Monoclonal antibodies against Olea europaea major allergen: allergenic activity of affinity-purified allergen and depleted extract and development of a radioimmunoassay for the quantitation of the allergen.
Several monoclonal antibodies (MAbs) were raised against Olea europaea pollen-extract components. Two of these antibodies, named OL 2 and OL 7, recognize two nonoverlapping, nonrepeating epitopes on the olive-allergen Ole e I, as demonstrated by different techniques. The allergen was purified in a single step by MAb-based affinity chromatography, and the allergen revealed a band at molecular weight 20 kd as well as a minor band at 18 kd on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The contribution of allergen Ole e I to the allergenic activity of O. europaea pollen extracts was determined from the effect of allergen depletion by affinity chromatography on skin reactivity and a histamine-release test. The removal of allergen caused a large reduction in the activity of the preparation in 25 monospecific olive-allergic patients. In agreement, the affinity-purified allergen demonstrated a similar response when it was compared with the whole extract in these assays. The results indicated that Ole e I is by far the most important olive-pollen allergen. A two-site solid-phase radioimmunoassay was developed for the quantitation of the allergen Ole e I in mass units. The assay was based on the MAbs, OL 2 and OL 7, and had a detection limit in the nanogram range. A good correlation was found between allergenic activity, as determined by RAST inhibition, and allergen content in 18 olive-pollen extracts. This result indicates that the assay can be a good alternative to RAST inhibition for the standardization of O. europaea extracts.
Research Department, Alergia e Inmunología Abelló SA, Madrid, Spain.
M
M
Lombardero
S
S
Quirce
O
O
Duffort
D
D
Barber
J
J
Carpizo
M J
MJ
Chamorro
A
A
Lezaun
J
J
Carreira
D000485:Allergens / Q000276:immunology* / Q000302:isolation & purification; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D002846:Chromatography, Affinity; D005260:Female; D006636:Histamine Release; D051379:Mice; D008807:Mice, Inbred BALB C; D010936:Plant Extracts / Q000276:immunology; D011058:Pollen / Q000276:immunology*; D011852:Radioallergosorbent Test; D014197:Trees
D000485:Allergens; D000911:Antibodies, Monoclonal; D010936:Plant Extracts