3. Innate Immunity III Flashcards
(20 cards)
What triggers the immediate reaction in the complement activation process?
Introduction of a pathogen to the body
This reaction is part of the body’s immune response to infections.
What are the two main types of immunity involved in complement activation?
Innate and adaptive immunity
Both types of immunity work together to protect the body from pathogens.
How many activation pathways are there in the mammalian complement system?
Three activation pathways
These pathways include the classic, mannose-binding lectin, and alternative pathways.
What activates the classic activation pathway of the complement system?
Antigen/antibody immune complex
This pathway is initiated when antibodies bind to antigens.
Which activation pathway is triggered by microbes with terminal mannose groups?
Mannose-binding lectin activation pathway
This pathway recognizes specific carbohydrate structures on pathogens.
What types of entities activate the alternative activation pathway?
Bacteria, fungi, viruses, or tumour cells
This pathway can be activated by a wide range of pathogens.
What is the key event that merges all complement activation pathways?
Proteolytic activation of C3 to C3b
This step is crucial for the downstream effects of the complement system.
What does C3b get converted into, and what does it bind to?
C5, which can be cleaved and bound to C6, C7, and C8
This conversion is part of the complement cascade leading to membrane attack.
What is the outcome of Poly C9 formation?
Creates a membrane gap leading to lysis
This process can effectively kill pathogens by disrupting their cell membranes.
What are opsonins and what role do they play in the immune response?
They promote phagocytosis of antigens
Opsonization enhances the efficiency of phagocytosis by marking pathogens for destruction.
What are anaphylatoxins and their function?
Recruit immune cells to the site of production
These molecules are important for amplifying the immune response.
What is the primary function of neutrophils?
Detect and phagocytose pathogens
Neutrophils are essential components of the innate immune response.
What is the lifespan of neutrophils if not activated?
A few hours
Neutrophils are short-lived cells that quickly respond to infections.
Where are neutrophils produced?
Bone marrow
This is their primary site of generation before entering circulation.
What mechanism do neutrophils use to kill pathogens?
Lysosomal killing mechanism
Neutrophils contain lysosomes that release enzymes to destroy pathogens.
What are the three stages of leukocyte extravasation?
- Chemoattraction 2. Tethering and rolling 3. Migration
These stages describe how leukocytes move from the bloodstream to tissues.
What is the role of sialyl lewis x in neutrophil tethering?
Binds to e- and p-selectins on endothelial cells
This interaction is crucial for the initial adhesion of neutrophils to the blood vessel wall.
What happens during the migration stage of leukocyte extravasation?
Leukocytes are pulled through the membrane into affected tissue
This allows immune cells to reach sites of infection or injury.
What types of macrophages are found in the liver, brain, bone, and lungs?
Liver: Kupffer cells, Brain: Microglia, Bone: Osteoclasts, Lung: Alveolar macrophages
Each type of macrophage has specialized functions in their respective tissues.
What do macrophages possess to bind to pathogens?
Many receptors to bind to specific structures
These receptors allow macrophages to recognize and respond to a variety of pathogens.
