Magnetically tagged subsets of human lymphocytes for assays with laboratory robotics

We demonstrate the possibility of automation of whole-cell functionality assays, e.g., mitogen-activated DNA synthesis, DNA repair synthesis, and assessment of drug-metabolizing enzymes, by use of magnetic separation technology. We have attached antibody-coupled magnetic microspheres to the surface of human T-lymphocytes before performing various assays. Evaluating the biological functions of T-cells estimated by the DNA-synthesis assays showed that the presence of antibody-coupled magnetic microspheres did not affect the results (P greater than 0.05). The concentration of adenosine diphosphate ribosyltransferase (EC 2.4.2.30) was shown to be influenced by the magnetic microspheres. However, the amount of enzyme activity induced by oxidative stress was not significantly altered. The results from assays of the phase II drug-metabolizing enzymes glutathione transferase (EC 2.5.1.18) and epoxide hydrolase (EC 3.3.2.3) as well as evaluation of the proliferative response of polyclonal activators (phytohemagglutinin, staphylococcal enterotoxin A, and pokeweed mitogen) support our conclusion that assays can be performed on viable magnetized cells. The use of magnetized cells holds promise for further applications in automated genotoxic and immunological cell assays of mononuclear leukocyte subsets. Laboratory robotics will be essential in bringing these assays into routine use.