Virulence factors Flashcards
difference in virulence factors between intracellular and extracellular pathogens
intracellular = strategies aimed at blocking steps after phagocytosis
extracellular = strategies aimed at blocking steps before phagocytosis
composition of bacterial capsule
water + Polysaccharide
function of bacterial capsule
-prevents phagocytosis
-prevents binding of complement system
Bacilius anthracis capsule
made of protein! (D-glutamate)
*this is an exception
name a common encapsulated bacteria
strep. pneumonia
How does strep. pneumonia cause meningitis?
strep. pneumonia has a polysaccharide capsule that is antiphagocytoic
its capsule causes an increased cytokine response, thus increasing the severity of infection / meningitis
How can our immune system target capsules?
B-cells can secrete capsular antibodies IgG
IgG binds the capsule
What 3 bacteria can commonly cause meningitis?
N. meningitidis
S. pneumoniae
H. Influenzae
What is true of bacteria that commonly causes meningitis?
capsulated bacteria
What other symptoms can strep pneumo cause?
C-MOPS
How can strep pneumo cause meningitis?
can cross blood brain barrier since capsule allows you to attach to host cells
invade host cells and cause meningitis
What can a capsule do? (2 things)
block neutrophils / phagocytosis
block complement binding
Why are elderly more likely to get pneumonia?
they have a weaker immune system
ex: thymus not making T-cells to the same degree
immune senescence
Why are young children more likely to get pneumonia?
immune systems are not developed and they cannot respond to capsule yet
How does penicilin work?
binds PBPs to stop peptidoglycan wall synthesis
