Immune function studies cell culture

The effects of MeHg on lymphocyte function have been studied in cell-culture systems in an attempt to elucidate the mechanisms involved in its ability to modulate immune function. Exposure of cultured lymphocytes to MeHg has been shown to inhibit mitogen-induced DNA synthesis, cell proliferation, and antibody synthesis. Electron micro... 

Conneely, 2001). LF has the ability to bind to the surface of several types of immune cells, which suggests that it can modulate immune functions. Both stimulatory and inhibitory effects of LF on lymphocyte proliferation have been described in the literature. LF has been reported to induce in vitro maturation of T- and B-lymphocytes, to modulate the activity of natural killer cells and to enhance the phagocytic activity of neutrophils. In mice, bovine LF has been shown to induce both mucosal and systemic immune responses (Debbabi et al., 1998). Cell-culture studies have demonstrated that LF and peptides derived from LF influence the production of various cytokines which regulate the immune and inflammatory responses of the body (Crouch et al., 1992 Shinoda et al., 1996). 

A number of chemicals with demonstrable suppression of immune function produce this action via indirect effects. By and large, the approach that has been most frequently used to support an indirect mechanism of action is to show immune suppression after in vivo exposure but no immune suppression after in vitro exposure to relevant concentrations. One of the most often cited mechanisms for an indirect action is centered around the limited metabolic capabilities of immunocompetent cells and tissues. A number of chemicals have caused immune suppression when administered to animals but were essentially devoid of any potency when added directly to suspensions of lymphocytes and macrophages. Many of these chemicals are capable of being metabolized to reactive metabolites, including dime-thylnitrosamine, aflatoxin Bi, and carbon tetrachloride. Interestingly, a similar profile of activity (i.e., suppression after in vivo exposure but no activity after in vitro exposure) has been demonstrated with the potent immunosuppressive drug cyclophosphamide. With the exception of the PAHs, few chemicals have been demonstrated to be metabolized when added directly to immunocompetent cells in culture. A primary role for a reactive intermediate in the immune suppression by dimethylnitrosamine, aflatoxin Bi, carbon tetrachloride, and cyclophosphamide has been confirmed in studies in which these xenobiotics were incubated with suspensions of immunocompetent cells in the presence of metabolic activation systems (MASs). Examples of MASs include primary hepatocytes, liver microsomes, and liver homogenates. In most cases, confirmation of a primary role for a reactive metabolite has been provided by in vivo studies in which the metabolic capability was either enhanced or suppressed by the administration of an enzyme inducer or a metabolic inhibitor, respectively. 

Dendritic cells may be involved with any impacts of lead on acquired immunity. Data are largely from cell culture studies, wherein Gao et al. (2007) reported Pb-delayed dendritic cell maturation and function with Pb addition, such as a significantly reduced ratio of IL-12/1L-10. 

A human in vitro model has been used for this study. The interaction between metal surfaces or metal ions and immune cells or bone cells was investigated. Cell culture, immune fluorescence and electron microscopy, functional tests, flow cy-tometry and molecular methods were applied. 

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