Development of acute autoimmune encephalomyelitis in mice: Factors regulating the effector phase of the disease

The development of acute experimental autoimmune encephalomyelitis (EAE) in mice is potentiated by the use of Bordetella pertussis vaccine as an adjuvant. Histamine sensitizing factor (HSF) extracted from B. pertussis is the active adjuvant agent and causes a mild increase in cerebrovascular permeability. During the development of EAE, there is an additional increase in vascular permeability of the brain and spinal cord. The adjuvant action of B. pertussis HSF does not appear to mimic a generalized beta-adrenergic blockade, since the course of EAE is not potentiated by adrenalectomy. The cerebrovascular permeability changes observed in EAE are probably mediated by vasoactive amines, since the expression of EAE can be blocked by vasoactive amine antagonists.     

Clinical,hematologic, and immunologic effects of interleukin-10 in humans

We conducted a double-blind, placebo-controlled study to investigate the safety, pharmacokinetics, and immunological properties of interleukin-10 (IL-10) administration in healthy humans. Volunteers received a single intravenous bolus injection of recombinant human IL-10 (1, 10, or 25g/kg) or placebo. Cytokine production in whole blood and peripheral blood mononuclear cells (PBMC) was assessed before and 3, 6, 24, and 48 hr after the injection. Peak serum concentrations of IL-10 (15±1.1, 208±20.1, and 505±22.3 ng/ml) occurred after 2–5 min for 1, 10, and 25g/kg IL-10, respectively. The terminal-phase half-life was 3.18 hr. A transient leukocytosis (24–63% above baseline) was observed 6 hr after injection, which coincided with a dose-dependent decrease (12–24%) in neutrophil superoxide generation. There was a marked inhibition (60–95%) of endotoxin-induced IL-6 production from whole blood in each group receiving IL-10. Production of IL-8 in endotoxin-stimulated blood was reduced in the 10g/kg group. In PBMC stimulated with phytohemagglutinin and phorbol ester, there was a decrease (72–87%) in interferon- (IFN) production 6 hr after IL-10 with a return to pre-IL-10 levels after 24 hr. This reduction was only partially associated with a decrease in the number of CD2-bearing cells. We conclude that IL-10 administration into humans is without significant side effects, and a single injection reducesex vivo production of IL-6, IL-8, and IFN.     

Molecular mechanisms underlying IFN-{gamma}-mediated tumor growth inhibition induced during tumor growth inhibition induced during tumor immunotherapy with rIL-12

The present studnt Investigates the molecular by which IFN-produced as a result of in vitroIL-12 addministration exertsits anty-tumor,rIL-12 was administered three or five times intomice bearing CDA1M fibrosarcoma, OV-HM ovarian carcinoma orMCH-1-A1 fibosarcoma. This regimen induced complete regressionof CSA1M and OV-HM tumors but only transient growth inhibitionof MCH-1-A1 tumors. The anty-tumor effects of Il-12 were associatatedwith enhanced induction of IFN-becouse these effects were abrogatedby pretreatment of hosts with anti-IFN- antibody.Exposure inin vitro of the three types of tumor cells to rIFN- resultedin moderate to potent inhibition of tumor cell growth.IFNstimulatedthe expression of mRNAs for an inducible type of NO synthasa(INOS)in CSA1M cells and indoleamine 2,3-dioxygenasa (IDO),an enzyme capable of degrading tryptophan, in OV-HM cells ,but induced only marginal levels of these mRNAs in MCH-I-ALcells. In association withiNOS gene expression, INF--stimulatedCSA1M cells produced a large amount of NO which functioned toinhibit their own growth in vitro. Although OV-HM and MCH-1-A1cells did not produce NO, they also exhibited NO susceptibility.Whereasthe tumor masses from IL-12-treated CSA1M-bearing mice inducedhigher levels of INOS (for CSA1M) or IDO and iNOS (for OV-HM)mRNAs,the MCH-1-A1 tumor mass expressed lower levels of iNOS mRNAalone.Moreover, massive infiltration of CD4⁺and CD8⁺ T cellsand Mac-1⁺ cells was seen only in the CSA1M and OV-HM tumors.Thus, these results indicate that IFN- produced after IL-12treatment induces the expression of various genes with potentialto modulate tumor cells and growth by acting directly on tumorecells or stimulating tumor-infiltrating lymphold cells and thatthe effectiveness of IL12 therapy is assoiated with the operation if these mechanisms.     

Glycoprotein B of bovine herpesvirus type 4: Its phylogenetic relationship to gB equivalents of the herpesviruses

In order to estimate the phylogenetic relationship of BHV-4 among the herpesviruses, we have cloned and sequenced its glycoprotein B (gB). The 2.6 kb open reading frame codes for a 874 amino acid long protein. The comparison of its deduced amino acid sequence with those of its counterparts in 19 distinct herpesviruses groups BHV-4 into the -herpesvirinae. The calculation of an evolutionary tree emphasized that BHV-4 is more closely related to herpesvirus saimiri (HVS) than to Epstein-Barr virus (EBV). However, in contrast to EBV and HVS, the gB of BHV-4 contains a putative protease cleavage site and 20 potential N-glycosylation sites. The alignment of the amino acid sequences revealed that 10 cysteine and 7 proline residues, as well as the motifs SPF and GQLG, were completely conserved among the 20 investigated gBs.     

Hypersensitivity pneumonitis in rabbits. Modulation of pulmonary inflammation by long-term aerosol challenge with antigen

Immunized rabbits that were aerosol challenged for 2 to 3 wk with pigeon dropping extract, an etiologic agent of hypersensitivity pneumonitis, developed chronic pulmonary inflammation associated with cell-mediated immunity in bronchoalveolar cells. However, prolonged aerosol challenge for 12 wk resulted in the diminution of pulmonary inflammation (modulation) and the loss of demonstrable cell-mediated immunity. This was probably not due to loss of sensitized lymphocytes that mediated pulmonary inflammation. Furthermore, rabbits undergoing modulation when they were challenged with an unrelated antigen were refractory to the development of pulmonary inflammation for at least 9 wk. After this refractory period, animals reimmunized and aerosol challenged with pigeon dropping extract displayed an anamnestic response and produced pulmonary lesions that were strikingly similar to the histopathology of human hypersensitivity pneumonitis.     

Differential dynamics of the peripheral and intrahepatic cytotoxic T lymphocyte response to hepatitis B surface antigen

The distribution and dynamics of the cytotoxic T lymphocyte (CTL) response to hepatitis B surface antigen (HBsAg) were studied in mice after intramuscular DNA immunization and after hepatic infection by a recombinant adenovirus that expresses the hepatitis B virus genome (Ad-HBV). CTLs specific for HBsAg accumulate preferentially in the spleen after DNA immunization but are primarily intrahepatic after Ad-HBV infection. The secondary CTL response to Ad-HBV in DNA-primed mice is characterized by rapid depletion of effector CTLs from the spleen, and their expansion in the liver where they cause hepatitis, secrete interferon gamma (IFNγ), and inhibit HBV gene expression. Suppression of HBsAg synthesis is accompanied by disappearance of intrahepatic IFNγ-producing CTLs and their reaccumulation in the spleen. The data suggest a possible explanation for the paucity and functional deficiency of HBV-specific CTLs in the periphery during chronic HBV infection, and that the severity of infection can be worsened by a preexisting CTL response if neutralizing antibody is not also present.     

Triggering of respiratory burst by phagocytosis in monocytes of patients with systemic lupus erythematosus.

The triggering of the respiratory burst by phagocytosis via different receptors in monocytes of patients with systemic lupus erythematosus (SLE) was investigated. The superoxide anion synthesis was assayed by reduction of ferricytochrome C that was inhibited by superoxide dismutase. The mononuclear cell suspensions were triggered by IgG-coated latex, C3 complement fragment-coated and uncoated yeast (Saccharomyces cerevisiae). Superoxide generation induced by phagocytosis via Fc gamma R was decreased in monocytes of patients with SLE. On the other hand, MoAbs against Fc gamma RI, Fc gamma RII and especially CR3 could also induce superoxide anion synthesis. At the same time, superoxide generation induced by anti-CR3 could be inhibited with C3-coated yeast.     

Renal tubular transport of glutathione in rat kidney

Filtered glutathione (-glutamyl-cysteinyl-glycine or GSH) is rapidly hydrolyzed by brush-border enzymes facing the tubular lumen and is reabsorbed in the form of the constituent amino acids. The first step of hydrolysis is catalyzed by -glutamyltransferase (-GT). We investigated localization and capacity of the rat renal glutathione degradation/reabsorption during elevation of the filtered load (intravenous infusion of 12 resp. 18 mol GSH/min). Fractional excretion went up from about 0.003 to 0.31±0.02 SEM during infusion of the lower and to 0.49±0.03 SEM during infusion of the higher glutathione dose. GSH degradation/reabsorption took place along the entire proximal tubule and was partially saturated by a 150–200-fold elevation of the normal filtered load. Net reabsorption of GSH up to the last accessible superficial loop was significantly lower during infusion of 18 mol GSH/min (0.3 mol/min) than during infusion of 12 mol GSH/min (1.6 mol/min). In further experiments, infusion of 18 mol GSH/min was preceded by the i.v. administration of acivicin (0.5 mmol/kg body wt.), an inhibitor of -GT. In these experiments, fractional glutathione deliveries to late proximal and early distal tubules did not significantly differ from 1, fractional excretion of GSH at the same time was 1.46±0.11 SEM, revealing net secretion of GSH with the final urine. Tubular secretion of GSH in the acivicin-treated animals occurred either in distal tubules and/or collecting ducts or in the proximal tubules of deep nephrons which are not accessible to micropuncture. The low net reabsorption of GSH up to the late proximal tubule during infusion of 18 mol GSH/min without prior administration of acivicin indicates tubular secretion of GSH along the proximal convolution of superficial nephrons. Net secretion of glutathione with the final urine in the acivicin-treated animals therefore probably originates from proximal tubules of deep nephrons.Supported by the Wilhelm-Sander-Stiftung. Parts of this work were presented at the 4th International Workshop on Ammoniagenesis, Cadarache, France, August 1987, and at the 65th meeting of the Deutsche Physiologische Gesellschaft, Würzburg, March 1988 (Pflügers Arch 411:R97)