Transplantation Lecture Flashcards by Michaela Miles

list the 3 problems with organ transplantation

transplant must be able to maintain normal function
health of recipient and transplant must be maintained during surgery
the recipient’s immune system must be prevented from responding to the transplant causing rejection

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What is autologous transplantation

when stem cells are from the patients own body

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What is allogeneic transplantation

When stem cells are taken from donor to recipient

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In order for allogenic transplantation to be successful both donor and recipient must be

histocompatible

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What does it mean to be histocompatible

the donor and recipient have compatible tissue types and can coexist without provoking a strong immune response

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Serum of blood group O people have which class of antibodies against A and B antigens

IgG

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ABO antigens are present on 
A. Kidneys
B. Erythrocytes
C. Endothelial Cells of blood vessels
D. All of the above

D: all of the above

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Describe how hyperacute rejection occurs

Incompatible tissue between donor and recipient results recipient antibodies that bind the blood vessels of the graft(donor antigen), complement if fixated throughout the vasculature

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What procedures can avoid hyperacute rejection

typing

- cross matching for ABO

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Antibodies against donor blood group antigens bind vascular endothelium of graft initiating an inflammatory response that occludes blood vessels describes which process?

A. Acute Rejection
B. Hyperacute Rejection
C. Histocompatibility
D. Graft Versus Host Disease

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Hyperacute rejection is

A. Slow
B. Rapid

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Blood antigen Incompatibility can cause type __ hypersensitivity

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what type of rejection is the most devastating rejection of organs

hyperacute

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Where and when is HLA I expressed

vascular endothelium, constitutively

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Where and when is HLA II expressed

vascular endothelium when there is infection, inflammation and trauma

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What are alloantigens

self antigen that vary between members of the same species

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Alloreactions are

immune responses induced by alloantigens

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What is immunogenetics

the study of genetics of alloantigens and the impact on the immune system

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What are the two types of alloreactions

transplant rejection

2. graft versus host disease

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What is an autograft

when tissue is transplanted from donor to recipient

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When tissue or organ is grafted and transferred from one person to another who is genetically identical that is called.

A. Allograft
B. Xenograft
C. Isograft
D. Autograft

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When donor and recipient are of different species, this type of transplant is called

A. Allograft
B. Xenograft
C. Isograft
D. Autograft

What are the effects of hemolytic reactions

fever
chills
shock
renal failure
death

HLA class I antibodies react with

B cells and T cells

HLA class II antibodies react with ____ cells

What are the 3 general steps of hematopoietic stem cells transplantatoin

1. irradiation and chemotherapy to clear recipient stem cells making space for donor cells 2. hematopoietic cell infusion 3. patient is healthy

What cells are responding in graft vs host disease?

T cells

Describe what generally happens in Graft Versus Host Disease

The donor T cells in the graft attack the recipients healthy tissue

What is an autograft?

when a patients tissue is transplanted from one area to another

What is an isograft?

an syngeneic transplant: a transplant between two genetically identical individuals

Acute rejection is a type __ hypersensitivity

____ T cells respond to HLA class _

CD8, 1

_____ T cells respond to HLA class ___

CD4, 2

Inflamed state of transplanted organ induces A. Recipient T cells to migrate to secondary lymphoid tissue B. Donor derived T cells to migrate to secondary lymphoid tissue C. Donor Derived Dendritic cells to migrate to secondary lymphoid tissue D. Recipient dendritic cells to migrate to secondary lymphoid tissue

Donor derived dendritic cells present A. Donor derived antigen to recipient T cells B. Donor Derived antigen to recipient macrophages C. Recipient antigen to other donor dendritic cells D. Recipient antigen to donor B cells

A | *slide 16

Describe what happens in the direct pathway of allorecognition

Recipient T cells are stimulated by a direct interaction between their receptors with allogenic HLA molecules expressed by DONOR cells

In the direct path of allorecognition, _____ T cells are stimulated by _____ dendritic cells

recipient, donor

Describe the direct pathway of allorecognition

Donor dendritic cells from transplant activate recipient T cells that go back to the transplant and damage the epithelial cells of the transplant

What is used to treat chronic rejection

Anti B cell antibody (rituximab)

____ antibodies against HLA I form immune complexes that deposit in blood vessels of transplanted organ occurs in _____ rejection

IgG, Chronic

What is the function of Anti CD52

it binds leukocytes and activates complement on the cell to destroy it in preparation for organ transplant to prevent it from initiating an immune response

Calcium influx during T cell activation results in the activation of A. cyclosporin B. NFAT C. Tacrolimus D. Calcineurin

What is calcineurin

a phosphatase that activates NFAT

What is the role of NFAT in T cell activation

it binds AP-1 to form an active transcription factor

How does cyclosporin act?

it binds calcineurin preventing the binding of NFAT to AP-1 thus inhibiting IL-2 transcription

Belatacept binds_____ and prevents engagement of CD28

Antibodies that bind to pig endothelial cells

Xenoantibodies

What is the function of belatacept?

A drug that binds B7 and prevents B7:CD28 engagement thus preventing the co-stimulatory signal

T/F: Anti CD25 engages the low affinity IL-2 receptor ON naive alloreactive T cells

False, binds the HIGH affinity IL-2 receptor on ACTIVATED T cells

What is the function of Anti CD25

to bind high affinity IL-2 receptor on active T cells and prevent the generation of signal 3 of activation of cyclin D

Where are the targets for immunosuppressive drugs

1. MHC and TCR binding 2. B7 and CD28 costimulatory signal 3. Anti-CD52 to initiate complement on T cell 4. Calcineurin via Cyclosporin to prevent NFAT activation and blocking IL-2 Transcription 5. Anti-CD25 to block the IL-2 receptor

What is myeloblative therapy?

a procedure that cripples the patients immune system and creates space for donor cells

The allogenic difference in minor histocompatibility H-Y antigens is due to

the bound peptide NOT the MHC molecule

What gives rise to minor histocompatibility antigen differences between donor and recipient?

polymorphic self proteins that differ sin amino acid sequence between people