Health Topics

  1. #
  2. A
  3. B
  4. C
  5. D
  6. E
  7. F
  8. G
  9. H
  10. I
  11. J
  12. K
  13. L
  14. M
  15. N
  16. O
  17. P
  18. Q
  19. R
  20. S
  21. T
  22. U
  23. V
  24. W
  25. X
  26. Y
  27. Z
Browse All Topics

Clonal Selection Theory of Immunity

We may have a billion different types of antibody-releasing cells in our immune system, such that each recognizes a different molecular signature.

December 11, 2012 |
GD Star Rating


Supplementary Info

Sources Cited


Images thanks to: Aldo samulo via Wikimedia Commons and Stowe Boyd.


To understand the dietary implications of the new autoimmune theory of cancer, we first have to understand how the immune system works. This was one of the greatest mysteries in all of biology—  solved by a brilliant scientist who won the Nobel in 1960 for figuring out the   clonal selection theory of immunity. Each one of our antibody producing immune cells, called B-cells, produces only one type of antibody. Antibodies are one of the main weapons our immune system uses to attack foreign invaders. And they’re specific. It’s not just like we have one B-cell that covers grass pollen and another that covers bacteria, we have a B-cell in our body whose only job is to make antibodies against the pollen of   purple Siberian oniongrass, whether or not we ever come in contact with it. Another whose only job it is to make antibodies against the tail proteins of bacteria that live only in the thermal vents at the bottom of the ocean. Wait a second. There must be a billion different things in the world. If each of our B cells produces only one type of antibody, then we’d have a billion different types of B cells. And we do, which is totally amazing. So, let’s suppose one day you’re walking along and get   attacked by a platypus. They actually have poison spurs on their heels, you know. And so for your whole life up until that point the B-cell in your body that produces antibodies against duck-billed platypus venom was just hanging around, twiddling its thumbs, until that very moment.  As soon as the venom is detected it raises its hand and says me me me, starts dividing like crazy, making copies of itself, and soon you have a whole swarm of clones specialized for platypus poison protection, fending off the toxin, and you live happily ever after. That’s, how the immune system works.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ashley Rhinehart, RN.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

Isn't our immune system spectacular?! In Wednesday's video of the day Clonal Deletion Theory of Immunity we'll explore the flipside—how our immune system avoids attacking us. See yesterday’s video-of-the-day Cancer as an Autoimmune Disease for an explanation of the autoimmune theory of cancer. Why all this background? This is all a set up so everyone can understand the dietary implications of Thursday's video The Inflammatory Meat Molecule Neu5Gc.

For some more context, please check out my associated blog post: Plant-Based Diets for Multiple Sclerosis

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • HemoDynamic, M.D.

    Enjoyed it!-)

  • Jeffrey Zayda

    This is amazing! I no longer have fear of platypus attacks! Lol

    • R Ian Flett

      You should; platypus envenomation is excruciatingly painful and enduring.

  • Thea

    wow. And I even learned something about platypuses (sp?).

    Our immune system is amazingly large, but also so specific. I would have guessed that humans had a system that was more general. In thinking about it, this video makes me think that our immune system is pretty fragile/not very strong. While a billion types of cells, give or take, is quite a high number, what happens when we need our immune system to work on something we don’t already have a cell for? It seems like our immune system is pretty weak in that way.

    Then again, I think, “How did we get all those types of cells to begin with?” Our bodies developed those types of cells at some point probably in reaction to a problem. And then we passed the new cell type down to our offspring? And so maybe our immune system is not so fragile/unchangeable after all? Just thinking…

  • Dave

    How does our body have the knowledge of every potential attack it could face in this world?

  • coacervate

    How do the b cells avoid reacting with our own antigens?

  • Tee

    I’m very curious to know what impact, if any, chemotherapy has on one’s immunity. Does your immune system every FULLY recover from chemo?

  • Bruno L

    Very interesting; many thanks!

  • Seth Kaplan

    Sounds related to the theory of homeopathy. Questions, though: (1) how do B cells and the immune system know when the threat has been neutralized; (2) where do all those clonal B cells go after they’ve rid the town of that specific outlaw?

    • Dr. Connie Sanchez, N.D.

      Hi Seth,
      This is a gross oversimplification of what actually takes place when a B-cell (lymphocyte) is activated by coming into contact with an antigen or allergen. Upon activation, the B-cell multiplies and creates many clones (clonal selection) of itself (as seen in Dr. Greger’s video).

      B-cells (lymphocytes) create two main types of cells: (1) Effector (plasma) cells which secrete antibody and (2) Memory cells. Effector (plasma) cells are either short-lived cells that die within 3-5 days after being made and are used for immediate immunological defense; or the long-lived plasma cells which migrate primarily to the bone marrow where they remain for extended periods of time secreting high-affinity antibody.

      B-cells that have differentiated into Memory cells remain after the infection has cleared to provide “memory” of that specific antigen/allergen and provides long-term protection (immunity) allowing for a more rapid response if one becomes exposed again to that same antigen.

      Source: Minges Wols, Heather. Plasma Cells. Barat College of DePaul University, Lake Forest, Illinois, USA., doi:10.1038/npg.els.0004030.

      • Tan Truong

        Amazing, thanks.

  • Randy

    Great topics and great science, explaining it very easy to understand.

    Thank you!

  • Daniel Bidjae

    This is fantastic for be antibody in our immune system and how our body avoids any sickness

  • Daniel Bidjae

    kind of triggers the immune system to develop an antibody against it. like againts antibody generator or “antigen”

  • Merio

    if one is really curious about this mechanism got to make a visit to the relative wikipedia page(“clonal selection”)… and then read out the “VDJ recombination”… it’s not easy, but it is really fascinating… i’ve got a course in my university about this stuff…

  • Malia

    Dear Dr. Greger,
    I am fascinated with your work. I am strictly vegan now but one thing I don’t understand… if our B cells are designed to attack all foreign invaders that naturally occur on this earth, what will the B cells do if they don’t recognize a Genetically Modified Organism. I would think that you above ALL people would be recommending staying completely away from these. I also would expect that you would be helping our community to better understand what is happening to our food supply as this affects our whole foods. Please do your research on this subject and don’t be afraid of the Big Ag companies. I know they are scary but we got your back. :-)