How the Coronavirus Hacks the Immune System
This is mind blowing:> For the first half of the twentieth century, the going theory was that the invading element—the “antigen”—served as a template around which a corresponding antibody was molded. Only in 1955 did scientists discover the much stranger truth. It turned out that the cells that produce antibodies—called B cells, because they were first discovered in the bursa of Fabricius, an organ that does for birds what bone marrow does for humans—can produce only one kind each. Its structure is random, and nearly every B cell is discarded unused. If, however, an antibody created by a B cell happens to match some part of an antigen, that B cell will not just survive but clone itself. The clone incorporates many mutations, which offer the possibility of an even better match. After a few generations, an antibody with the best fit is “constructed” through a process of mini-evolution that occurs continuously in our lymph nodes and spleen. (Our ancestors the bony fish adapted the machinery of the B-cell system from an even more ancient parasite.)So, natural selection discovered a way to run an embedded natural selection search process in an individual. Talk about meta.