Lymphocytes II

Question 1

What are the functions of IgG?

Answer 1

To opsonize bacteria and to neutralize viruses; to activate compliment (p.195)

Question 2

What types of B cells activate compliment?

Answer 2

IgM and IgG (p.195)

Question 3

What type of B cells sensitizes mast cells?

Answer 3

IgE (p.195)

Question 4

What are the functions of IgE?

Answer 4

To sensitize mast cells; to mediate type I hypersensitivity allergic reactions (p.195)

Question 5

What immunoglobin type mediates cytotoxic (type II) and immune complex (type III) hypersensitivity reactions?

Answer 5

IgG (p.195)

Question 6

What is the function of CD4+ T cells?

Answer 6

To help B cells make antibody and produce cytokines to activate other cells of the immune system (p.195)

Question 7

What is the function of CD8+ T cells?

Answer 7

To kill virus infected cells directly (p.195)

Question 8

What class of immune cells is responsible for mediating delayed type hypersensitivity reactions (type IV)?

Answer 8

T cells (p.195)

Question 9

What class of immune cells is responsible for mediating acute and chronic cellular organ rejection?

Answer 9

T cells (p.195)

Question 10

What class of immune cells is responsible for mediating hyperacute and humorally mediated acute and chronic organ rejection?

Answer 10

B cells (p.195)

Question 11

Where do T cell precursors get tagged with CD4+ and CD8+ T cell markers?

Answer 11

In the thymus (p.195)

Question 12

Where do T cells with CD4+ and CD8+ tags differentiate into CD8+ or CD4+ T cells?

Answer 12

In the thymus (p.195)

Question 13

Where do cytotoxic T cells kill virus infected, neoplastic cells, and donor graft cells?

Answer 13

In the lymph node (p.195)

Question 14

What is the first signal in naiive T cell activation?

Answer 14

When foreign antigen is presented on MHC II and recognized by TCR on Th (helper) cells; Antigen is presented on MHC I to Tc cells (p.196)

Question 15

What is the second signal in naiive T cell activation?

Answer 15

The interaction of B7 and CD28 causes a costimulatory signal (p.196)

Question 16

What are the four steps in B cell activation and class swirtching?

Answer 16

1.) Helper T cell activation; 2.) B cell receptor mediated endocytosis; foreign antigen is presented on MHC II and recognized by TCR on Th cells (signal 1); 3.) CD40 receptor on B cell binds CD40 ligand on Th cell (signal 2); 4.) Th cell secretes cytokines that determine Ig class switching of B cells. B cell activates and undergoes class switching, affinity maturation, and antibody production (p.196)

Question 17

What is the first signal in B cell activation and class switching?

Answer 17

B cell receptor mediated endocytosis; foreign antigen is presented on MHC II and recognized by TCR on Th cells (p.196)

Question 18

What is the second signal in B cell activation and class switching?

Answer 18

CD40 receptor on B cell binds CD40 ligand on Th cell (p.196)

Question 19

What is secreted by Th1 cells?

Answer 19

IFN y (p.196)

Question 20

What is secreted by Th2 cells?

Answer 20

IL-4, IL-5, IL-10, IL-13 (p.196)

Question 21

What is the primary function of Th1 cells?

Answer 21

To activate macrophages (p.196)

Question 22

What is the primary function of Th2 cells?

Answer 22

To recruit eosinophils for parasite defense and to promote IgE production by B cells (p.196)

Question 23

What inhibits the Th1 cell pathway?

Answer 23

IL-4 and IL-10 (both from Th2 cells) (p.196)

Question 24

What inhibits the Th2 cell pathway?

Answer 24

IFN-y from Th1 cells (p.196)

Question 25

What is the macrophage-lymphocyte interaction?

Answer 25

When activated lymphocytes (that release IFN-y) and macrophages (that release IL-1, TNFa) stimulate one another (p.196)