Monoclonal antibodies against the candidate lupin allergens alpha-conglutin and beta-conglutin.
BACKGROUND
The ingestion of dietary products containing sweet lupin (such as Lupinus albus or Lupinus angustifolius) has been reported to cause IgE-mediated allergic reactions. Recent studies have indicated lupin globulins as important IgE binding proteins. The aim of the present study was to generate and characterize monoclonal antibodies (mAbs) against lupin seed proteins.


METHODS
Mice were immunized with a protein isolate from L. albus and mAbs were obtained by hybridoma techniques. Albumins and globulins were extracted, and the globulin fraction was separated further into conglutins by anion exchange chromatography. Specificities, binding patterns and applications of the mAbs were investigated by immunochemical methods.


RESULTS
Five mAbs were produced: Lu11 (an IgG2b antibody), Lu8, Lu18, Lu34 and Lu35 (all IgM antibodies). The mAbs reacted strongly with protein isolates from both L. albus and L. angustifolius. All mAbs are directed towards the lupin globulin fraction; Lu11 and Lu18 recognize alpha-conglutin, while Lu8, Lu34 and Lu35 recognize beta-conglutin. In addition, Lu11 inhibited the binding of IgE from patients with positive skin prick tests to lupin proteins in a competitive ELISA by approximately 30%. Furthermore, preliminary results show that Lu11 can be used to develop a sensitive method for the detection of alpha-conglutin in foods.


CONCLUSIONS
Lupin globulins are immunogenic and alpha-conglutin is a potential allergen. This is the first study describing mAbs against the candidate lupin allergens, emphasizing the importance of additional studies on conglutins in lupin allergy.
Dooper
Maaike M B W
MM
Institute of Immunology, University of Oslo and Rikshospitalet University Hospital, Oslo, Norway.
Holden
Lise
L
Faeste
Christiane K
CK
Thompson
Keith M
KM
Egaas
Eliann
E
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D000918:Antibody Specificity; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007114:Immunization; D007073:Immunoglobulin E / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010940:Plant Proteins / Q000276:immunology*; D055314:Seed Storage Proteins
D000911:Antibodies, Monoclonal; D010940:Plant Proteins; D055314:Seed Storage Proteins; C042457:conglutin protein, Lupinus angustifolius; D007073:Immunoglobulin E