Immunochemical characterization of antigenic fragments of Olea europaea and Phleum pratense

Background:The modulation of T cell responses by natural peptides is of pot ential use in the treatment of allergic diseases and reduces the risk of Ig E-mediated reactions. The objectives of this study were to evaluate the all ergenicity of depigmented, pepsin-digested fragments of Oela europaea and P hleum pratense extracts and their capacity to induce T cell proliferation. Methods: Lyophilized O. europaea and P. pratense extracts were depigmented following standardized methods, digested with pepsin and fractionated by ul trafiltration; a fraction containing components in the molecular weight ran ge of 1-10 kD was selected. The blood of 20 allergic individuals was used t o conduct T cell proliferation studies. Results: Pepsin-digested fragments of both pollen extracts lost more than 95% of their IgE-binding capacity by ELISA inhibition. Greater proliferation indexes than their respective nati ve extracts were obtained in 55% of O. europaea and in 95% of P. pratense a llergic patients. Conclusions: This study demonstrates that pepsin-digested allergenic fragments of depigmented extracts can be produced in a standard ized, reproducible manner. These fragments are significantly less allergeni c and retain, or even increase, their capacity to induce T cell proliferati ons. Copyright (C) 2001 S. Karger AG,Basel.