final exam immuno

• Host Cd4 is the host cell receptor for the AIDS virus. it enables the AIDS virus to specifically infect helper T cells, it binds to the CD4 and injects its RNA genetic instruction into the cell
• Viral reverse transcriptase is the enzyme that converts viral RNA into DNA
• viral integrase is the enzyme that integrates the viral DNA into the host genome to make a provirus
• viral protease is the enzyme that cuts newly synthesized viral polyproteins into functional individual proteins. without it, the proteins remain non-functional and cannot be used to assemble a new virua
• viral protease and reverse transcriptase have been successful targets for drug development for AIDS
• SCID affects the whole adaptive immune system, both T cells and B cells. XLA only affects B cells and T cell functions remain intact
• graft-versus-host disease is where transplanted immune cells from the donor attack the host tissue. It can be avoided by a simple procedure that removes the mature T cells from the donor cells before they are transplanted into the host. Bone marrow stem cells from the donor will regenerate new T cells but they will become tolerant to the host as they develop
• The host-versus-graft response is when mature T cells in the host reject the foreign transplanted tissue from the donor. It is not normally a problem for the treatment of SCID because the patients lack functional T cells
• an allotransplant is a transplant between members of the same species that are genetically different. an autologous transplant is when cells are taken out of an individual, modified in some way and then transplanted back to the same individual
• the defective gene is x-linked. boys only need to inherit one defective gene from their mother to get the disease, girls need to inherit a defective gene from both parents to get the disease
• immunoediting refers to the roles of the adaptive immune system in detecting and destroying cancers. Immunoevasion refers to ability of cancers to evolve to evade the immune system
• some cancer proteins appear abnormal because of mutations
• some cancer proteins are expressed at unusually high levels in some cancers
• some proteins are normally expressed only during embryonic development but are re-expressed in cancer so that the immune system has never seen them and identifies them as foreign
• immune checkpoint is a natural inhibitor of the adaptive immune system to control the immune response and prevent an excessive response that could lead to toxic effects such as autoimmunity. it is relevant to cancer immunotherapy because many cancers hijack immune checkpoints, they overexpress them to shut down the immune response and evade immune destruction. therefore, drugs called checkpoint inhibitors help to reactivate the immune system and facilitate immune attack of cancers
• monoclonal antibody to PD-1 is a checkpoint inhibitor that blocks an interaction between cytotoxic t cells and cancer cells
• monoclonal antibody to CTLA-4 is a checkpoint inhibitor that blocks an interaction between dendritic cells and helper T cells
• CAR-T cells are an autologous cell therapy that genetically engineers cells to express hybrid receptors
• dendritic cell vaccine is an autologous cell therapy that facilitates antigen presentation on cells to initiate anti-cancer immune responses
• one disadvantage of using an autologous cell therapy for cancer is that it is more expensive and has to be tailored to each individual patient
• one advantage of using an autologous cell therapy is that it can be more specific for the cancer and reduce side effects because a single tumor antogen can be targeted
• chimeric antigen receptors are a synthetic hybrid containing the extracellular domain of the b cell receptor and the intracellular domain of the t cell receptor
• blood group O is the universal donor because red blood cells lack both A and B antigens so they cannot be attacked by recipient antibodies to A and B
• blood group AB is the universal recipient because recipient does not have any antibodies to A or B and cannot attack donor red blood cells
• recipient O and donor A= reject
• recipient A and donor O = accept
• recipient B and donor AB = reject
• recipient AB and donor B = accept
• A baby has hemolytic disease of the newborn:

   

  (i) The baby RhD+

   

  (ii) The mother RhD-

   

  (iii) The father RhD+
• Xenografts: Pig are considered because they are easily farmed and have organs of similar size to humans. This would solve the “availability” problem but not the tissue rejection problem
• cyclosporine A = immunoglobulin ligand
• advil = NSAID
• azathioprine = cytotoxic drug
• rapamycin = immunoglobulin ligand
• prednisone = glucocorticoid
• immunoglobulin ligand- inhibits calcinuerin and blocks activation of T cells by the T cell receptor signal transduction pathway
• NSAID = inhibits cyclooxygenase enzymes and blocks production of prostaglandins
• cytotoxic drug = inhibits DNA synthesis
• immunoglobulin ligand = inhibits mTOR and blocks T cell proliferation by blocking the IL-2 receptor signal transduction pathway
• glucocorticoid = activates transcription of an inhibitor of NFkB