humoral response

• B cells (lymphocytes)


  • Made and also mature in bone marrow
  • Have antibodies on surface complementary to different antigens
• Many antibodies produced rapidly

  Pathogen destroyed before symptoms occur (active immunity)
• Humoral response


  1. Antigens in blood collide with complementary antibody on B cell, B cell takes in via endocytosis, presents on cell surface membrane
  2. When B cell collides with helper T cell receptor, it's activated to go through clonal selection and clonal expansion
  3. B cells undergo mitosis to make lots of cells which differentiate into plasma (which make antibodies) or memory B cells
  4. If you're reinfected with same pathogen, B memory cells divide rapidly into plasma cells to make lots of antibodies
• Clonal selection definition


  Only the B-cell that forms an antigen-antibody complex (complementary to the antigen) is selected to divide into plasma cells
• Plasma cells


  Clones of the selected B cell, with complementary antibody to pathogen's antigen

  • make monoclonal antibodies (one clone of antibody) which form antigen-antibody complexes with antigen
  • agglutination occurs
• Agglutination 


  Process of sticking pathogens together

  • pathogens can destroy may pathogens at once