Adaptive Immunity Summary

  • Adaptive Immunity

  • Specific immunity that protects against particular threats.

  • Depends on specific lymphocytes (T cells and B cells) and produces specific resistance.

  • Innate vs Adaptive Immunity

  • Innate Immune System:

    • Physical and chemical barriers (e.g., skin, stomach acid).
    • Includes inflammatory response and various immune cells (neutrophils, macrophages).

  • Adaptive Immune System:

    • Involves T cell-mediated and B cell-mediated responses.
    • Produces antibodies and activates specific immune responses.

  • Properties of Adaptive Immunity

  1. Specificity: T and B cells have receptors for specific antigens.
  2. Versatility: Millions of lymphocytes for different antigens; clonal expansion upon activation.
  3. Memory: Produces memory cells for faster response to future exposures.
  4. Tolerance: Distinction between self and non-self cells; avoids attacking body’s cells.

  • Types of T Cells

  • Cytotoxic T Cells: Attack infected or foreign cells directly.

  • Helper T Cells: Stimulate other T and B cells.

  • Regulatory T Cells: Moderate immune responses.

  • Memory T Cells: Respond to previously encountered antigens.

  • B Cell Activation

  • When activated, B cells differentiate into plasma cells that produce antibodies.

  • Helper T cells are essential for full B cell activation.

  • Antibody Structure and Function

  • Composed of heavy and light chains; variable regions bind specific antigens.

  • Function includes neutralization, opsonization, and triggering inflammation.

  • Antibody Response

  • Primary Response: Initial exposure to antigen; slower and less robust.

  • Secondary Response: Faster and stronger upon re-exposure due to memory B cells.

  • Hypersensitivities (Allergies)

  • Abnormal reactions to antigens, causing excessive immune responses.

  • Can be localized (e.g., allergic rhinitis) or systemic (e.g., anaphylaxis).

  • Autoimmune Disorders

  • Malfunction of self-recognition; production of autoantibodies against self antigens.

  • Examples: Thyroiditis, rheumatoid arthritis, type 1 diabetes, multiple sclerosis.

  • Leaky Gut and Autoimmunity

  • Increased permeability in gut can lead to autoimmune responses.

  • Factors include stress, toxins, pathogens, and undigested food particles entering the bloodstream.