EPITOPE MAPPING WITH PEPTIDES OF CHI-T-I COMPONENT-III AND IMMUNOMODULATION OF THE CHI-T IMMUNE-RESPONSE

Background: Hemoglobins of the Diptera family are known as aggressive inhalant allergens. Methods: The whole sequence of the insect allergen Chi t I component III was studied for T-cell epitope activity in cell cultures of 15 sensitized patients with a panel of 17 overlapping syn thetic peptides and 12 peptides obtained by tryptic cleavage. Results: All but one of the peptides tested were found to be immunogenic. The nonstimulatory sequence 102-109 and two other tryptic peptides (69-90 and 110-135) were used in inhibition experiments. The Chi t I-induced proliferation was downregulated by all tested peptides when compared w ith stimulation with Chi t I alone. Conclusions: Because stimulation w ith phytohemagglutinin or tetanus toxoid was not influenced by the abo ve-mentioned peptides, this mechanism seems to be specific for the ant igen. Specific immunomodulation with nonstimulating peptides may offer new therapy approaches.