Week 2 - T cells and Immune System in Health and disease

Question 1

What do T cell receptors bind to?

Answer 1

they bind to antigens that are bound to MHC

Question 2

how does T cell activation occur?

Answer 2

1. cell binds to T lymphocyte
2. signal transduction activates T lymphocyte

Question 3

types of T cells

Answer 3

helper T cells, T reg cells and cytotoxic T cells

Question 4

helper T cells and Treg cells

Answer 4

they release cytokines that activate or suppress the immune system

Question 5

cytotoxic T cells

Answer 5

they kill target cells by using perforin and granzymes or by activating the “death receptor” fas

Question 6

location of MHC class II

Answer 6

located on dendritic cells, macrophafes and B cells

Question 7

what does MHC class II do

Answer 7

they present exogenous antigen and activate helper T cells

Question 8

activation of helper T cells

Answer 8

helper T cells have CD4 on their surface, which interacts with MHC class II and get activated

Question 9

location of MHC class I

Answer 9

located on all nucleated cells

Question 10

what does MHC class I do

Answer 10

they present endogenous antigen and activate cytotoxic T cells

Question 11

activation of cytotoxic T cells

Answer 11

activated due to CD8 receptor binding to MHC class I molecules. This interaction ensures that the cytotoxic T cell recognizes and targets infected or abnormal cells. CD8 strengthens the binding between the T cell receptor (TCR) and the MHC Class I-antigen complex, facilitating effective activation of the T cell

Question 12

allergy

Answer 12

immune response to non pathogenic antigen

Question 13

2 types of allergy

Answer 13

immediate hypersensitivity and delayed hypersensitivity

Question 14

immediate hypersensitivity

Answer 14

upon re-exposure to allergen the immune cells activate more quickly. the body reacts very strongly with the release of histamine from mast cells, cytokines and other mediators causing allergic symptoms.
can result in local rashes or anaphalaxis

Question 15

general outline of what happens in an allergy

Answer 15

1. allergen ingested and processed by antigen-presenting cell
2. antigen presenting cell activated helper T cell
3. activated helper t cell in turn activated B lymphocyte
4. Activate dB lymphocytes become plasma cells and memory cells
5. Memory B and T cells retain memory of exposure to allergen

Question 16

what type of antigen is the Rh factor

Answer 16

D antigen

Question 17

how do anti-D antibodies develop in an Rh- individual

Answer 17

transfusion of Rh- an individual with Rh+ blood and pregnancy Rh- mother and Rh+ baby

Question 18

what happens when Rh- mother has Rh+ baby

Answer 18

first pregannacy okay, roblems with subsequnt ones
sometimes the blood can mix. antibodies developed from first pregnancy will begin to attack baby’s blood.
clumps can clock small capillaries causing fluid to leak into the tissues and destructions of RBCs take place

Question 19

hemolytic disease of newborn

Answer 19

anaemia, jaundice, enlarged liver and spleen and severe edema

Question 20

how do doctors prevent hemolytic disease of the newborn

Answer 20

1. inject antigen D antibodies into Rh mother during and following her pregnancy
2. the antibodies bind and remove fetal red blood cells in mother’s bloodstream before they can trigger an immune response in mother
3. thus B cells are not activated in the mother and immunological memory of the D antigen is acquired
4. therefore in a subsequent pregnancy with an Rh+ fetus, the mother does not produce anti-D antigen antibodies upon exposure to fetal red blood cells with D antigen