Serum tumour necrosis factor in children suffering from Plasmodium falciparum infection in Kilifi District, Kenya.

Tumour necrosis factor-alpha (TNF alpha) levels were measured by bioassay and immunoassay in sera of children infected with Plasmodium falciparum and uninfected children in the same community in Kilifi District, Kenya. Seventy-one children, mean age 2.9 years (range 4 months-6.8 years), were enrolled; 34 children had severe malaria, 23 had mild (non-severe) malaria and 14 had no malaria. TNF alpha levels were significantly elevated in children with severe malaria compared with those with non-severe malaria and the uninfected group (P < 0.001 and P < 0.00001, respectively). The levels correlated directly with parasite densities (r = 0.54, P < 0.002). Among the children with severe malaria, TNF alpha levels correlated directly with the degree of anaemia but inversely with age. High tumour necrosis factor levels were associated with manifestations of severe malaria infection but declined to normal levels after effective antimalarial treatment.

Sleep and cerebrospinal fluid interleukin-1-like activity in the cat.

Exogenous interleukin-1 (IL-1), applied intraventricularly, has been reported to enhance slow wave sleep. Here, we demonstrate that endogenous interleukin-1-like activity and IL-1 beta of the cat CSF increases during sleep in comparison to wake.

Regulation of MHC expression in vivo. Bacterial lipopolysaccharide induces class I and II MHC products in mouse tissues by a T cell-independent, cyclosporine-sensitive mechanism.

The effect of injections of bacterial LPS on the expression of class I and II products of the MHC in mouse tissues was investigated. MHC products were assessed in tissue homogenates by radiolabeled antibody binding and in tissue sections by indirect immunoperoxidase (IIP) staining. In mice given two i.p. injections of LPS from Escherichia coli or Salmonella minnesota, there were increases in class I and II MHC products in kidney, liver, heart, lung, and pancreas. Focusing on the changes in kidney, we demonstrated that the increase in MHC expression occurred in tubules and, in the case of class I, in glomeruli. LPS treatment also increased the deposition of Ig in glomeruli. Expressed on a standard curve, the total kidney class I and II expression was elevated approximately 10-fold. Time course studies indicated that increased class I expression could be induced by a single LPS injection, whereas class II induction required a second injection. The induction was influenced by the LPS sensitivity of the mice, being much greater in LPS-sensitive C3H/HeSn mice than in LPS-resistant C3H/HeJ mice. LPS induced class I and II Ag in nude mice and in mice with severe combined immunodeficiency, indicating that T cells were not required. Nevertheless, the effect of LPS was inhibitable by cyclosporine and by a mAb against IFN-gamma indicating that IFN-gamma was required for the MHC induction. We conclude that LPS induces an increase in expression and a redistribution of MHC products in kidney and in other tissues by a T cell-independent, cyclosporine-sensitive pathway. These findings are probably related to the known ability of LPS to mediate release of IFN-gamma and other cytokines.

Systemic immunologic stimuli increase class I and II antigen expression in mouse kidney.

The effect of systemic immunologic stimulation on renal expression of the H-2K (class I) and Ia (class II) antigens of the mouse major histocompatibility complex was explored. We previously reported that graft-vs-host (GvH) disease in mice caused an increase in host renal Ia expression. In the present experiments, we demonstrated that Kk antigen expression also increased during GvH. Other immune stimuli (allogeneic tumor grafts or injections of allogeneic spleen cells) caused increased renal Ia (and, where studied, Kk) expression in the epithelium of some renal tubules, as demonstrated by indirect immunofluorescence (IIF) or immunoperoxidase (IIP) staining. The normal interstitial Ia staining was frequently diminished in the kidneys of mice given these stimuli. At least in the case of allogeneic tumor grafts, the changes in renal Ia and H-2K were dependent on host T cells, in that no similar change appeared in nude (nu/nu) mice bearing allogeneic tumor grafts. By histochemical techniques, most of the change was in proximal tubules. In semiquantitative absorption, the total renal Ia was usually increased (two- to 20-fold) in parallel with the IIF or IIP changes. Serial studies revealed that MHC product induction was frequently transient and was not associated with detectable histologic abnormalities. In cultured renal cells, increased Iak and Kk could be demonstrated by IIF after 4 days of culture in supernatants of lymphocytes stimulated with concanavalin A: the activity in these supernatants was probably not interleukin 2, but might have been IFN-gamma, because IFN-gamma also induced this change. We conclude that systemic immunologic stimuli alter MHC product expression in renal tubule epithelium and that this effect can be stimulated in vitro by supernatants of stimulated lymphocytes.