Effect of ozone on immunoglobulin production by human b cells in vitro

Abstract

Animal studies indicate that ozone (O₃) inhalation results in reduced ability to generate a humoral response to soluble and paniculate antigens. In this study, human lymphocytes have been exposed to O₃ in vitro (1.0, 0.5, and 0.1 ppm/2 h) and then evaluated for the ability of B cells to produce immunoglobulin C (IgG) in response to the T‐cell‐dependent stimulus pokeweed mitogen (PWM), and to the T‐cell‐independent stimulus Staphylococcus aureus Cowan I strain (SAC). Suppression of IgG production was found with O₃‐exposed PWM‐stimulated lymphocytes, while no effect of O₃ was seen with SAC‐stimulated cells, suggesting that T cells, but not B cells, were sensitive to O₃. However, exposing either cell type alone to O₃ indicated that both T cells and B cells were affected by the pollutant. The O₃‐exposed B cells produced less IgG in response to PWM but produced more IgG in response to SAC. On the other hand, O₃‐exposed T cells were suppressive in both PWM and SAC responses. Since the differentiation of B cells into plasma cells is regulated by complex interactions of cytokines secreted by T cells and antigen‐presenting cells, possible O₃‐induced alterations in secretion of some of these regulatory lymphokines (IL‐2, IL‐4, IL‐6, and IFN‐γ) were investigated in lymphocyte cultures stimulated with PWM. A decrease in IL‐2 production was found, while in contrast, IL‐6 production was significantly increased. IFN‐γ secretion was not altered, and IL‐4 levels were below the limits of detectability. These results suggest that O₃‐induced changes in IgG production may be mediated by altered production by T cells of important immunoregula‐tory molecules, in addition to any direct effects of O₃ on the IgG‐producing cells themselves.