Alexins

Part of speech: noun

Definitions

1. A type of substance in the body that supports immune response by aiding in the destruction of pathogens
2. Referring to factors produced by the body that enhance defenses against infections
3. Describing components involved in the body's natural defense mechanisms against disease-causing agents

Etymology: This word is the plural of "alexin," and the story of its coinage is a neat piece of scientific naming. In 1891, the German bacteriologist Hans Buchner was writing a review of bacteriology in the Münchener Medizinische Wochenschrift. He had found that a heat-sensitive protective substance in blood serum was a protein unlike any known at the time, and he wanted a name for it. He proposed "alexine," meaning roughly "protective stuff," in an explicit nod to the Greek verb "aléxein," "to fight off" or "to defend." The word thus reached English as a deliberate technical coinage rather than a term that grew up over centuries. Its Greek root, "aléxein," is an ordinary verb of defence, and Buchner simply reached back to it to name a substance that was defending the body against invaders. The name has since been applied in English to the same class of blood proteins, which we now more often call complement components, though the older term survives in the plural "alexins."