Regulation of delayed-type hypersensitivity (DTH) response to hen egg-white lysozyme (HEL)

Delayed-type hypersensitivity (DTH) can be demonstrated in A/J mice immunized with hen egg-white lysozyme (HEL) in complete Freund's adjuvant (CFA) by challenging primed animals in the ear with aqueous HEL. Normal A/J mice receiving soluble HEL derivative peptide, P-Ib, sequence 29-54 and 109-123 linked by a single S-S bond, 7 days prior to immunization with HEL showed much lower DTH response specific to the protein. The inhibition of DTH reactivity is due to active suppression and involves the generation of suppressor T-cells (Ts). Thus, the suppression induced with a single i.v. injection of P-Ib solution was able to be transferred into syngeneic recipients by the spleen cells from mice pretreated with P-Ib. These suppressor cells are T-cells, since their ability to suppress DTH is completely abrogated by treatment wit anti-Thy 1.2 and complement. Amongst HEL derivative peptides tested in the present study, only P-Ib could induce the tolerance.