Adaptive immunity

Question 1

Define cell mediated immunity

Answer 1

• involves activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
• doesn’t involve antibodies.
• T-cells

Question 2

Define humoral immunity

Answer 2

• involves antibodies B-cells.

Question 3

What are the 2 cells involved in adaptive immunity?
Where do these cells develop?
How are these cells transported across the body?
Where do these cells reside?

Answer 3

• B & T cells (lymphocytes).
• both develop in primary lymphatic tissue e.g. red bone marrow.
• transported in lymph vessels.
• can reside in secondary lymphatic organs e.g. spleen & lymph nodes.

Question 4

Where do T cells mature?

Answer 4

• T-cells mature in thymus.

Question 5

Where do B cells mature?

Answer 5

• B-cells mature in the bone marrow.

Question 6

What is the MHC? What is its role? What cells is it on?

Answer 6

• Major Histocompatibility Complex.

- involve with recognition of pathogens by B&T-cells.

Question 7

What does the MHC bind to?

Answer 7

• peptide proteins, antigens, non-self material (and self).

Question 8

Where is MHC 1 found? What pathogen is it used to detect? What immune cell does this recruit?

Answer 8

• MHCI = all nucleated body cells (not RBC).

- detect virus.

Question 9

Where is MHC 2 found? What do these cells do?

Answer 9

• MHCII = antigen presenting cells (B cells (some t-cells), dendritic cells, macrophages).

Question 10

What type of cell produces antibodies?

Answer 10

• plasma cells

Question 11

Sketch and label an antibody

Answer 11

• see example

Question 12

What do antibodies bind?

Answer 12

antigens of pathogens or foreign bodies in the blood, lymph or tissue.

Question 13

What happens when a b cell binds a pathogen antigen? What chemicals are involved? What cells aid this?

Answer 13

• this activates the B-cell causing them to proliferate and differentiate into plasma or memory B-cells.
• t-helper cells, interleukin-4&6 encourage this .

Question 14

What are the effector cells of this b cell pathway?

Answer 14

• plasma cells.

Question 15

What enables the body to “remember a pathogen”?

Answer 15

• memory cells are long lived and contain specific antibodies (epitope) that will react in the case of a reinfection.

Question 16

What are the 4 things an antibody can do?

Answer 16

• neutralise antigens, toxins.
• immobilise bacteria, prevent flagella or cilia movement.
• Agglutination, easier to be engulfed by phagocytes.
• activates the complement system.

Question 17

What is the primary antibody produced? What are properties of this? What is the secondary and properties?

Answer 17

• IgM - less specific and titre is small.

- IgG - very specific and secreted in high amounts.

Question 18

What are the types of T cell? What does each do?

Answer 18

• Cytotoxic killer cells: bind to MHCI complex and use CD-8 protein to form perforin and granzymes to lyse the infected cell.
• Helper t-cells: bind to MHC-TCR complex. this causes activation to produce memory t-cells (clonal selection).
  they also produce cytokines and interleukins to stimulate B-cell activation.

Question 19

How are T cells activated? What costimulation is needed?

Answer 19

• binding to MHC using T-cell receptors (TCR) and costimulation from interleukin-2.

Question 20

What do T helpers bind to MHC Class ____ on the surface of APCs. They use ____________ to bind to the MHC-TCR complex. _________ also occurs and the cell is activated. ______________________ is the term used for proliferation and production of memory T cells.

Answer 20

-2, CD-4 protein, costimulation, clonal selection.

Question 21

Active T cells produce ________ to stimulate _________ and other _________________ which costimulate the activation of B cells.

Answer 21

• cytokines, phagocytosis, interleukins.

Question 22

What do cytotoxic T cells do? What MHC do they bind? What protein do they use to form a complex?

Answer 22

• elimination.
• Class I.
• CD-8 protein.

Question 23

How do T cells eliminate infected cells (2)? Describe the chemicals involved

Answer 23

• apoptosis: release granzymes - digest proteins inducing apoptosis - any microbes release after are killed via phagocytosis.
• cytolysis: perforin & granulising from granules inside cell.
  perforin is inserted = channels & granulising = holes - lyses membrane - fragments - phagocytosis.

Question 24

How are T cells controlled for self-tolerance? Where?

Answer 24

• Thymus

- tests to see if self MHC complex is bound to - if so KILLED.

Question 25

What occurs if T cells are not controlled for self-tolerance?

Answer 25

• autoimmunity - body attacks itself.

Question 26

How are B cells controlled for self-tolerance? Where?

Answer 26

• bone marrow.

- test to make sure they don’t attack self MHC or antigens.

Question 27

___________________ is the term used to describe proliferation of selected cells. And active and memory T cells are produced.

Answer 27

• clonal selection