Synthesis and properties of polymeric latex particles and their conjugates with human immunoglobulin G

Abstract

Polymeric latex particles of uniform size in the range of 750 to 10 000 Å in diameter were prepared by emulsion copolymerization of methyl methacrylate, methacrylic acid, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, using sodium dodecylbenzene sulphonate as an emulsifier and ammonium persulphate as an initiator. With a fixed composition of monomers the carboxyl groups on the latex particles ranged from 5 × 10 3 to 180 × 10 3 per particle, but the average number per unit surface area remained within a limited variation. Human immunoglobulin G (IgG) was covalently bonded to the latex particles by either the carbodiimide or the cyanogen bromide method, taking advantage of carboxyl and hydroxyl groups, respectively. The resulting conjugates exhibited a specific agglutination with rabbit anti-human IgG and sera from rheumatoid arthritis ( RA) patients. The immunolatex particles were found to be superior to those derived from nylon-6, which had been used in our previous work, and are expected to offer useful means in various immunological studies.