Transplantation and Immunosupressive Drugs

Question 1

Transplantation

Answer 1

the introduction of biological material (eg organs, tissue, cells) into an organism

-the immune system has evolved to remove anything it regards as non-self

Question 2

Donor/recipient relationships - Autologous and syngeneic

Answer 2

Autologous
Transplantation of tissue from 1 part of the organism into another part of the same organism. So, although there may be inflammatory responses, you wouldn’t expect there to be an immune response as it is self transplanting into self.

Syngeneic
Donor material transplanted into a recipient, where the donor and recipient are genetically identical. Doesn’t usually generate an immune response.

Question 3

Donor/recipient relationships - allogeneic

Answer 3

Donors and recipients are from the same species but genetically different

Question 4

Donor/recipient relationships - xenogeneic

Answer 4

Donor and recipient are different species

Question 5

Major histocompatibility antigens

Answer 5

Histocompatibility = tissue compatibility

Immune responses to transplant are caused by genetic differences between the donor and the recipient

The most important are differences between the antigens forming the major histocompatibility complex

human MHC proteins = HLA (Human Leukocyte Antigen)

Question 6

biggest site of variability in the human genome?

Answer 6

MHC

Question 7

HLA diversity

Answer 7

can be split into class I and class II
-class I has 3 alleles (A,B,C), and class II are dimers and there are 6 alleles

only immune cells (WBC’s) express HLA class I and HLA class II – important for rejection.

Question 8

Importance of epitopes on donor MHC

Answer 8

B-cell epitopes on donor MHC
T-cell epitopes derived from donor MHC

There could be HLA’s which are different, BUT they don’t have any different epitopes, therefore rejection won’t occur

– we are moving from matching recipient and donor HLA’s to matching recipient and donor epitopes on the HLA, but NGS is too expensive for this to become a regular thing rn

Question 9

what do T cells recognise?

Answer 9

short peptide fragments presented to them by MHC proteins

MHC class I, fragments of intracellular proteins, CD8

MHC class II, fragments of proteins which have been taken up by endocytosis, CD4

Question 10

helper T cells vs cytotoxic T cells?

Answer 10

Helper T cells – information and support for other immune cells via cytokine production

Cytotoxic T cells – highly specific killer cells