title: Sensitization prevalence, antibody cross-reactivity and immunogenic peptide profile of Api g 2, the non-specific lipid transfer protein 1 of celery.
abstract: BACKGROUND
  Celery (Apium graveolens) represents a relevant allergen source that can elicit severe reactions in the adult population. To investigate the sensitization prevalence and cross-reactivity of Api g 2 from celery stalks in a Mediterranean population and in a mouse model.
  
  
  METHODS
  786 non-randomized subjects from Italy were screened for IgE reactivity to rApi g 2, rArt v 3 (mugwort pollen LTP) and nPru p 3 (peach LTP) using an allergen microarray. Clinical data of 32 selected patients with reactivity to LTP under investigation were evaluated. Specific IgE titers and cross-inhibitions were performed in ELISA and allergen microarray. Balb/c mice were immunized with purified LTPs; IgG titers were determined in ELISA and mediator release was examined using RBL-2H3 cells. Simulated endolysosomal digestion was performed using microsomes obtained from human DCs.
  
  
  RESULTS
  IgE testing showed a sensitization prevalence of 25.6% to Api g 2, 18.6% to Art v 3, and 28.6% to Pru p 3 and frequent co-sensitization and correlating IgE-reactivity was observed. 10/32 patients suffering from LTP-related allergy reported symptoms upon consumption of celery stalks which mainly presented as OAS. Considerable IgE cross-reactivity was observed between Api g 2, Art v 3, and Pru p 3 with varying inhibition degrees of individual patients' sera. Simulating LTP mono-sensitization in a mouse model showed development of more congruent antibody specificities between Api g 2 and Art v 3. Notably, biologically relevant murine IgE cross-reactivity was restricted to the latter and diverse from Pru p 3 epitopes. Endolysosomal processing of LTP showed generation of similar clusters, which presumably represent T-cell peptides.
  
  
  CONCLUSIONS
  Api g 2 represents a relevant celery stalk allergen in the LTP-sensitized population. The molecule displays common B cell epitopes and endolysosomal peptides that encompass T cell epitopes with pollen and plant-food derived LTP.
authors: Christian Doppler Laboratory for Allergy Diagnosis and Therapy, University of Salzburg, Salzburg, Austria. Gabriele.Gadermaier@sbg.ac.at
authors: Gabriele
authors: G
authors: Gadermaier
authors: Michael
authors: M
authors: Hauser
authors: Matthias
authors: M
authors: Egger
authors: Rosetta
authors: R
authors: Ferrara
authors: Peter
authors: P
authors: Briza
authors: Keity Souza
authors: KS
authors: Santos
authors: Danila
authors: D
authors: Zennaro
authors: Tamara
authors: T
authors: Girbl
authors: Laurian
authors: L
authors: Zuidmeer-Jongejan
authors: Adriano
authors: A
authors: Mari
authors: Fatima
authors: F
authors: Ferreira
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D052179:Antigens, Plant / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D000077102:Apium / Q000276:immunology*; D002352:Carrier Proteins / Q000737:chemistry / Q000276:immunology*; D045744:Cell Line, Tumor; D002648:Child; D015331:Cohort Studies; D003429:Cross Reactions; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D005459:Fluorides; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007114:Immunization; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008689:Methacrylates; D051379:Mice; D008875:Middle Aged; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D011058:Pollen / Q000276:immunology; D011140:Polyurethanes; D011487:Protein Conformation; D051381:Rats; D055815:Young Adult
chemical_list: D000485:Allergens; D000906:Antibodies; D052179:Antigens, Plant; C559814:Api g 2 allergen, celery; C495881:Art v 3 allergen, Artemisia vulgaris; D002352:Carrier Proteins; D018984:Epitopes, T-Lymphocyte; D008689:Methacrylates; D010446:Peptide Fragments; D010940:Plant Proteins; D011140:Polyurethanes; C463181:Pru p 3 allergen; C091935:Sequence (bonding agent); C511920:lipid transfer proteins, plant; D007073:Immunoglobulin E; D005459:Fluorides