Bacterial pathogenesis of infeciotn III Flashcards
How does the host respond to neisseria meningitidis?
Phagocytosis, neutralisation, complement activation
Where are IgG and IgM found?
Blood
Which antibody is mainly involved wphagocytosis?
IgA
Where is IgA found?
Musocal layers
IgM structure?
Pentameric
IgG structure?
Monomeric
IgA structure?
Dimeric
How does phagocytosis of a bacteria work?
Antibody attaches to bacteria
Antibody attaches to Fc receptor on phagocyte membrane
Bacteria is engulfed
Phagocytosis
Why is IgA important for neisseria meningitidis infections?
It is produced in nasopharynx and mucosal layers
IgA “life cycle” start?
Plasma cell produces IgA
Where does IgA go after production by a plasma cell?
Transported through an epithelial cell into the lumen
What happens once the igA is in the lumen?
Looks for infections there
How does igA pass through epithelial cells?
Recognised by a poly-Ig receptor on the base of epithelial cells
Neutralisation of neisseria meningitidis?
Antibodies surround the bacteria and prevent attachment to a host cell
How does IgA form an immune complex?
It can bind to multiple bacteria, and cause them to be consumed by phagocytes
How can neisseria meningitidis prevent IgA from working?
It secretes an IgA protease
What does IgA protease do?
Cleave IgA, disrupting the immune complex
What can porA(porin) do?
Inhibit C4 binding protein (complement component)
Necessary for small molecules to enter and exit the bacteria
What can NalP do?
Cleave human complement C3, facilitating C3b degradation
Where on neisseria meningitidis is porA found?
Outer membrane
Why is porin a possible vaccine target?
It is immunogenic
Which specific bits of porin are immunogenic?
Tips of some loops
Difference between T cell recognition and antibody recognition?
antibodies rely a lot on shape whereas t cells often use linear peptides
Which protein looked similar to PorA?
Outer membrane protein F from E. Coli
