Immuno 11: Innate Immunity Flashcards
(67 cards)
Parasites are a group of disease-causing agents that include ____ and ____.
worms and protozoa
The tremendous diversity of pathogens has led the immune system to develop 2 critical features. They are:
- specific BCRs and TCRs of equal or greater diversity than pathogens
- wide range of distinct effector mechanisms to combat the pathogens
Pathogens that remain in extracellular locations are best combated by \_\_\_\_ immune responses (complement fixing and neutralizing Ab isotypes) and by \_\_\_\_.
humoral; phagocytosis
Pathogens that grow in the cytoplasm of cells (intracellularly) are cleared primarily by ____ and ____ cells.
CTLs and NK cells
Protection against pathogens that grow in vesicles of phagocytes (intracellularly) is mediated primarily by ____-mediated
activation of ____.
T cell-mediated
activation of macrophages
Direct methods of tissue damage include __________, whereas indirect mechanisms involve ________.
production of exotoxins and endotoxins, and direct cytopathicity of host cells; innate and acquired immune responses of the host
What is molecular mimicry?
indirect mechanism of tissue damage wherein pathogen elicits antibodies specific for host cell proteins
Cryptidins/defensins are ____ ____ produced by ____ cells (lining the small intestine) and by
____.
antibacterial peptides; Paneth cells and neutrophils
How do amphipathic peptides attack bacteria?
they insert into their outer envelope and disrupt their integrity
What prevents bacteria from colonizing in the stomach
acid and hydrolytic enzymes
What component of tears and saliva degrades bacterial cell walls?
lysozyme
What are the two main mechanisms by which normal flora are a defense against pathogens?
- they compete for attachment to epithelial cells, and nutrients
- they produce antibacterial proteins called colicins
If it’s true that complement component C3 is constantly activated at low level in the blood, how does it respond to an infection?
the rate of C3 cleavage increases in the vicinity of some pathogens; also when C3 is cleaved it is rapidly degraded unless a pathogen is present for it to bind to
Factor __ binds to the C3 convertase to stabilize it by preventing Factor __ from dampening the complement activation cascade.
Factor P (properdin); Factor H
Please name the host cell surface proteins that prevent the complement cascade from marking them for uptake and destruction.
- CR1
- DAF
- MCP
What host cell surface proteins interfered with MAC formation on host cells?
CD59 (protectin)
Is factor H a plasma protein or a cell surface protein? What does it do?
plasma protein; it renders C3 convertase susceptible to cleavage by factor I in the process of protecting host cells from complement destruction
What 2 cells initiate the inflammatory response and provide innate cell-mediated immunity (CMI)?
macrophages and neutrophils
Macrophages and neutrophils have what 2 receptors on their surface that allow them to recognize/phagocytose bacterial material?
- PRRs - recognize PAMPs
2. complement receptors - recognize opsonized material
Once pathogens are ingested, what agents do macrophages/neutrophils produce to kill or deactivate the pathogen?
- acid
- toxic oxygen derivatives
- antibacterial peptides/proteins
- competitors
Big duties of macrophages include releasing ____, ____, and to act as ____.
cytokines, phagocytosis, professional APCs
What is considered the first of a series of reactions known as the imflammatory response?
arrival of neutrophils at the site
Neutrophils are specialized for working under ____ conditions.
anaerobic
How long do neutrophils survive after entering inflamed tissue, and what happens to their dead cell body?
they survive about 5-6hrs; the dead cells form pus
