Chapter 11: Immunity

Overview

• Two parts:
  1. The Immune Response
  2. Immunity, Vaccination, and Autoimmunity

Part One: The Immune Response

Definitions

• Immunity: Protection against diseases.
• Immune System: The body's defense mechanism against diseases.

Lines of Defense

• First Line (External): Non-specific barriers
  • Saliva, tears, skin, mucus, stomach acid.
• Second Line (Internal): Non-specific immune response
  • Phagocytes: Engulf and destroy pathogens.
• Third Line (Specific): Specific immune response
  • Lymphocytes: Target specific pathogens.

Key Concepts

• Antigens:
  • Non-Self Antigens: Macromolecules on foreign surfaces that trigger immune response, including pathogens and allergens.
  • Self Antigens (Cell Markers): Macromolecules on self-cells that do not trigger immune response.
  • Immune Response: Body's reaction targeting non-self antigens involving white blood cells.

Types of White Blood Cells

Phagocytes

• Non-Specific Defense:
  • Responds to many non-self antigens.
• Types:
  • Neutrophils: Short-lived, die after digesting pathogens.
  • Monocytes/Macrophages: Long-lived, initiate immune response by presenting antigens on their surface (Antigen Presenting Cells - APC).

Lymphocytes

• Specific Defense:
  • Responds to specific antigens.
• Types:
  • B Lymphocytes (B Cells): Mature in bone marrow, produce antibodies.
  • T Lymphocytes (T Cells): Mature in thymus, do not produce antibodies.

Mechanism of Phagocytes

• Have receptor proteins to detect non-self antigens.
• Engage in phagocytosis, forming phagocytic vacuole.
• Present antigens on cell surface to activate lymphocytes.

Summary

• Both non-specific and specific immune responses work together to protect the body.
• Phagocytes and lymphocytes have different roles but complement each other in fighting pathogens.

This concludes the summary of part one of Chapter 11 on Immunity. Further details on lymphocytes and their functions will be covered in subsequent sections.