Comet assay analysis of DNA damage in T- and B-lymphocytes separated by MACS for human biomonitoring studies

In this study, we developed and tested a method for human biomonitoring using Comet assays with human T- and B-lymphocytes obtained by magnetic cell sorting (MACS). We evaluated DNA damage induced by treatment with hydrogen peroxide (H ₂O ₂; 5, 25 and 50μM) and methyl methane sulfonate (MMS; 5, 25 and 50μM) in both human B- and T-lymphocytes obtained by MACS, and compared their DNA damage levels. Significant, dose-dependent levels of DNA damage were found in T-lymphocytes and B-lymphocytes. Furthermore, the level of DNA damage was significantly greater in B-lymphocytes than in T-lymphocytes, suggesting that human B-lymphocytes may be a more sensitive target than T-lymphocytes for the evaluation of DNA damage. In addition, we compared these in vitro exposure data with previous studies that showed DNA damage in B- and T-lymphocyte and granulocytes of control subjects and industrial workers exposed in vivo to environmental toxicants. The use of single types of human peripheral blood mononuclear cells obtained by MACS, for Comet assays gave sensitive and reliable data for human biomonitoring for environmental toxicants.