Finals Autoimmunity

Question 1

What is clonal deletion?

Answer 1

If B or T cells are auto-reactive they are killed through apoptosis

Question 2

What is apoptosis

Answer 2

Programmed cell suicide/death

Question 3

What is central tolerance?

Answer 3

Clonal deletion

Question 4

What is peripheral tolerance?

Answer 4

If B or T cells encounter auto-antigens in the periphery

Question 5

What are the two steps that occur in peripheral tolerance?

Answer 5

1. Stimulation is so strong it induces activation-induced cell death (apoptosis)
2. Recognition of antigen in the absence of costimulation leads to anergy

Question 6

What is anergy?

Answer 6

Functional unresponsiveness, cell is still alive but unable to be activated

Question 7

What are the four ways autoimmunity can occur?

Answer 7

• auto-reactive T cells escape thymic deletion
• failure of peripheral regulation
• polyclonal/bystander activation (wrong place wrong time)
• molecular mimicry (pathogen looks like self)

Question 8

What is molecular mimicry?

Answer 8

Antigens from pathogens look like self antigens and an immune response against pathogen can lead to autoimmunity

Question 9

What is and does cyclophosphamide do?

Answer 9

• alkylating agent
• cross-links DNA resulting in death of proliferating cells (immune cells)
• total immune suppression

Question 10

What is and does plasmapheresis do?

Answer 10

-machine that removes either all antibodies or specifically remove autoimmune antibodies from blood

Question 11

When is a bone marrow transplant useful?

Answer 11

The autoimmunity is caused by the immune system , you can replace the immune system

Question 12

What is an autologous bone marrow transport?

Answer 12

Replace bone marrow with stem cells collected from the patient

Question 13

What is an allogeneic bone marrow transport?

Answer 13

Replace bone marrow with matched bone marrow from another person

Question 14

What are the types of grafts?

Answer 14

• autograft
• isograft
• allograft
• xenograft

Question 15

What are autografts?

Answer 15

• transplant self tissue

- burn victims, bone reconstruction, bypass

Question 16

What are isografts?

Answer 16

-transplant tissue from a genetically identical individual

Question 17

What are allografts?

Answer 17

-another person, same species different genes

Question 18

What are xenografts?

Answer 18

• transplant tissues between species

- primate kidneys, heart; pig skin, heart, valves

Question 19

What are the 3 general mechanisms of graft rejection?

Answer 19

• hyperacute
• acute
• chronic

Question 20

What is graft vs host disease?

Answer 20

-bone marrow and hematopoietic stem cell transplants have the risk of transferring T cells from the donor to the recipient resulting in the disease

Question 21

What is the paradox of graft vs host disease?

Answer 21

• donor T cells are needed for bone marrow engraftment and to prevent malignancy
• but donor T cells cause GvH disease