Chapter 4 - Cellular Immunity Flashcards

1
Q

What is the basis of an “immune network”?

A
  • Activation of T cells

- Essential to a strong and successful immune response

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2
Q

What 2 cells are needed for an immune response to occur?

A
  • Experiment shows that antigen presenting cells + T cells needed for a response
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3
Q

Cellular Interactions: experiment wherein animals were irradiated to remove all immune cells, then reconstituted with B cells, T cells, or both

  • which could generate a response?
  • what is the MHC restriction?
A
  • Only animals with both could make a response
  • Antigen presenting cell and the T cell has to be of the same MHC haplotype for the response to occur
    • Response called MHC restricted
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4
Q

Antigen Presenting Cells

- what are the 6 major types?

A
  • B cells
  • Macrophages
  • Dendritic cells
  • Fibroblasts
  • Thymic epithelial cells
  • Vascular endothelial cells
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5
Q

Professional APCs

  • what does this mean?
  • what are the three types of professional APCs?
A
  • Major antigen presenting cells
  • Types:
    • Dendritic cells
    • Macrophages
    • B cells
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6
Q

Professional APCs: Dendritic cells

  • efficiency level?
  • which MHC class?
  • what patterns do they recognize?
A
  • Most efficient
  • High levels of MHC class II molecules
  • Recognize pathogen-associated molecular patterns (PAMP)
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7
Q

Professional APCs: Macrophages

  • What MHC class do these interact with?
  • what do they do to those molecules?
  • what markers do they recognize?
A
  • Upregulate surface MHC class II after phagocytosis

- Recognize certain carbohydrate markers on the surface of a pathogen (PAMPs)

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8
Q
  • What are the three major types of T cells?

- What CD markers are seen on each type?

A
  • Helper T cells (CD4+)
  • Cytotoxic T cells (CD8+)
  • Regulatory T cells (CD25+ and usually CD4+)
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9
Q
  • What are the three types (2 major) Helper T cells?

- What is each type responsible for?

A
Two major:
- Th1
-- Stimulate CD8 T cells
-- Stimulate macrophage and phagocytosis
- Th2
-- Stimulate antibody production 
Third
- Th17 
Involved in autoimmunity
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10
Q

Professional APCs

- How do B cells recognize antigen?

A
  • Recognize antigen via surface immunoglobulin
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11
Q

Cytotoxic T cells

  • what type of antigen do they recognize?
  • what action do they take when they recognize the antigen?
A
  • Recognize antigen associated with MHC class I and kill target cell presenting that antigen
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12
Q

Regulatory T cells

- what is there responsibility?

A
  • Downregulate the immune response
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13
Q

Immunological Tolerance

- what are three characteristics?

A
  • Unresponsiveness to a specific antigen
  • Induced by prior exposure to the antigen
  • Prevents body from attacking itself
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14
Q

Immunological Tolerance

  • describe the process
    • where does it occur?
    • when and for what cell does this occur?
    • what cells does it target and what does it do to those cells?
A
  • Process in the thymus during development of T cells that removes self reactive cells
  • Positive and negative selection occurs in thymus
  • Not genetically programmed
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15
Q

Immunological Tolerance

- Describe the process of positive selection.

A
  • Double positive thymocytes are presented with MHC Class I or II
    • If they recognize self MHC survive and proliferate
    • If they do not recognize self-MHC, they die within the thymus
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16
Q

Cytokines:

  • what are they?
  • what functions are they essential for?
A
  • Peptide mediators; chemical communications among cells of the immune system
  • Essential for successful immune response
    • Also important in bone metabolism, CNS function, tissue development
17
Q

Cytokines:

  • what are four examples that are used in the clinical setting?
  • in what instances are they used?
A
  • Interferon: hairy cell leukemia, renal cancer, MS, hepatitis
  • Interleukin-2: renal cancer, melanoma
  • Granulocyte/Macrophage Colony Stimulating Factor (GM-CSF): in neutropenia
  • Antibody to Tumor necrosis factor (TNF) alpha: downregulates the immune response for the treatment of a variety of autoimmune diseases
18
Q
  • What are four types of cytokines?
  • How did they get their names?
  • How do they function?
A
  • Lymphokines, monokines, interleukins, and chemokines
  • Terms based on either a particular function or the cell that secretes it or that it acts upon
  • Function by binding to specific receptors on the surface of the cell they act upon
19
Q

General Properties of Cytokines

  • what is a pleiotropic cytokine?
  • what is a redundant cytokine?
A
  • Pleiotropic: One cytokine can act on multiple cells and have multiple functions
  • Redundant: Two or more cytokines can have same function
20
Q

General Properties of Cytokines

  • what are synergistic cytokines?
  • what are antagonistic cytokines?
A
  • Synergistic :Their combined action is greater than the sum of the actions of a single cytokine
  • Antagonistic: The action of one cytokine can have the opposite effect of the action of another cytokine or can downregulate the action of that second cytokine
21
Q

Cytokine effects: Define:

  • Autocrine effect
  • Paracrine effect
  • Endocrine effect
A
  • by acting on the cell that secreted it
  • by acting on a nearby cell
  • involves entering the circulation and acting on a distal target cell
22
Q

Functions of Cytokines

- name 4

A
  • Most cytokines are involved in cell proliferation
  • Some involved in cell differentiation
  • Some involved in cell apoptosis
  • Some have anti-viral properties
23
Q

Functions of Cytokines

- What are three functional categories?

A
  • Regulators of innate immunity
  • Regulators of adaptive immunity
  • Regulators of hematopoiesis
24
Q

Cytokines That Regulate Adaptive Immunity: Chemokines

  • influence in immune system?
    • what is chemotaxis?
  • what is the name of the subclass of this type of cytokine?
A
  • Immune system cells move directed by chemical signals in a process called chemotaxis
    • Directed movement of cells along a concentration gradient of chemo-attractants
  • Chemoattractant cytokines
25
Q

Assays for Measuring T-Cell Function

- name them (3)

A
  • Tritiated thymidine uptake assay with antigen
  • Mixed lymphocyte reaction
  • Cr^51 release cytotoxicity assay
26
Q

Assays for Measuring T-Cell Function: Tritiated thymidine uptake assay with antigen
- what is it used for?

A
  • Used to demonstrate cell proliferation
27
Q

Assays for Measuring T-Cell Function: Mixed lymphocyte reaction
- what is it used for?

A
  • Used in transplantation to evaluate the histocompatibility of lymphocytes between donor and recipient (one way)
28
Q

Assays for Measuring T-Cell Function: Cr^51 release cytotoxicity
- what is it used for?

A
  • Used to measure CD8+ cytotoxic T cells