Host immune responses and hypersensitivity reactions in the lungs Flashcards
what are the cells of the basic innate system of the respiratory system?
Cilaited epithelial cells
Goblet cells
How does the respiratory system gets rid of particulates?
Goblets produce mucous to trap particulates
Ciliated cells beat and expel particulates by coughing
What does ciliated epithelial cells secrete for defense with infectious agents?
β-defensins
IgA antibodies
Antioxidants (glutathione
What does Bordatella cause?
What are the characteristics of bordetella?
Bordetella pertussis “Whooping cough” encapsulated, Gram negative coccobacilli Spread by respiratory droplets Rapid multiplication in mucous membrane No bacteremia Toxins cause local tissue damage
How does bordatella attach to cilia?
By filamentous hemagluttinin
How does bordatella cause whooping cough?
Pertussis toxin induces ADP-ribosylation of inhibitory subunit of G protein leading to activation of adenyl cyclase
Activated adenyl cyclase induce cyclic AMP which in turn activates cyclic AMP dependent protein kinase
Activated protein kinase induces mucous production and lymphocytosis (by inhibiting the signal transduction by chemokine receptors)
The adenyl cyclase toxin of the bacteria is also taken up the macrophages where it inhibits the antimicrobial mechanisms.
What is the mechanism of the tracheal toxin of bordatella?
the tracheal cytotoxin produced by the bacteria is a fragment of the bacterial peptidoglycan and in concert with endotoxin,
induces nitric oxide production which in turn damages the ciliated epithelial cells.
Describe mycoplasma pnuemoniae?
causes atypical
smallest free living organism
Lack cell wall
Cholesterol rich cell membrane
Can assume any shape
Tapered end (cytoadhesins)-attaches to sciliac acid in epithelial cells-causes host cell to produce ROS
Blocks cell from disabling ROS leading pathogenesis
What are the strains of Haemophilus influenzae?
Type B
Non encapsulated strains
What does type B of haemophilus cause?
Type B encapsulated strain cause meningitis and sepsis
What does non encapslated strain of haemophilus cause?
non-invasive and cause upper respiratory tract infections
What does haemaphilus influenzae produce?
IgA proteases that can degrade IgA enabling the pathogen to colonize the lungs.
What are alveolar macrophages defense mechanism?
Pattern recognition receptors such as toll like receptor-4 (TLR-4), TLR-2 and complement receptors.
Kill by oxygen dependent and oxygen independent mechanisms.
