European journal of immunology
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We report our investigations of circulating interleukin (IL) 1 beta, IL 6 and tumor necrosis factor (TNF)-alpha, as well as cell-associated IL 1 alpha, IL 1 beta and TNF-alpha in plasma and monocytes of 21 patients with sepsis syndrome and 6 patients with non-septic shock. Longitudinal studies reveal that (a) the most frequent detectable plasma cytokines were TNF-alpha and IL 6, (b) the presence and the kinetics of circulating cytokines were independent of one other, (c) detectable levels of cytokines could be found for a long period of time, and (d) significantly higher levels of IL 6 were found for non-surviving patients. Because of the in vivo half-life of cytokines and of the existence of numerous specific high-affinity receptors, it is quite probable that detectable plasma cytokines represent the excess of produced mediators which have not been trapped by the target cells. ⋯ At the end of the longitudinal study (day 14 +/- 2), only 2/12 surviving patients still had plasma TNF-alpha, whereas 8/12 had monocyte-associated TNF-alpha. These results indicate that activation of monocytes still occurs in patients for whom no plasma cytokines can be detected. Thus, in addition to the measurement of plasma cytokine, measurement of cell-associated cytokine appears useful to assess cytokine production and monocyte activation in vivo.
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In these studies we analyzed the adjuvant effect of cholera holotoxin or cholera toxin (CT) B subunit on the B cell response to mucosal antigens. Purified Peyer's patch B cells obtained from mice at varying periods of time after oral administration of inactivated influenza virus, with or without a CT preparation, were stimulated in vitro in the absence or presence of various lymphokines. Responses were measured by an antigen- and isotype-specific ELISPOT assay. ⋯ These results thus indicate that CT preparations enhance the memory B cells response in Peyer's patches and, in addition, suggest that CT enhances isotype switching. In this antigen-specific B cell system IL 4 augmented responses in cultures containing IL 5 but not IFN-gamma; in addition, IL 5 and IFN-gamma acted in an additive fashion. Thus, these findings suggest that the effects of IL 5 and IFN-gamma are at least in part, mediated via different cellular differentiation pathways.