Vishy - Innate Defenses

Question 1

Components of innate immunity include:

Answer 1

1. skin: made up of 2 layers, epidermis and dermis

2. mucous membranes

Question 2

The outermost layer of epidermis is called ___ ___ which is made up of dead cells and is formed from _____ present in underlying layers of epidermis. Sebaceous glands produce sebum which maintains a low pH to prevent colonization of microbes.

Answer 2

stratum corneum; keratinocytes

Question 3

Vagina is colonized by ____which produces lactic acid which maintains pH of 4.5 which prevents colonization of fungus. Stomach produces ____ secrete stomach ___cells secrete alpha defensins which inactivate bacteria.

Answer 3

lactobacillus; HCL; panneth

Question 4

The respiratory cells secrete ___ defensins which has antimicrobial effects similar to alpha defensins

Answer 4

beta

Question 5

What are cells of the innate defense system

Answer 5

1. Neutrophils
2. Monocytes
3. Macrophages
4. Dendritic cells
5. Natural killer cells

Question 6

Phagocytic cells recognize microbial infection using pattern recognition receptors such as ____ ___ ____ and complement receptors. TLR-2 recognize _____ and ____acid. TLR-4 recognize ___.Phagocytosis occur through special areas called ___ ___ pits

Answer 6

toll like receptors; peptidoglycan; lipotechoic; LPS; clathrin coated

Question 7

Phagoctyes kill intracellular organisms via 2 pathways:

Answer 7

1. Oxygen dependent:
   - Generation of reactive oxygen intermediates
   - Generation of reactive nitrogen intermediates
2. Oxygen independent:
   - Generation of antimicrobial peptides
   - Fusion between phagosome containing microbes with lysosome.

Question 8

How are reactive oxygen intermediates produced?

Answer 8

NAPH oxidase reduces molecular oxygen to form superoxide molecule which serves as precursor for rest of reactive oxygen species. Superoxide molecule reacts with another superoxide molecule to form hydrogen peroxide (dismutation rxn). Hydrogen peroxide kills microorganisms. But some are not resistant to it. So, it then combines with chloride ions in the presence of myeloperoxidase to produce hypochlorous acid. This can react with hydrogen peroxide to form singlet oxygen.

Question 9

Macrophages can’t generate ____ acid and singlet oxygen bc they dont have myeloperoxide. But they can generate superoxide and hydrogen peroxide. , and nitric oxide.

Answer 9

hypochlorous

Question 10

____converts argenine to nitric oxide used by macrophages. ____ is produced by CD4 T cells and ____ is produced by macrophages. IFN-gamma activates macrophages to control the infection and induce iNOS in macrophages and mobilize NKs

Answer 10

iNOS; IFN-gamma; TNF-alpha

Question 11

Pathway of oxygen indpendent include the following:

Answer 11

1. lactoferrin
2. lysozyme
3. alpha defensins (neutrophils only)
4. DNAase and RNAase

Question 12

During infection, cells release ____, a major cytokine

Answer 12

interferon (IFN)

Question 13

What are the two types of interferons

Answer 13

1. Type I: IFN-alpha and IFN-beta (when infected with virus)

2: Type II: IFN-gamma

Question 14

____ is released by the virus infected cells and induces uninfected cells to produce ____which has antimicrobial effects.

Answer 14

IFN-alpha; PKR

Question 15

FIbroblasts secrete ___interferon. FDA approved alpha IFN is used as an antiviral drug against hepatitis ____ and also to treat genital warts

Answer 15

beta; C

Question 16

What are the four cardinal signs of inflammation

Answer 16

1. pain
2. redness
3. swelling
4. increase in temp and fluid accumulation

Question 17

If gram negative infection , LPS is recognized by ____. Then there is downstream signaling which leads to activation of _____and induces transcription of ____, ___ and TNF-alpha. But if too much production of these it can lead to septic shock, cachexia (muscular waisting), anorexia, and inflammation

Answer 17

TLR-4; NFkB; IL-1; IL-6

Question 18

what are characteristics of septic shock

Answer 18

1. hypotension
2. disseminated intravascular coagulation
3. inflammation

Question 19

NO synthase enzyme exists in 3 forms:

Answer 19

eNOS: endothelium
nNOS: neurons
iNOS: expressed in macrophages and smooth muscle

Question 20

Nitric oxide can

Answer 20

1. kill pathogen

2. decrease blood pressure

Question 21

describe the clotting process

Answer 21

1. ex: TNF-alpha activates tissue factor on macropharages–>7–>10–>prothrombin–> thrombin ->fibrinogen –> fibrin

Question 22

COmplement are serum proteins. ___ activates the alternate pathway of complement activation.

Answer 22

LPS; activation of C3–> 5, 6, 7, 8, 9 –>6-9 form membrane attack complex which binds to cell wall of bacteria leading to rupture of bacteria.

Question 23

B participates in chain reaction to form membrane attack complex. ___ serves as an anaphylotoxin inducing mast cells and basophils to release ___ which is how inflammation occurs.

Answer 23

c5a ; histamine

Question 24

TNF-alpha also induces the expression of P selectin ____selectin and ____. Explain what happens after

Answer 24

E- selectin; ICAM; immune cells will bind here and since vasculatre is permeable they would be able to go to extravascular site and cause inflammation.