Evolution
and the
Immune Response to infection.
Up until the 1960s, the human immune system presented biologists with three intriguing mysteries:
(1) How does the body realise exactly which antibody genes need to be activated to fight a specific infection so that it can produce just the right antibodies?
(2) How does our DNA store the immense amount of information necessary to encode specific antibodies against all the foreign invaders that we may encounter? This mystery is compounded by seemingly conflicting estimates that we have no more than 40,000 genes but can make more than 30,000,000 different antibodies, each of which would seem to require its own gene.
(3) How can the progressive increase in antibody affinity during an immune response be explained? They get progressively better at binding to specific antigens.
These mysteries have now been solved and the animations included here illustrate the mechanisms responsible for these remarkable capabilities.
Diagrams
Animations