N5315 Advanced Pathophysiology Inflammation, Altered Immunity and Infection Core Concepts Objectives with Advanced Organizers Immune System 1. Examine the structure and function of the immune system.  Evaluate how the normal function of T-lymphocyte and B-lymphocyte cells differ.  T-lymphocyte : (mature in thymus) provide weapons to act antigens. Some kill virus-infected cells directly, some help B- cells make antibodies which circulate to bind to antigens (4 types)  B-lymphocyte : (mature in bone marrow) With help of T cells, B-cells make Y shaped proteins called antibodies that stick to antigens on the surface, stopping them and then creating clumps that alert your body to the presence of intruders. Your body then starts to make toxic substances to fight them. Phagocytes engulf and then destroy antibody-covered antigens  Differentiate between the function of humoral and cell mediated immunity.  Humoral immunity : Immunity conferred by B cells (provides immunity against some viral infections, toxin induced diseases, diseases caused by pneumococci, meningococci, haemophilius)  B cells : mature into plasma cells that then produce antibodies (5 classes of antibodies- glycoproteins)  Cell mediated immunity : Immunity conferred by T cells (active against cells infected with intracellular bacteria/viruses).  Defends against: fungal infections, parasitic infections, tumors, responsible for organ transplantation rejection  T cells differentiated (named) by expression of antigens on their cell membrane called “cluster of differentiation”  Analyze the difference between active acquired immunity and passive acquired immunity.  Active acquired immunity : Adaptive. 3 rd line of defense o State of immunity obtained after natural exposure to an antigen or after immunization (improves with repeat exposure) o Slower acting, specific, long lived  Passive acquired immunity : Via transfer of antibodies (T cells) to the recipient- doesn’t involve the host’s immune response at all o Natural passive immunity : Mother to fetus (cross placenta/breast milk) o Artificial passive immunity : Occurs when antibodies are given to a recipient to provide immunity (Used to tx: rabies, tetanus, hepatitis, snake bites)  Unvaccinated individual who are exposed to particular agents (hep A, rabies virus) are given immunoglobulins that are prepared form individuals who already have antibodies against particular pathogen

 *Good way to fight infection, immediate protection, immunity only lasts as long as the antibodies (~2 weeks) > T cells are eventually destroyed  Define the following terms:  Antigen: Harmful molecule that can react with antibodies or antigen receptors on B and T cells o Foreign, “non-self” o Viruses, bacteria, fungi, parasites o Can also be found on noninfectious environmental agents (pollens, food, bee venom, drugs, vaccines, transfusions) o To function: at least a portion of a molecule’s chemical structure must be recognized by and bound to an antibody and/or to specific receptors on a lymphocyte 