MONOCLONAL AND POLYCLONAL ANTIBODIES AGAINST CASEIN COMPONENTS OF COWMILK FOR EVALUATION OF RESIDUAL ANTIGENIC ACTIVITY IN HYPOALLERGENIC INFANT FORMULAS

Background Hydrolysed casein and whey protein formulas have been devel oped with the aim of preventing sensitization in infants at high risk of cow milk allergy. Subsequently these products have also been used f or treatment of children with cow milk allergy. However, severe reacti ons have occurred in some allergic infants fed with these formulas rai sing doubts about their absolute safety and suggest the need for devel oping in vitro techniques for detection of eventual residual allergeni c activity in such preparations. Objectives Our purpose was to evaluat e the usefulness of monoclonal and polyclonal antibodies against casei n components (alpha, beta and kappa casein) as reagents for the detect ion of the residual antigenic activity of casein components in several hydrolysed formulas. Methods The monoclonal and polyclonal antibodies were produced according to standard procedures by immunizing female B alb/c mice with casein fraction (a mixture of alpha, beta and kappa ca sein). ELISA assays were developed to test the specificity of the anti bodies and to detect and evaluate the amount of residual antigenic act ivity of the casein components in hydrolysed formulas. Results Use of polyclonal antiserum specific for casein allowed detection of residual antigenic activity of casein components in all partial hydrolysates a nd in the two extensive whey protein hydrolysates in the amounts rangi ng from 0.05 to 0.67% of total protein, No such activity was detectabl e in either the two extensive casein hydrolysates tested or the aminoa cid based formula. The polyclonal antiserum proved to be more suitable than monoclonals for detecting residual antigenic activity in the hyd rolysates. The monoclonal antibodies were directed against epitopes ex pressed on different casein components, Conclusions In this study the ELISA inhibition assay with polyclonal antibodies specific for casein components of cow milk proved to be a sensitive method for estimating residual antigenicity in the hydrolysed formulas commercially availabl e for infants with cow milk allergy suggesting their potential applica tion for the quality control of hypoallergenic infant formulas.