Preparation and standardization of perotidase-labeled anti-human IgG antibody for use in determination of serum antinuclear antibody levels.

Peroxidase-labeled antibody conjugates were prepared by a two-step conjugation procedure using glutaraldehyde. Immunoadsorbent-purified antibody and the gamma-globulin fraction of sheep anti-human IgG antiserum were employed for these preparations, Procedures for the determination of the antibody and enzymatic activity, as well as the specificity of the enzy-e-antibody reactions, were outlined. Peroxidase-anti-human-IgG conjugates were prepared with approximately a 1:1 molar ratio of peroxidase to IgG, which demonstrated a loss of 10-15% of precipitating antibody activity. Standardization procedures for use of peroxidase-labeled antibody in the indirect ANA test were established. The peroxidase-labeled antibody in the indirect ANA test were established. The peroxidase-antibody procedure was found to demonstrate a reproducible plateau endpoint which was comparable to that of the fluorescent antibody preparations.