High-performance immunoaffinity chromatographic detection of immunoregulatory anti-idiotypic antibodies in cancer patients receiving immunotherapy.

Anti-idiotypic antibodies are regulatory antibodies responsible for the shutdown of active immune responses against growing tumor cells. In an attempt to study these antibodies, a technique for isolating specific anti-idiotypic antibodies by immunoaffinity chromatography was devised. Human anti-tumor antibodies were isolated by affinity absorption to fixed autologous tumor cells. These antibodies were biotinylated, immobilized on streptavidin-coated beads, and used as a ligand to isolate reactive anti-idiotypes from the plasma of patients during periods when immune reactivity against their tumors could not be detected. The isolated anti-idiotypes demonstrated the ability to react with the original antibodies and to inhibit their binding to autologous tumor cells. Thus functional anti-idiotypic antibodies can be isolated by immunoaffinity chromatography with the original idiotype as the ligand. This technique can be used to monitor regulatory antibodies in cancer patients receiving immunotherapy.