Introduction to Innate Immunity

Question 1

What are the roles of the immune system (IS)?

Answer 1

1. Defense (Host)
   - Against disease by pathogenic infectious organisms
2. Protection against some tumors
3. Vaccines
   - infections
   - Cancer therapy
4. Chronic immune responses (Long term conditions)
   - sepsis
   -autoimmunity
   -Type-2 Diabetes

Question 2

Describe the myeloid lineage.

Answer 2

Hematopoietic Stem Cell (common progenitor) -> Myeloid lineage
-> Neutrophil
->Mast cell and Basophil
->Eosinophil
->Monocytes -> differentiate -> Dendritic cell
-> Macrophage

Question 3

Innate immunity is…

Answer 3

Rapid
Halts infection
No memory

Question 4

The immediate response to infection includes:

Answer 4

1. Awareness
   -> Detection of pathogens to signal their presence
2. Immediate response
   -> Resident tissue cells/factors
   -> Recruitment of cells from the blood - chemical signals generated
   3.Signals sent to the acquired response
   -> Provision of immunity - long lasting
   -> The desired response of vaccination

Question 5

Name the nonspecific anatomic barriers?

Answer 5

Skin
Mucous Membranes

Question 6

Name the nonspecific physiological barriers.

Answer 6

Temperature
Low pH
Chemical mediators

Question 7

Other nonspecific barriers include.

Answer 7

Phagocytic/endocytic
Inflammatory

Question 8

Skin Mechanism

Answer 8

Mechanical Barrier
Retards entry of microbe
An acidic environment (pH 3-5) retards the growth of microbes

Question 9

Mucous Membrane mechanism

Answer 9

Mucus entraps foreign microorganisms
Cilia propel microorganisms out of the body

Question 10

Temperature mechanism

Answer 10

Normal body temperature inhibits the growth of some pathogens
Fever- inhibits the growth of some pathogens

Question 11

Low pH mechanism

Answer 11

Acidity of stomach kills most ingested microorganisms

Question 12

Examples of Chemical mediators

Answer 12

1. Lysozyme
2. Interferons
3. Complement
4. Toll-like receptors
5. Collectins

Question 13

Lysozyme

Answer 13

Cleaves bacterial cell wall

Question 14

Interferon

Answer 14

Induces antiviral state in uninfected cells

Question 15

Complement

Answer 15

Lysis microorganisms
Facilitates phagocytosis

Question 16

Toll-like receptors

Answer 16

Recognise microbial molecules
Signal cell to secrete immunostimulatory cytokines

Question 17

Collectins

Answer 17

Disrupt cell wall of pathogen

Question 18

Phagocytic barrier mechanism

Answer 18

Specialised cells - blood monocytes, neutrophils, tissue macrophages
Phagocytose - > kill and digest whole microorganism

Question 19

Endocytic barriers

Answer 19

Internalize (endocytose)
Break down foreign macromolecules.

Question 20

Inflammatory barrier mechanism

Answer 20

Tissue damage + infection induce leakage of vascular fluid
Contains serum proteins with antibacterial activity
Influx of phagocytic cells into the affected area

Question 21

What is inflammation?

Answer 21

Complex biological response to harmful stimuli - pathogen/injury

Question 22

What are signs of inflammation?

Answer 22

Redness
Swelling
Heat
Pain

Question 23

Latin for Redness

Answer 23

Rubor

Question 24

Latin for Swelling

Answer 24

Tumor

Question 25

Latin for heat

Answer 25

Calor

Question 26

Latin for pain

Answer 26

Dolor

Question 27

Latin for loss of function

Answer 27

Functio laesa

Question 28

Explain how a tissue becomes inflamed upon a pin piercing a skin’s surface.

Answer 28

Pin entry - bacteria enters (foreign matter)
Bacteria sensed by cells underneath and by histamines
Chemotactic factors
Dilation and increased leakiness of local blood vessels
Migration of macrophages and neutrophil to site of infection
Consumes bacteria + debris -> tissue heals

Question 29

Importance of Natural Killer cell?

Answer 29

Immune surveillance of cancer + viral infected cells

Question 30

Importance of Dentritic cell?

Answer 30

Antigen presentation + cytokine production

Question 31

Importance of Macrophages?

Answer 31

Phagocytosis + cytokine production

Question 32

Importance of Neutrophil?

Answer 32

Phagocytosis + enzyme production
eN(neutrophil)zyme