Immunology 5th lecture

Question 1

T/F : No IgM remaining when secondary immune response + underlying concept

Answer 1

F: Always some IgM remaining in the organism. No immune response is pure (more precisely, this can mean never only 1 immunoglobulin class)

Question 2

Where most B cells killed

Answer 2

Bone marrow (system similar to clonal selection/deletion / central immune tolerance in the thymus but less understood)

Question 3

What happens during pure cell-mediated response

Answer 3

No pure cell-mediated response Always humoral component as well

Question 4

What cells do viruses choose to infect

Answer 4

Cells they are specific to

Question 5

3 antigen presenting cells

Answer 5

Macrophage, dendritic cells and B lymphocytes (so monocytes and B lymphocytes)

Question 6

What happens to viruses (that is similar to the bacterial infection)

Answer 6

Are chewed up by dendritic cells and MHC II + epitope presented on surface

Question 7

What kills viruses ultimately but what does that not stop from happening ?

Answer 7

Ultimately, T cytotoxic cells kill viruses, but there is still a humoral response

Question 8

First cell involved in specificity of cell-mediated response

Answer 8

T helper cell 1

Question 9

What TH1 does similarly to TH2 and what cytokines it releases

Answer 9

Recognizes MHC II + epitope with its TCR. Coreception between B7 (dendritic cell) and CD28 (on TH1)

Question 10

How can cell-mediated response be downregulated similarly to the humoral response

Answer 10

T regulatory cells can stop it (just like TH cells - TH1 and TH2, have CTLA4 and PD-1 that will displace CD28 and B7) - peripheral tolerance

Question 11

What cytokines TH1 releases

Answer 11

INF (interferon) and IL 2 (interleukin 2)

Question 12

What cells Tc must bind for a proper cell-mediated response to start

Answer 12

No cell. We do not know whether there is a link between Tc and the dendritic cell (or a virus on it) and between Tc and TH1

Question 13

Effect of INF and IL2 on Tc

Answer 13

Causes a further SPECIALIZATION and EXPANSION of the Tc cell clone

Question 14

How Tc recognizes virally infected cells

Answer 14

All cells have MHC 1 on surface, virally infected ones will present MHC 1 + epitope

Question 15

How Tc cell binds to virally infected cells and what does it do then and afterwards

Answer 15

Binds with its TCR on MH1 + epitope and kills the cell. Continues killing other infected cells after

Question 16

What is absolutely necessary for a functional T cell (primordial importance)

Answer 16

Must recognize MHC molecules, otherwise destroyed

Question 17

When development of T cell tolerance in thymus happens

Answer 17

In utero

Question 18

3 mechanisms for the maintenance of immunological tolerance in adults

Answer 18

1) Ongoing thymic tolerance mechanisms as new T cell clones arise
2) T regul. cells inhibiting TH activation using CTLA4
3) Tolerance of the route of exposure (TOLEROGENIC MALT)

Question 19

Proportion of allergies and region of the body where allergens are recognized

Answer 19

1/3 people = allergic. allergen (foreign entity) often seen in gut or bronchial tree

Question 20

How allergies are conserved through evolution

Answer 20

Passed on genetically

Question 21

Characteristic of TCR formation

Answer 21

Random (not caused by antigenic stimulation)

Question 22

What CD4 helps for

Answer 22

(on TH1 and TH2 but NOT ON Tc) Bind to MHC II of MHC II + epitope complex, WHILE TCR BINDS TO OTHER PARTS OF THIS COMPLEX

Question 23

What CD8 helps for

Answer 23

(on Tc cells) Bind to MHC I of MHC I + epitope complex, WHILE TCR BINDS TO OTHER PARTS OF THIS COMPLEX

Question 24

How is it that virally infected cells can present an epitope of a virus on a MHC I on their surface

Answer 24

All cells do some phagocytosis/capable of digestion (but some better than others) (+ all cells have MHC I)