The specificity of rabbit anti-native ovalbumin antibodies against native ovalbumin (NOA) or heat-denatured ovalbumin (HDOA) was studied by affinity chromatography, ELISA techniques, quantitative immuno-precipitation and HPLC. Affinity-purified antibodies were prepared either by passing antisera successively on an NOA column and an HDOA column, or vice versa. Antisera were found to contain about 85 % of antibodies directed against NOA, 7% specific for HDOA and 8% retained by both columns.
It is shown that antibodies specific for NOA fully precipitated NOA in liquid-phase precipitation but were unable to bind NOA in ELISA using NOA-coated plates, while recognising NOA trapped on the solid phase by a first layer of antibodies: ovalbumin was thus completely denatured during interaction with plastic as shown also by the fact that antibodies specific for HDOA reacted with NOA-coated plates.
These results point out the need to modify ELISA tests for monoclonal antibodies selection and for structural studies of food molecules in complex mixtures. However, this observation, which holds true for ovalbumin, might not apply to all antigens.