Introduction to Immunology - Diebel

Question 1

What is the purpose of the immune system?

Answer 1

Prevent us from dying from infection by pathogens.

Protect us from constant exposure to microogranisms in the environment.

Question 2

What are the major cellular players in the innate immune system?

Answer 2

• Epithelium
• Myeloid progeny:
  
  • Monocytes
    
    • Macrophages
    • Dendritic cells
  • Granulocytes
    
    • Neutrophils
    • Mast Cells

Question 3

What are the major cellular players in the adaptive immune system?

Answer 3

• Lymphoid precursor cells
  
  • T-cells
  • B-cells

Question 4

What is the function of the Innate Immune System?

Answer 4

• Stops most infections before they can cause symptoms
• “Built-in” immunity
  
  • noninducible
  • preexisting ability to recognize and destroy pathogens and their associated products
  • does not require previous exposure to a pathogen
• Rapidly reduces the number of invading organisms
  
  • Phagocytosis of pathogen
• Complement - control inflammation
• Signal transduction

Question 5

What are the three basic steps in signal transduction?

Answer 5

• Reception
  
  • Pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs)
• Transduction
  
  • dsRNA PAMP causes confirmational change in Toll-Like-Receptor3 (TLR3)
  • activates TRIF+TAK1 → activates TBK1+IKK_E → phosphorylates IRF3 → IRF3 dimerizes → active transcription factor
  • IRF3 dimer+NF_KB produces → cytokine IFN-beta
• Response
  
  • IFN-beta displayed on cell plasma membrane (cell-cell signaling)
  • limit the spread of viral infections

Question 6

What is the difference between a cytokine and a chemokine?

Answer 6

• Cytokine = secreted molecules involved in cell-to-cell signaling
  
  • protein or glycoprotein
  • soluble messenger molecules secreted by cells of the immune system
• Chemokine = large family of cytokines (subset of cytokines)

Question 7

What is the role of a cytokine in immune system function?

Answer 7

Used by cells of the immune system to communicate and coordinate action.

Question 8

What are the major cytokine categories? What are their general functions?

Answer 8

• Interferons (IFNs):
  
  • limiting the spread of viral infections
• Interleukins (ILs):
  
  • produced by T cells
  • causing neighboring cells to divide and differentiate
• Colony Stimulating Factors (CSFs):
  
  • directing the division & differentiation of bone marrow stem cells and precursors of blood leukocytes
• Chemokine:
  
  • direct the movement of leukocytes around the body
• Tumor Necrosis Factors (TNFs):
  
  • mediate inflammation & cytotoxic reactions
• Transforming Growth Factors (TGFs):
  
  • regulate cell division & tissue repair

Question 9

What is the role of a chemokine in immune system function?

Answer 9

• direct the movement of leukocytes around the body
  
  • leukocyte homing
• attract cells into inflamed tissues
• recruit cells of the innate/adaptive immune response to fight off an infection

Question 10

What is a CD molecule?

Answer 10

• Cluster of Differentiation
• Protocol used for the identification and investigation of cell surface molecules
  
  • allows for immunophenotyping of cells
• Can be receptors or ligands

Question 11

What is the function of the Adaptive Immune System?

Answer 11

• Acquired ability to recognize and destroy an individual pathogen
  
  • pathogen-specific receptors are produced in large numbers only after exposure to the pathogen or ts products
  • “memory”
  • mediated by the binding of antigens to T-cell receptors and antibodies/immunoglobulins
  • protects against re-exposure
  • provides reinforcement for the innate immune response

Question 12

What is the bridge between Innate Immunity and Adaptive Immunity?

Answer 12

• Antigen Presenting Cells (APCs)
  
  • take up and process antigens so that they can be recognized by T-cells
  • essential for activation of T-cells
  • Macrophages, Dendritic Cells, & B-cells
    
    • able to recognize foreign material
    • break it down
    • display it on MHC II

Question 13

What is the difference between Active and Passive Immunity?

Answer 13

• Active Immunity:
  
  • Develop natural active immunity by acquiring an infection that initiates an adaptive immune response
  • outcome of exposure to antigens through infection
  • results in protective immunity conferred by antibodies & T-cells
• Passive Immunity:
  
  • Nonimmune person’s acquisition of preformed immune cells or antibodies via the transfer of cells/antibodies from an immune person
  • transient - does not last forever

Question 14

What cytokine(s) influences a pluripotent stem cell to become a lymphoid progenitor cell?

Answer 14

IL-3

Question 15

What cytokine(s) influences a pluripotent stem cell to become a myeloid progenitor cell?

Answer 15

IL-3 & GM-CSF

Question 16

Where do most immune system cells originate from?

Answer 16

Hematopoietic stem cells in fetal liver and in the postnatal bone marrow.

Question 17

What Innate Immune System Cells come from the myeloid lineage?

Answer 17

• Macrophage
• Neutrophil (PMN)
• Eosinophil
• Basophil

Question 18

What Adaptive Immune System Cells come from the lymphoid lineage?

Answer 18

• Memory B-cells
• Plasma Cells
• CD4⁺ T-cells (helper)
• CD8⁺ T-cells (killer)
• Memory T-cells