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Flashcards in Chapter 4: Immunology Deck (44):
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

Helper T cells (CD4)

2

Causes maturation of cytotoxic T cells

IL-2

3

Causes B-cell maturation into plasma cells

IL-4

4

Brings in inflammatory cells by chemokine secretion

Delayed-type hypersensitivity

5

Regulate CD4 and CD8 cells

Suppressor T cells (CD8)

6

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

Cytotoxic T cells (CD8)

7

Used to test cell-mediated immunity

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

8

Infections associated with defects in cell-mediated immunity

Intracellular pathogens (TB, viruses)

9

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

MHC class 1 (A, B, C)

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

MHC class II (DR, DP, and DQ)

11

Mechanism of immune response to viral infection

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

12

Mechanism of immune response to bacterial infection

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.

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

Natural Killer Cells

14

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

IgM

15

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

IgG.

16

What type of cells do natural killer cells recognize?

Recognize cells that lack self-MHC

17

Two signals that cause activation of T and B cells

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.

18

Endogenous antigen processing and presentation

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.

19

Exogenous antigen processing and presentation

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.

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.

IgA

21

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

IgD

22

Allergic reactions, parasite infections

IgE

23

Opsonins

IgM, IgG

24

Fix complement

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

25

Region: antigen recognition

Variable region

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Region: recognized by PMNs and macrophages.

Constant region

27

Fragment that does not carry a variable region

Fc fragment

28

Have multiple binding sites to the antigen at multiple epitopes

Polyclonal antibodies

29

Have only 1 binding site to 1 epitope

Monoclonal antibodies

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

Type 1
(Ex: bee stings, peanuts, hay fever)

31

Hypersensitivity: IgG or IgM reacts with cell-bound antigen

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

32

Hypersensitivity: Immune complex deposition

Type 3
(Ex: Serum sickness, SLE)

33

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

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

34

Major source of histamine in the blood

Basophils

35

Major source of histamine in tissue

Mast cells

36

Primary lymphoid organs

Liver, bone, thymus

37

Secondary lymphoid organs

Spleen and lymph nodes

38

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

Immunologic chimera

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

IL-2

40

What two cells does IL-2 convert lymphocytes into?

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

41

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

Give tetanus toxoid only if patient has received

42

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

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

43

Criteria for tetanus-prone wounds

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

44

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

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