MD137 Immunology - Lecture 1 Introduction

MD137 Immunology - Lecture 1: Introduction

• Course: Immunology, specifically lecture 1 focusing on the introduction to the immune system
• Lecturer: Dr. Louise Horrigan, Physiology department, University of Galway
• Course Outline/Objectives:
  • Introduction to the immune system
  • Innate Immunity
  • Adaptive Immunity (cell-mediated and antibody-mediated immunity)
  • Allergy & Autoimmunity
• Learning Objectives (Today's Lecture):
  • Understand the functions of the immune system
  • Identify the cells and tissues of the immune system
  • Describe cytokines
  • Explain the evolutionary arms race between hosts and pathogens
  • Review historical milestones in immunology
• Functions of the Immune System:
  • Fighting infectious diseases (viruses, bacteria, parasites, fungi)
  • Wound healing and tissue regeneration
  • Eliminating cellular debris
  • Cancer fighting
• Tissues of the Immune System:
  • Primary lymphoid organs: Bone marrow, Thymus
  • Secondary/Peripheral lymphoid organs: Lymph nodes, Spleen, Mucosal immune system
• Lymphoid Organs: (Diagram included)
  • Tonsils (pharyngeal region)
  • Thymus
  • Spleen
  • Aggregated lymphoid nodules (intestine)
  • Appendix
• Cells of the Immune System:
  • Sentinels in the tissues: Dendritic cells, macrophages, mast cells, Paneth cells
  • Circulating cells (also present in tissues):
    • Innate/Natural Immunity: Neutrophils, monocytes, eosinophils, natural killer cells
    • Adaptive/Acquired Immunity: Lymphocytes (T lymphocytes, B lymphocytes)
• Cells involved in innate and adaptive immunity: (Diagram included). Innate response is measured in hours, adaptive in days.
• Cytokines:
  • Small proteins (5-20 kDa)
  • Secreted by cells, acting in autocrine and paracrine fashion.
  • Bind specific receptors on cells.
  • Examples: Interleukins (IL-1 to IL-22), Interferons (IFN-α, β, γ), tumour necrosis factors (TNF-α, β), transforming growth factor-β (TGF-β)
  • Profile of cytokines secreted by a cell determines its function
  • Orchestrate immune responses
• Pathogens and Hosts: Evolutionary Arms Race:
  • Survival of the fittest
  • Immunocompetent hosts survive; successful microbes survive
  • Evolutionary immune adaptations in both hosts & pathogens occur throughout generations
• Pathogens Reproduction:
  • Mutations occur during reproduction, leading to strains resistant to immune functions.
  • Hosts and pathogens can adapt through genetic and epigenetic mechanisms. (Diagram of bacterial growth included)
• Evidence of Selective Genetic Pressure and Immune Adaptation – The Black Death:
  • Yersinia pestis spread across Europe in the 14th century.
  • Roma gypsies had travelled from North India to Europe in the 11th Century.
  • Their genetic difference from native Romanians correlated with immune adaptations to Yersinia pestis. (Data shows Toll-like receptors and cytokine responses were different.)
• Basis of Modern Immunology:
  • Edward Jenner (smallpox vaccine in 1796)
  • Louis Pasteur (Germ theory, cholera & rabies vaccines)
  • Elie Metchnikoff (discovered phagocytosis in 1882)
  • Paul Ehrlich (predicted antibodies, self/non-self discrimination)
  • Charles A. Janeway (innate immunity, pattern recognition theory)
• Edward Jenner: Credited for developing the smallpox vaccine in 1796; WHO declared eradication of smallpox in 1979. (Image, diagrams included)
• Cowpox and Smallpox: Comparison of the viruses' surface antigens shows that cowpox and smallpox antigens share similarities. This allows the immunization process to work. (Diagram included)

Summary of main points:

• The immune system is a complex network of cells, tissues, and factors that function throughout the body.
• It goes beyond preventing disease and performs many additional important functions.
• The system is mainly made up of cells originating from bone marrow stem cells and is continuously evolving through interactions with pathogens.
• Immunology is a relatively new field with cutting-edge research building upon work from pioneers like Jenner, Pasteur, and others.

This quiz covers Lecture 1 of the MD137 Immunology course, focusing on the fundamentals of the immune system. It explores innate and adaptive immunity, as well as concepts such as allergy, autoimmunity, and historical milestones in immunology. Test your understanding of the immune system's functions, components, and evolutionary dynamics.