question 8

In TH2 cells, what does IL 4, 5 and 13 do?

Answer 8

IL 5 will cause eosinophils to release granules. The IL4 and IL13 cause the mucus production to increase and gut motility

Question 9

What does IL17 do from TH17 cells?

Answer 9

-causes neutrophils to leave blood into tissue
-cells produce defenses against microbes outside the cells

Question 10

What is a granuloma?

Answer 10

When TH1 cells surround infected macrophages and can cause tissue damage

Question 11

Anti-LFA1

Answer 11

stops adhesion molecules on the surface of leukocytes in the blood

Question 12

How is TH17 related to psoraiasis

Answer 12

TH17 releases cytokines (IL17 that cause recruitment of neutrophils) and also make TH22 release, which causes tissue damage.

Question 13

What happens if there is a CD40Ligand defficiency?

Answer 13

This is on the helper T cells…..
1) can’t do germinal center rxns with B cells
2) can’t interact with microbes in the tissue to tell them to be better microbes/phagocytosis