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

Animal studies indicate that ozone (O3) inhalation results in reduced ability to generate a humoral response to soluble and particulate 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 G (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-gamma) 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-gamma 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 immunoregulatory molecules, in addition to any direct effects of O3 on the IgG-producing cells themselves.