Changes in T‐lymphocyte subpopulations and natural killer cells following exposure to ambient levels of nitrogen dioxide

Abstract

The effects of ambient levels of NO₂ on murine splenic T‐lymphocyte subpopulations and natural killer cells were investigated. AKR/cum and C57BL/6) mice were exposed, in inhalation chambers, to 0.25 ppm NO₂ for 7 wk and 0.35 ppm NO₃ for 12 wk, respectively. Monoclonal antibody technology was used in conjunction with fluorescence‐activated cell sorter (FACS) analysis to detect quantitative changes in total T‐lymphocytes (Thy‐1.2‐positive), mature T‐lymphocytes (Lyt‐1‐positive), T‐helperlin‐ducer lymphocytes (L3T4‐positive), T‐cytotoxic/suppressor lymphocytes (Lyt‐2‐positive), and natural killer cells (asialo GM₁‐positive). Percentages of all T‐lymphocyte subpopulations tested and natural killer cells were lower in spleens of mice exposed to NO₂ compared to filtered‐air controls. This is the first report providing evidence linking alterations in T‐lymphocyte subpopulations and natural killer cells to NO₂ exposure at ambient levels. Changes in T‐lymphocyte subpopulations detected by FACS and correlated to impaired immune function may provide an extremely sensitive means of demonstrating NO₂‐induced changes in the immune system.