Olive pollen allergen Ole e 8: identification in mature pollen and presence of Ole e 8-like proteins in different pollens

In a first approach, Ole e 8, a novel Ca2+-binding protein from olive pollen, was cloned and produced in Escherichia coli. We have obtained the natural form of Ole e 8 (nOle e 8) from the pollen and examined its immunologic equivalence with its recombinant form (rOle e 8). Size exclusion chromatography and a phenyl-Sepharose CL-4B affinity column were used to obtain nOle e 8 from the olive pollen. Inhibition assays by immunoblotting, using rOle e 8-specific rabbit antiserum, were performed to analyze the immunologic equivalence between the natural and the recombinant allergen, as well as to detect its presence in other pollens. Recombinant and natural Ole e 8 resulted immunologically equivalents, since they completely inhibited the IgG binding of the polyclonal antiserum to each other. Ole e 8-like proteins were detected in Oleaceae and Juniperus communis pollen, and might contribute to cross-reactivity processes between taxonomically related pollens.