Chapter 4: Immunology

Question 1

• Release IL-2 (causes maturation of cytotoxic T cells)
• Release IL-4 (causes B-cell maturation into plasma cells)
• Involved in delayed-type hypersensitivity

Answer 1

Helper T cells (CD4)

Question 2

Causes maturation of cytotoxic T cells

Answer 2

IL-2

Question 3

Causes B-cell maturation into plasma cells

Answer 3

IL-4

Question 4

Brings in inflammatory cells by chemokine secretion

Answer 4

Delayed-type hypersensitivity

Question 5

Regulate CD4 and CD8 cells

Answer 5

Suppressor T cells (CD8)

Question 6

Recognize and attack non-self-antigens attached to MHC class 1 receptors (e.g. viral gene productS)

Answer 6

Cytotoxic T cells (CD8)

Question 7

Used to test cell-mediated immunity

Answer 7

Intradermal skin test (i.e., TB skin test)

Question 8

Infections associated with defects in cell-mediated immunity

Answer 8

Intracellular pathogens (TB, viruses)

Question 9

• CD8 cell activation
• Present on all nucleated cells
• Single chain with 5 domains
• Target for cytotoxic T cells (binds T cell receptor)

Answer 9

MHC class 1 (A, B, C)

Question 10

• CD4 cell activation
• Present on antigen-presenting cells (e.g., monocytes, dendrites)
• 2 chains with 4 domains each
• Activates helper T cells (binds T cell receptor)
• Stimulates antibody formation after interaction with B cell surface IgM

Answer 10

MHC class II (DR, DP, and DQ)

Question 11

Mechanism of immune response to viral infection

Answer 11

Endogenous viral proteins are produced, are bound to class I MHC, go to cell surface, and are recognized by CD8 cytotoxic T cells

Question 12

Mechanism of immune response to bacterial infection

Answer 12

Endocytosis, proteins get bound to Class II MHC molecules, go to cell surface, recognized by CD4 helper T cells -> B cells which have already bound to the antigen are then activated by the CD4 helper T cells; they then produce the antibody to that antigen and are transformed to plasma cells and memory B cells.

Question 13

• Not restricted by MHC, do not require previous exposure, do not require antigen presentation
• Not considered T or B cells
• Recognize cells that lack self-MHC
• Part of the body’s natural immunosurveillance for cancer

Answer 13

Natural Killer Cells

Question 14

Initial antibody made after exposure to antigen. It is the largest antibody, having 5 domains (10 binding sites)

Answer 14

IgM

Question 15

Most abundant antibody in body.
Responsible for secondary immune response.
Can cross the placenta and provide protection in newborn period.

Answer 15

IgG.

Question 16

What type of cells do natural killer cells recognize?

Answer 16

Recognize cells that lack self-MHC

Question 17

Two signals that cause activation of T and B cells

Answer 17

1. Alloantigen binds to antigen specific receptors. (TCR - T cells; IgM - B cells)
2. IL-1 release by APC.
   CD4 helper T cells release IL-2/4 which provide help for CD8 T cells and B-cell activation.

Question 18

Endogenous antigen processing and presentation

Answer 18

Endogenous proteins are degraded into peptides that are transported to ER. Peptides bind to MHC-1 and transported to surface of APC. CD8 cells recognize complex by way of TCR complex.

Question 19

Exogenous antigen processing and presentation

Answer 19

Exogenous antigen is broken down into peptide fragments in endosomes. Class-2 molecules transport to endosome, bind the peptide, and delivered to surface of APC cell, where they are recognized by CD4+ cells.

Question 20

Found in secretions, in Peyer’s patches in gut, and in breast milk (additional source of immunity in newborn); helps prevent microbial adherence and invasion in gut.

Answer 20

IgA

Question 21

Membrane-bound receptor on B cells (serves as an antigen receptor)

Answer 21

IgD

Question 22

Allergic reactions, parasite infections

Answer 22

IgE

Question 23

Opsonins

Answer 23

IgM, IgG

Question 24

Fix complement

Answer 24

IgM, IgG (requires 2 IgGs, or 1 IgM)

Question 25

Region: antigen recognition

Answer 25

Variable region

Question 26

Region: recognized by PMNs and macrophages.

Answer 26

Constant region

Question 27

Fragment that does not carry a variable region

Answer 27

Fc fragment

Question 28

Have multiple binding sites to the antigen at multiple epitopes

Answer 28

Polyclonal antibodies

Question 29

Have only 1 binding site to 1 epitope

Answer 29

Monoclonal antibodies

Question 30

Immediate hypersensitivity reaction (allergic reaction) eosinophils have IgE receptors for the antigen and release major basic protein, which in turn activates mast cells and basophils, which release histamine, serotonin and bradykinin

Answer 30

Type 1 | Ex: bee stings, peanuts, hay fever

Question 31

Hypersensitivity: IgG or IgM reacts with cell-bound antigen

Answer 31

Type 2: | Ex: ABO blood incompatibility, Graves' disease, myasthenia gravis

Question 32

Hypersensitivity: Immune complex deposition

Answer 32

Type 3 | Ex: Serum sickness, SLE

Question 33

Hypersensitivity: Delayed-type hypersensitivity - antigen stimulation of previously sensitized T cells

Answer 33

Type 4 | Ex: TB sin test (PPD), contact dermatitis

Question 34

Major source of histamine in the blood

Answer 34

Basophils

Question 35

Major source of histamine in tissue

Answer 35

Mast cells

Question 36

Primary lymphoid organs

Answer 36

Liver, bone, thymus

Question 37

Secondary lymphoid organs

Answer 37

Spleen and lymph nodes

Question 38

2 different cell lines in one individual (e.g., bone marrow transplant patients)

Answer 38

Immunologic chimera

Question 39

- Converts lymphocytes to lymphokine-activated killer (LAK) cells by enhancing their immune response to tumor. - Also converts lymphocytes into tumor-infiltrating lymphocytes (TILs) - Has shown some success for melanoma

Answer 39

IL-2

Question 40

What two cells does IL-2 convert lymphocytes into?

Answer 40

Lymphokine-activated killer (LAK) cells and tumor-infiltrating lymphocytes (TILs)

Question 41

When do you give tetanus toxoid to non-tetanus prone wounds?

Answer 41

Give tetanus toxoid only if patient has received

Question 42

When do you give tetanus toxoid to tetanus-prone wounds?

Answer 42

Always give tetanus toxoid unless the patient has had > 3 doses and it has been

Question 43

Criteria for tetanus-prone wounds

Answer 43

``` > 6 hours old. Obvious contamination and devitalized tissue. Crush. Burn. Frostbite. Missile injuries. ```

Question 44

When would you give tetanus immune globulin with tetanus prone wounds?

Answer 44

Give only with tetanus-prone wounds in patients who have not been immunized or if immunization status is unknown.