Adaptive Immune Response

The adaptive immune response provides specific, long-lasting defense against pathogens. Unlike the innate immune system, which responds quickly and non-specifically, the adaptive immune system tailors its response to specific pathogens and improves with repeated exposures.

Key Features of the Adaptive Immune Response:

  1. Specificity – Targets specific antigens (molecules found on pathogens).

  2. Memory – Remembers past infections, allowing for a faster and stronger response upon re-exposure.

  3. Diversity – Can recognize a vast array of antigens.

  4. Self-tolerance – Typically avoids attacking the body’s own cells.

Major Components:

  • Lymphocytes:

    • B cells – Produce antibodies that neutralize pathogens.

    • T cells –

      • Helper T cells (CD4+) assist other immune cells.

      • Cytotoxic T cells (CD8+) destroy infected or abnormal cells.

  • Antibodies – Proteins produced by B cells that specifically bind to antigens and help eliminate pathogens.
  • Antigen-presenting cells (APCs) – Such as dendritic cells, which process and present antigens to T cells to initiate the adaptive response.

Two Main Arms:

  • Humoral Immunity – Mediated by B cells and antibodies, effective against extracellular pathogens.

  • Cell-mediated Immunity – Mediated by T cells, effective against intracellular pathogens like viruses and some bacteria.

Would you like a diagram to visualize how it works?

+++++++++++++++++++++

01. Antigen Processing

01. Antigens

Immune System

Digital World Medical School
© 2025