Session 3 ILOs - Adaptive immunity (part 1) and Sepsis Flashcards

1
Q

Describe the features of acute sepsis

A
  • Increased heart rate
  • Increased respiratory rate
  • Decreased urine output
  • Decreased blood pressure

Use NEWS to help identify possible sepsis
Use ‘Red Flag Sepsis’ to diagnose sepsis (QSOFA less common way)

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2
Q

Understand the mechanism by which micro-organisms trigger the inflammatory cascade

A

Infection is triggered when a pathogen breaches the body’s barriers - leading to the generation of an immune response which causes inflammation
Sepsis occurs when the inflammatory process becomes overwhelming and occurs systemically (rather than locally)

  • Vasodilation
  • Capillary leakage
  • Amplification fo the immune system
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3
Q

Understand the principles of supportive and specific treatment for acute sepsis

A

Supportive treatment:

  • Fluids
  • Oxygen (if appropriate) or breathing support
  • Renal dialysis if kidneys are damaged

Specific treatment:
- Antibiotics (specific)

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4
Q

Describe the Sepsis Six Bundle

A

Give 3, take 3:

Give:

  • Antibiotics
  • Fluids
  • Oxygen (if appropriate)

Take:

  • Cultures
  • Urine output
  • Lactate and Hb
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5
Q

Describe features of Antigen Presenting Cells (where are they located etc.)

A

Strategic location:

  • Mucosal membranes
  • Skin
  • Blood
  • Lymph nodes
  • Spleen

Diversity in pathogen sensors (PRRs looking for PAMPs)

  • Extracellular pathogens (e.g. bacteria)
  • Intracellular pathogens (viruses)

Diversity in pathogen capture mechanisms:

  • Phagocytosis (for whole microbe)
  • Macropinocytosis (for solute particles)
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6
Q

Describe MHC molecules in relation to microbe presentation

A

Antigen presenting cells have Major Histocompatability Complex (MHC) molecules - also known as Human Leukocyte Antigens (HLA)

There are 6 types of MHC molecules in 2 classes:
Class 1: 
HLA A, HLA B and HLA C
- Expressed on all nucleated cells
- Present intracellular microbes

Class 2:
HLA DP, HLA DQ, HLA DR
- Expressed on antigen presenting cells
- Present extracellular microbes

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7
Q

Describe the processing and presentation of microbial antigens to T lymphocytes

A

Endogenous pathway (e.g. viruses):

  • Marked for description by proteasome and it’s cut up
  • Viral peptide transported to ER by TAP proteins
  • Formation of peptide-MHC complex (class 1) if right match
  • This is then presented to CD8+ T cell

Exogenous pathway (e.g. bacteria):

  • Microbe is captured by phagocytosis or micropinocytosis
  • Degraded into small peptides
  • Small peptides fuse with a vesicle containing the class 2 MHC molecules
  • Formation of peptide-MHC complex (class 2) if right match
  • This is then presented to CD4+ T cell
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8
Q

Describe T cells (2 types) and their role with regard to infections

Describe how antigen presenting cells activate the right adaptive immune response

A

Naive T cells:

  • T cells that have not previously encountered the antigen
  • Examples: dendritic and Langerhan cells

Effector T cells:

  • T cells that have previously encountered the antigen and are capable of performing effector functions during an immune response
  • Examples: macrophages and B cells

Each of the different Antigen presenting cells has a different function:

Dendritic cells: T cell response against most pathogens
Langerhan cells: T cell response against most pathogens
Macrophages: Phagocytic activities
B cells: Antibody response (humeral response)

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