Week 1: Host-pathogen interactions Flashcards
Question

Question

Question

Question

Innate immunity effectors
- Macrophages
- Dendritic cells
- Granulocytes
- Antimicrobial peptides
Adaptive immunity effectors
- B cells
- CD4+ T cells
- CD8+ T cells
- Antibodies
Innate immunity Response/Specificity
- Relatively non-specific
- Recognition of broadly conserved microbial antigens or their effects
Adaptive immunity specificity
- Specific
- Recognition of microbial peptides in context of MHC I (CD8+ T cells), MHC II (CD4+ T cells) or sepcific antigens (antibodies/B cells
Innate immunity Response time
Constitutive and/or rapid (hours to days)
Adaptive immunity Response time
Delayed (days to weeks)
Innate immunity Memory
*Usually* no memory
Adaptive immunity memory
*Usually* has memory
What protects us from pathogens?
Physical barriers
- skin
- mucous membranes
pH
Iron hoarding
Innate immune response
Acquired immunity (adaptive)
beneficial bacteria and their products
Abnormal physiology that can increase risk of infection
- Vesicoureteral reflux
- Auto-splenectomy
- Atopic dermatitis
Vesicoureteral reflux role in increased risk of infection
increased risk of pyelonephritis
Auto-splenectomy role in increased risk of infection
- Splenic necrosis induced by sickle cell anemia, SLE
- Prone to infections by encapsulated organisms (ie Streptococcus pneumoniae and Haemophilus influenzae)
Atopic dermatitis role in increased risk of infection
Increased risk of skin infections (Staph aureus, Strep pyogenes, HSV)
How does the innate immune system protect us from pathogens?
- response is early or constitutive and non-specific
- Essential for immune cells to go to the site of infection
How does the acquired immune system protect us from pathogens?
Delayed because cells and products need to be made - but high specificity and MEMORY! (usually)
Describe the role/mechanisms of normal flora in protecting us from pathogens
- Occupy space
- Angry neighbors
- Assist in host function
- Immunomodulation
Describe the mechanisms of COST of normal flora in protecting us from pathogens
- Opportunistic pathogens
- Staph infections
- Dental caries
- Gastritis
- Sepsis
- Nutrient competition
- Can be passed on to susceptible individuals
What are the components of the microbiome
- Bacteriome
- Virome
- Mycobiome
Adaptive immune cells
- CD4+ T cells
- CD8+ T cells
- B cells
Basic function of CD4+ T cells
- Direct immune responses
- required for CD8+ T cell memory and Ig class switching




