L13 Innate Immunity

Question 1

What is innate immunity

Answer 1

Immediate response to a pathogen that does not confer long lasting protective immunity.
Non specific defense system

Question 2

What Are the 3 phases of response to initial infection

Answer 2

Innate immunity(0-4 hrs)
Early induced innate response(4-96hrs)
Adaptive immune response(>96 hrs)

Question 3

What are innate immune mechanisms

Answer 3

Act immediately

Followed by early induced responses which can be activated by infection but do not generate lasting protective immunity

Question 4

When would adaptive immunity occur

Answer 4

Only if an infectious organism can breach these lines of defense will an adaptative immune response ensue with the generation of antigen specific effector cells that specifically target the pathogen and memory cells that can prevent reinfection with the same microorganism

Question 5

What are the cells of innate immunity

Answer 5

Neutrophils 
Monocytes 
Natural killer cells
Eosinophils 
Basophils

Question 6

First responders to infection and phagocytose bacteria in to phagosomes before hydrolyzing and destroying them

Answer 6

Neutrophils

Question 7

Rapid response and not prolonged effect

Answer 7

Neutrophils

Question 8

Phagocytose pathogens

Answer 8

Macrophages

Question 9

When do monocytes become macrophages

Answer 9

When they are in tissues

Question 10

Provide prolonged defense

Answer 10

Monocytes

Question 11

What are natural killer cells and what do they do

Answer 11

Large granular lymphocytes that recognize non specifically the surface changes on tumor cells and virus infected cells and damage these cells without prior sensitization

Question 12

Cells that fail to express MHC class 1 molecules

Answer 12

Natural killer cells

Question 13

What is the process of ADCC and which cell carries it out

Answer 13

Natural killer cell

Binding to antibody already attached to antigen on a target cell using their Fc receptors

Question 14

Naturally present in spleen and peripheral blood

Answer 14

Natural killer cells

Question 15

Have granules containing a variety of enzymes and toxic proteins which are released when these cells are activated

Answer 15

Eosinophils and basophils

Question 16

Which cells are Important against defense of parasites and why

Answer 16

Eosinophils and basophils as they are too large to be ingested by macrophages or neutrophils

Question 17

What are the barriers to infection

Answer 17

Epithelial layers

Antimicrobial substances

Question 18

Where are epithelial cells a barrier and how

Answer 18

Skin 
Airways
GIT
Genitourinary tract
Have tight junctions and produces a number antimicrobial peptides that help provide protection against invading pathogens

Question 19

What are the antimicrobial substances

Answer 19

Lysozyme
Defensins
Lactoferrin

Question 20

What is the lysozyme and what does it do

Answer 20

Tears mucus saliva

Splits the sugar from the mucopeptide layer of the cell wall of gram positive bacteria

Question 21

What are defensins and what do they do and where are they produced

Answer 21

Peptides produced by neutrophils epithelial cells and other cells that disrupt microbial membranes
Primarily produced in GIT and lower respiratory tract that create pores in lipid membranes of bacteria fungi and some viruses

Question 22

What is lactoferrin and what does it

Answer 22

Iron binding protein

Deprives micorbes of the free iron they need for growth

Question 23

How does mucous protect

Answer 23

Trapping mechanism
And action of cilia sweeps secretion with inhaled microorganisms either outside through coughing and sneezing or towards stomach where they are acted upon by hcl

Question 24

Describe phagocytosis

Answer 24

1–phagocytic cells engulf microorganisms and remove them from lymph and blood stream
2-phagosome containing microbe fuses with lysosome
3-microbe is killed within phagolysosome by proteases as well as by reactive oxygen species and reactive nitrogen radicles

Question 25

How can phagocytosis be enhanced

Answer 25

enhanced by opsonization of the particles by opsonin which include complement fragments C3b and IgG

Question 26

What are the pattern recognition receptors of innate immunity cells

Answer 26

Toll like receptors | Nucleotide binding oligomerization like receptors

Question 27

What are toll like receptors

Answer 27

They are a group of pattern recognition receptors found either on the surface or in the endosomal compartment of innate immune cells such as macrophages and dendritic cells they are glycoprotein in nature and are an important part of innate immunity

Question 28

What do toll like receptors recognize and bind to

Answer 28

they recognize and bind to highly conserved structures present in different organisms known as pathogen associated molecular patterns

Question 29

What do PAMPs include

Answer 29

1-Bacterial components as flagellant peptidoglycan Tiechoic cells lipopolysaccharides 2-Fungal molecules as zymosan and mannas 3-viral molecules as viral nucleic acid and proteins

Question 30

What do cell surface TLRs sense | And what do those in endosomal compartment bind to

Answer 30

Cell surface TLR‘s typically sense PAMPS of microbial cell envelopes flagella or Lipopolysaccharide In the endosomal compartment bind to nucleic acids

Question 31

What happens after binding of TLRs to PAMPS of bacteria and fungi

Answer 31

Triggers the activation of signal transduction pathways resulting in the activation of innate immune cells and synthesis of cytokines as IL2 IL8 and TNFa that in turn triggers immune defenses as inflammation,fever and phagocytosis binding of TLRs to viral components trigger synthesis of interferon and blocks viral replication

Question 32

Describe nucleotide binding oligomerization domain like receptors

Answer 32

They are specialized set of intracellular cytosolic receptors that are essential components of the innate immune system and function by the recognition of cytoplasmic PAMPS resulting in activation of signaling pathways

Question 33

What is the result of NLRS activating signaling pathways

Answer 33

Production of cytokines and chemokines which alert the immune system to the presence of pathogenic bacteria and Aid in the clearance of infection

Question 34

What is inflammation

Answer 34

Acute local inflammation as an early defense mechanism to contain the infection prevent its spread from the initial focus and activates subsequent immune response

Question 35

How does fever protect organism snd how is it triggered

Answer 35

Triggered by resetting hypothalamic thermostat triggered by toxins or cytokines The higher temperature inhibit bacterial growth intensifies the effect of antiviral interferons and speeds of the body‘s reaction aiding tissue repair

Question 36

Complement system

Answer 36

It is another key component of innate immunity the alternative and lectin pathways of complement activation serve as critical first line of defense and provide immediate protection against microorganisms