Use of a multiwell assembly for chemotaxis and evaluation by enzyme-linked immunosorbent assay (ELISA).

A multiwell chamber assembly for chemotaxis tests was designed, which integrates the established microtiter system. A microtiter plate is covered with a plastic plate containing up to 96 holes of the diameter of the microtiter wells. Between the plates, a Nucleopore filter sheet (5 micron) and a silicon rubber gasket is placed. As a model system, human monocytes and lymphocyte-derived chemotactic factors were used. As it was observed that monocytes migrate through the membrane and settle on the bottom of the microtiter wells, an ELISA was adapted for quantitation of cells. After washing and incubation with a xenoantiserum against human monocytes, the bound antibody was quantitated using protein-A-conjugated alkaline phosphatase and p-nitrophenyl phosphate as detection system. The plates were read in a multichannel photometer. Cell numbers were determined directly from a calibration curve established before with varying numbers of monocytes. Current experience allows the following conclusions: The chemotaxis test in microtiter plates is simpler, faster and uses less material than conventional Boyden chambers. Evaluation by ELISA is much faster and more accurate than by microscopy.