Altered expression of constitutive type and inducible type heat shock proteins in response of D-galactosamine-sensitized mice to lipopolysaccharide as an experimental endotoxic shock model

The expression of heat shock proteins (HSPs) as stress-induced proteins was studied in mice injected with D-galactosamine (D-GalN) and lipopolysaccharide (LPS) as an experimental endotoxic shock model. The expression of constitutive type heat shock protein 70 (HSC70) was significantly reduced in livers of mice injected with D-galactosamine and lipopolysaccharide, while its expression was unaffected in livers of mice injected with D-galactosamine or lipopolysaccharide alone. The expression of other constitutive type heat shock proteins, namely HSP60, HSP32 and HSP25 was also reduced in mice injected with D-galactosamine and lipopolysaccharide. On the other hand, inducible type HSP70 was detected in livers from mice injected with D-galactosamine and lipopolysaccharide, but not in livers from mice injected with D-galactosamine or lipopolysaccharide alone. Simultaneous injection of anti-tumor necrosis factor (TNF)-alpha antibody prevented the liver from reduced expression of constitutive type HSC70, and lead to marked expression of inducible type HSP70 in the liver. Reduced expression of constitutive type HSC70 was also found when D-galactosamine and recombinant TNF-alpha was injected. Therefore, TNF-alpha was suggested to play a critical role on altered expression of constitutive HSC70 and inducible type HSP70 in response of D-galactosamine-sensitized mice to lipopolysaccharide.

Synthesis of Escherichia coli O9a polysaccharide requires the participation of two domains of WbdA, a mannosyltransferase encoded within the wb* gene cluster

WbdA (previously MtfA) is one of the mannosyltransferases encoded within the Escherichia coli O9a wb* gene cluster. It is composed of two domains of similar size, connected by an alpha-helix chain. Elimination of the C-terminal half by transposon insertion or gene deletion caused synthesis of an altered structural O-polysaccharide consisting only of alpha-1,2-linked mannose. O9a polysaccharide synthesis was restored by the C-terminal half of WbdA in trans. No membrane incorporation of mannose from GDP mannose was observed in a strain carrying only the gene for truncated WbdA. For mannose incorporation, it was necessary to introduce both wbdB and wbdC genes into the strain. Therefore, it is likely that the N-terminal half of truncated WbdA synthesizes the altered O-polysaccharide together with other mannosyltransferases which participate in the initial reactions of the O9a polysaccharide synthesis. Both N- and C-terminal domains of WbdA are required for the synthesis of the complete E. coli O9a polysaccharide. The chi sequence location between the two domains and homology plot analyses of the wbdA and the WbdA protein suggested that the wbdA gene might have arisen by fusion of two independent genes.

Differential release of endotoxin from Pseudomonas aeruginosa treated with beta-lactam antibiotics and its effect on the lethal activity

The relationship between the level of endotoxin released from Pseudomonas aeruginosa by exposure to beta-lactam antibiotics and the lethal activity against D-galactosamine (D-GalN)-sensitized mice was examined. In vitro treatment of P. aeruginosa with imipenem (IPM) exclusively caused low-level release of free endotoxin, which was not lethal for D-GalN-sensitized mice. Treatment with other beta-lactam antibiotics, such as ceftazidime (CAZ), meropenem (MEPM) and cefozopran (CZOP) caused high-level release of free endotoxin and it exhibited the lethal action against D-GalN-sensitized mice. This study demonstrated close association of free endotoxin released by antibiotic treatment with the lethal activity.

Low-level release of Shiga-like toxin (verocytotoxin) and endotoxin from enterohemorrhagic Escherichia coli treated with imipenem

Shiga-like toxin (SLT) and endotoxin may participate in the pathogenesis of enterohemorrhagic Escherichia coli (EHEC) infection. Levels of release of SLT and endotoxin from EHEC treated in vitro with antibiotics were estimated. There were differential levels of release of SLT and endotoxin from EHEC treated with different antibiotics. Treatment of EHEC strains, namely, E. coli O157, O111, and O26, with imipenem induced much lower levels of release of SLT and endotoxin than treatment with ceftazidime.

Evolutionary relationship among rfb gene clusters synthesizing mannose homopolymer as O-specific polysaccharides in Escherichia coli and Klebsiella

In order to clarify the evolutionary relationship among rfb gene clusters synthesizing mannose homopolymer as O-specific polysaccharides in Escherichia coli and Klebsiella, we studied the DNA sequence of the boundary region between the rfb and his genes in a series of strains possessing mannose homopolymer as O-specific polysaccharide. All had a characteristic gene organization carrying no gene between the rfb and his genes. Further, the recombination event was suggested to occur at the same site of the hisI gene in those strains. It was suggested that there was a close evolutionary relationship among rfb gene clusters synthesizing mannose homopolymer as O-specific polysaccharide in E. coli and Klebsiella.

A new type of illegitimate recombination is dependent on restriction and homologous interaction

Illegitimate (nonhomologous) recombination requires little or no sequence homology between recombining DNAs and has been regarded as being a process distinct from homologous recombination, which requires a long stretch of homology between recombining DNAs. Under special conditions in Escherichia coli, we have found a new type of illegitimate recombination that requires an interaction between homologous DNA sequences. It was detected when a plasmid that carried 2-kb-long inverted repeats was subjected to type II restriction in vitro and type I (EcoKI) restriction in vivo within a delta rac recBC recG ruvC strain. Removal of one of the repeats or its replacement with heterologous DNA resulted in a reduction in the level of recombination. The recombining sites themselves shared, at most, a few base pairs of homology. Many of the recombination events joined a site in one of the repeats with a site in another repeat. In two of the products, one of the recombining sites was at the end of one of the repeats. Removal of one of the EcoKI sites resulted in decreased recombination. We discuss the possibility that some structure made by homologous interaction between the long repeats is used by the EcoKI restriction enzyme to promote illegitimate recombination. The possible roles and consequences of this type of homologous interaction are discussed.

Dietary effect of a symmetrical triacylglycerol, 1,3-biseicosapentaenoyl-2-gamma-linolenoyl glycerol, on fatty acid composition of guinea pigs

The dietary effect of 1,3-biseicosapentaenoyl-2-gamma-linolenoyl glycerol (STG) on the fatty acid composition of guinea pigs was examined and compared with that of an eicosapentaenoic acid ethyl ester (EPA-E) and of a soybean oil (SBO) diet. In terms of content of plasma lipid, EPA-E had a greater hypolipidemic effect than STG. On the other hand, in terms of EPA incorporation, contents of EPA in liver lipid were almost the same in the STG and EPA-E groups. Considering that the amount of EPA administered in the EPA-E group was almost 1.5 times that of the STG group, EPA may be absorbed more effectively as the glycerol ester than as the ethyl ester in guinea pigs. In all the tissue lipids, the STG group had a higher unsaturation index (UI) than the EPA-E group even though there is a lower UI in the STG diet than the EPA-E diet. These results suggest that greater amounts of desaturase products as a whole were synthesized in the STG group than in the other two groups. The dihomo-gamma-linolenic acid/arachidonic acid (DGLA/AA) ratio in plasma total lipids in the STG group was 3.5 times that of SBO group, and the DGLA/AA ratio in the EPA-E group was half that of the SBO group. In liver lipid, the ratios of DGLA/AA and EPA/AA in the STG group were 0.687 and 0.488 (phosphatidylcholine fraction) and 0.237 and 0.752 (phosphatidylethanolamine fraction), respectively. The ratio of DGLA/AA as well as the high EPA/AA ratio obtained in the present study with the STG diet may lead to physiological alterations, including enhanced synthesis of 1- and 3-series eicosanoids.

Endotoxin contamination in fetal bovine serum and its influence on tumor necrosis factor production by macrophage-like cells J774.1 cultured in the presence of the serum

Trace amounts of endotoxin (lipopolysaccharide: LPS) are assumed to contaminate commercially available fetal bovine serum (FBS) for tissue or cell culture during the manufacturing process. We examined how cultured cells were affected by the endotoxin and how much endotoxin was in the FBS. Macrophage-like J774.1 cells maintained in RPMI1640 medium supplemented with FBS containing low doses of LPS for 15 or 21 days showed less TNF production in response to LPS than the cells maintained under LPS-free conditions, and the affected responses of the cells were not recovered by an additional 21 day culture in medium with LPS-free FBS. Concentrations of LPS in 40 lots of FBS obtained from 13 international manufacturers were measured by a highly sensitive and LPS-specific chromogenic limulus assay. The median of endotoxin levels in these lots was 46 ng/ml and the maximum was 38.8 ng/ml. Relatively higher concentrations of LPS (> 1 ng/ml) or lower levels (< 10 pg/ml) were found in 9 and 6 lots, respectively. The majority of the FBS lots contained various levels of (1-->3)-beta-D-glucan, and all lots contained high-density lipoprotein (HDL). However, no correlation was found between LPS and (1-->3)-beta-D-glucan or HDL level in the lots. Each FBS was added to macrophage-like J774.1 cells which had been maintained in LPS-free medium. Five lots of FBS induced significant TNF production by the cells without addition of any stimulant. These active 5 FBS contained relatively higher levels of LPS and pretreatment of the FBS with polymyxin B eliminated their ability to induce TNF production. No correlation was found between (1-->3)-beta-D-glucan levels in FBS and the TNF-inducing capability of FBS. These results show that considerable lots of FBS contain significant levels of LPS, which must affect cell culture.

Augmentation of lipopolysaccharide-induced thymocyte apoptosis by interferon-gamma

The role of interferon (IFN)-gamma on thymocyte apoptosis in response to lipopolysaccharide (LPS) was investigated. The administration of LPS into mice induced marked apoptosis of thymocytes in vivo, but the simultaneous injection of anti-IFN-gamma antibody with LPS completely prevented thymocyte apoptosis. Pretreatment of mice with IFN-gamma markedly enhanced LPS-induced thymocyte apoptosis. Thymocyte apoptosis augmented by IFN-gamma occurred in the thymic cortex, and target cells undergoing apoptosis were CD4+8+ immature thymocytes. IFN-gamma itself did not induce thymocyte apoptosis in vivo and in vitro. IFN-gamma exhibited no synergistic action with effector molecules, such as tumor necrosis factor (TNF)-alpha and glucocorticoids. Further, it was shown that IFN-gamma did not enhance the susceptibility of thymocytes to apoptosis. Pretreatment of mice with IFN-gamma significantly augmented the serum TNF-alpha level and the serum cortisol level in response to LPS. Therefore, we suggest that IFN-gamma might augment LPS-induced thymocyte apoptosis through elevating serum TNF-alpha and cortisol levels.

Expression of intercellular adhesion molecule-1 (ICAM-1) on vascular endothelial cells and renal tubular cells in the generalized Shwartzman reaction as an experimental disseminated intravascular coagulation model

The participation of adhesion molecules in systemic vascular injuries of the generalized Shwartzman reaction was studied. The generalized Shwartzman reaction was induced in mice by two consecutive injections of lipopolysaccharide. Intercellular adhesion molecule-1 (ICAM-1) was expressed on vascular endothelial cells, renal tubular cells and alveolar wall in generalized Shwartzman reaction-induced mice. The preparative injection of lipopolysaccharides induced ICAM-1 expression in those cells, and the provocative injection of lipopolysaccharides for the generalized Shwartzman reaction augmented it further. The simultaneous administration of anti-gamma interferon antibody with the preparative injection of lipopolysaccharides completely inhibited ICAM-1 expression on vascular endothelial cells. The injection of recombinant gamma interferon in replacement of lipopolysaccharides resulted in ICAM-1 expression. The administration of anti-ICAM-1 antibody together with the provocative injection of lipopolysaccharides significantly blocked the apoptosis of vascular endothelial cells in generalized Shwartzman reaction-induced mice. It was suggested that ICAM-1 expression on vascular endothelial cells might be involved in systemic vascular injuries of the generalized Shwartzman reaction, and that it might be regulated by gamma interferon.

B7/BB-1 expression and hepatitis activity in liver tissues of patients with chronic hepatitis C

Cytotoxic T lymphocytes (CTL) are closely related to the mechanism of liver injury in chronic viral hepatitis. Recently, it has been suggested that antigen-specific T cell activation requires both presentation of antigen by major histocompatibility complex (MHC) molecules and the delivery of costimulatory signals. Such signals are provided by B7/BB-1, one of the most important accessory molecules, sufficient for causing antigen-specific MHC-restricted T cell activation. To evaluate the role of B7/BB-1 in chronic hepatitis C, we immunohistochemically studied its expression in liver tissues obtained from 61 patients with hepatitis C virus (HCV) infection and compared them based on hepatitis activity. In HCV-infected liver, B7/BB-1 was strongly expressed in the cytoplasm of hepatocytes. B7/BB-1-positive cells accompanied liver-infiltrating lymphocytes and were mainly detected in the periportal region. B7/BB-1 expression was closely correlated with the activity of viral hepatitis as evaluated from scores of periportal or intralobular inflammation and necrosis, or serum alanine transferase (ALT) levels. Further study by immunostaining with anti-HCV core and anti-human leukocyte antigen (HLA) class I antibody showed B7/BB-1 positive cells near HCV core antigen- and HLA class I-positive cells, with B7/BB-1-positive cells mostly included among HLA class I-positive cells. These findings suggested that B7/BB-1 expression by hepatocytes may be induced by HCV infection and may trigger generation and activation of CTL, which may cause damage to HCV-infected HLA class I-expressing hepatocytes.

Relationship between a low toxicity of the mutant A subunit of enterotoxigenic Escherichia coli enterotoxin and its strong adjuvant action

In the work described here it was determined if and how unnicking in the A subunit of Escherichia coli enterotoxin at Arg192 or nearby residues affected biological activities of the toxin. The mutant toxin was constructed to lack the nick site in the A subunit by deleting the tripeptide Arg192-Thr193-Ile194, which is essential for toxicity. The mutant toxin did not exhibit agmatine ADP-ribosyltransferase activity in the presence or absence of the ADP-ribosylation factor and had less diarrhoeal activity and lower induction of cyclic AMP than did LT. The mutant toxin exhibited a much stronger adjuvant action on antibody responses to measles virus, keyhole limpt haemocyanin, bovine immunoglobulin and ovalbumin compared with LT. The altered toxicity of the mutant toxin might be closely related to the potent adjuvant action on antibody responses to antigens. The relationship between two activities is discussed.

Production of monoclonal antibody discriminating serological difference in Escherichia coli O9 and O9a polysaccharides

A monoclonal antibody (mAb) with a unique antigenic specificity against Escherichia coli O9 was produced. The O9a mAb was reactive with a part of the strains in E. coli O9. The O9a mAb did not react with LPS from the E. coli O9 test strain Bi316-42. The distribution of the antigen defined by the O9a mAb in E. coli O9 was consistent with that of E. coli O9a present in E. coli O9 strains. The chemical structure of the repeating unit of the O-specific polysaccharide detected by the mAb was demonstrated to be a mannotetraose by two-dimensional nuclear magnetic resonance spectroscopy. It was confirmed that the mAb recognized E. coli O9a serotype in E. coli O9 serotype strains, suggesting that E. coli O9a serotype might be a dominant strain in E. coli O9.

Marked reduction of mouse peritoneal CD5+ B cells by intraperitoneal administration of lipopolysaccharide

Intraperitoneal administration of lipopolysaccharide to mice induced a marked reduction of CD5+ B cells in the peritoneal cavity. The reduction was not induced by intravenous, subcutaneous, or oral administration of lipopolysaccharide. The reduction continued for about 10 days after the injection, and the CD5+ B-cell count recovered to the normal state about 14 days after the injection. The reduction of peritoneal CD5+ B cells might be caused by apoptotic cell death. Injection of lipopolysaccharide did not result in production of antibody to lipopolysaccharide. On the other hand, intraperitoneal injection of heat-killed bacteria did not induce a reduction of peritoneal CD5+ B cells and elicited the definite production of antibody to lipopolysaccharide.

Apoptotic cell death of vascular endothelial cells and renal tubular cells in the generalized Shwartzman reaction

The participation of apoptotic cell in the generalized Shwartzman reaction was examined. The generalized Shwartzman reaction was induced in mice by two consecutive injections of lipopolysaccharide. Vascular endothelial cells in various organs of those mice were stained positively by the in situ specific labeling of fragmented DNA. Renal tubules were also stained focally. It was suggested that apoptotic cell death might participate in the development of vascular endothelial cell damage and acute tubular necrosis in the generalized Shwartzman reaction. Simultaneous administration of anti-gamma-interferon antibody in the preparative injection of lipopolysaccharide completely blocked apoptosis of vascular endothelial cells. Priming with recombinant gamma-interferon instead of lipopolysaccharide could produce apoptosis of vascular endothelial cells. It was suggested that gamma-interferon might play a critical role on sensitization of endothelial cells for apoptosis.

DNA nicking by Escherichia coli topoisomerase IV with a substitution mutation from tyrosine to histidine at the active site

BACKGROUND

Escherichia coli topoisomerase IV is a type II topoisomerase composed of ParC and ParE subunits and plays a major role in the decatenation of replicated molecules. The reaction with type II topoisomerases involves the cutting through transesterification between an active-site tyrosine and a DNA phosphodiester bond and a rejoining of cleaved DNA.

RESULTS

To genetically analyse the mechanism of this reaction, we isolated dominant-negative topoisomerase IV mutants. In one of them, the parC10 mutant, there was a substitution by histidine of the active-site tyrosine. Purified mutant topoisomerase IV did not show normal DNA cutting activity but retained DNA nicking activity, even in the absence of ATP. The DNA ends of the product were not covalently bound to the ParC subunits, suggesting that the DNA is not cut via transesterification but by hydrolysis.

CONCLUSIONS

We have shown genetically that the 120th tyrosine residue is important for the DNA cutting step in the topoisomerase reaction. The 120th amino acid residue, tyrosine or histidine, appears to be activated and the histidine residue forces the hydrogen-bonded water to attack the phosphoryl group of the DNA in hydrolysis, while the tyrosine residue directly attacks the phosphoryl group during transesterification.

Regulation of IFN-alpha/beta genes: evidence for a dual function of the transcription factor complex ISGF3 in the production and action of IFN-alpha/beta

BACKGROUND

Efficient production of interferons (IFNs) in virally infected cells is an essential aspect of the host defence. The transcription factor complex ISGF3 (IFN-stimulated gene factor 3) was originally identified as a critical mediator of the IFN signal; it is formed upon IFN receptor (IFNR) stimulation and binds to ISREs (IFN-stimulated response elements) to activate IFN-inducible genes. It has recently been shown that the DNA binding component of ISGF3, p48 (ISGF3gamma) also binds to virus-inducible elements in the IFN-alpha/beta genes, suggesting a potential new role of p48 in IFN production.

RESULTS

Primary cells from mice with a targeted disruption of the p48 gene show severe defects in virus-induced IFN-alpha/beta gene expression. A similar defect was also observed in cells lacking type I IFNR or Stat1, further demonstrating the role of IFN signalling in the induction of these IFN genes. ISGF3 in fact binds to the virus-inducible elements within the IFN-alpha/beta promoters. We also provide evidence showing that these elements are additionally controlled by an unidentified factor(s) which presumably triggers the primary phase of IFN gene induction.

CONCLUSIONS

Our results demonstrate that the IFN signal transducing complex ISGF3 plays a crucial role in IFN production and suggest that ISGF3 may participate directly in the activation of IFN-alpha/beta promoters. This dual function of ISGF3 may insure the efficient operation of this cytokine system in the host defence.

Differential release of smooth-type lipopolysaccharide from Pseudomonas aeruginosa treated with carbapenem antibiotics and its relation to production of tumor necrosis factor alpha and nitric oxide

Endotoxin release from Pseudomonas aeruginosa treated with cell wall-active carbapenem antibiotics and its effect on the production of tumor necrosis factor alpha and nitric oxide were examined. Treatment of bacteria with imipenem induced much lower levels of endotoxin release than treatment with meropenem. The endotoxin released was demonstrated to be of the smooth type and O-specific polysaccharide-rich. The exposure of the filtrates of P. aeruginosa treated with imipenem to physiologically relevant cells caused low-level production of tumor necrosis factor alpha and nitric oxide, while similar treatment with meropenem induced high levels of production.

A screening method for antimitotic and antifungal substances using conidia of Pyricularia oryzae, modification and application to tropical marine fungi

A bioassay method detecting deformations of mycelia germinated from conidia of Pyricularia oryzae P-2b, has been modified to give quantitative estimations. The method was first developed using antimitotic agents which showed characteristic curling effect. Morphological deformations include curling, swelling, hyper-divergency, beads shape and so on, and inhibition of the germination was also observed. For quantitative estimations, indices were introduced for the hyphal growth inhibition and a quantity of conidia in each assay cell and concentration of test solutions were adjusted. Details of the modified method and the application to screening assay of marine fungi isolated in Yap Islands are described. Eight strains of 109 tested showed morphological deformations, and chaetoglobosin A was isolated from the broth filtrate of a strain assigned to Chaetomium sp. This bioassay is a cheap, quick and easy method to be applied to the primary screening for antimitotic and antifungal substances from natural sources.

Lipopolysaccharide induces apoptotic cell death of B memory cells and regulates B cell memory in antigen-nonspecific manner

Lipopolysaccharide (LPS) was administered into sheep red blood cells (SRBC)-primed mice, and the effect of LPS on SRBC-specific memory cells was investigated. Spleen cells from SRBC-primed mice which were injected with LPS exhibited much lower in vitro secondary plaque-forming cells (PFC) responses to SRBC than those from untreated SRBC-primed mice. The in vitro anti-SRBC response of the spleen cells to LPS was also reduced. The combination experiments of B cells and T cells from SRBC-primed mice which were injected with or without LPS demonstrated that the reduction of immune responses to SRBC after administration of LPS was caused by the defect of SRBC-specific B memory cells, but not T memory cells. B cell type rosette-forming cells (RFC) for SRBC markedly decreased after injection of LPS, while PFC as antibody-forming cells did not increase subsequently. Therefore, the reduction of RFC was not due to their differentiation into PFC. The lymphoid follicles in the spleens from mice injected with LPS were stained positively by in situ nick end labeling specific for fragmented DNA. A large percentage of Ig+ spleen cells from SRBC-primed mice which were injected with LPS was also stained positively. The injection of glucocorticoids into SRBC-primed mice induced similar reduction of B memory cells. It was suggested that LPS might induce apoptosis of B memory cells and regulate B cell memory in antigen-nonspecific manner.

Construction of beta-lactamase-encoding ApR gene cassettes for rapid identification of cloned genes

We have constructed two Escherichia coli plasmids, pYK18 and pYK19, from which the BamHI, SmaI or EcoRI DNA fragments containing the ApR gene, conferring resistance to ampicillin, can be excised. The ApR cassettes have an annealing site for the sequencing primer of pUC plasmids at each end. Therefore, when the cassette is inserted into a gene, we can determine the nucleotide sequence of the gene from the insertion site using the sequencing primers of the pUC plasmids. This method is useful for identifying a cloned gene.

Characterization of lipopolysaccharides of polymyxin-resistant and polymyxin-sensitive Klebsiella pneumoniae O3

Lipopolysaccharides isolated from the polymyxin-resistant Klebsiella pneumoniae O3 mutant OM-5 and its polymyxin-sensitive parent LEN-1 were analyzed for chemical composition, and their lipid A portions were structurally characterized. The lipopolysaccharide of OM-5 contained approximately five times more 4-amino-4-deoxy-L-arabinopyranose than that of LEN-1. Other saccharide and phosphate components exhibited no significant differences. Structural characterization, including analyses by phosphorus magnetic resonance spectroscopy and by fast atom bombardment mass spectrometry, revealed a novel type of lipid A. In the OM-5 lipopolysaccharide, both phosphates of lipid A were almost totally present as phosphodiesters with 4-amino-4-deoxy-L-arabinopyranose. In the sensitive-type LEN-1 lipid A, the extent of this substitution was much lower, especially in the glycosidically linked phosphate. Phosphate in these K. pneumoniae lipopolysaccharides was almost exclusively found in lipid A. These results show that cationic substituents of phosphates of lipid A play a decisive role in determining polymyxin reactivity. OM-5 was also found to contain a large proportion of heptaacyl lipid A, which represented only a small fraction of lipid A in LEN-1.

Apoptotic cell death in the response of D-galactosamine-sensitized mice to lipopolysaccharide as an experimental endotoxic shock model

The apoptotic cell death induced in D-galactosamine-sensitized mice by administration of lipopolysaccharide was characterized. Administration of lipopolysaccharide caused apoptotic cell death in livers of D-galactosamine-sensitized mice. Apoptotic cells were also detected in the kidney, thymus, spleen, and lymph node. Severe hepatic apoptosis in D-galactosamine-sensitized mice was reproduced by transfer of the sera from mice injected with D-galactosamine and lipopolysaccharide. The hepatocyte apoptosis induced by lipopolysaccharide was completely prevented by an anti-tumor necrosis factor alpha antibody but not by an anti-gamma interferon antibody. Administration of recombinant tumor necrosis factor into D-galactosamine-sensitized mice also caused hepatocyte apoptosis. Lipopolysaccharide-induced hepatocyte apoptosis in D-galactosamine-sensitized mice did not seem to be mediated by Fas antigen. It was suggested that lipopolysaccharide- induced hepatic injury and failure in D-galactosamine-sensitized mice was due to the apoptotic cell death of hepatocytes caused by tumor necrosis factor alpha released in the circulation.

Expression of heat shock protein 72 on peripheral blood mononuclear cells from patients with pustulosis palmaris et plantaris

The expression of heat shock protein (HSP) 72 on peripheral blood mononuclear cells (PBMC) from patients with pustulosis palmaris et plantaris (PPP) was studied. PBMC isolated freshly from patients with PPP expressed HSP72, while those from psoriasis patients did not. PBMC from patients with PPP continued to express it in in vitro cultures at 37 degrees C. This expression was further augmented by in vitro heat stimulation at 43 degrees C. Immunofluorescence studies showed that approximately 20% of PBMC from patients with PPP were stained positively with anti-HSP72 antibody. HSP72 was expressed on both nonadherent and adherent cells of PBMC. These findings suggest that PBMC from patients with PPP may produce HSP72 spontaneously through their in vivo exposure to stressful agents.

Augmented immunological activities of recombinant lipopolysaccharide possessing the mannose homopolymer as the O-specific polysaccharide

Recombinant lipopolysaccharide possessing the mannose homopolymer as the O-specific polysaccharide was manufactured genetically by transforming Escherichia coli K-12 with various rfb genes capable of synthesizing the mannose homopolymer. Recombinant lipopolysaccharide exhibited levels of anticomplement activity, adjuvant activity, and regional lymph node-enlarging activity much higher than those exhibited by the original rough-type lipopolysaccharide from E. coli K-12 or lipopolysaccharide possessing the heteropolysaccharide from E. coli O111. Immunological activities of recombinant lipopolysaccharide were as strong as those of wild-type lipopolysaccharide possessing the mannose homopolymer. Characteristic activities of wild-type lipolysaccharide possessing the mannose homopolymer were exhibited by recombinant lipopolysaccharide. The abilities of lipopolysaccharide to activate B cells polyclonally and to produce cytokines did not seem to be related to the presence of the mannose homopolymer. Therefore, it was suggested that the mannose homopolymer in the O-specific polysaccharide might exclusively enhance anticomplement activity, adjuvant activity, and regional lymph node-enlarging activity among various lipid A activities.