[f. TOX(IN (cf. TOX-1) + -OID.] A modification or transformation product of a toxin, in which the toxophoric group of atoms is lost, and which has therefore no toxic effect, but retains affinity for the antitoxin. Also attrib.
1900. Lancet, 18 Aug., 528/1. Very sensitive animals such as mice and guinea-pigs might … be easily and rapidly immunised against tetanus by means of toxoids only.
1902. Brit. Med. Jrnl., 29 March, 785. The modified toxin consists of a molecule with a haptophoric but no toxophoric group and is called ‘toxoid.’ Ibid. (1903), 21 March, 654. The toxoids may again be subdivided into three groups, according to their affinity for the antitoxin, which may obviously be either greater (protoxoid), equal (syntoxoid), or less than (epitoxoid) that of the toxin. Ibid. (1904), 10 Sept., 577. They were however able to produce toxoid formation in this constituent.
