LATEX IMMUNOASSAYS - COMPARATIVE-STUDIES ON COVALENT AND PHYSICAL IMMOBILIZATION OF ANTIBODIES - II - IGG

Latex particles coated with IgG, currently used for immunoassay tests, are not colloidally stable under physiological conditions. Post-treat ment of sensitized polystyrene microspheres with different substances (BSA, surfactants) to increase colloidal stability has been often used to solve this problem. We propose the possibility of stabilizing the antibody-latex conjugates by hydration forces at high ionic strength. On the other hand, immobilization of the proteins may be performed eit her by physical adsorption or by covalent binding to functionalized su rface groups. In this second parr of these series we have studied the immunoreactivity of IgG antibody partly covalently bound and physicall y adsorbed, and the results were compared to those obtained with F(ab' )2 fragments in Part I.