USMLE

Memory B Cells

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B Cells and T Cells
  1. MHC I
  2. MHC II
  3. B Cells - Overview
  4. B Cells - Activation
  5. Plasma B Cells
  6. Memory B Cells
  7. T Cells - Overview
  8. T Cells - Activation
  9. T Cells - Differentation
  10. Cytotoxic (Killer) T Cells
  11. Helper T Cells - Overview
  12. Th1 Cells
  13. Th2 Cells
  14. Th17 Cells
  15. Regulatory T Cells (Tregs)

Summary

Memory B-cells are a type of B-lymphocyte that remembers threats, in the form of specific antigens that our body has been exposed to before. Memory B-cells have antigen-binding sites on their membranes that are highly sensitive to a target antigen, allowing for a faster immune response when the target antigen appears again (e.g. new infection by same pathogen). Memory B-cells have a long lifetime, and generally are found in lymphoid tissues (lymph nodes, spleen, tonsils). They also do not produce antibodies like plasma cells, although they can proliferate and convert into plasma cells when activated against a threat. 

Key Points

  • Memory B-cells
    • Effector B-cell produced after B-cell Activation
    • Develops antigen memory
      • Enable quick anamnestic antibody response on reexposure (e.g. secondary immune response)
      • Long lifespan (decades)
        • Contrast vs Plasma B-cells (only survive months)
        • Long survival is necessary for long-term antigen memory
      • Do not produce antibodies
        • may proliferate and differentiate into Plasma B-cells upon reexposure to antigen
    • Found in lymphoid tissues
      • Spleen, lymph nodes, tonsils