ANTIBODY-RESPONSES TO BEE MELITTIN (API-M-4) AND HORNET ANTIGEN-5 (DOL-M-5) IN MICE TREATED WITH THE DOMINANT T-CELL EPITOPE PEPTIDES

Background: Mice treated with the dominant T-cell epitope peptides of allergens were reported to have reduced peptide- or allergen-specific T-cell responses on subsequent immunization, but the extent of reducti on of allergen-specific antibodies is not clear. Objective: This study was done to compare the extent of reduction of T-cell and antibody re sponses in peptide-treated mice. Two allergens were tested. Bee melitt in (Api m 4), an allergen of 26 amino acid residues, has a single domi nant Tor B-cell epitope. Hornet antigen 5 (Dol m 5), an allergen of 20 4 amino acid residues, has multiple dominant T- or B-cell epitopes. Me thods: Mice were treated with T-cell peptides of Api m 4 or Dol m 5 an d then immunized biweekly with their respective allergen with alum adj uvant. T-cell peptides tested were residues 7-19 of Api m 4 and residu es 41-60, 141-160, and 176-195 of Dol m 5. T-cell responses at week 9 or 11 were assayed by proliferation of spleen cell cultures. Antibody responses of different isotypes were measured biweekly by ELISA. Resul ts: Partial reduction of 30% to 50% of T-cell responses to peptide or allergen was observed in bee and hornet peptide-treated mice. About 65 % reduction of Api m 4-specific antibody response was observed early i n the immune response but gradually subsided to about 40% late in the response. Partial reduction of about 40% of Dol m 5-specific antibody response was only observed early in the immune response. Conclusion: P eptide treatment is partially effective in the reduction of T-cell res ponses of univalent or multivalent allergens. It is also partially eff ective in the reduction of antibody response of a univalent allergen, but it is poorly effective for a multivalent allergen.