lecture 26- immunology

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What is the primary reason for the rejection of transplanted tissue?

Inflammation

DAMPs

Alloantigens (correct)

Ischemic damage

Which molecules are described as the most important alloantigens responsible for strong and rapid transplant rejection?

Polymorphic genes

MHC molecules (correct)

DAMPs

Proteins

Why do most alloantigens differ among individuals?

Codominance of polymorphic genes (correct)

Due to ischemic damage

Because of DAMPs

Inflammatory response

How are host T cells (alloreactive T cells) described in relation to recognizing alloantigens?

They indirectly recognize alloantigens Signup and view all the answers

What triggers the cellular and humoral immune responses in the recipient's immune system?

Alloantigens Signup and view all the answers

What is the prime target of graft vasculature for alloreactive antibodies?

Endothelial cells Signup and view all the answers

What is the primary role of the adaptive immune system in responding to transplanted tissue?

Attack grafted tissue Signup and view all the answers

Which immune system plays a critical but not primary role in responding to grafts?

Innate immune system Signup and view all the answers

In the direct pathway of alloreactive T cell activation, which cells present alloantigens directly to host T cells?

Donor dendritic cells Signup and view all the answers

How do host and donor cells contribute to innate immune responses to grafts?

Directly kill donor cells Signup and view all the answers

What is the main effector function engaged by alloreactive antibodies?

Complement activation Signup and view all the answers

Which MHC molecules are most frequently recognized by alloantibodies?

Donor Class I MHC molecules Signup and view all the answers

What initiates ischemic damage in grafts?

Reduced blood and oxygen supply Signup and view all the answers

Which immune responses are discussed in relation to the initial reactions of the recipient's immune system to transplanted tissue?

Activation of alloreactive T cells Signup and view all the answers

What is the process where host dendritic cells take up and process donor MHC molecules, presenting peptides to host T cells?

Indirect pathway Signup and view all the answers

What is the primary focus of the lecture content on transplantation vocabulary?

Defining terms related to transplantation in the medical context Signup and view all the answers

Which term describes tissues or organs transplanted between genetically different individuals of the same species?

Allogeneic Graft (Allograft) Signup and view all the answers

What do allogeneic antigens refer to in the context of transplantation?

Molecules recognized as foreign in the allograft Signup and view all the answers

How do host T cells recognize alloantigens through direct mechanisms?

By directly binding to specific molecules on the graft Signup and view all the answers

What is the main outcome of molecules being recognized as foreign in an allograft?

Inducing an immune response in the recipient Signup and view all the answers

What is the primary role of CD8+ cytotoxic T cells in transplant rejection?

Directly killing graft tissue cells presenting alloantigens Signup and view all the answers

How do CD4+ helper T cells contribute to tissue rejection in transplantation?

Inducing inflammation and cytokine production Signup and view all the answers

Which effector mechanisms target the vasculature of transplanted tissue?

Alloantigen-specific antibodies Signup and view all the answers

What is the consequence of damage to the graft vasculature in a transplant?

Compromised blood flow to the transplanted tissue Signup and view all the answers

What is the main outcome of sensitization in transplantation immunology?

Proliferation of alloreactive T cells Signup and view all the answers

What is the significance of MHC proteins in allorecognition?

They are the primary alloantigens recognized by host T cells. Signup and view all the answers

How do effector CTLs contribute to graft rejection?

By recognizing and killing graft tissue cells presenting alloantigens. Signup and view all the answers

What is the outcome of direct recognition of alloantigens by host T cells?

Activation of immune responses targeting and eliminating transplanted tissue. Signup and view all the answers

Why does mismatch between donor and recipient MHC proteins increase the likelihood of graft rejection?

It increases the likelihood of alloreactive T cell responses, leading to graft rejection. Signup and view all the answers

What role does direct presentation of alloantigens by donor dendritic cells to host T cells play in immunity?

It bypasses the need for antigen processing by host APCs. Signup and view all the answers

What is the primary focus of transplantation immunology?

Understanding how the immune system responds to grafted tissues Signup and view all the answers

What distinguishes fundamental questions from clinical/applied questions in transplantation immunology?

Fundamental questions focus on understanding immune responses. Signup and view all the answers

In transplantation immunology, why is distinguishing between 'self' and 'foreign' important?

To improve transplant success rates Signup and view all the answers

What area does clinical or applied questions in transplantation immunology primarily aim to address?

Preventing rejection and improving transplant success rates Signup and view all the answers

How do host T cells recognize alloantigens in the context of transplantation?

Through direct and indirect mechanisms Signup and view all the answers

What is the main goal of understanding how the immune system recognizes transplanted tissues?

To prevent graft rejection and improve transplant success Signup and view all the answers

What role do alloreactive T cells play in recognizing alloantigens during transplantation?

Identifying alloantigens through direct and indirect mechanisms Signup and view all the answers

Why is it important to understand recognition and rejection mechanisms in transplantation?

To control immune response and improve transplant success rates Signup and view all the answers

What is the main target of alloreactive B cells activation in transplantation immunology?

Graft antigens Signup and view all the answers

In transplantation immunology, which route involves donor dendritic cells presenting antigens directly to recipient T cells?

Direct Route Signup and view all the answers

What is the primary role of recipient dendritic cells in the indirect pathway of alloantigen recognition?

Capture and process donor alloantigens Signup and view all the answers

Endothelial cells expressing Class I MHC are a prime target for what mechanism in transplantation immunology?

Alloantibodies recognition Signup and view all the answers

What is the key role of lymph nodes in the immune response in transplantation immunology?

Travel of APCs carrying antigens Signup and view all the answers

Which mechanism do alloreactive antibodies engage through in response to allograft recognition?

Fc receptor-mediated pathways Signup and view all the answers

In allograft rejection, what contributes significantly to the recognition of graft antigens?

Donor MHC molecules Signup and view all the answers

What is the key difference between the direct and indirect pathways in transplantation immunology?

Source of APCs presenting antigens Signup and view all the answers

What is the primary role of CD8+ cytotoxic T cells in the rejection of transplanted tissue?

Attacking and killing graft tissue cells presenting alloantigens Signup and view all the answers

What effector functions do CD8+ cytotoxic T cells primarily engage in?