Characterization of potential allergens in fenugreek (Trigonella foenum-graecum) using patient sera and MS-based proteomic analysis.
BACKGROUND
Fenugreek is a legume plant used as an ingredient of curry spice. Incidents of IgE-mediated food allergy to fenugreek have been reported. Coincidence with allergy to peanut, a major food allergen, seems to be common suggesting a rather high rate of cross-reactivity.


OBJECTIVE
Characterization of fenugreek allergens using patient sera and mass spectrometry-based proteomic analysis.


METHODS
Allergenic fenugreek proteins were detected by immunoblotting, using sera from 13 patients with specific IgE to peanut and fenugreek. IgE-binding proteins were analyzed by peptide mass fingerprinting and peptide sequencing.


RESULTS
A fenugreek protein quintet in the range from 50 kDa to 66 kDa showed high IgE-affinity, the protein at 50 kDa reaching the strongest signals in all patients. Proteomic analyses allowed the classification of several fenugreek proteins to a number of allergen families. Fenugreek 7S-vicilin and 11S-legumin were partly sequenced and revealed considerable homologies to peanut Ara h 1 and Ara h 3, respectively. The presence of a fenugreek 2S albumin and pathogenesis-related (PR-10) plant pollen protein was assumed by database searching results.


CONCLUSIONS
In this study, individual fenugreek proteins were characterised for the first time. Observed homologies to major peanut allergens provide a molecular explanation for clinical cross-reactivity.
Faeste
Christiane Kruse
CK
National Veterinary Institute, Oslo, Norway. christiane.faste@vetinst.no
Christians
Uwe
U
Egaas
Eliann
E
Jonscher
Karen R
KR
D052179:Antigens, Plant / Q000097:blood / Q000737:chemistry* / Q000276:immunology*; D005240:Feasibility Studies; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D010449:Peptide Mapping / Q000379:methods*; D012698:Serologic Tests / Q000379:methods; D029910:Trigonella / Q000276:immunology*
D052179:Antigens, Plant