Lecture 7 The immune system and cancer developed a cancer treatment that relied on boosting immune Dr William Coley response by exposing the body to bacteria Certain tumors regress spontaneously Antibodies and immune T lymphocytes have been detected in patients with tumors Lymphatic system and immunity Barrier 1 the skin Innate immunity ready to go knows there s an invader and out to destroy fast These components are always ON and are not antigen specific Adaptive immunity B cells create antibodies T cells have helper T cells and Killer T Cells There components are TURNED ON in response to specific antigens Leukocytes white blood cells Formed in bone marrow Come from 2 different undifferentiated cells Myeloid stem cells innate immune system cells Adaptive immune system cell functions Lymphoid cells because T cells T cells mature in the thymus They need to learn how to not destroy themselves Autoimmune diseases arise when this system fails to detect self recognizing T cells Antibodies B cells mature in the bone marrow They become plasma cells and memory cells both produce antibodies Protein produced in response to antigen invasion Antibodies are antigen specific meaning that antibody A only recognizes antigen A Antigen foreign protein recognized by immune system as a threat Induces antibody production How the immune system works Tumor host interactions How cancer escapes detection On the outside tumor cells look like normal host cells self The immune system does not recognize self If a cancer cell expresses a protein that resembles non self the immune system will recognize and destroy it Natural selection favors cancer cells that do not induce strong immune response because strongly immunogenic cells are killed off Weakly Non immunogenic cells survive and proliferate Sometimes strong immunogenic cells can survive and proliferate Some cancer cells divide and grow too big the immune system can t deal with it Cancer cells also surround themselves with dense connective tissue that shields them Some cancer cells produce molecules that destroy T cells Some cancers escape via immunoediting How immune system can help Monoclonal antibodies Cancer cells rely on proteins from nearby healthy cells to hide from the immune system Engineered antibodies can strip way disguises Check point inhibitors cancer cells produce proteins that suppress the immune system New drugs that can suppress the suppressors are being tested Adoptive cell therapy we can take T cells from tumor site and in the lab increase the numbers genetically engineer them to recognize proteins unique to the cancer cell Cancer vaccines A few cancer cells and immune system cells are removed from patients The cancer and immune cells are cultured together Training group of lymphocytes to recognize cancer cells The immune cells will take antigens from the cancer so they can now recognize the cancer Immune cells are put back in the patient so they can recognize the tumor and alert the rest of the immune system Cancer immunotherapy Treating the patient instead of the disease Designed to boost the immune system We can produce anticancer antibodies in the lab Rituxan binds the CD 20 protein on normal and cancerous B cells It then recruits cells of the immune system to destroy B cells Normal B cells regrow after the body has been cleared These antibodies function by targeting proteins on the surface of cancer cells Conjugated antibodies Utilizes antibodies to target toxic molecules to the cancer cells Radiolabeled small radioactive particles attached Chemolabelled powerful chemotherapy drugs attached Immunotoxins cells toxins attached Antibodies that block receptors These antibodies function as a blockade of growth signals Trastuzumab recognizes breast cancer cells that produced too much of the protein HER 2
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