Enumeration of (auto)antibody producing cells in human using the “spot-ELISA”

An enzyme-linked immunosorbent assay (spot-ELISA) for individual immunoglobulin secreting cells, which became recently available, was applied to the enumeration of human B lymphocytes secreting specific antibodies of thyroglobulin. Polyclonally activated B cells from patients with auto-immune thyroid disease are incubated in thyroglobulin coated plates. After removal of the cells specific antibodies are visualized by means of an immunoenzyme technique employing agarose to localize converted substrate. Individual specific antibody secreting cells are counted as blue spots using an inverted microscope. Numbers and isotype of spots correlate well with the amount and isotype of secreted antibody as detected with a conventional ELISA. This easy to perform, complement-independent technique offers a useful alternative to conventional plaque forming cell assays.