60 Questions
What is a result of cancer cells dividing rapidly?
The immune system is outpaced, allowing cancer cells to dominate
What happens when tumors stop expressing antigens targeted by the immune response?
T and B cells are unable to kill cancer cells
What is the role of MHC I in antigen recognition?
It helps CTLs recognize cytoplasmic microbes or cancer
What is the consequence of losing MHC I expression in cancer cells?
CTLs are unable to kill cancer cells
What is the result of granzymes being delivered to the target cell?
The target cell undergoes apoptosis
What is a characteristic of more invasive and metastatic cancers?
They lose MHC I expression
Why is hyperacute rejection not a common problem in clinical transplantation?
Because every donor and recipient are matched for blood type and tested for antibodies
What is the primary cause of early graft failure?
Acute rejection
What type of cells may react against cells in graft vessels, leading to vascular damage?
T cells
What is the main mechanism of antibody-mediated injury to graft vessels?
Complement activation by the classical pathway
What is the primary goal of current immunosuppressive therapy in transplantation?
To prevent and reduce acute rejection
What is a characteristic of chronic rejection?
Leading to progressive loss of graft function
What triggers the release of DAMPs in cancer?
Damage caused by cancer
What is the role of receptors on APCs?
To recognize and respond to DAMPs
What is the result of cross presentation of cancer antigens?
Activation of both CD4 and CD8 T cells
Why does the immune system often fail to eliminate cancer cells?
Because cancer cells constantly mutate to evade the immune response
What type of cells play a critical role in the response to cancer-associated antigens?
Cytotoxic lymphocytes (CD8 T cells)
What is the fate of activated APCs?
They traffic to the lymph nodes
What is the primary concern in transplant patients?
Responding to non-self antigens
What type of transplant occurs between animals of the same species but not genetically identical?
Allogenic transplant
What is the typical lifespan of tissue valves made from pig heart valves or cow heart-sac tissue?
15 years
What is the term for tissue from another individual of the same species?
Allograft
Why are tissue valves preferred over mechanical valves for those over 70?
They don't require the lifelong use of anti-clotting drugs
What is the term for a transplant from one's own tissue?
Autograft
What occurs when T cells in the recipient recognize donor allogeneic MHC molecules on graft dendritic cells?
Direct recognition of alloantigens
What is the main difference between direct and indirect allorecognition?
The processing of graft cells by recipient dendritic cells
What is the outcome of indirect recognition of alloantigens?
Activation of alloreactive CTLs that cannot recognize and kill graft cells
What is the main mediator of graft rejection in indirect allorecognition?
Alloreactive CD4+ T cells
What is the role of dendritic cells in direct allorecognition?
To carry graft alloantigens to the recipient's immune system
What is the result of direct recognition of alloantigens?
Activation of alloreactive CTLs that recognize and attack the graft
What is the role of the immune system in preventing cancer?
To eliminate cancerous and pre-cancerous cells
What is the concept of immune surveillance?
The immune system is constantly searching for cancerous and pre-cancerous cells and eliminating them
What is the evidence of immune surveillance in humans?
Lymphocytes infiltrate tumors and draining lymph nodes surrounding the tumors are frequently enlarged
What is the result of stimulating the immune system by blocking inhibitory receptors in some cancer types?
Cancer regression
What is the increased risk of cancer associated with?
Immunosuppression
What is the role of T cells and antibodies in cancer?
They are specific for tumor-related antigens
What is the primary concern in a cancer patient versus a transplant patient?
Mounting an immune response against modified self-antigens
What is the term for a transplant between animals identical to one another?
Syngeneic transplant
What type of valves are typically used for people over 70?
Biologic valves
What is the term for tissue from a different species?
Xenograft
What is the typical lifespan of tissue valves made from pig heart valves or cow heart-sac tissue?
15 years
What is the purpose of using pig heart valves in human transplants?
To avoid the need for lifelong anti-clotting drugs
What is the role of FasL in the tumor environment?
To lead to the death of lymphocytes through FasL/Fas pathway
What is the goal of stimulating the host's immune response to combat cancer?
To reduce the side effects of traditional cancer treatments
How do monoclonal antibodies work in passive immunotherapy?
By binding to the surface of cancer cells, targeting them for elimination
What is the main difference between traditional cancer treatments and immunotherapy?
Immunotherapy stimulates the host's immune response
What are the three main approaches to modern immunotherapy?
Passive immunotherapy, adoptive transfer of anti-tumor T cells, stimulation of the host's immune response
What is the limitation of traditional cancer treatments?
They have serious side effects
What is a common symptom of GvHD?
Diarrhea
What is the goal of immunosuppressive therapy in transplantation?
To prevent tissue damage
What is a consequence of immunosuppressive therapy in transplantation?
Increased risk of severe infections and cancer
What is the role of the immune system in cancer?
To suppress cancer growth
What is the term for the process by which the immune system targets cancer cells?
Immune surveillance
What is a type of therapy that modulates the immune system to fight cancer?
Passive immunotherapy
What is the goal of tumor vaccines?
To generate CTLs against tumor cells
What type of vaccines are given to individuals before they are infected with a virus?
Preventive vaccines
What type of cells are expanded ex vivo and exposed to tumor cells or a defined tumor antigen in a tumor vaccine approach?
Dendritic cells
What is the result of vaccination against oncogenic viruses?
Tumors caused by oncogenic viruses are prevented
Why have tumor vaccines achieved only modest success?
Because they are therapeutic vaccines administered to patients in whom tumors may have established mechanisms that suppress immune responses
What is the relation between transplantation and the immune response?
Transplantation is the other side of the immune response
Learn the fundamental concepts of transplant immunology, including the difference between modified self antigens and non-self antigens, and the roles of the donor and recipient in transplants. Understand the terminology and principles of syngeneic transplants. Test your knowledge of the immune system in transplantation.
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