MECHANISM OF INDUCTION OF IMMUNOLOGICAL TOLERANCE .4. EFFECTS OF ULTRA-LOW DOSES OF FLAGELLIN

Abstract

Minute amounts of Salmonella adelaide flagellin were capable of inducing tolerance in newborn Wistar rats. With the range of doses, 10-9-10-1 [mu]g, the following results were obtained: Tolerance could be induced in 2 zones of dosage by daily injections of the flagellin during the 1st 2 wks. of life. The low zone corresponded to a dose of 10-7 [mu]g/g body weight and the high zone to 10-3 [mu]g/g body weight. Doses between these evoked an immune response. Daily injections of flagellin for 6 wks. resulted in a shift in the dosage required for low zone tolerance from 10-7 [mu]g/g body weight to 10-5 [mu]g/g body weight. The events of low zone tolerance occurred at an antigen concentration, which, in an organ such as the spleen of a newborn rat, never exceeded about 10-14[image]. The high zone of tolerance corresponded to an antigen concentration of about 10-10 [image].