Enzyme-Linked Immunosorbent Assay, Elisa

TLDR

The study reports a sensitive, simple method for quantitatively determining antibodies. The assay uses antigen‑coated polystyrene tubes incubated with antiserum and enzyme‑labeled anti‑IgG; after washing, the retained enzyme activity quantifies specific antibodies, with specificity confirmed by hapten inhibition. The assay detects as little as 1 ng/ml of specific antibody, quantifies unknown sera against a standard, yields results comparable to existing methods, and shows specificity via hapten inhibition.

Abstract

Abstract A sensitive and simple method for the quantitative determination of antibodies is reported. Tubes coated with antigen are incubated with antiserum followed by an enzyme-labeled preparation of anti-immunoglobulin. The enzyme remaining in the tubes after washing provides a measure of the amount of specific antibodies in the serum. Coating of polystyrene tubes with antigen is described, as well as the preparation of specifically purified antibodies against rabbit IgG, and their conjugation to alkaline phosphatase. When rabbit antisera against human serum albumin or against the dinitrophenyl group (DNP) were incubated in tubes coated with antigen, less than 1 ng/ml of specific antibody could be detected in both systems. Antibodies in unknown sera could be quantitated by comparison with a standard antiserum. The results obtained compared well with those obtained with other methods for antibody determination. In the DNP system, the specificity of the reaction was assessed by inhibition with hapten. The reaction of immune serum against DNP with DNP-protein, adsorbed to the tubes, was completely inhibited by hapten in solution.