Week 1 - adaptive immunity and B cells

Question 1

what are the features of adaptive immunity

Answer 1

specificity, versatility, memory, tolerance

Question 2

how are the features of adaptive immunity achieved?

Answer 2

1. specificity - both B and T cells have receptors that recognize specific shapes
2. versatility - different B and T cells have different receptors
3. memory - some B and T cells are long lasting
4. tolerance - B or T cells with receptors that identify self are deleted or not activated

Question 3

what do B cell receptors bind to?

Answer 3

they bind to extracellular antigens

Question 4

what do T cell receptors bind to?

Answer 4

they bind to antigens displayed on the surface of cells (macrophages, tissue cells, etc)

Question 5

clonal expansion

Answer 5

allows immune system to produce a large number of T cells to fight infections

Question 6

short lived effector cells

Answer 6

carry out immediate response after antigen binding

Question 7

memory cells

Answer 7

long lived and continue to reproduce

Question 8

primary immune response

Answer 8

we dont start to see antibody fromation until just before the first week
reaches peak at two weeks and then dies off

Question 9

secondary immune response

Answer 9

immune response is instantaneous and stronger
vaccines based on this concept

Question 10

where T and B cells undergo positive and negative selection

Answer 10

T cells undergo positive ad negative selection in the thymus
B cells undergo positive and negative selection in the bone marrow

Question 11

humoral immunity

Answer 11

Humoral immunity is an aspect of specific immune responses directed at particular antigens. It takes the form of unique antibodies produced by B lymphocytes that have been specifically selected to neutralize the antigen at hand.

Question 12

How are B cells activated?

Answer 12

1. Antigen binds to s[ecific B cell via B cell receptors
2. Antigen is internalized, digested and combined with MHC and then transported to cell surface.

Question 13

What do helper T cells do after B cell is activated?

Answer 13

Specific helper T cell recognizes antigen and MHC becomes activated and secreted cytokines (especially interleukin 4,5,6 which activates the B cell and triggers a change in the splicing of B cell receptor)

Question 14

What happens after the helper T cell recognizes antigen?

Answer 14

The secreted cytokines (interleukins 4,5 and 6) activates B cell, The B cell divides. some daughter cells become plasma cells and secrete antibodies, other become memory B cells.

Question 15

antibody functions

Answer 15

1. antigen clumping
2. inactivation of bacterial toxins
3. act as opsonins to tag antigens for phagocytosis
4. trigger denaturation
5. activate complement
6. activates B lymphocytes

Question 16

classes of antibodies

Answer 16

IgG, IgM, IgA, IgE, IgD

Question 17

IgG

Answer 17

1. most common type of circulating antibody
2. transferred across the placenta from mother to baby

Question 18

IgM

Answer 18

1. First type of antibody to be secreted in response to a new antigen
2. Good at causing antigen clumping and activating complement

Question 19

IgA

Answer 19

Crosses epithelial cells. Protects epithelial surfaces and present in breast milk, mucus

Question 20

IgE

Answer 20

fights parasites. eosinophils have receptors for the IgE. Release histamine. Associated with allergic reactions.

Question 21

IgD

Answer 21

Are the B cell receptors on the surface of B cells

Question 22

Active adaptive immunity

Answer 22

exposure to a pathogen. Long lasting generates memory B and T cells.

Question 23

Passive adaptive immunity

Answer 23

Transfer of antibody from another organism. Lasts about 3 months because antibody degraded.