Part 4: Adaptive (acquired) Immunity Flashcards

1
Q

What are the characteristics of adaptive immunity?

A

Specificity
Self recognition
Memory

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2
Q

In the adaptive (acquired) immune response, the ability to distinguish cells from self and non-self is called

A

Self recognition

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3
Q

In the adaptive (acquired) immune response, what does specificity refer to?

A

Recognition of foreign substances

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4
Q

A small molecule called a _____ can also act as an antigen, but only when bound to a larger molecule

A

Hapten

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5
Q

In the adaptive (acquired) immune response, what does memory refer to?

A

After the 1st exposure to antigen (primary response), the immune system develops memory to provide a rapid secondary response to the same antigen

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6
Q

What is the 2-part strategy for eliminating foreign material?

A

Humoral response

Cell-mediated response

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7
Q

The response that eliminates antigens that are extracellular (ie bacteria in the bloodstream)

A

Humoral response

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8
Q

The response that deals with antigens residing within a host cell, for example a virus infected cell

A

Cell-mediated response

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9
Q

What is an ANTIbody GENerator?

A

Antigen

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10
Q

What is the structure of antigen?

A

Large carrier molecule with epitopes projecting from surface

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11
Q

Antigenic determinants are

A

Epitopes

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12
Q

Antigens come from two places

A

Exogenous

Endogenous

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13
Q

Antigens that have entered the body from the outside (plus give examples)

A

Exogenous

Examples: inhalation, ingestion, injection

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14
Q

Antigens that have been generated within the cell, as a result of normal cell metabolism or because of viral or intracellular bacterial infection

A

Endogenous

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15
Q

What does it mean to say that antigens can be cross reactive?

A

They elicit and bind to same antibody

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16
Q

What type of antigen does not behave normally and, instead of attaching to MHC groove and triggering normal immune response, they attached to the sides of the binding site?

A

Superantigens

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17
Q

What happens because of superantigens irregular attachment?

A

T-cells go on an unregulated rampage, releasing regulatory molecules (cytokines) — like interferons — in toxic amounts

For example: bacterial toxins, especially Staphylococcus and Streptococcus

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18
Q

What do epitopes do?

A

Interact with antibody and T cells

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19
Q

The ___ is a cluster of many genes for antigen recognition

A

Major Histocompatibility Complex (MHC)

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21
Q

In humans, where is the HLA complex (Human Leukocyte Antigen) the human MHC?

A

Genes on chromosome 6

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22
Q

What class of MHC presents antigens from inside cell (endogenous proteins)

A

Class I MHC

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23
Q

MHC I is found on

A

All nucleated cells

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24
Q

What class of MHC presents antigens from outside the cell?

A

Class II MHC

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25
Q

MHC II proteins display _______ which will be recognized by helper T cells

A

Non-self

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26
Q

MHC II proteins found ONLY on immune cells called

A

Antigen presenting cells (APCs)

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27
Q

Antigen presenting cells have what kind of classes?

A

Both MHC I and MHC II

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28
Q

Antigen presenting cells (have both MHC I and MHC II) includes:

A

Activated dendritic cells
Activated macrophages
Activated B cells

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29
Q

The Major Histocompatibilty Complex (MHC) is divided into:

A

3 regions: MHC I, MHC II, MHC III

30
Q

What antigen presenting cell is found in tissues that are in contact with the environment?

A

Activated dendritic cells

31
Q

Give examples of where activated dendritic cells are found

A

In the skin (Langerhans cells) and lining of nose, lungs, stomach and intestines

32
Q

What antigen presenting cell presents antigen early in infection?

A

Activated macrophages

Note: Activated B cells are used later in infection

33
Q

How does the presence of antigen activate macrophages?

A
  • increased number of lysosomes (organelle filled with digestive enzymes)
  • produce cytokine called interleukin-1 which can induce fever and activate other cells
34
Q

After the activated macrophage digests the antigenic material, what shows up on the macrophage surface?

A

Epitopes from antigen in combination with MHC proteins (MHC I and MHC II)

35
Q

When activated macrophage presents epitopes from antigen in combination with MHC proteins (MHC I and MHC II), what cell notices and what happens?

A
  • Helper T cells recognize presented antigen

- Recognition activates the helper T cell

36
Q

What antigen presenting cells is activated later in infection as antigen presenting cell (APC)?

A

Activated B cells

37
Q

In order to produce cytokines, Helper T cells must recognize

A

MHC II

38
Q

What regulates cell mediated and humoral immunity?

A

Activated helper T cells

NOTE: Cell mediated: T cell and Humoral: B cell, antibody

39
Q

In order for B cells to produce antibody, they must interact with

A

Activated T cell

40
Q

Cellular immunity is mediated by

A

T lymphocytes (T cells)

41
Q

T cells never produce

A

Antibody

Note: T cells never interact with free antigen, antigen must be presented to T cell by another cell

42
Q

Inactive (naive) T cells cannot

A

Migrate into tissue

43
Q

Activation of T cell require 2 signals

A
  1. Encounter antigen presented on cell in antigen-MHC complex
  2. Must be concurrently stimulated (co-stimulated) by other molecules
44
Q

Activation of T cell leads to 2 things

A
  1. Formation of specific effector T cell types

2. Effector T cells have different roles in cell mediated immunity

45
Q

What are the functions of activated T cells?

A
  1. Proliferate
  2. Bring antigens to naive T cells
  3. Release cytokines
46
Q

One function of activated T cell is to release cytokines. Why?

A

Cytokines act as messengers, they do not respond to specific antigen. They recruit other cell types, particularly macrophages

47
Q

All T cells are identical in appearance, but there are 2 distinct functional populations

A

CD4 T lymphocytes

CD8 T lymphocytes

48
Q

T cells that carry the CD4 marker can be

A

T helper cells (TH)

49
Q

The role of TH cells is what?

A

Judge the significance of antigen presented by APCs (antigen presenting cells)

Note: These APCs have MHC class II molecules which are recognized by TH (T helper cells)

50
Q

2 subsets of TH cells

A

TH1 - judge and orchestrate cell mediated response by releasing cytokines to stimulate proliferation of T cells

TH2 - judge and stimulate proliferation of B cells (humoral immunity)

51
Q

Outcome of TH1 vs TH2 cells?

A

Cell activity (cell mediated) and indogenous antigen VS antibody (humoral) and exogenous antigen

52
Q

What are T regulatory cells?

A

They can stop the action of a T cell. Treg cells stimulated by cytokine interleukin 2(IL-2) and 10 (IL-10)

53
Q

Most T cells have CD8 marker, including

A

Cytotoxic and memory cells

54
Q

T cytotoxic cells induce ____ in what kind of cells?

A

Apoptosis in “self” cells infected with virus or other microbes

55
Q

How do T cytotoxic cells recognize dysfunctional self cells?

A

By recognition of antigen presented on MHC 1 molecules

56
Q

T memory cells are what kind of cells?

A

Long lived, antigen activated T cells that respond with heightened reactivity to 2nd exposure with specific antigen

57
Q

Type IV hypersensitivity immune response is mediated by

A

Cellular immunity

58
Q

What happens when there is an imbalance in numbers of CD4 and CD8 cells?

A

Compromised cellular immunity

59
Q

Cytokines produced by lymphocytes act as

A

Chemical messengers and activate other cell types

60
Q

What cell types does a cytokine activate?

A
  • Macrophages
  • Polymorphonuclear Leukocytes (granulocyte s)
  • Lymphocytes
61
Q

Humoral immunity is mediated by

A

B lymphocytes/cells

62
Q

B cells develop in

A

Bone marrow

63
Q

Immunoglobulin (antibody) classes:

A

IgG - binding to antigen results in opsonization
IgM - first class to be produced in response to antigen
IgA - found in mucosal associated tissue with T cells
IgE - can cause anaphylactic shock
IgD - does not bind complement

64
Q

What immunoglobulin crosses the placental barrier to provide passive immunity to fetus? (And is also in colostrum)

A

IgG - monomer (aka gamma globulin)

65
Q

What is the most efficient class of immunoglobulins at activating complement cascade? And also agglutination and precipitation

A

IgM - pentamer

66
Q

What immunoglobulin is found in body secretions? (Saliva, mucus, milk, tears)

A

IgA

Note: exists as monomer in blood, secreted as a dimer

67
Q

Which immunoglobulin class is involved in allergy, and triggers release of histamines by binding mast cell?

A

IgE - monomer

68
Q

What class of immunoglobulin is primarily found on B cell surfaces where if functions as a receptor for antigen?

A

IgD

69
Q

What is the function of complement? (Hint: OIL)

A
  1. Opsonization preparing cells for phagocytosis
  2. Inflammation, release active substances to promote
  3. Lyse cell by attaching to cell surfaces, forms membrane attack complex (MAC)