Antigens

Question 1

What does the innate immune system recognize?

Answer 1

PAMPS - pathogen associated molecular patterns

Question 2

What does the adaptive immune system recognize?

Answer 2

Antigens

Question 3

Define antigen

Answer 3

Any molecule that can interact specifically with the immunoglobulin (Ig) receptor of B-cells or the T-cell receptor complexed with MHC

Question 4

Do all molecules induce immunity?

Answer 4

No

Question 5

What is an immunogen?

Answer 5

A molecule that induces a specific immune response

Question 6

Are all antigens immunogens?

Answer 6

No

Question 7

Are all immunogens antigens?

Answer 7

Yes

Question 8

Humoral Immunogens

Answer 8

(B cells)

Question 9

Cell mediated Immunogens

Answer 9

T cells

Question 10

Are proteins recognized directly?

Answer 10

No

Question 11

How can we recognize proteins?

Answer 11

Peptides processed from the protein are seen in association w MHC molecules

Question 12

What are the 4 properties of an immunogen?

Answer 12

1. Foreignness
2. Molecular size
3. Chemical Heterogeneity
4. Degradability

Question 13

To serve as an immunogen, a molecule must be seen as “….”?

Answer 13

Non-self

Question 14

What is the degree of immunogenicity dependent on?

Answer 14

The degree of foreignness

Question 15

The greater phylogenic distance b/w species typically means what?

Answer 15

Greater the chance of immunogenicity

Question 16

What are 2 exceptions to foreigness?

Answer 16

1. Highly conserved molecules like collagen or cytochrom c may not be immunogenic even in distant species
2. Some self molecules may sequester an immune response (sperm or lens tissue) in animal they came from

Question 17

Is there a correlation b/w size and immunogenicity?

Answer 17

Yes, there is a sweet spot

Question 18

What are the best immunogens in the range of?

Answer 18

100,000 Da

Question 19

Small molecules - what size? are generally poor immunogens

Answer 19

5-10,000

Question 20

Will size alone make a good immunogen?

Answer 20

No, the more complex the better

Question 21

Are sythentic homopolymers immunogenic?

Answer 21

No, they are boring we want complex

Question 22

How do we increase immunogenicity in terms of chemial heterogeneity?

Answer 22

Proteins w more complexity in primary structure and those showing secondary, tertiary, and quaternary structure

Question 23

What do we have to do to proteins in roder for them to be presented by MHC to activate Tcells?

Answer 23

Degrade proteins

Question 24

Why is an insoluble antigen better than a soluble?

Answer 24

Insoluble is more likely to be phagoctosed & processed

Question 25

Is a large or small antigen better?

Answer 25

Large - more processing, more epitopes

Question 26

Substances that are injected Ag serve to..

Answer 26

enhance the immunogenicity

Question 27

What 3 things do adjuvants do?

Answer 27

1. Stimulate immune response
2. Prolong Exposure to Ag
3. Co-stimulatory signal

Question 28

Freund’s

Answer 28

Freund’s adjuvant is a solution of antigen emulsified in mineral oil and used as an immunopotentiator (booster)

Question 29

What is Freund’s adjuvant composed of?

Answer 29

is composed of inactivated and dried mycobacteria

Question 30

What part of the adjuvant stimulates macrophage activity

Answer 30

Heat killed mycobacteria

Question 31

What two things bind and precipitate the Ag to keep it in the system longer and allow for slow release of Ag

Answer 31

Alum and Freunds adjuvant

Question 32

How long does the adjuvant increase the time of exposure of the Ag?

Answer 32

From a few days to a few weeks

Question 33

How does precipitation facilitate phagocytosis?

Answer 33

Increase the size

Question 34

When the cells are stimulated by the Ag they require a second co-stimulatory response, what up-regulates this?

Answer 34

Freund’s adjuvant, LPS