Definition of the human T-cell epitopes of Fel d 1, the major allergen of the domestic cat.
BACKGROUND
A heterodimeric acidic glycoprotein (Fel d 1) has been defined as the major allergen of the domestic cat. Because T-cell help is required for the initiation and maintenance of allergic responses, it is of importance to determine the T-cell-reactive regions of the Fel d 1 molecule.


METHODS
Overlapping peptides corresponding to the two chains of Fel d 1 were tested in proliferation assays on polyclonal T-cell lines and for the ability to bind Fel d 1-specific IgE in ELISA and histamine release assays.


RESULTS
Assay of T-cell lines derived from 53 subjects allergic to cats demonstrated that the majority of T-cell reactivity is found in chain 1 of Fel d 1. Two peptides (Fel-1 and Fel-2) containing major epitopes, alone or as a mixture, efficiently activated T cells and exhibited minimal detectable reactivity with IgE by ELISA or histamine release assay.


CONCLUSIONS
Two Fel d 1 peptides containing major T-cell epitopes have been identified, have been shown to bind minimal Fel d 1-specific IgE, and are now being tested for the ability to decrease T-cell responses in patients with cat allergy as a new form of immunotherapy.
Counsell
C M
CM
ImmuLogic Pharmaceutical Corporation, Waltham, MA 02154, USA.
Bond
J F
JF
Ohman
J L
JL
Greenstein
J L
JL
Garman
R D
RD
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002415:Cats / Q000276:immunology*; D002461:Cell Line, Transformed; D003888:Desensitization, Immunologic; D000939:Epitopes / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology*; D004854:Herpesvirus 4, Human; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000276:immunology; D008211:Lymphocyte Cooperation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000276:immunology*
D000939:Epitopes; D006023:Glycoproteins; D010446:Peptide Fragments; D007073:Immunoglobulin E; C059296:Fel d 1 protein, Felis domesticus