Immunology Lec 9 Flashcards
Lecture 9:
What is transplantation?
Transplantation is the process of taking cells, tissue, or organs (graft) from one individual and placing them into another (recipient).
Differentiate between orthotopic and heterotopic transplants.
Orthotopic: Transplant placed in the same anatomical location (e.g., heart).
Heterotopic: Transplant placed in a different anatomical location (e.g., kidney).
What are the two main immune recognition mechanisms in transplantation?
Direct Allorecognition: Host T cells recognize intact MHC molecules on donor APCs within the graft.
Indirect Allorecognition: Donor MHC molecules are processed by recipient APCs, and host T cells recognize these processed donor peptides.
Name the four types of graft rejection.
Hyperacute Rejection
Accelerated Rejection
Acute Rejection
Chronic Rejection
Describe hyperacute rejection.
Hyperacute rejection occurs minutes to hours post-transplant and is mediated by preexisting antibodies.
What is the typical timeframe for acute rejection?
Acute rejection occurs around 10-30 days post-transplant and is mediated by CD4, CD8, NK cells, and macrophages.
What factors influence transplant success?
Matching MHC types and ABO blood groups, and the use of immunosuppressive therapy to prevent rejection while avoiding infections and cancer.
What is the purpose of bone marrow transplantation (BMT)?
BMT replaces diseased or damaged bone marrow with healthy cells.
What is graft-versus-host disease (GVHD)?
GVHD is a condition where donor immune cells attack recipient tissues after a bone marrow transplant.
Name an immunosuppressive therapy that inhibits calcineurin to reduce T cell activation.
Cyclosporine A and Tacrolimus.
What is the function of Mycophenolate Mofetil (MMF) in immunosuppression?
MMF inhibits lymphocyte proliferation by blocking guanine nucleotide synthesis.
How does Azathioprine work as an immunosuppressive drug?
Azathioprine inhibits DNA synthesis, blocking lymphocyte proliferation.
What are some side effects of corticosteroids like Prednisone?
Side effects include fluid retention and bone mineral loss.
