Innate Immunity - Part 1 - after class

Question 1

What is the first line of defence against a pathogen?

Answer 1

Innate immunity

Question 2

A key property of innate immunity is that it works ______.

Answer 2

quickly/immediately

Question 3

What are the two major groupings of innate immunity?

Answer 3

Barriers

Innate cells and proteins

Question 4

Are the innate and adaptive branches of immunity separate?

Answer 4

No, certain innate cells can initiate adaptive immunity to help eliminate the pathogen

Question 5

What do barriers do, broadly?

Answer 5

Prevent pathogens from entering the tissues

Question 6

What do innate cells and proteins do, broadly?

Answer 6

Rapidly eliminate pathogens that enter tissues

Question 7

Innate immunity functions at what time scale?

Answer 7

Immediately after contact. Works quickly.

Question 8

What are the properties of innate immunity?

Answer 8

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

Question 9

Often, we never know we were infected in the first place. Why?

Answer 9

Because the innate immunity is so effective at eliminating pathogens that it often does so before symtpoms arise

Question 10

What are the four modes of pathogen entry into the body?

Answer 10

1. • Skin (through wound)
     2 . - Respiratory tract
2. GI tract
3. Reproductive tract

Question 11

Most pathogens enter through which route(s)?

Answer 11

GI and respiratory tract

Question 12

What is the main physical barrier that prevents pathogen entry?

Answer 12

Epithelial cells

Question 13

What are properties of epithelial cells that prevent pathogen entry?

Answer 13

Tight junctions
rapidly renewable
Shed - desquamation
secretion of antimicrobial peptides
Keratin, mucus, cilia

Question 14

What are other barriers that prevent pathogen entry?

Answer 14

Mechanical barriers - flushing out
Chemical barriers
Microbiological barriers

Question 15

What are the microbiota assocaited wtih?

Answer 15

Associated with epithelial cells that line ALL pathogen entry points.

Question 16

How does one acquire his or her microbiota?

Answer 16

From birth

• vaginal - will acquire mom’s microflora
• c-section - will acquire from the environment: mom and dad, air, nurse, breast feeding, etc.

Question 17

The vast majority of the microflora resides where?

Answer 17

Mouth and LI

Question 18

What is a potential issue relating antibiotics and microflora?

Answer 18

Antibiotics do not kill discriminately - kill both pathogenic and normal bacterial flora

Question 19

Many microfloral components can be considered opportunistic, meaning what?

Answer 19

When the opportunity arises, normal microfloral components can become virulent and cause problems (often in areas where they are not normally associated)

Question 20

Why does a catheter necessarily lead to infection?

Answer 20

Breaks epithelial cells, weakening that barrier and reduces urine flow, preventing mechanical flushing

Question 21

What is the difference between an extracellular pathogen and an intracellular one?

Answer 21

extracellular - outside the cell

intracellular - inside the cell

Question 22

What are the main differences between viruses and bacteria?

Answer 22

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.