Types Of Antigens

Question 1

: immune response against autoantigens.

Answer 1

• Autoimmune disease

Question 2

Antigens that belong to the host.

Answer 2

AUTOANTIGEN

Question 3

They are not capable of eliciting an immune response under normal circumstances.

Answer 3

Autoantigen

Question 4

” Important to consider in tissue transplantation and
blood transfusions.

Answer 4

ALLOANTIGEN

Question 5

They are different from the host’s antigens and are capable of eliciting an immune response.

Answer 5

ALLOANTIGEN

Question 6

Come from other members of the host’s species.

Answer 6

ALLOANTIGEN

Question 7

• For example, human blood group A and B antigens are related to bacterial polysaccharides.

Answer 7

HETEROANTIGEN

Question 8

are a type of heteroantigen that exist in unrelated plants or animals.

Answer 8

Heterophile antigens

Question 9

• Examples include antigens from other animals, plants, or microorganisms.

Answer 9

HETEROANTIGEN

Question 10

• Come from a different species than the host.

Answer 10

HETEROANTIGEN

Question 11

Effect of proteus vulgaris in blood typing

Answer 11

Proteus vulgaris is a type of bacteria that can be found in the environment, including soil and water.

Proteus vulgaris can interfere with blood typing by causing false reactions or autoagglutination, leading to inaccurate blood type results. Proper sample handling and testing are crucial to prevent and manage such interference.

Question 12

No agglutination reaction.

Type A blood donated to a type A recipient does not cause an agglutination reaction… why?

Answer 12

Type A blood can be safely donated to a Type A recipient because both have the same A antigens, and the recipient’s immune system does not have antibodies (anti-B antibodies) against A antigens. This compatibility prevents agglutination reactions.

Question 13

Agglutination reaction.

Type A blood donated to a type B recipient causes an agglutination reaction…why?

Answer 13

Type A blood causes an agglutination reaction in a Type B recipient because the recipient’s anti-A antibodies attack the A antigens on the donated red blood cells. This incompatible antigen-antibody interaction leads to clumping and potential destruction of the donor blood cells.

Question 14

A mitogen is a substance that…

Answer 14

stimulates mitosis (cell division) in all T cells or all B cells, regardless of antigen specificity.

Question 15

Mitogen for T cells

Answer 15

Phytohemagglutinin (PHA)
(red kidney bean)

Concanavalin (ConA)
(jack bean)

Question 16

Mitogen for B and T cell

Answer 16

Pokeweed mitogen (PWM)
(pokeweed)

Question 17

Mitogen for B cells

Answer 17

Lipopolysaccharide (LPS)
(Escherichia coli)

Question 18

Microbial proteins that can act as potent T- cell mitogens.

Answer 18

SUPERANTIGENS

Question 19

” Massive T-cell activation leads to a surge in cytokine release, resulting in a systemic inflammatory response known as…

Answer 19

toxic shock syndrome

Question 20

• Generated within a cell
• Typically derived from viruses or intracellular bacteria that are actively replicating within the host cell.

Answer 20

ENDOGENOUS ANTIGENS

Question 21

originate from outside the cell.

are taken up by specialized antigen-presenting cells (APCs), such as macrophages, dendritic cells, and B cells, through phagocytosis or endocytosis.

Answer 21

EXOGENOUS ANTIGENS

Question 22

Most protein antigens are classified as…

Answer 22

T-dependent.

Question 23

T-CELL DEPENDENT ANTIGENS…

Answer 23

Require T-cell help for B cells to mount an effective antibody response..

Question 24

Steps in T-cell dependent antigens

Answer 24

Steps:
• Antigen presentation
• T-cell activation
• B-cell activation and differentiation
• Antibody production

Question 25

These antigens typically possess repetitive structures (ex. those found in polysaccharides, lipopolysaccharides, and some polymeric proteins)

Answer 25

T-CELL INDEPENDENT ANTIGENS

Question 26

Can activate B cells directly without the
TI-1 antigen need for T-cell help.

Answer 26

T-CELL INDEPENDENT ANTIGENS

Question 27

• Two types of T-independent antigens:

Answer 27

Type 1
Type 2

Question 28

primarily activated by dendritic cells and macrophages.

Answer 28

• Type 2 T cell independent

Question 29

activated by binding to immunoglobulin receptors and other receptors, such as Toll-like receptors (TLRs).

Answer 29

Type 1 t-cell independent antigen

Question 30

SEQUESTERED ANTIGENS
• A.k.a.

Answer 30

cryptic antigens

Question 31

This concealment prevents the immune system from learning to tolerate these antigens, potentially leading to autoimmune reactions if they are later exposed.

Answer 31

SEQUESTERED ANTIGENS

Question 32

• Self-antigens hidden from the immune system during its development.

Answer 32

SEQUESTERED ANTIGENS

Question 33

Sequestered antigens in humor of eyes

Answer 33

sequestered antigens in the eye are hidden to protect the delicate structures from immune system attacks. If these hidden antigens are exposed due to injury or disease, it can trigger an immune response that might harm the eye.

Question 34

Differentiate T-cell dependent and independent antigens

Answer 34

T-Cell Dependent Antigens:
Need T cells to help stimulate an immune response, leading to a stronger and longer-lasting response.

T-Cell Independent Antigens:
Can directly activate B cells without T-cell help, leading to a weaker and shorter-lived immune response.

Question 35

M proteins as superantigens

Answer 35

M protein acts as a superantigen by directly stimulating a large number of T cells in a non-specific manner, bypassing the normal antigen processing and presentation.

This causes an exaggerated immune response that can lead to severe conditions like toxic shock syndrome.