Week 3 Diebel Bacterial Pathogenesis and Host Defense Flashcards
What type of toxin forms a hole in the host’s cell membrane?
Cytolytic exotoxin
What are three types of hemolysins? Describe each type.
gama-non hemolytic
alpha-damage RBC but don’t destroy
beta-very hemolytic, destroy cell
How do AB toxins work?
“B” toxin, binds to receptor protein
“A” toxin, released into cytoplasm causing some form of metabolic disruption
These toxins affect excitation signals from the CNS.
Neurotoxins
-can inhibit contraction (botulism)
or
-can inhibit relaxation (tetnus)
These exotoxins link to t-cells causing “runaway” massive systemic inflammatory response
superantigens
Whats a PAMP?
Pathogen Associated Molecular Pattern
-recognized by PRRs (innate)
What are complement components of the innate immune system?
serum proteins that bind to invading organisms and facilitate their phagocytosis
their overall goal is to control inflammatory response
activation is a cascade rxn
can be activated by antibodies or mannose binding lectin to the pathogen surface
What are interferons?
cytokines that mediate early response to viral infections by the innate immune system
Type 1: IFNa and IFNb are produced by infected cells
Type 2: IFNgama are released by T cells
What are PRRs?
Pattern Recognition Receptors-recognize PAMPs and trigger macrophage response to invasion
What are toll-like receptors?
a family of PRRs that bind PAMPs
TLR1-TLR9
What are APCs?
Antigen Presenting Cells
they link innate and adaptive immune systems by taking up and processing antigens so they can be recognized by t-cells
Definen epitope.
restricted part of antigen bound by antibodies
antibodies are?
immunoglubulin molecules that bind antigens with a high degree of specificity “tagging” them for destruction
What is the purpose of the constant or Fc region of an antibody?
binds to Fc receptors on phagocytes initiating phagocytosis of the bound antigen
What are the differences between active and passive immunity?
Active: the outcome of exposure to an antigen
- immune response made by infected individual
- immune memory in effect
- response can be maintained
- develops over a period of weeks
Passive: acquisition of PREFORMED immune cells or antibodies from a donor
- no exposure to antigen
- no immune memory
- not maintained
- immunity develops immediately
