LATEX IMMUNOASSAYS - COMPARATIVE-STUDIES ON COVALENT AND PHYSICAL IMMOBILIZATION OF ANTIBODIES - I - F(AB')(2) FRAGMENTS

Colloidal particles coated with antibodies are currently used in diagn ostic test systems for the detection of antigens in biological fluids. Immobilization is usually carried out by physical adsorption. Covalen t coupling of antibodies to particles, however, offers certain advanta ges. The present research deals with the study of these possible advan tages. A sulphonated polystyrene latex has been used to prepare an imm unolatex with physically adsorbed antibodies, while a functionalized l atex with chloromethyl groups on the surface has been used for the par tly covalent coupling of the antibody (F(ab')2 fragments). The immunor eactivity was studied by measuring the variations in scattered light i ntensity after mixing a solution of CRP antigen and the sensitized lat ex. The influence on the immunoresponse of the scattering angle (5, 10 , and 20 deg), protein coverage and storage time have been studied for both systems.