Lecture Notes: Understanding the Immune System

Introduction

• Presenter: Iron Melman, Scientist at Genentech
• Topics: The immune system and its functions

Functions of the Immune System

• Protects against environmental pathogens (bacteria, viruses, toxins)
• Distinguishes between self and non-self to avoid harming the host
• Key in preventing infections routinely encountered in daily life

Complexity Across Organisms

• All multicellular organisms have immune systems
  • Complexity varies (humans more complex than insects)
• Fundamental principles of immune response conserved through evolution

Importance of Understanding the Immune System

• Essential for understanding diseases like infectious diseases, AIDS, asthma, lupus, cancer, allergies
• Helps to comprehend the biology of diseases caused by immune system breakdowns

Components of the Immune System

• Specialized cell types mostly derived from bone marrow
• Key Cells: Lymphocytes (T-cells, B-cells), macrophages, dendritic cells, monocytes, NK cells, granulocytes
• Present throughout the body, not just in blood

The Lymphatic System

• Separate from blood vessels, involved in transporting immune cells
• Lymph nodes: Central processing centers for immune cells
• Lymph nodes function as communication hubs where immune cells share information

Immune Response Types

• Innate Immune System

  • Evolutionarily ancient, first found in insects
  • Recognizes shared components among all pathogens

• Adaptive Immune System

  • Recognizes specific components unique to individual pathogens
  • Requires cellular level specificity

Discoveries in Immunology

• Ellie Metchnikoff

  • Discovered innate immune response
  • Identified macrophages as key cells in innate immunity

• Paul Ehrlich

  • Discovered adaptive immune system
  • Identified antibodies in the blood that target specific pathogens

Functionality of Immune Cells

• Macrophages: Identify and ingest pathogens, initiate inflammatory response
• Toll-Like Receptors (TLRs): Detect pathogens and activate immune cells
• Lymphocytes: B cells produce antibodies; T cells aid in immune response

Antibodies and Their Functions

• Structure includes Fab (specificity) and FC (effector function) regions
• Work with complement proteins and macrophages to neutralize pathogens

Adaptive Immunity

• B cells produce antibodies with the help of T cells
• T cell receptors identify antigens and help B cells
• Dendritic Cells: Present antigens to T cells, activating them

Summary of Immune System Logic

• Innate Immune System: Recognizes general pathogen components
• Adaptive Immune System: Provides specificity against unique pathogens through antibodies

Recent Discoveries

• Dendritic cells bridge innate and adaptive immunity
• Discovered by Ralph Steinman, Nobel Prize awarded posthumously

Conclusion

• The immune system is a crucial aspect of biology with resources available for further learning

These notes reflect an understanding of the immune system's structure and function as presented by Iron Melman. They cover the roles of various cells and systems in protecting the host from pathogens and implicate the immune system in a wide range of diseases.