History Introduction Classification of grafts The Immunology of Allogeneic Transplantation Genetics of graft rejection Types of rejection Recognition of Alloantigens Effector Mechanisms of Allograft Rejection Prevention of graft rejection Graft versus host reaction 

1. Rinkesh Joshi
M.Sc Sem : 3
Bioscience ( Micro)
09924113838
Surat,
Gujarat.

2. History
Introduction
Classification of grafts
The Immunology of Allogeneic Transplantation
Genetics of graft rejection
Types of rejection
Recognition of Alloantigens
Effector Mechanisms of Allograft Rejection
Prevention of graft rejection
Graft versus host reaction

3.  1944 : Medawar showed that skin allograft
rejection is a host versus graft response.
 1954 : The first successful identical twin
transplant of a human kidney was
performed by Joseph E. Murray in Boston
 1967 : The first successful liver transplant was done
by Dr. Thomas E. Starzl
 1967 : The first heart transplantation by Christian
Barnard
 1968 : The first successful bone marrow transplant
was done by E. Donnall Thomas

4. Transplantation is a act of transferring
cells, tissue, or organ from one site to another
Graft : Implanted cell, tissue or organ
Donor : Individual who provides the graft
Recipient or host : Individual who receives the
graft

6.  Self tissue is transferred from one body site to
another
 Antigen present in autograft is same as that present
in body
 So immune system recognizes the autograft antigen
as a self antigen
 No immune response is elicited
 Autograft survive through out the life
 Eg., - Transferring healthy skin to burned
area,
- Use of healthy blood vessels to
replace blocked coronary arteries,
- Plastic surgery of skin.

7. It is also called syngraft
Tissue is transferred between
genetically identical individuals of
same species
In isograft the histo compatibility
antigens are identical hence the
graft survives and not rejected.
Eg in human isograft can be
performed between two twins.

8. Tissue is transferred between two genetically
different members of same species
In allograft histocompatibility antigens are
dissimilar hence immune response is elicited
and graft is rejected
Eg., In humans graft is transferred from one
individual to another

9. Tissue is transferred between two different
species
Eg., Graft of human transferred to animal
In xenografts histocompatibility complex
antigens are so different that the graft is
more vigorously rejected

10. • Alloantigens elicit both cell-mediated and
humoral immune responses.
• Recognition of transplanted cells that are self
or foreign is determined by polymorphic
genes that are inherited from both parents
and are expressed co-dominantly.

12. Rate of allograft rejection varies according to
tissue involved
Skin graft are rejected faster than other tissue
organ kidney or heart
If inbred mouse of strain A is grafted with skin
from strain B , Primary graft rejection occur called
first set rejection
When again strain A is grafted with skin from
strain B , Secondary graft rejection occur called
second set rejection

14. Direct recognition of Alloantigens
host T cells recognize intact allo-MHC molecules
on the surface of the donor cell.
host T cells see allo-MHC molecule + allo-peptide
as being equivalent in shape to self-MHC +
foreign peptide and hence recognize the donor
tissue as foreign.
This pathway is the dominant pathway.

16. 
Indirect recognition of Alloantigens
Donor MHC is processed and presented by
recipient APC
Basically, donor MHC molecule is handled like any
other foreign antigen

17. Donor APCs migrate to regional lymph nodes
and are recognized by the recipient’s T cells
Alloreactive T cells in the recipient may be
activated and they migrate into the graft and
cause graft rejection

18. Used by immune system to reject allograft
It is based on histopathological features or time
duration of rejection after transplantation
There are three type of patterns
1. Hyperacute Rejection
2. Acute Rejection
3. Chronic Rejection

19.  Graft is rejected within minutes to hours because
vascularization is rapidly destroyed.
 It occurs because the recipient has pre-existing
antibodies in circulation against the graft.
 Which could be induced by prior blood
transfusions, multiple pregnancies, prior
transplantation, or xenografts.
 Antibodies bind with donor endothelial cell.
 The antigen-antibody complexes activate the
complement system, causing massive thrombosis in
the capillaries, which prevents the vascularization of
the graft.
 The kidney is most susceptible to hyperacute
rejection.

20. 1)
2)
3)
4)
5)
Preformed Ab,
complement activation,
Neutrophil margination,
Inflammation,
Thrombosis formation.

21.  Vascular and parenchymal injury mediated by T
cells and antibodies that usually begin after the
first week of transplantation if there is no
immunosuppressant therapy
 Antibodies from after transplantation may also
contribute to vascular injury.

22. Occurs in most solid organ transplants
o Heart
o Kidney
o Lung
o Liver
Characterized by fibrosis and vascular
abnormalities with loss of graft function over a
prolonged period

23. Arthrosclerosis
Cell proliferation
Occlusion

24. I.
II.
III.
IV.
Blood grouping
Cytotoxic antibody testing
Tissue matching
Immunosuppressive drugs
(azathioprine,cyclosporine,rapamycin, cortic
osteroids)

26. In some instance the graft tissue elicits an
immune response against host antigen and
that immune response is called graft versus
host reaction
Graft versus host reaction brings damage to
host cells and host
When grafted tissue has mature T cells, they
will attack host tissue leading to GVHR.

27. Graft lymphocytes aggregate in the host
lymphoid organs
Graft lymphocytes are stimulated by the host
lymphocyte
Stimulated lymphocytes of graft produce
lymphokines
Lymphokines activate host T- cell which produce
polyclonal b-cell activation
Activated b-cell react with the self antigens and
cause damage to the host cell

28. Skin rash
Emaciation ( becoming thin)
Retarded growth
Diarrhoea
Hepatomegaly
Splenomegaly
Increase in bilirubin production
Bileducts are damaged
anaemia