Innate Immunity - Part 1 - after class Flashcards
What is the first line of defence against a pathogen?
Innate immunity
A key property of innate immunity is that it works ______.
quickly/immediately
What are the two major groupings of innate immunity?
Barriers
Innate cells and proteins
Are the innate and adaptive branches of immunity separate?
No, certain innate cells can initiate adaptive immunity to help eliminate the pathogen
What do barriers do, broadly?
Prevent pathogens from entering the tissues
What do innate cells and proteins do, broadly?
Rapidly eliminate pathogens that enter tissues
Innate immunity functions at what time scale?
Immediately after contact. Works quickly.
What are the properties of innate immunity?
Born with innate immune defences All humans have the same innate immunity Always initiated when the pathogen contacts the body Responds immediately to a pathogen No memory
Often, we never know we were infected in the first place. Why?
Because the innate immunity is so effective at eliminating pathogens that it often does so before symtpoms arise
What are the four modes of pathogen entry into the body?
- Skin (through wound)
2 . - Respiratory tract
- Skin (through wound)
- GI tract
- Reproductive tract
Most pathogens enter through which route(s)?
GI and respiratory tract
What is the main physical barrier that prevents pathogen entry?
Epithelial cells
What are properties of epithelial cells that prevent pathogen entry?
Tight junctions rapidly renewable Shed - desquamation secretion of antimicrobial peptides Keratin, mucus, cilia
What are other barriers that prevent pathogen entry?
Mechanical barriers - flushing out
Chemical barriers
Microbiological barriers
What are the microbiota assocaited wtih?
Associated with epithelial cells that line ALL pathogen entry points.
How does one acquire his or her microbiota?
From birth
- vaginal - will acquire mom’s microflora
- c-section - will acquire from the environment: mom and dad, air, nurse, breast feeding, etc.
The vast majority of the microflora resides where?
Mouth and LI
What is a potential issue relating antibiotics and microflora?
Antibiotics do not kill discriminately - kill both pathogenic and normal bacterial flora
Many microfloral components can be considered opportunistic, meaning what?
When the opportunity arises, normal microfloral components can become virulent and cause problems (often in areas where they are not normally associated)
Why does a catheter necessarily lead to infection?
Breaks epithelial cells, weakening that barrier and reduces urine flow, preventing mechanical flushing
What is the difference between an extracellular pathogen and an intracellular one?
extracellular - outside the cell
intracellular - inside the cell
What are the main differences between viruses and bacteria?
Bacteria are often larger, have DNA genomes and organelles and can replicate on their own. Can have intracellular and extracellular phases, but only some do.
Viruses are smaller, have DNA or RNA genomes, are obligate intracellular parasites and cannot self-replicate. Have both extracellular and intracellular stages.
