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Terms in this set (47)
1. Secretions help expel pathogens
2. Mucus traps pathogens and are expelled by cilia
3. Acidic pH of stomach and vagina
How are skin and mucosal membranes more than just a "protective coating"?
Lysozyme, lactoferrin, and calprotectin
What are three proteins that epithelial cells make that inhibit and/or kill microorganisms?
It is in saliva, tears, and respiratory secretions, and it cleaves peptidoglycan components of bacterial cell walls
Where is lysozyme located and what does it do?
Sequesters metal ions needed by bacteria and fungi to grow
How do lactoferrin and calprotectin inhibit microorganisms?
Protein produced by epithelial cells that inhibits growth of E. coli on skin
What is psoriasin?
They kill a variety of bacteria and viruses generally by disrupting lipid membranes
What do antimicrobial peptides do?
Tissue response to infection or damage which serves to eliminate infection; hallmarks are heat, pain, redness, and swelling
What is inflammation?
Proteins secreted by cells that act on immune cells to regulate the intensity, duration, and quality of immune responses; there are many different kinds that serve many different functions
What are cytokines?
A subset of cytokines that mediate the recruitment of immune cells to a particular location in the body (called chemotaxis)
What are chemokines?
Engulfment and internalization of materials such as microbes for their clearance and destruction
What is phagocytosis?
Neutrophils, monocytes, macrophages, and dendritic cells
Which immune cells are phagocytes?
Through various surface receptors
How do phagocytic cells recognize microbes?
They have surface proteins that recognize molecules expressed on stressed or infected cells resulting in NK cell killing of the cell
How do NK cells work?
IFNgamma - helps activate macrophages
Which cytokine do NK cells produce?
Bacteria, viruses, protozoa, fungi, multicellular parasites, prions, and toxins from plants, animals, bacteria, and algae
Which microbes and toxic agents usually interact with our immune system?
Pathogen Associated Molecular Patterns
What does PAMPs stand for?
Conserved molecular patterns on the surface of microbes
What are PAMPs?
On broad groups of microbes (bacteria, or fungi, or viruses, or parasites), but NOT on the cells of the body
Where are PAMPs present?
LPS (lipopolysaccharide), peptidoglycan, flagellin
What are some examples of bacterial PAMPs?
Mannan, beta-glucan, and chitin (all of these components are present in the cell wall of fungi)
What are some examples of fungal PAMPs?
Differences in nucleic acid composition (ex. influenza has an RNA genome with exposed 5' triphosphate on the end)
What are some examples of viral PAMPs?
Protein receptors expressed on or in host cells (immune cells and others) that recognize PAMPs
What are pathogen recognition receptors (PRRs)?
Yes - they are germline encoded
Are pathogen recognition receptors (PRRs) inherited?
Toll-like receptor (TLR) family structure
Which family of PRRs is membrane spanning?
LPS present on Gram-negative bacteria
Which PAMP does TLR4 recognize?
Flagellin present on bacteria
Which PAMP does TLR5 recognize?
single-stranded RNA (ssRNA) present in viruses
Which PAMP does TLR7 recognize?
CpG unmethylated dinucleotides present in bacterial DNA
Which PAMP does TLR9 recognize?
As homodimers or heterodimers
How are TLRs expressed?
In cell at locations where they are likely to encounter the PAMP
Where are TLRs expressed?
In lysosomal/endosomal membranes, because PAMPs found inside viruses or inside bacteria only become exposed when broken down in intracellular lysozomes
Where are TLRs that recognize PAMPs found inside viruses or inside bacteria?
Induces intracellular signaling which activates transcription factors that induce expression of important anti-microbial proteins and cellular functions
How do PAMPs activate TLRs?
sensing of viral infection
What are RLRs important for?
The cytosol of host cells
Where are RLRs usually expressed?
What do RLRs usually recognize?
RNA with 5' triphosphate (made during the lifecycle of some RNA viruses)
What does RIG-I usually recognize?
Initiates cell signaling, which increases production of proteins involved in inflammation and immune response
What happens when RLRs recognize viral RNA?
A family of about 23 cytosolic proteins in humans
What are nod-like receptor families (NLRs)?
Products of bacterial peptidoglycans and some host cell substances that are generated due to host cell damage (sometimes called "damage associated molecular patter" or DAMP)
What do NLRs recognize?
Plasma membrane of some host cells
Where are CLRs expressed?
Specific carbohydrate components present on bacteria, fungi, and viruses
What do CLRs generally recognize?
Beta-1,3 glucans from fungi
What does Dectin-1 (a CLR) recognize?
Initiates cell signaling which increases production of proteins involved in inflammation and immune response
What does recognition of PAMP by CLR initiate?
Antimicrobial peptides, Type I interferons, cytokines, chemokines
What do PRR signaling pathways activate?
Increased vascular permeability, recruitment of neutrophils and other leukocytes from the blood to the site of damage/infection, and increased production of neutrophils from HSCs
What are the early effects of cytokines and chemokines on inflammation?
Which cells are a key bridge between innate and adaptive immune responses?
via PRR signaling
How do dendritic cells become activated?
THIS SET IS OFTEN IN FOLDERS WITH...
Immunology and Immunity
Hematopoietic Stem Cells
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