From ScienceDaily:
The ‘bad apples’ of the immune system are also its secret weapon, according to major Australian research published today in the world-leading journal Science.
In a world first, scientists from Sydney’s Garvan Institute of Medical Research have revealed how a population of ‘bad’ antibodies in the immune system — which are usually ‘silenced’ because they can harm the body — can provide crucial protection against invading microbes. The research was carried out in mice.
The ‘bad’ antibodies are known to react against the body’s own tissues and can cause autoimmune disease. For this reason, it was once thought that they were discarded by the immune system or that they were made inactive in the long term. However, the new findings show for the first time that ‘bad’ antibodies go through a rapid ‘redemption’ process and are activated when the body is faced with a disease threat that other antibodies cannot tackle.
As a result, the ‘redeemed’ antibodies no longer threaten the body, but instead become powerful weapons to fight disease — and particularly diseases that evade the immune system by disguising themselves to look like normal body tissue.
Professor Chris Goodnow, who co-led the new research with A/Prof Daniel Christ (both Immunology Division, Garvan), says the new findings will fundamentally change thinking about how the immune system protects us.
“We once thought that harmful antibodies were discarded by the body — like a few bad apples in the barrel — and no one had any idea that you could start with a ‘bad’ antibody and make it good. Paper. (paywall) – Deborah L. Burnett, David B. Langley, Peter Schofield, Jana R. Hermes, Tyani D. Chan, Jennifer Jackson, Katherine Bourne, Joanne H. Reed, Kate Patterson, Benjamin T. Porebski, Robert Brink, Daniel Christ, Christopher C. Goodnow. Germinal center antibody mutation trajectories are determined by rapid self/foreign discrimination. Science, 2018; 360 (6385): 223 DOI: 10.1126/science.aao3859 More.
Well, you could “start with a ‘bad’ antibody and make it good” if the system was preloaded with information.
See also: A pattern of laws of tooth development identified