Chapter 18.2 Innate Immune Responses Flashcards
Innate immune responses defend against foreign cells or matter without:
Having to recognize specific identities
Innate responses recognize a _____ ______ property marking the invader as foreign
Innate responses recognize a general molecular property marking the invader as foreign
Innate responses include:
- Response to injury or infection known as inflammation
- Response to interferons (family of antiviral proteins)
What is inflammation?
Local response to infection or injury
What are two functions of inflammation?
destroy or inactivate foreign invaders and set the stage for tissue repair
The key mediators of inflammation are the cells that function as_____
The key mediators of inflammation are the cells that function as phagocytes
What are the three most important phagocytes for inflammation?
- neutrophils
- macrophages
- dendritic cells
Four common and familiar signs of tissue injury and inflammation?
- local redness
- swelling
- heat
- pain
What are the two general categories that mediators of inflammation fall into?
- Polypeptides (eg group known as kinins) generated in infected area by enzymatic actions of proteins that circulate in the plasma
- Substances secreted into the extracellular fluid from cells that either already exist in infected area (mast cells or injured cells) or enter it during inflammation (neutrophils)
Some chemical mediators cause local capillaries and venules to become permeable to _____ by inducing endothelial cells to contract = opening spaces between them
Some chemical mediators cause local capillaries and venules to become permeable to protein by inducing endothelial cells to contract = opening spaces between them
What are two reasons that vasodilation coupled with the ability for capillaries and venules to become permeable to proteins is advantageous?
- increased blood flow to inflamed area increases delivery of proteins and leukocytes
- increased permeability to protein ensures that the plasma proteins that participate in inflammation can gain entry to the interstitial fluid
Swelling in inflamed area is the result of what?
Edema caused by net filtration of plasma into interstitial fluid because of vasodilation and increased permeability to protein
What is chemotaxis?
the process by which neutrophils begin to move out of the blood across the endothelium of capillaries and venules to enter the inflamed area at the onset of inflammation
The messengers that mediate chemotaxis are called:
Chemoattractants (also called chemotaxins or chemotactic factors)
What is an opsonin?
chemical factor produced by the body that can bind the phagocytes tightly to the pathogen and thereby enhance phagocytosis
The internal, microbe-containing sac formed as a phagocyte engulfs a bacterium is called:
a phagosome
When the phagosome and lysosome (which is full of hydrolytic enzymes) combine, what are they called?
Phagolysosome
A family of proteins known as ______ proteins are always circulating in the blood and provide another means for extracellular killing without prior phagocytosis
A family of proteins known as Complement proteins are always circulating in the blood and provide another means for extracellular killing without prior phagocytosis
the central protein in the complement cascade is:
C3
Activation of C3 causes the deposition of _____ on the microbial surface
C3b
C3b acts as an _____ that is recognized by receptors on phagocytes targeting the pathogen for destruction
C3b acts as an Opsonin- that is recognized by receptors on phagocytes targeting the pathogen for destruction
C3b is also part of a ______ enzyme that amplifies the complement cascade and leads to the downstream development of a multiunit protein called the ________
C3b is also part of a proteolytic enzyme that amplifies the complement cascade and leads to the downstream development of a multiunit protein called the membrane attack complex (MAC)
What does the MAC do?
remember MAC = Membrane attack complex
The MAC embeds itself in the bacterial plasma membrane (or protein coat of a virus) and forms porelike channels making it leaky = disruption to the intracellular environment kills the pathogen
What is required to activate the first complement protein, C1, in the classical complement pathway?
antibodies
The _____ ______ pathway is NOT antibody dependent and bypasses C1
The alternative complement pathway is NOT antibody-dependent and bypasses C1
The alternative complement pathway is initiated as a result of interactions between ________ on the surface of the _______ and ______ ______ _____ beyond ____
The alternative complement pathway is initiated as a result of interactions between carbohydrates on the surface of the microbe and inactive complement molecules beyond C1
Tissue repair:
______ (a type of connective tissue cell) that reside in the area divide rapidly and begin to secrete large quantities of collagen, and blood vessel cells proliferate in a process called _______
Tissue repair:
Fibroblasts (a type of connective tissue cell) that reside in the area divide rapidly and begin to secrete large quantities of collagen, and blood vessel cells proliferate in a process called angiogenesis
________ include several proteins that nonspecifically inhibit viral replication inside host cells.
Type 1 interferons include several proteins that nonspecifically inhibit viral replication inside host cells
How do type 1 interferons work?
- secreted by most cell types into ECF
- once in ECF type 1 interferons bind to plasma membrane receptors on the cell that secreted them as well as other cells whether they are infected or not
- Binding triggers synthesis of dozens of different antiviral proteins by the cell which interfere with the viruses ability to replicate
Are the actions of type 1 interferons specific or non-specific?
Non-specific
There is one member of the Type II interferons: ______
Interferon-gamma
Interferon-gamma (the sole member of the _______) is produced by ______ cells and functions in potentiating some of the actions of _______, enhancing bacteria-killing activity of ______ and acts as a ______ in the inflammatory response
Interferon-gamma (the sole member of the Type II interferons) is produced by Immune cells and functions in potentiating some of the actions of type I interferons, enhancing bacteria-killing activity of macrophages and acts as a chemokine in the inflammatory response
Innate immunity often depends upon an immune cell recognizing some general molecular feature common to many types of pathogens. These features are called:
Pathogen-associated molecular patterns (PAMPs)
Which proteins function to recognize and bind to highly conserved molecular features associated with pathogens (that is the PAMPs)?
Toll Proteins
Because many of the Toll proteins are plasma-membrane bound, bind to extracellular ligands and induce second messenger formation, they are referred to as _____; the family of proteins is known as _______
Because many of the Toll proteins are plasma-membrane bound, bind to extracellular ligands and induce second messenger formation, they are referred to as receptors; the family of proteins is known as Toll-like receptors (TLR’s)
TLR’s (toll-like receptors) belong to a family of proteins called
pattern-recognition receptors (PRRs)
