Key Elements of Adaptive Immunity

Question 1

What cells mediate adaptive immunity?

Answer 1

T- & B-cells

Question 2

This process allows for B & T cells to have highly diverse & specialized receptors

Answer 2

Somatic recombination

Question 3

What is direct recognition?

Answer 3

Whole, unprocessed antigen is recognized in its native form

Question 4

What lymphocyte is able to carry out direct recognition?

Answer 4

B-lymphocytes

Question 5

What must happen for a T-cell to be able to recognize an antigen?

Answer 5

Mediated by APC
Antigen processed into linear peptide
Presented in association with MHC molecules on APCs

Question 6

What is MHC?

Answer 6

Major histocompatibility complex
Responsible for presenting antigens to T-cells

Question 7

What are the two antigen processing pathways?

Answer 7

Exogenous and endogenous

Question 8

What are the two main classes of MHC molecules?

Answer 8

MHC I and MHC II

Question 9

What are the two classes of T-cells?

Answer 9

Helper T-cells (CD4)
Cytotoxic T cells (CD8)

Question 10

These cells act as APCs and make antibodies

Answer 10

B-cells
Humoral immunity

Question 11

What are antibodies?

Answer 11

Versions of antigen-specific receptor expressed on B cell surface

Question 12

What is somatic hypermutation?

Answer 12

Differentiation of B cells to make antibodies that are specific to an antigen
Done with “help” from T cells to

Question 13

What is isotype switching?

Answer 13

Aka class switch recombination
B cell changes the type of Ig it’s making but keeps it specific to the antigen

Question 14

Which class of T-cells can kill infected cells or cells expressing non-self or modified self-antigens?

Answer 14

CD8+ aka cytotoxic T-cells

Question 15

Which class of T-cells make cytokines that affect the function of other cells?

Answer 15

CD4+ aka helper T-cells

Question 16

What is needed for T-cells to be able to take action?

Answer 16

T cell receptors need to be presented a peptide by an MHC
Both types of T cells have specific MHC they can interact with

Question 17

What is antibody-dependent cell-mediated cytotoxicity?

Answer 17

Antibody binding to cell surface —> immune cells (macrophages, NK, or neutrophils) responding

Question 18

What is the importance of lymph nodes in adaptive immunity?

Answer 18

They act as meeting centers for B and T cells
B cells are residents
T cells traffic through
APCs migrate here when they capture antigens

Question 19

What are the key features of adaptive immunity? (3)

Answer 19

Specificity
Memory
Self-tolerance

Question 20

What does self-tolerance depend on?

Answer 20

Selection of antigen-specific B and T cells
Post-selection regulation