Immunology - Part 2

4PY019 Pharmacy Stage 1 Immunology- Part 2 Dr Abhishek Gupta Senior Lecturer Physiology and Pharmacology a.gupta@wlv.ac.uk Learning objective - Gain an overview of the immune system - acquired immunity - Understand the types of cells associated with Acquired immunity - The concept of the Antigen-Antibody Interaction - Overview of the lymphatic system Adaptive (Specific or Acquired) Immunity • Unlike the innate immune system, the adaptive immunity is activated by exposure to pathogens, and uses an immunological memory to learn and recognise the threat to react the right way. • There are two types: – humoral immunity – cell mediated immunity • B cells • T cells B Cells • B cells are lymphocytes • Committed to differentiate into the plasma cells that produce antibodies • Like all lymphocytes, B cells are derived from stem cell precursors in the red bone marrow (within the liver and spleen during fetal life) • These plasma cells produce antibodies to react with a specific antigen • B cells continually circulate through the blood, tissues and lymph • Large numbers of B cells are located in the lymph nodes, spleen and other lymphatic tissues • Antibodies attach to antigens Humoral immunity • Also called Antibody-mediated immunity • It depends on B cells • Involves the production and release of antibodies to antigens Antibodies • Antibodies belong to a family of proteins called globulins • Referred as immunoglobulins (Ig) • Basic structure: • Y-shaped monomer • 2 “heavy” and 2 “light” chains https://www.britannica.com/science/antibody Antigen-Antibody complex • Antibodies inactivate or destroys foreign substances by: • Neutralisation • Precipitation • Lysis of pathogen • Opsonisation • Agglutination https://www.allthescience.org/what-is-antigen-binding.htm Classes of Immunoglobulins https://courses.lumenlearning.com/suny-mcc-biology2/chapter/antibodies/ GAMED to remember different antibodies Cell mediated immunity • In cell mediated immunity the antigens are displayed by the cells infected with the pathogen which activate the T-cells • These T cells destroy them as well as engaging other cells to make them aware of the infection. T-Cells • The T cells recognise and contribute to the immune response . • These may be: 1.Cytotoxic T cells: destroy the antigen 2. Helper T cells activate other immune cells 3. Memory T cells remember the reaction for next encounter https://www.researchgate.net/figure/The-humoral-and-cell-mediated-branches-of-the- The Lymphatic System • • • • • Lymph Lymph vessels Tonsils Spleen Thymus The Lymphatic system Figure. Lymph transport along lymphatic vessels. (A) Unidirectional lymph flow route: lymphatic capillaries collect peripheral tissue fluid and converge into larger collecting vessels, then lymph drains into the lymph node from the afferent lymphatic vessels and flows out from the efferent lymphatic vessel. Afterwards lymph fluid flows through the thoracic duct and the right lymphatic trunk, eventually enters into venous circulation. Arrows indicate the direction of lymph flow. (B) Interstitial fluid, macromolecules and immune cells which extravasate from blood vessels are collected by lymphatic capillaries. Initial lymphatics are composed of a layer of oak leaf-shaped endothelial cells and lack of muscle layers. (C) Lymphatic collectors contain intraluminal valve and SMC layers that enable the unidirectional lymph flow. https://www.researchgate.net/publication/335458965_Pathophysiology_of_aged_lymphatic_vessels/figures?lo=1 The Lymphatic system References • Kuby, J. (1997) Immunology. 3rd ed. Freeman and Company. • Playfair, J. and Bancroft, G. (2007) Infection and Immunity. 3rd ed. Oxford University Press. • Waugh, A. and Grant, A. (2014) Ross and Wilson Anatomy and Physiology in Health and Illness.12th ed. Edinburgh: Churchill Livingston Elsevier • Moini, J. (2020) Anatomy and Physiology For Health Professionals. 3rd ed. Jones & Bartlett Learning • Totorta, G. and Derrickson, B. (2011) Principles of Anatomy and Physiology. 13th ed. Wiley & Sons. • Web links for extra reading (Optional): • Antibodieshttps://courses.lumenlearning.com/suny-mccbiology2/chapter/antibodies/