Clonal Selection Theory of Immunity

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

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 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 produce antibodies against the pollen of purple Siberian onion grass—whether or not we ever come in contact with it. Another whose only job it is to make antibodies against the tail proteins of a bacteria that lives only in the thermal vents at the bottom of the ocean.

Wait a second. There must be like a billion different things in the world. If each of our B cells produces only one type of antibody, then we’d have to have like 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, me—starts dividing like crazy, makes 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.

Please consider volunteering to help out on the site.

• Hodgkin PD, Heath WR, Baxter AG. The clonal selection theory: 50 years since the revolution. Nat Immunol. 2007 Oct;8(10):1019-26.
• Forsdyke DR. The origins of the clonal selection theory of immunity as a case study for evaluation in science. FASEB J. 1995 Feb;9(2):164-6.
• The Nobel Prize in Physiology or Medicine 1960.

Images thanks to Aldo samulo via Wikimedia; funnyasduck; and Stowe Boyd via flickr. Images have been modified.

• cáncer
• enfermedades autoinmunes
• función inmune