L4 - Extracellular pathogens Flashcards
What are soluble mediators?
Lysozymes, lactoferrin
Defensins
…
What are natural antibodies?
polyreaction, low affinity
What are innate defences?
Phagocytic recognition - concomitant antimicrobial mechanisms
What are Th1 cells regulated by?
T-bet
IFN-y causes an intracellular response
What are Th2 cells regulated by?
GATA3
What are Th17 cells regulated by?
RORyt
What does the Th2 response do?
produces neutralising antibodies
results in skewed class switching - high affinity antibodies
What do Th2 mediators also activate?
non-B cells
IL-9 activates basophils
IgE binds basophil/mast cells
IL-5
Eosinophils
What is the Th17 response?
inflammatory response - recruit neutrophils
important in anti fungal and anti-bacterial immunity
Absences in what ILs can lead to recurrent fungal/bacterial infection?
IL-17
What are virulence factors of group A streptococcus
Surface M protein
C5a protease - CD11b homologue - allows migration of neutrophils and macrophages
Streptolysin - pore forming units - destroy RBCs and WBCs
Protein G - bind to antibodies, preventing binding to the bacteria
What are consequences of infection of group A streptococcus
Tissue necrosis (Hyaluronidase)
Rheumatic fever (molecular mimicry)
Glomerulonephritis
Toxic shock (non-specific T cell activation)
What is Toxic shock?
Superantigen triggers T-cells nonspecifically
cytokine storm = multiple organ failure
What is endotoxic shock from non-pathogenic E.coli?
LPS component
switch on transcription factors
overzealous response
What is Helicobacter pylori?
gastric ulcers
stomach cancer
take on virulence factors by horizontal transfer
