In situ localization of a high molecular weight cross-reactive allergen in pollen and plant-derived food by immunogold electron microscopy.
BACKGROUND
A high molecular weight (60 kd) allergen has been recently identified as a cross-reactive moiety in pollen and plant-derived food. While the cross-reactive allergen has been characterized by immunochemical techniques, little is known concerning its biologic properties.


OBJECTIVE
In this investigation we studied the in situ localization of the 60 kd cross-reactive allergen in tree, grass, and weed pollen, as well as in plant-derived food (apple and celery).


METHODS
A monoclonal antibody (3A4) that was raised against the major mugwort pollen allergen, Art v 1, was used to demonstrate the presence of related allergens in nitrocellulose-blotted pollen and plant-food extracts. The tissue localization of the cross-reactive allergen was investigated by immunogold electron microscopy.


RESULTS
Monoclonal antibody 3A4 recognized IgE epitopes of the 60 kd mugwort allergen and cross-reacted with moieties of comparable molecular weights in birch and timothy grass pollen, as well as in apple and celery extracts. In pollen and plant-derived food the allergen could be localized intracellularly in ribosome-rich areas in the mitochondria and the nucleus. No labeling was observed in the pollen or cell walls or in organelles that are engaged in storage (e.g., starch granules and lipid particles).


CONCLUSIONS
Tree, grass, and weed pollen, as well as plant-derived foods, contain a high molecular weight Art v 1-cross-reactive allergen that maps to similar cell compartments.
Grote
M
M
Institute of Medical Physics and Biophysics, University of Münster, Germany.
Fischer
S
S
Müller
W D
WD
Valenta
R
R
D000485:Allergens / Q000032:analysis* / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal; D019306:Artemisia / Q000737:chemistry / Q000276:immunology; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis / Q000276:immunology; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology; D005638:Fruit / Q000737:chemistry* / Q000276:immunology; D007073:Immunoglobulin E / Q000032:analysis / Q000276:immunology; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron / Q000379:methods; D008970:Molecular Weight; D010944:Plants / Q000737:chemistry* / Q000276:immunology; D010946:Plants, Medicinal; D006109:Poaceae / Q000737:chemistry / Q000276:immunology; D011058:Pollen / Q000737:chemistry* / Q000276:immunology; D014197:Trees / Q000737:chemistry / Q000276:immunology; D014675:Vegetables / Q000737:chemistry* / Q000276:immunology
D000485:Allergens; D000911:Antibodies, Monoclonal; D000939:Epitopes; D007073:Immunoglobulin E