4. Adaptive Immune Response (Chapter 15) (Part 2)

Question 1

what is the difference between T-dependent and T-independent antigens?

Answer 1

T-independent antigens can activate B cells without help from the Th cells, T-dependent antigens cannot

Question 2

what is clonal selection and expansion?

Answer 2

the adaptive immune draws from a large population of lymphocytes to respond to antigens. when the immune system recognizes an antigen, only the lymphocytes that recognize it can multiply. thus, the antigen determines which lymphocytes multiply.

Question 3

what are immature lymphocytes?

Answer 3

antigen-specific receptors haven’t developed yet

Question 4

what are naive lymphocytes?

Answer 4

have antigen receptors, but have not yet encountered the antigen to which they are programmed to respond

Question 5

what are activated lymphocytes?

what can they do?
what has happened to them?
what now?

Answer 5

can proliferate, recognize the presence of an antigen because their antigen receptor has attached to it and they’ve received the necessary signals

Question 6

what are effector lymphocytes?
what are some examples?

Answer 6

descendants of activated lymphocytes. ex. plasma cells, Tc cells, Th cells

Question 7

what are memory lymphocytes?

Answer 7

long-lived descendants of activated lymphocytes that can quickly become activated when an antigen is encountered again. that’s why the secondary response is so fast and effective.

Question 8

what is affinity maturation?
how does it work?

Answer 8

form of natural selection among proliferating B cells.

as they multiply, spontaneous mutations occur, making some better at binding to antigens than others, and those ones are most likely to proliferate.

Question 9

what is class switching?

Answer 9

process that allows a B cell to change the antibody class it is programmed to make

Question 10

what is the primary response?

Answer 10

first encounter with an antigen

Question 11

what is the secondary response?
aka?

Answer 11

memory response. enhanced response that is caused by the activation of memory cells. faster and more effective.

Question 12

what is CD4?

Answer 12

CD marker on a helper t cell

Question 13

what is a CD marker?

Answer 13

surface molecule that guides antigen to receptor

Question 14

what is C8?

Answer 14

CD marker on a cytotoxic T cell

Question 15

what is the name of T cell activation via dendritic cells?

Answer 15

cross-presentation

Question 16

what is cross-presentation?

Answer 16

the ability of dendritic cells to present exogenous or endogenous antigens on MHC I or MHC II, regardless of the origin

Question 17

what are NK cells? what are their two jobs?

Answer 17

induce apoptosis in antibody-bound self-cells, aka mediate ADCC (antibody-dependent cellular cytotoxicity)

recognize and destroy stressed self cells that do not have MHC I molecules on their surface