6: Antigens and Antigenicity

Question 1

Antigen

Answer 1

any substance that can induce antibody generation

Question 2

T cell receptors only recognize peptides that have been ____ or degraded and are on an antigen presenting cell

Answer 2

processed

Question 3

Allergen

Answer 3

an antigen that induces an allergic reaction

Question 4

What presents T-dependent antigens?

Answer 4

MHC

Question 5

2 types of epitopes

Answer 5

linear and discontinuous

Question 6

What factors make a good antigen?

Answer 6

size, stability, antigenicity, foreignness, complexity

Question 7

Proteins are ___ antigens

Answer 7

good

Question 8

Simple polysaccharides are ___ antigens

Answer 8

poor (readily degraded in cells)

Question 9

Complex carbohydrates are ___ antigens

Answer 9

usually good

Question 10

Nucleic acids are ___ antigens

Answer 10

usually poor

Question 11

Lipids are ____ antigens

Answer 11

usually poor

Question 12

What are some factors that influence immunogenicity?

Answer 12

genetics, age, health status, dose, route of exposure, adjuvants

Question 13

T-independent antigens

Answer 13

doesn’t need a T cell to trigger antibody secretion

Question 14

T-dependent antigens

Answer 14

needs a T cells to trigger antibody secretion (more common)

Question 15

Haptens

Answer 15

small molecules that are not normally immunogenic, but become antigens when liked to another structure

Question 16

What 3 types of antibodies will haptens generate?

Answer 16

1. against the carrier
2. against the hapten
   3.against the new epitope generated by the hapten-carrier linkage

Question 17

Autoantigens

Answer 17

self antigens that antibodies and T cells are generated against in error

Question 18

Molecular mimicry

Answer 18

some pathogens express proteins or carbohydrate residues that resemble host molecules, resulting in activation of T cells

Question 19

Cross-reactivity

Answer 19

the process by which one epitope is similar enough to another epitote, resulting in specific immunity against unrelated antigens

Question 20

What are some diseases caused by cross-reactivity?

Answer 20

rheumatic fever, false positive tests, autoimmunity

Question 21

Superantigens

Answer 21

secreted exotoxins that are highly mitogenic and stimulatory for T cells; do not require prior processing to bind to T cell receptor