Hemagglutinins

Part of speech: noun

Definitions

1. Proteins found on the surface of certain viruses or red blood cells that cause the clumping of red blood cells; molecules that facilitate binding between viruses and host cells; agents used in blood typing and immunology
2. Substances present on viral envelopes or erythrocyte membranes that induce red blood cell aggregation; proteins responsible for viral attachment to target cells; tools important in medical diagnostics involving blood cells
3. Viral or cellular proteins that promote the agglutination of erythrocytes; molecules essential for initiating infection by mediating cell recognition; components frequently utilized in laboratory tests to detect blood group antigens or antibodies

Etymology: Hemagglutinin is a compound built from two pieces, and the second is the older one. Its core is "agglutinin," a term that goes back to Latin "glutinare," meaning to glue together, from "gluten," glue. Latin "agglutinare" added the prefix "ad-," giving the sense of gluing something onto something else, and English borrowed "agglutinate" from that Latin verb. The "-in" ending, which chemists use to name proteins, descends from a Latin suffix "-inus" that came into English through Old French and Middle English. The first part, "hem-," is the Greek-derived combining form for blood, the same element found in "hemoglobin" and "hemophilia." Put together, "hemagglutinin" literally names a substance that makes blood cells clump together. The word is a modern scientific coinage, built from classical materials, and it describes a protein that does exactly that: it binds to red blood cells and causes them to stick together, a property that laboratories exploit when testing for blood groups.

Synonyms: agglutinins, lectins