Fetal Transplant Flashcards

1
Q

What is the main barrier to transplant?

A

MHC compatibility

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2
Q

What is an autograft?

A

Self to self

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3
Q

What is an isograft?

A

Self to identical twin

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4
Q

What is an allograft?

A

Person to person

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5
Q

What is a xenograft?

A

Interspecies

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6
Q

How do lymphocytotoxic Ab function?

A

Incubate recipient serum with lymphocytes of known HLA.

If there are HLA antibodies in the serum they will bind to their MHC antigen on the lymphocyte cell surface.

Complement is then added to all the wells. Lymphocytes that have bound antibody on their MHC will be lysed.

Since the MHC is known for each lymphocyte well, the exact anti-MHC specificity can be determined.

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7
Q

What is the mixed lymphocyte reaction?

A

Mixing MHC T cells from the recipient with the MHC non-T cells of the donor as APCs (that have been paralyzed) and measure the T cell proliferation and detection of CD8 cells to determine the immune response.

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8
Q

What is direct Ag presentation?

A

Activation of the immune system occurs through the foreign MHC occurs without MHC processing or Ag presentation via the “passenger leukocytes”

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9
Q

Why is direct Ag presentation a HERESY?

A

There is not MHC Ag presentation

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10
Q

What is indirect Ag presentation?

A

It is the classic presentation method with the allo-Ag uptaken and presented on Class II MHC by APCs to CD4 cells

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11
Q

What is hyper acute rejection and why does it occur?

A

It is accelerated rejection that will occur due to the presence of the allo-Ab complex within 48 hours. This occurs due to the prior presence of Ab as in pregnancy sensitization or difference in blood types.

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12
Q

What is acute rejection?

A

Anti-donor cells that are formed within 3 weeks due to TMMI reaction via CD4 with B cell Th2 and Th17 response following after

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13
Q

What is chronic rejection?

A

Slow graft attrition with arteriolar narrowing which causes intimate thickening and graft ischemia

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14
Q

What are the difficulties of bone marrow transplant?

A

Causes a graft VS host disease that occurs with the marrow forming Ab against the host as the host is in an immunocompromised state

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15
Q

What is the main gene that is a problem fro xenotransplantation?

A

Inactivation of alpha-1,3-Gal gene that is absent in higher primates

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16
Q

What MHC is displayed at the fetal-maternal interface instead of the normal MHCs?

A

HLA-G is displayed instead of A/B/C.

17
Q

What is the function of HLA-G?

A

It functions to inhibit maternal NK cells

18
Q

What happens to cytokine genes that promote CD8?

A

Downregulated

19
Q

What is unique about the NK cells in the uterus in pregnancy?

A

They lack CD16 and do not have ADCC

20
Q

What is the status of gamma-delta T cells?

A

They are present in high amounts

21
Q

What is the systemic immune balance shifted towards in pregnancy?

A

Progesterone presence will inhibit the Th1 responses and instead increase the Th2 response

22
Q

What Tregs are increased in pregnancy?

A

Paternal MHC Ag Tregs are increased in pregnancy

23
Q

What is the function of DAF display and what triggers it?

A

DAF display is triggered by progesterone

It functions to inhibit complement mediation

24
Q

What is the problem with the Th2 preference of pregnancy?

A

It exacerbates diseases that need Th1 responses like flu and tuberculosis

25
Q

What happens if Th1 is dominant in pregnancy?

A

Fetal loss

26
Q

What can happen with the infection of the fetus in pregnancy?

A

It may lead to tolerance of the pathogen in the future

27
Q

What happens when maternal T lymphocytes contact the fetus?

A

When maternal T lymphocytes (ly) come in contact with fetal ly (maternal & paternal MHC) at the placental interface maternal ly or in the fetus itself, they are converted by fetal TGF- to paternal specific T-regs.