Regulation of Anti‐Hapten Antibody Response by Chemically Modified Carrier Antigen Preferentially Provoking Delayed‐Type Hypersensitivity (DTH)

Abstract

AbstractExperiments were carried out to determine whether or not the cell populations involved in DTH and in the suppression of antibody response are identical. The effects of four treatments, i.e., adult thymectomy (ATx), X‐irradiation, anti‐mouse thymocyte serum (ATS) and hydrocortisone (HC) on the induction of DTH and on the carrier‐specific suppression of antibody response were observed in mice immunized with chemically modified antigen, dodecanoyl‐BSA (d‐BSA), emulsified with complete Freund's adjuvant (CFA), with the following results: 1) DTH induced by immunization with D‐BSA remained constant in adult thymectomized mice, whereas the suppression of antibody response was not inducible in these animals. 2) Injection of low doses of ATS caused the depression of DTH in mice primed with D‐BSA, but did not affect the suppressive activities of their spleen cells. 3) Sublethal X‐irradiation 1 week prior to D‐BSA priming inhibited the generation of suppressor cells but did not affect the generation of cells mediating DTH. The suppressive effect was also abrogated by sublethal X‐irradiation given 2 days after immunization with DNP‐BSA (14 days after priming with D‐BSA). 4) The treatment of animals with HC 2 days before the footpad challenge or immunization with DNP‐BSA depressed the ability of animals to induce both DTH and the suppression of antibody response. However, the latter was more sensitive to HC than the former.In addition to these results, it was also found that D‐BSA‐primed spleen cells were capable of suppressing anti‐DNP response, but not of inducing DTH‐reactivity upon transfer to recipient mice. These results suggest that DTH‐reactivity and the carrier‐specific suppression of anti‐hapten antibody response induced by injection of D‐BSA are mediated by different cell populations.