Transplant immunology Flashcards

1
Q

What is the primary reason for morbidity and mortality in transplants?

A

The immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In a graft, if the MHC molecule doesn’t match, what will happen?

A

The T cells will recognize the graft as foreign and reject it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

CD4+ T cells recognize what?

A

Antigen + MHC II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

CD8+ T cells recognize what?

A

Antigen + MHC I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do T cells need to do during education in order to not die?

A

The need to bind a self peptide and MHC with low avidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do T cells need to be activated other than binding something with high avidity?

A

Costimulatory molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Can alloantigen recognition be both direct and indirect?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens due to a hyperacute rejection?

A

IgM activates the complement cascade, cells die and the blood supply to the graft is clogged and the graft dies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In an acute reaction, what other reaction is also present?

A

The hyperacute reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the hyperacute reaction due to?

A

preexisting alloreactive antibodies. Antibodies then activate the complement cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens in an acute reaction?

A

CD8+ T cells are activated and they lyse host target cells. B cells are activated which produce antibodies and the hyperacute response occurs as well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What ultimately causes the rejection of a graft?

A

the loss of vascular supply to the tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens in a chronic graft rejection?

A

Alloreactive T cells produce cytokines that activate parenchymal macrophages. The inflammation can induce growth factor production which induces intimal thickening, thereby closing off the vascular supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the best way to prevent graft rejection?

A

Prevention- so autologous or syngeneic transplants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the purpose of a bone marrow transplant?

A

Treatment for hematological disease- cancer, immunodeficiency etc. and to restore the immune system destroyed by radiation and chemotherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a potential major problem with a bone marrow transplant (other than what has already been talked about?)

A

The graft could target the host… basically it’s a new immune system attacking the alien host

17
Q

Even though the primary physiological role of the immune system is to protect the organism from infectious microbes, can the immune system look for transformed cells and destroy them?

A

Yes

18
Q

Some cancers can down-regulate the expression of MHC I, why is this important for the immune system?

A

Well, NK cells have 2 receptors- and inhibitory domain and an activating domain. The default for NK cells (no signal) means it’s activated. The inhibitory receptor is MHCI, so viruses and cancers that downregulate MHCI will actually serve to activate NK cells and then they die

19
Q

T/F the function of macrophages depends upon the cytokine microenvironment, or those cytokines that surround the macrophages?

A

True

20
Q

M1 macrophages do what?

M2 macrophages do what?

A

M1- can suppress tumors and kill tumor cells

M2- help repair wounds- cell proliferation/growth factors- so these can enhance tumors

21
Q

What do cytotoxic T cells do?

A

They recognize antigen specific cells, bind to them and degranulate, inducing apoptosis- can occur with cancer cells

22
Q

T cells are activated where?

A

In the lymph nodes

23
Q

Most T cells in circulation are activated or dormant?

A

dormant

24
Q

What is cross priming?

A

It is where an APC engulfs an infected host cell and expresses the microbe or tumor antigen.

25
Q

CD4+ T cells are important to killing cancer why?

A

Because they produce cytokines that lead to M1 macrophage activation

26
Q

Why are B cells important in cancer and killing cells?

A

There is something called antibody dependent cellular cytotoxicity- if antibodies are attached to a cancer cell, the NK cell can degranulate and kill it

27
Q

How can the immune system lead to the development of cancer?

A

Cytokines can lead to increased cell proliferation (hyperplasia)
Hyperplasia can lead to dysplasia (abnormal cell development)
Free radicals can be formed and damage nucleic acids