Cruelty-free ELISA for human insulin

In the January issue of Clinical Biochemistry, scientists and physicians with the Physicians Committee for Responsible Medicine (PCRM) outline the method used to develop a cruelty-free ELISA for human insulin that uses monoclonal antibodies produced by cells cultured in an animal-serum-free medium.

PCRM's insulin ELISA, the first of its kind, provides precision and reliability equal to methods currently used in clinical research.

PCRM's insulin ELISA is now commercially available for research purposes from Millipore of St. Charles, Mo., which reports that it is selling briskly. The new ELISA also serves as a guide for the development of serum-free immunoassays for other hormones and bio-markers.

The ELISA, or enzyme-linked immunosorbant assay, is a method of detecting specific proteins in complex protein mixtures--in this case, for detecting insulin in human blood. Laboratories traditionally detect human insulin using antibodies produced by cells that had been placed into the abdomens of living mice. The procedure, called the ascites method, is so cruel that it is banned in some European countries. Even when the antibodies are produced from cells in test tubes, fetal bovine serum is commonly used to grow live cells. The serum is obtained from bovine fetuses by puncturing their hearts with a needle without the use of anesthesia.

PCRM's insulin ELISA does not rely on the ascites method or fetal bovine serum. In addition to ethical advantages, growing cells without animal serum ensures that fewer variables are introduced into experiments, meaning that results are easily reproducible by different laboratories. The method outlined in Clinical Biochemistry, the official journal of the Canadian Society of Clinical Chemists, permits the growth of antibody-producing cells in a medium free of animal serum, enabling scientists to make cell culture safer and more humane.

"The ethical and scientific advantages of avoiding fetal calf serum and the ascites method are clear, and we hope the methodology used to produce our ELISA serves as a guide for developing other animal-serum-free immunoassays," says Chad Sandusky, Ph.D., a co-author of the paper and PCRM's director of research and toxicology.