To specify the role of individual cytokines in the immune response to pyrogens, isolated and cultivated human peripheral blood mononuclear cells (PBMC) were used for the experiments. Different pyrogens (lipopolysaccharide from Escherichia coli - LPS and live Borrelia afzelii) were applied and the time course of changes in concentrations of different cytokines in the medium was followed using the ELISA method. It was found that nonstimulated human PBMC proliferate under in vitro conditions and produce IL-6, TNF-a, IL-10 and finally also IL-1b. Productions of IL-12 and INF-g are not changed. Proliferation of PBMC is potentiated after incubation with LPS or live Borrelia. PBMC stimulated by LPS increase the net production (stimulated minus unstimulated) of IL-1b and TNF-a significantly, while production of IL-6 was smaller. A delayed increase in the production of IL-10 was also observed. Productions of IL-12 and INF-g were not influenced. In contrast to LPS, stimulation of PBMC with live Borrelia, increases also the production of IL-12 and IFN-g, besides IL-1b, TNF-a, IL-6 and IL-10. Productions of IL-1b, IL-6 and TNFa increased immediately after incubation with both LPS and Borrelia, while productions of IL-12 and INF-g begin to increase 8 hours and production of IL-10 12 hours after stimulation. Data indicate that stimulation with different pyrogens may activate the cells of the immune cascade in a different way. Stimulation of BPMC by LPS seems to activate the initial steps of the immune response (macrophages and granulocytes) only, while infection with live Borrelia also stimulates the later phase of the immune response, probably due to effect of initially produced cytokines., L. Janský, P. Reymanová, J. Kopecký., and Obsahuje bibliografii
The effect of repeated infestations of BALB/c mice with Ixodes ricinus (L.) nymphs on tick borne encephalitis (TBE) virus infection was studied. Enhancement of nymphal feeding, occurring in noninfected mice during the quaternary infestations, was less apparent or absent in female nymphs engorged on TBE virus infected mice. The mice infected with TBE virus during quaternary tick infestation survived significantly longer (P < 0.01) than mice infected with TBE virus during the primary tick infestation. The mean titre of virus in murine blood (determined by plaque assay) was significantly lower (P < 0.01) and the number of nymphs acquiring virus was reduced (P < 0.05) when feeding on hosts infected during the quaternary infestation. The results indicate that repeated infestations of I. ricinus nymphs on BALB/c mice, although enhancing tick feeding, reduced infection with TBE virus when inoculated intraperitoneally.
Body fat content is controlled, at least in part, by energy charge of adipocytes. In vitro studies indicated that lipogenesis as well as lipolysis depend on cellular ATP levels. Respiratory uncoupling may, through the depression of ATP synthesis, control lipid metabolism of adipose cells. Expression of some uncoupling proteins (UCP2 and UCP5) as well as other protonophoric transporters can be detected in the adipose tissue. Expression of other UCPs (UCP1 and UCP3) can be induced by pharmacological treat
ments that reduce adiposity. A negative correlation between the accumulation of fat and the expression of UCP2 in adipocytes was also found. Ectopic expression of UCP1 in the white fat of aP2-Ucp1 transgenic mice mitigated obesity induced by genetic or dietary factors. In these mice, changes in lipid metabolism of adipocytes were associated with the depression of intracellular energy charge. Recent data show that
AMP-activated protein kinase may be involved in the complex changes elicited by respiratory uncoupling in adipocytes. Changes in energy metabolism of adipose tissue may mediate effects of treatments directed against adiposity, dyslipidemia, and insulin resistance.