The immune complexes are decomposed into their individual components in an acid or alkaline medium, suitably at pH 2-5 or 10-12 which, if required, after fractionation and, if necessary, after adding salts such as NaCl, MgCl2, LiCl or urea or guadinine hydrochloride to keep the reactants dissociated after reaching a certain concentration, are coupled to solid materials at pH 2-12 by applying conve