immunoglobulin M
Share:
Tweet n. Abbr. IgM 1. The class of antibodies that are the first to appear after initial exposure to an antigen and that function to activate the complement system, promote phagocytosis of pathogens, and neutralize toxins. IgM antibodies are composed of five identical subunits and are found chiefly in the blood. 2. An antibody of this class. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.