Immune System Comparison

Immune System Overview

• Immune system divided into innate and adaptive immunity.
• Innate immunity: non-specific response, immediate action, initiates adaptive immunity development.
• Adaptive immunity: pathogen-specific, develops memory, requires pre-activation, and enhances response over time.

Key Components of Innate Immunity

• Exterior Defenses: Include epithelial barriers, mucosa, and various secretions.
• Cellular Components: Involves leukocytes like natural killer cells, neutrophils, monocytes/macrophages, eosinophils, basophils, mast cells, and platelets.
• Soluble Mediators:
  • Complement: System of proteins inducing acute inflammatory response, damaging microbial membranes.
  • Cytokines: Proteins modifying cellular behavior, crucial for immune regulation.

Key Types of Cytokines

• Chemokines: Induce leukocyte migration, enhance inflammation by altering vascular permeability and blood flow.
• Interferons: Produced by virus-infected cells, increase resistance to viral replication.
• Acute Phase Proteins: Promote inflammation, alter metabolism and blood flow, and assist in protein production.

Components of Adaptive Immunity

• Humoral Immunity: Involves antibodies produced by B cells.
• Cell-Mediated Immunity: Involves T cells, essential for targeting infected cells.

Antigens vs. Immunogens

• Antigen: Any molecule binding to antibodies or T-cell receptors.
• Immunogen: A type of antigen that triggers an immune response, e.g., adjuvants enhance vaccine efficacy.

Active vs. Passive Immunity

• Active Immunity: Long-lasting protection from exposure to antigens, through natural infection or vaccination.
• Passive Immunity: Temporary immunity from transferred antibodies, occurring naturally (e.g., transplacental) or artificially (e.g., injection of antibodies).

Antibody Structure and Function

• Produced by B lymphocytes, with two critical regions:
  • Fragment Antigen Binding Site: Contains variable regions for specificity.
  • Constant Regions: Define the antibody class.

Major Immunoglobulin (Ig) Classes

• IgM: First antibody produced, activates complement system.
• IgG: Major antibody in blood, long-lasting immunity, crosses placenta.
• IgA: Predominant in mucosal areas, protects against pathogens.
• IgE: Binds to mast cells, involved in allergic responses and parasite defense.
• IgD: Acts as an antigen receptor on B cells.

Clinical Relevance of Cell-Mediated Immunity

• Essential for protection against intracellular pathogens.
• Involved in tissue transplant rejections and certain autoimmune diseases.

Process of Cell Mediated Immunity

• Antigen phagocytosis by macrophages/dendritic cells, followed by antigen presentation to T cells in lymph nodes.
• Activated T cells undergo clonal expansion, migrating to attack pathogens and activating B cells.

Formation of T-Lymphocytes

• Derived from bone marrow, mature in the thymus, developing specific receptors.
• Self-reactive cells are eliminated to prevent autoimmune diseases.

Formation/Maturation of B-Lymphocytes

• Exit bone marrow displaying IgM and IgD.
• Upon activation by antigens, B-cells proliferate and produce antibodies, maturing into plasma cells or memory B cells for future responses.

Phases of the Immune Response

• Involves five phases:
  • Recognition
  • Amplification
  • Effector
  • Termination
  • Memory

Immunodeficiency Types

• Primary Immunodeficiency: Congenital deficit in T-cells, B-cells, or lymphoid tissue.
• Secondary Immunodeficiency: Result of diseases that impair immune response.

Iatrogenic Immunodeficiency Sources

• Can be caused by: cytotoxic drugs, corticosteroids, immunosuppressive drugs, radiation therapy, and splenectomy.

Explore the key differences between innate and adaptive immunity in this quiz. Understand how each system functions, including their roles in pathogen elimination and memory generation. Ideal for students studying biology or immunology.