Lecture 8 - Triggers of Adaptive Immunity

Question 1

2 Rs of adaptive immunity

Answer 1

recognize and respond to almost all foreign macromolecules present in invading microbe

Question 2

Antigens

Answer 2

foreign macromolecules in invading microbe

Question 3

Antigenicity

Answer 3

inherent capacity of molecule to be recognized by immune system

Question 4

Microbial antigens (3)

Answer 4

1. bacterial antigens
2. viral antigens
3. fungi, protozoan parasites, arthropods, helminths

Question 5

Non-microbial antigens

Answer 5

1. cell surface antigens
2. autoantigens

Question 6

Examples of bacterial antigens

Answer 6

1. peptidoglycans
2. lipotechoic acid
3. LPS
4. lipoproteins
5. capsular antigens (K)
6. Pili (F)
7. flagellar antigens (H)
8. porins
9. HSP
10. exotoxins
11. bacterial nucleic acids

Question 7

Viral structure

Answer 7

nucleic acid surrounded by protein layer

Question 8

Capsid

Answer 8

viral protein layer that surrounds nucleic acid core

Question 9

Capsomere

Answer 9

subunits that make up capsid

Question 10

What are good viral antigens

Answer 10

capsid proteins

Question 11

What type of viral antigens can provoke adaptive immunity

Answer 11

viral proteins expressed on the surface of infected cells

Question 12

What are other microbial antigens that can trigger adaptive immunity

Answer 12

structural components of many fungal pathogens, protozoan parasites, arthropods, and helminths

Question 13

Microbial antigenicity vary and the adaptive response triggered ….

Answer 13

may not always be sucessful in protecting animal / eliminating invader

Question 14

Non microbial antigens specific examples

Answer 14

1. FOOD may trigger immune response and cause allergic reaction
2. inhaled dust may have pollen grains
3. blood-group antigens (glycoproteins)
4. tissue graft reejction in genetically different individuals is triggered by histocompatibility antigens
5. autoantigens

Question 15

Autoantigens

Answer 15

induce autoimmune response, thyroglobulin, myelin, mitochondrial proteins, ect

Question 16

3 characterisitics of best antigens

Answer 16

large, complex, and foreign

Question 17

What reduces antigenicity

Answer 17

excessive or insufficient stability

Question 18

Ability of an antigen to elicit immune response also depends on:

Answer 18

1. route of administration
2. amount of antigen adminstered
3. genetic makeup of immunized animal

Question 19

What antigens have the greatest antigenicity

Answer 19

large

Question 20

What can increase the intensity of the immune response

Answer 20

greater the difference between foreign antigen and animal’s own antigens

Question 21

Why do animals not recognzie self proteins

Answer 21

B-cells and T-cells that have the potential to recognize the self-proteins are eliminated from the body

Question 22

What is directly proportional to its antigenicity

Answer 22

structural complexity

Question 23

What specific antigens tend to be poorly antigenic

Answer 23

large repeating polymers such as lipids, nucleic acids, and carbohydrates

Question 24

Why do flexible molecules such as flagellin and gelatin make poor antigens

Answer 24

BCR and antibodies cannot recognize unstable molecules that change conformation

Question 25

How to increase antigenicity of flexible molecules

Answer 25

stabilizing by cross-linking

Question 26

Why are antigens that are enzymatically broken down too quickly not antigenic

Answer 26

not enough time for recognition by BCRs and to be presented by APC

Question 27

Why are simple polysaccarides such as starch and glycogen poor antigens

Answer 27

readily digested

Question 28

In order to elicit an immune response, a molecule must

Answer 28

be degradable within APCs

Question 29

Why are plastics and stainless steel generally NOT antigenic

Answer 29

large organic molecules that make up plastics form uniform repeated polymers which are very inert

Question 30

What happens to inert molecules

Answer 30

cannot be broken down and presented to TCR to initiate an immune response

Question 31

In general, what makes best antigens

Answer 31

large, complex proteins

Question 32

What can large polysaccarides be complexed with to be highly antigenic

Answer 32

proteins

Question 33

What immune response do glycoproteins illicit

Answer 33

antibodies are directed specifically against the polysaccharide moiety of the molecule

Question 34

Why are lipids and nucleic acids poor antigens

Answer 34

readily degradable

Question 35

What nucelic acids are antigenic

Answer 35

in nucleoproteins bc the NA is lined to the carrier nucleoprotein

Question 36

Epitope/antgenic determinant

Answer 36

specific regions on large molecules against which immune responses are directed

Question 37

immunodominant epitope

Answer 37

in a complex protein molecule, multiple epitopes are recognized by the immune system.

Question 38

There is about 1 epitope per __ kDa of protein

Answer 38

5

Question 39

If small molecules are chemically linked to a large protein molecule, ....

Answer 39

new epitopes will be formed on surface of large molecule and the complex will trigger immune response

Question 40

Haptens

Answer 40

small molecules that can function as epitopes only when bound to other larger molecules

Question 41

Carrier

Answer 41

antigenic molecule to which the haptens are attached

Question 42

Toxic component of poison ivy that can bind to any protein it contacts

Answer 42

urushiol

Question 43

PAthway of poison ivy allergiy contact dermatitis

Answer 43

1. urushiol binds with skin proteins of person who rubs against plant 2. modified skin proteins are treated as foreign and attacked by lymphocytes 3. allergic contact dermatitis

Question 44

Cross-reactivity of antigens

Answer 44

Identical or similar epitopes may sometimes be found on apparently unrelated molecules. Antibodies directed against one antigen may thus react with an unrelated antigen.

Question 45

examples of cross-reactivity of antigens

Answer 45

1. bacterial or food antigen carrying epitode for blood group glycoprotein 2. Brucella abortus and some strains of Yersinia enterocolitica 3. Feline infectious peritonitis (FIP) and virus of pig transmissible gastroenteritis (TGE)