Adaptive Immunity

Question 1

(T/F) Adaptive immunity lasts longer than innate immunity.

Answer 1

True.

Question 2

Define cell mediated.

Answer 2

The responses through cells of the immune system.

Question 3

Define humoral.

Answer 3

Antibodies.

Question 4

What type of lymphocytes are responsible cells in the cell mediated arm of immunity?

Answer 4

T lymphocytes.

Question 5

What type of lymphocytes are responsible for the antibody production in humoral immunity?

Answer 5

B lymphocytes.

Question 6

What are the two sub-classes of T cells?

Answer 6

Cytotoxic and helper T cells.

Question 7

After T-cell formation, T-cell precursors leave the bone marrow and are transported by circulating blood to where?

Answer 7

Thymus.

Question 8

Once T-cells reach the thymus, T-cell precursors become known as what?

Answer 8

Thymocytes.

Question 9

What are the three major stages of T-cell development?

Answer 9

The double-negative (DN) stage, double-positive (DP) stage, and mature T-cells.

Question 10

CD markers provide a sort of ___, allowing the classification of T and B cells and their developmental stage.

Answer 10

fingerprint.

Question 11

How are Tc and Th cells differentiated?

Answer 11

By their surface markers, CD4 and CD8.

Question 12

Discuss why cells turn into double-negative (DN) thymocytes.

Answer 12

Because of their lack of CD4 and CD8 surface markers, it is considered a double-negative thrombocyte.

Question 13

It is during the DN stage of T-cell development that the rearrangement of what begins?

Answer 13

The rearrangement of the genes for the T-cell receptor (TCR).

Question 14

In what stage of T-cell development does the thrombocyte express a functional beta chain?

Answer 14

The double-negative phase.

Question 15

In the double positive stage, thrombocytes become what two subtypes?

Answer 15

CD4-positive (CD4+) and CD8-positive (CD8+).

Question 16

What is the CD3/TCR complex?

Answer 16

The TCR alpha and beta chains occur in a complex with six other molecules that are common to all T-cells.

Question 17

The six chains of the nonspecific CD3 portion of the CD3/TCR complex assist in what?

Answer 17

Intracellular signaling when an antigen binds to the TCR.

Question 18

What does MHC stand for?

Answer 18

Major Histocompatibility Complex.

Question 19

What two important molecules are needed for establishing the MHC restrictions of T-cells?

Answer 19

CD4 and CD8.

Question 20

What do thrombocytes possessing TCRs that recognize MHC-II express?

Answer 20

CD4.

Question 21

What do thrombocytes possessing TCRs that recognize MHC-I express?

Answer 21

CD8.

Question 22

Stable expression of either CD4 or CD8 and loss of expression of the opposite marker signify the entrance of the thymocyte into the next phase of differentiation. What is the next phase?

Answer 22

Single-Positive (SD) Differentiation.

Question 23

Thymocytes that survive positive selection must overcome one final developmental hurtle before exiting the thymus as mature T-cells, what is the final stage?

Answer 23

Negative Selection.

Question 24

Where does the negative selection process take place?

Answer 24

Corticomedullary and medulla regions of the thymus.

Question 25

What occurs to thymocytes to prevent self-reactive T cells from leaving the thymus and subsequently attacking the body’s own cells and tissues?

Answer 25

Thymocytes with strongly binding TCRs are negative selectively and undergo apoptosis.

Question 26

Once a T-cell exits the thymus, it is considered what?

Answer 26

Mature.

Question 27

Why would a T-cell be considered naīve?

Answer 27

Because the mature T-cell has not encountered the specific peptide epitope recognized by their TCR.

Question 28

To have higher odds of T-cells finding their specific antigen, where do they continuously circulate within the body?

Answer 28

Between the bloodstream and lymphatics.

Question 29

What do activated CD4+ Th cells secrete to induce an immune response?

Answer 29

Cytokines.

Question 30

What T-cells kill target cells?

Answer 30

CD8+ Tc cells.

Question 31

What are the two types of Th cells, and what is their function?

Answer 31

Th1 cells: activates cytotoxic lymphocytes and macrophages to fight intracellular paracites.

Th2 cells: help clear extracellular worms.

Question 32

What are the importance of T-regulatory cells (Treg)?

Answer 32

It possess the CD4 and CD25 antigen which allows them to suppress immune responses to self-antigens such as harmless food antigens.

Question 33

Where does B-cell differentiation occur?

Answer 33

Bone marrow.

Question 34

What is the name of the first step of B-cell differentiation?

Answer 34

Antigen-independent phase.

Question 35

What are the four distinct subpopulations in B-cell differentiation?

Answer 35

Pro-B cells, Pre-B cells, Immature B-cells, and Mature B-cells.

Question 36

For B-cells that reach maturity and encounter their specific antigen, what phase begins?

Answer 36

Antigen-dependent phase.

Question 37

Describe the pro-B cell stage.

Answer 37

A rearrangement of the B-cell-receptor (BCR) genes and undergo heavy-chain rearrangement.

Question 38

Describe the pre-B cell stage.

Answer 38

Heavy chains begin accumulating in the cytoplasm and light-chain gene rearrangement begins.

Question 39

At the end of B-cell differentiation, the B-cell is able to express what to be considered a mature B-cell?

Answer 39

CD21, CD40, and MHC-II.