|(Physiol. Chem.)||one of a class of proteid substances, present in some animal tissues and fluids, that make the body immune to certain infectious diseases by destroying or rendering inactive the toxic products of bacterial growth; - this is an older term replaced by more precise modern immunological concepts such as antibody and immunoglobulin.|
See also: Proteid
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.