Effect of Priming Doses of Chemically Modified Antigen on Helper Activity
1976 年 79 巻 6 号 p. 1323-1330
詳細
1976 年 79 巻 6 号 p. 1323-1330
Mice primed with chemically modified bacterial α-amylase (BaA) [EC 3.2.1.1 α-amylase, B. subtilis], which was neither cross-reactive with anti-BαA antibody nor able to induce a humoral anti-BαA antibody response, developed enhanced responses to a subsequent challenge with native BaA (Nakashima et al. (1974) J. Biochem. 76, 349-357). The present studies were designed to examine the relationship of priming doses of BaA derivatives to the level of enhancement of the helper activity.
Increasing the priming dose of modified antigens resulted in a greater degree of helper cell response until the maximal level of enhancement was reached. When injections for priming and challenge were given intraperitoneally, priming doses of D-BαA, M-BαA, and RM-BαA required for the maximal enhancement of helper activity were about 15, 50, and 15μg, respectively. Further increase in the priming dose, conversely, resulted in suppressin of the enhanced helper activity, irrespective of whether the time interval between priming and challenge was 10 or 28 days. Suppression of the enhanced helper activity upon excessive dose priming with modified BαA derivatives was not specific for the anti-BαA antibody response. On the basis of these results it is suggested that this phenomenon of suppression might be partly accounted for by the regulatory mechanism functioning in antigenic competition.
