Chapter 15 Flashcards
What are Autografts? and are the usually accepted or rejected?
Tissue Transfer from the same individual
- tissue transfer from healthy area to burnt
ACCEPTED
What are Isografts? or syngenic and are the usually accepted or rejected?
Tissue transfer between genetically identical individuals
-between genetically identical inbred mice (monozygotic twins)
ACCEPTED
What are allografts? or Allogenic and are the usually accepted or rejected?
Tissue transfer between genetically different members of the same species
-Human to Human or mice to mice
REJECTED
What are xenografts? and are the usually accepted or rejected?
Tissue transfer between different species
-Monkey heart into human
REJECTED
What is histocompatibility?
When tissues between the donor and recipient are antigenically similar, not inducing an inflammatory response
What is histoincompatibility?
When tissues between the donor and recipient are antigenically different, inducing an inflammatory response leading to tissue rejection
Which antigens determine histocompatibility?
Major Histocompatibility Complex or MHC
Blood transfusion and their antigens, explain the types and how blood is transfused to avoid rejection
Blood transfusion requires ABO compatibility
A+B recognize self of their RBC
Our blood cells either secrete Antigens, A, B, AB, or none, while within our blood, we contain antibodies Anti-A, B, both, or none
If Person with type A gives blood to type B, the antibodies of the donor would bind to RBC of the recipient and cause complementation activation via IgG leading to rapid rejection
To avoid rejection, blood is transfused without lymphocytes, only containing erthoctyes, called packed cells (no antibodies)
Explain Rh blood, and in pregnant women
Individuals have either Rh+ or Rh-
-Positive meaning antigen is present, or negative meaning no
If a pregnant women is Rh-, if her child is Rh+, she can still produce Rh antibodies
During her secondary pregnancy, if the child is Rh+, the antibodies from first fetus will cross placenta and cause hemolytic disease of newborn
To avoid this, Rh immunoglobium shots are given to Rh-women, to avoid antibody formation by the pregnant women
Alloantigens and Alloreactions?
Alloantigens: self antigens like MHC that differ within species
Alloreactions: immune response provoked by alloantigens
How can Anti-HLA antibodies form?
Pregnancy
Blood transfusion
Transplantation
What are alloreactive T-cells?
T cells that bind weakly to self MHC during positive selection, which have potential to bind strongly to other foreign antigens
Acute rejection of kidney transplantation (Direct pathway of allorecognition) explained?
donor dendritic cell in kidney graft meet recipient alloreactive T cells in host spleen, allowing them to be activated
-Activated alloreactive T cells leave the spleen and travel to kidney graft, damaging the organ
hence why immunosuppressive drugs are taken before and after transplantation
Takes days
Chromic Rejection: indirect pathway of allorecognition?
Takes months or years after transplantation
-Via IgG antibody complex formations with donor MHC to form deposits and reduce blood supply towards the grafted organ, similar to hypersensitivity 3
why don’t corneal transplant now require HLA compatibility?
What is ACAID?
Contains aqueux humour which contains immunomodularotory factors that inhibit activation of complement
Anterior Chamber associated immune devation
graft-versus-host disease in born marrow?
Patient attacked by alloreactive T cells in graft
-usually, all T cells in patient are destroyed in to avoid immune response in graft but what if graft contains its own alloreactive T cells?
-T cells interact with patient dendritic cells and proliferate, the CD4 + 8 then cause damage within the tissues of patient
What if Transplant patient receives hemapoetic cells with completely different HLA type from their own?
The thymus on the recipient selects T cells that recognize antigens in the context of the donor
Please understand this slide bruh
Anti-T cell drugs
rATG (rabbit anti-thymocyte globulin)
anti-CD52 monoclonal antibody
both cause complement for phagocytosis
Prednisone
-suppresses NfkB pathway
-steroid enters cell and binds to receptor which allows release from HSP90, further complex travels to nucleus to inhibit suppress NFkB pathway
Cyclosporin + Tacrolimus
-Suppress IL-2 , allowing T cell activation to not occur
Anti-CD3 MAB (OKT3)
-causes internalization of TCR complex and inability of TCR to recognize antigen
Basiliximab
-inhibits highaffinity IL-2 to bind for signal transduction pathway
Sirolimus
-Prevents signal transduction by IL-2 receptor
