Autoimmunity

Question 1

What is an autoimmune disorder?

Answer 1

A breakdown of tolerance resulting in humoral and cell-mediated immune responses against the host, resulting in localized or systemic injury.

Question 2

What is tolerance?

Answer 2

The ability of the immune system to differentiate between self and non-self

Question 3

What are autoantibodies?

Answer 3

Antibodies made by B cells that react with the host’s tissues.

Question 4

What are the three main mechanisms that result in autoimmunity?

Answer 4

1) neoantigens
2) molecular mimicry
3) failure of tolerance

Question 5

What is a neoantigen?

Answer 5

Haptens that binds to the host protein, becomes a immunogenic, results in immune response against altered host protein

Question 6

What is an example of neoantigens resulting in an immune response?

Answer 6

Autoimmune hemolytic anemia
Penicillin is the hapten, binds to RBCs making them look foreign, triggers immune response and creation of antibodies

Question 7

What is molecular mimicry?

Answer 7

Antibodies made for a foreign antigen that ends up reacting to self-cells because they look similar (epitopes)

Question 8

What is an example of molecular mimicry?

Answer 8

Group A beta-hemolytic streptococci (aka strep throat)
Attack heart valves because they look similar

Question 9

What are the two types of immunologic tolerance

Answer 9

Central - occurs in the lymphoid tissue
Peripheral - occurs in the vasculature