Pure IgG₁ and IgG₂ globulins were obtained by means of precipitation with ammonium sulphate and subsequent fractionation in DEAE Sephadex A-50 column. The IgM globulin was isolated by means of chromatography on Sephadex G-200 and DEAE-cellulose. Antibodies to these proteins were produced by immunization of rabbits and goats. Purity of proteins and monovalence of antibodies were checked up by means of immunoelectrophoresis and polyacrylamide gel electrophoresis.