Introduction to Immunology

Question 1

What are physical barriers to infection?

Answer 1

skin and mucous membrane barriers (to microbes, viruses, parasites, fungi, bacteria) - epithelial cells & leukocytes in there can produce antibiotics as well as toxic proteins (like defensin & cathelicidin)
for example: small peptides that are positively charged can combine with negative components of bacterial cell wall and neutralize it.

Question 2

What are the two different ways to fight infection?

Answer 2

Innate and Adaptive Immunities

Question 3

How does the innate immune system work in a nutshell?

Answer 3

1. engulf
   2.eliminate
2. induce inflammation
3. call & activate adaptive system
   innate immune cells are like a sensing organism - detect changes in the environment and respond to it Innate immune cells are quick to respond, but they aren’t very efficient, so one important function of innate immunity is to initiate adaptive immunity

Question 4

Which cells are involved in adaptive immune system?

Answer 4

Helper t-cells, antigen presenting cells, B-cells, T-cells

Question 5

What does the innate immune system sense?

Answer 5

foreign molecular structures called pathogen-associated molecular patterns (PAMPs), stress or damage indicators expressed by body cells, sometimes called damage-associated molecular patterns (DAMP), the ABSENCE of certain self marker molecules

Question 6

What are toll-like receptors?

Answer 6

receptors on innate immune cells that recognize patterns that are only expressed on infectious agents, not self-cells. Once toll-like receptors recognize PAMPs, they get activated, engulf the pathogen, eliminate, activate inflammation & activate adaptive immune system

Question 7

Talk about the TLR Signal Transduction Pathway

Answer 7

TLR4 recognizes LPS (lipo-polysaccharide) - TLR binding to PAMP causes a transduction pathway that eventually activates NFkB
NFkB is the master switch - when it is turned on, inflammation is induced - ultimate destination of TLR Signal Transduction pathway

Question 8

What are the physiological effects of inflammation?

Answer 8

increased blood vessel diameter, stickiness and leakiness w/an efflux of fluid and phagocytic white blood cells.