Immunology Flashcards

1
Q

CD4 cells are also known as?

A

Helper T cells

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2
Q

What roles do helper T cells play?

A

Release IL-2, IL-4, interferon gamma, and involved in delayed-type hypersensitivity (type IV, brings in inflammatory cells by chemokine secretion)

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3
Q

What is the main function of IL-2?

A

Maturation of cytotoxic T cells

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4
Q

What is the main function of IL-4?

A

B-cell maturation into plasma cells

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5
Q

What is another name for CD8 cells?

A

Cytotoxic T cells and suppressor T cells

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6
Q

What is the function of suppressor T cells?

A

To regulate CD4 and CD8 cells

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7
Q

What are the functions of cytotoxic T cells?

A

Recognize and attack non-self antigens attached to MHC class I receptors

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8
Q

What is responsible for the majority of liver injury due to HepB?

A

Cytotoxic T cells responding to viral gene products

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9
Q

Does cell-mediated immunity require AB’s?

A

NO

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10
Q

What are the effector cells in cell-mediated immunity?

A

Macrophages, cytotoxic T cells, natural killer cells

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11
Q

What kind of infections are associated with defects in cell-mediated immunity?

A

Intracellular pathogens (TB, viruses)

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12
Q

How does the intradermal skin test work?

A

Tests cell-mediated immunity. Takes 2-3 days

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13
Q

What stimulates B cells to become plasma cells?

A

IL-4 from helper T cells

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14
Q

What % of B cells become memory B cells which can be reactivated ?

A

10%

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15
Q

What type of antibody is secreted with first infection and with reinfection?

A

First infection- IgG

Reinfection- IgM

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16
Q

What types of MHC class I are there?

A

A, B, C

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17
Q

What type of T cell does MHC class I activate?

A

CD8

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18
Q

On what type of cells are MHC class I present on?

A

All uncleared cells

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19
Q

What types of MHC class II cells are there?

A

DR, DP, and DQ

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20
Q

What kind of T cell does MHC class II activate?

A

CD4 cells

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21
Q

On what type of cells are MHC class II present on?

A

Antigen-presenting cells (APCs)

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22
Q

What kind of cells are antigen-presenting cells?

A

Dendrites and monocytes

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23
Q

What is the purpose of antigen-presenting cells?

A

Activate helper T cells as they pass through lymph nodes AND stimulates antibody formation after interactions with B cells

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24
Q

How are viral infections recognized by the body?

A

Endogenous viral proteins are produced which are then bound to class I MHC —> proteins are presented on the surface of class MHC and recognized by cytotoxic CD8 cells

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25
Q

How are bacterial infections recognized and fought off by the body?

A

Endocytosis and proteins get bound to class II MHC molecules, which are presented on the cell surface and recognized by CD4 helper T cells —> CD4 cells activate the B cells which have already bound to the antigen —> B cells then produce antibody to that antigen and are transformed to plasma cells and memory B cells

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26
Q

Are NK cells considered T or B cells?

A

Neither

27
Q

What do NK cells do?

A

Recognize cells that lack self-MHC and attack cells with bound Ab (Fc receptor)

28
Q

Do NK cells require previous exposure or antigen presentation?

A

NO

29
Q

What cell serves as part of the body’s natural immunosurveillance for cancer?

A

NK cells

30
Q

What is the initial antibody secreted after exposure to antigen?

A

IgM —> primary immune response

31
Q

What is the largest antibody? How many domains/binding sites?

A

IgM is the largest. Contains 5 domains and 10 bindings sites

32
Q

What is the MC antibody in the spleen?

A

IgM

33
Q

What is the most common antibody in the body?

A

IgG

34
Q

Which antibody is responsible for secondary immune response?

A

IgG

35
Q

What antibody can cross the placenta and provides protection to newborn?

A

IgG

36
Q

Where is IgA found?

A

Secretions, Peyer’s patches in the gut, and in breast milk (which helps protect newborn)

37
Q

What is the function of IgA?

A

Helps prevent microbial adherence and invasion in the gut

38
Q

What is the function of IgD?

A

Membrane-bound receptor on B cells and serves as an antigen receptor

39
Q

In what situations are IgE antibodies involved in?

A

Allergic reactions, parasite infections, and type I hypersensitivity reactions

40
Q

Which antibodies are considered opsonins ?

A

IgM and IgG

41
Q

Which antibodies fix complement?

A

IgM and IgG—requires 2 IgGs or 1 IgM

42
Q

What is the function of the variable region on antibodies?

A

Antigen recognition

43
Q

What is the function of the constant region on antibodies?

A

Recognized by PMNs, macrophages, and NK cells

Fc fragment does not carry variable region

44
Q

What are polyclonal antibodies?

A

Have multiple binding sites to the antigen at multiple epitomes

45
Q

What are monoclonal antibodies?

A

Have only 1 binding site to the antigen at 1 epitope

46
Q

What is type I hypersensitivity reaction?

A

Immediate hypersensitivity reaction. IgE receptors on mast cells and basophils react with the antigens and cause release of histamine, serotonin, and bradykinin

47
Q

Name some type I hypersensitivity reactions. What are the symptoms?

A

Anaphylaxis, allergic reaction

Hypotension, bronchospasm, bronchoconstriction, urticaria, angioedema

48
Q

What occurs in type II hypersensitivity reactions?

A

IgG or IgM reacts with cell-bound antigen

49
Q

Name some examples of type II hypersensitivity reactions?

A

ABO blood incompatibility, hyperacute rejection, myasthenia gravis

50
Q

What causes type III hypersensitivity reactions?

A

Immune complex deposition

51
Q

Name some examples of type III hypersensitivity reactions.

A

Serum sickness, SLE

52
Q

What is type IV hypersensitivity reaction? What causes it?

A

Delayed-type hypersensitivity

APCs present antigen to helper T cells, which then activate macrophages to destroy the antigen

53
Q

What is the only hypersensitivity reaction to not involve antibodies?

A

Type IV

54
Q

What is the major source of histamine in the blood?

A

Basophils

55
Q

What is the major source of histamine in the tissues?

A

Mast cells

56
Q

What are the primary lymphoid organs?

A

Liver, bone, thymus

57
Q

What are the secondary lymphoid organs?

A

Spleen, lymph nodes

58
Q

What is immunologic chimera?

A

2 different cell liens in one individual (bone marrow transplant patients)

59
Q

What tetanus prophylaxis is necessary in someone with a non-tetanus prone wound?

A

Tetanus toxoid only if patient has received <3 doses or tetanus status is unknown, or >10 years since booster

60
Q

What constitutes a tetanus-prone wound?

A

> 6 hours old, obvious contamination and devitalized tissues, crush, burn, frostbite, or missile injuries

61
Q

When to give tetanus prophylaxis in tetanus prone wounds?

A

Always give tetanus toxoid unless patient has had 3 or more doses and it has been <5 years since last booster

62
Q

When should you give tetanus immune globulin?

A

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

63
Q

How is IL-2 used as a chemotherapeutic agent in cancer?

A

Converts lymphocytes to lymphokine-activated killer cells by enhancing the immune response to tumor
Converts lymphocytes into tumor-infiltrating lymphocytes
Show some success in melanoma