Characterization of latex and chestnut antigens by immunoblotting

Cross-reactions between latex, chestnut, and other fruits have been demonstrated by RAST, although the results show some discrepancies.

To detect and characterize cross-reacting antigens in both extracts by immunoblotting.

Polyclonal rabbit antisera were raised against ammoniated latex and an aqueous chestnut extract. The antigenic extracts were studied by immunoblotting using a diffusion transfer method. Cross-reactivities were measured by immunoblotting inhibition.

Both antisera detected a high number of antigenic proteins in both latex and chestnut extracts. Latex was a good self-inhibitor and inhibitor of chestnut with respect to both antisera. Chestnut was only a good inhibitor for the two antisera on the chestnut-blot as well as on the latex-blot when the anti-chestnut antiserum was employed. No inhibition was obtained on latex immunoblotting by chestnut using anti-latex antiserum.

The results suggested that latex and chestnut contained common epitopes detected by antibodies raised by immunization with both antigens. The anti-latex antiserum, however, possessed antibodies that could not be inhibited by other allergens. This could explain why latex has been described as a good inhibitor of chestnut-RAST while no inhibition by chestnut was found on the latex-RAST in latex and chestnut allergic patients. Other common pollen extracts were also inhibitors of immunoblotting with the exception of the latex/anti-latex pair. This suggests that antibodies induced by immunization with latex or chestnut showed unexpected cross-reactions.