6.1 Antigen Antibody Lec 6

Question 1

Antigen aka?

Answer 1

immunogen

Question 2

what is an antigen?

Answer 2

substance that binds to components of immune response

**foreign molecules which elicit antibody and/or T cell responses directed against them

Question 3

what is an immunogen

Answer 3

substance that induces an immune response

Question 4

Epitope

Answer 4

site on antigen recognized by antibody

Question 5

Homologous antigen

Answer 5

Substance used to induce is same as substance used to react

Question 6

Heterologous antigen

Answer 6

Substance used to induce is different than substance used to react

Question 7

Heterophile antigens

Answer 7

Inducer and reactor substances are unrelated

Question 8

Adjuvant

Answer 8

Substance that is not antigenic but enhances an immune response

Question 9

what do Adjuvants do?

4

Answer 9

1) Antigen persistence (around longer)
2) Co-stimulatory signals are enhanced
3) Local inflammation is increased universal thing
4) Nonspecific proliferation of B/T cells

Question 10

what are 3 Adjuvant types added to vaccine?

Which one is still used?

Answer 10

1) Aluminium potassium sulfate (alum)-precipitate= helps with persistance
* *classic example
2) Freund’s incomplete – oils
* not for humans
3) Freund’s complete – oils + heat-killed Mycobacteria *not for humans

Question 11

Most antigens are what macromolecules?

With what two characteristics?

Answer 11

proteins

1) high molecular weight
2) complex sequence of unique amino acids (EX: only thing that makes botanic D acid unique is the D?)

Question 12

is an epitope the entire antigen?

Answer 12

NO! only a portion of the entire antigen is

recognized

Question 13

is an entire antigen required if the epitope is only a portion of it?

Answer 13

YES!

Question 14

Is the ratio of antigen to epitope 1:1?

Answer 14

NO!

**each antigen has many epitopes

Question 15

If the antigen isn’t a protein, then what is it?

Answer 15

polysaccharide

*Most good antigens are proteins but some good antigens are polysaccharides

Question 16

Why do protein antigens have/want many epitopes?

Answer 16

Each epitope with different specificity and can induce different antibodies (IgG, IgA, IgM, IgE)

Question 17

what the difference between protein and polysaccharide antigens?

Answer 17

Poly has many epitopes with the SAME specificity and usually induced IgM
*Protein have diff epitopes with diff responses

Question 18

Polysaccharides usually induce only ____?

**

Answer 18

IgM

Antibodies against polysaccharides are usually IgM**

Question 19

two types of polysaccharides antigens that usually only induce IgM antibodies?

Answer 19

1) lipopolysaccharide

2) capsular dextran

Question 20

Mycobacterium has what antigen type?

Answer 20

Lipid

Question 21

why are Nucleic acids poor antigens?

Answer 21

sequestration in nucleoid of bacteria make these poor antigens to induce antibodies

Question 22

What are haptens?

Answer 22

small non-antigens found all over nature that cannot cause an immune response bythemselves BUT when COUPLED to a large carrier molecule (protein) can induce antibody response

Question 23

what usually recognizes the carrier epitopes of Haptens?

Answer 23

T cell usually recognizes the carrier epitopes

–then provide info to B-cell for response

Question 24

what usually recognizes the Haptenated epitopes in natural configuration?

Answer 24

B cell recognizes the haptenated epitopes in their native configuration
**EX: dinitrophenol

Question 25

difference between hapten and hapten carrier antigen?

Answer 25

• -hapten= one epitope non-antigenic

- -hapten carrier= one epitope antigenic

Question 26

example of heterologous antigen?

Answer 26

tetanus vaccine

-toxicologically inert but immunologically active

Question 27

are adjuvants always present regardless of it being a natural or vaccine antigen?

Answer 27

yes

Question 28

what is a diagnostic tool of autoimmune disease?

Answer 28

antibodies against nucleic acids because there is enough damage to our own cells

Question 29

dinitrophenol is a good example of?

Answer 29

naturally occuring hapten response where the small dinitrophenol protein attaches to self and we can now recognize it as non-self