Seeligeriolysin O, a protein toxin of Listeria seeligeri, stimulates macrophage cytokine production via Toll-like receptors in a profile different from that induced by other bacterial ligands

Seeligeriolysin O (LSO), a member of cholesterol-dependent cytolysins of Listeria seeligeri, exhibits cytokine-inducing activity. In this study, we examined the profile of cytokines expressed in macrophages of mice after stimulation with full-length form of recombinant LSO (rLSO530), C-terminal-truncated protein (rLSO483) and two authentic cytokine-inducing Toll-like receptor (TLR) ligands from bacteria, peptidoglycan (PGN) and LPS. Both rLSO530 and rLSO483 were able to induce IL-12 p40 and IL-12 p70 more strongly in macrophages than PGN or LPS. In contrast, IFN-beta and nitric oxide were induced by LPS but not by rLSO530, rLSO483 or PGN. In the presence of exogenously added IFN-beta, IL-12 p40 and IL-12 p70 production was inhibited after LSO stimulation, but IL-12 p70 production was enhanced after PGN stimulation. Although LSO signaling appeared to be associated with both TLR2 and TLR4, the profile of cytokine production by LSO stimulation was distinct from those by stimulation with PGN or LPS. Thus, it was shown that LSO is a unique bacterial ligand that induces macrophage cytokine production in a manner different from PGN or LPS.     

Epithelial myoepithelial tumour of the tracheal gland.

A case of epithelial myoepithelial tumour originating from the tracheal gland in a 57 year old woman is described. The tumour was removed by segmental tracheal resection and end-to-end anastomosis. Histologically, the tumour comprised clear cells and presented a monophasic pattern. Immunohistochemical analysis showed that the tumour cells were positive for both S-100 protein and smooth muscle actin. suggesting that this tumour resembles a subtype of epithelial-myoepithelial carcinoma described in the 1990 WHO international classification of salivary glands. Although some reports describe a clear cell dominant epithelial myoepithelial carcinoma, in this case local invasiveness or regional lymphnode metastasis was not proved through investigation. It is therefore concluded that this was an epithelial myoepithelial tumour rather than a carcinoma.     

Isolation and characterization of a highly divergent HIV-2[GH-2]: generation of an infectious molecular clone and functional analysis of its rev-responsive element in response to primate retrovirus transactivators (Rev and Rex).

A highly divergent HIV-2 designated as HIV-2[GH-2] was obtained from an AIDS-related complex (ARC) patient in Ghana. A full-length molecular clone of this isolate was obtained and a biologically active clone was constructed. Its restriction pattern differed from that of prototype HIV-2[GH-1] in 25 of 35 restriction sites, but was strikingly similar to a previously characterized HIV-2 isolate from a Ghanaian (HIV-2ALT). The conserved integrase region (288-bp fragment) previously displayed 95% identity with that of ALT but 17-20% divergence from the HIV-2 prototype member, and a new distinct subgroup (HIV-2b) of HIV-2 consisting of GH-2 and ALT was postulated (Miura et al. 1991.) These isolates, however, were biologically distinguishable from each other by its replication capacity in a monocyte line, U937, in which GH-2 could not grow but ALT grew well. In addition, the nucleotide sequence of the LTR of this new isolate displays 21% divergence from that of prototype HIV-2[GH-1], but the core enhancer, Sp1 binding sites and TATA box were conserved. Although the 3' half of the env gene sequence which is deleted in HIV-2ALT clone showed 27% diversity from the prototype, functional differences in the rev-responsive element were not observed.     

Dual functions of Runx proteins for reactivating CD8 and silencing CD4 at the commitment process into CD8 thymocytes

To understand how CD8 expression is regulated during the transition process from CD4+8+ (CD4 and CD8 double positive, DP) to CD4-8+ (CD8 single positive, CD8SP) cells in the thymus, the involvement of Runx proteins in the alteration of chromatin configuration was investigated. Using the chromatin immunoprecipitation assay, we first demonstrated that Runx proteins bind to the stage-specific CD8 enhancer, as well as the CD4 silencer, in CD8SP thymocytes. Among Runx family members, Runx3 expression was initiated in DP thymocytes receiving a positive selection signal and increased in concert with differentiation to the CD8SP stage. Furthermore, reactivation of the CD8 gene, as well as CD4 silencing, was suppressed in positively selected thymocytes of Runx dominant-negative transgenic mice. These results suggest that Runx proteins, especially Runx3, are involved in lineage specification of CD8 T cells and provide important information for understanding the mechanism for the mutually exclusive expression of coreceptors in mature thymocytes.     

Various types of corticotectal neurons of cats as demonstrated by means of retrograde axonal transport of horseradish peroxidase

Summary The retrograde labeling of cortical neurons with horseradish peroxidase (HRP) was used to investigate the morphological features of neurons in various cortical areas projecting to the superior colliculus in the cat.Corticotectal cells were found to be labeled in layer V of the entire cerebral cortex. The number of labeled cells and their locations varied according to the sites of injections of HRP in the colliculus. Most of the Corticotectal cells identified in the present study were small (9–20 m in diameter, 66%) and medium (20–40 urn, 30%) pyramidal neurons and only 4% of them were large (more than 40 m). The labeled cells, 261 in total number, had somal diameters of 20.8±8.0 m (mean and SD). The range of sizes of the labeled neurons was different in different cortical areas. For example, the labeled neurons in the Clare-Bishop area had a greater proportion of large diameter cells than in other areas.The present findings are largely in agreement with the previous data of anterograde degeneration methods with respect to the topographical correlation of the Corticotectal projections. However, in some cortical areas, e.g., the sensorimotor and the first visual (area 17) cortex of the lateral surface of the hemisphere, relatively small numbers of Corticotectal neurons appear to have been labeled by retrogradely transported HRP. The sparsity of the labeled neurons in certain cortical areas may reflect the existence of Corticotectal neurons with axon collaterals supplying brain structures other than the superior colliculus.Abbreviations A.c. Aqueductus cerebri - AEct Gyrus ectosylvius anterior - AEs Sulcus ectosylvius anterior - AI Stratum album intermediale - AL Gyrus lateralis anterior - AP Stratum album profundum - AS Gyrus sylvius anterior - Cd Nucleus caudatus - F.l.m. Fasciculus longitudinalis medialis - GI Stratum griseum intermediale - GP Stratum griseum profundum - GS Stratum griseum superficiale - Ic Inferior colliculus - L Left - MEct Gyrus ectosylvius medius - MS Gyrus sylvius medius - MSup Gyrus suprasylvius medius - N.r. Nucleus ruber - O Stratum opticum - P Pontine nuclei - P.c. Pedunculus cerebri - PEct Gyrus ectosylvius posterior - P.g. Periaqueductal gray matter - PSigm Gyrus sigmoideus posterior - PSup Gyrus suprasylvius posterior - R Right - Sc Superior colliculus - S.n. Substantia nigra - Z Statum zonale - II Optic nerve - III and IV Motor nuclei of cranial nerves     

High expression of the CD30 molecule in human decidual cells.

CD30 is a receptor-type membrane protein that belongs to the nerve growth receptor superfamily. It is expressed on Hodgkin's cells and activated lymphocytes, as well as in some human malignancies including malignant lymphomas, embryonal carcinomas, and other mesenchymal tumors. However, whether it is expressed in normal tissues remains unclear. To study the expression and biological function of CD30, we first examined various human tissues by immunohistochemistry. The monoclonal antibody Ber-H2 intensely stained the membranes of decidual and endometrial cells with decidual change in frozen sections. Western blots of these tissues with Ber-H2 revealed bands of 120, 105, and 90 kd as found on CD30-expressing cells. Northern blots of these tissues using a CD30 cDNA probe detected mRNAs of the same molecular mass and variety as those in the positive control cell line HUT 102. These results indicated that CD30 is expressed in human endometrial tissue with decidual change and imply that CD30 expression in endometrial tissue is induced by hormonal control.     

Increased migration of neutrophils to granulocyte-colony stimulating factor in rat carrageenin-induced pleurisy: Roles of complement,bradykinin, and inducible cyclooxygenase-2

Administration of human recombinant granulocyte colony-stimulating factor (G-CSF, 100 g/kg/day, s.c) to rats for 4 days significantly increased circulating neutrophil counts (by 1130%), together with an increase in mononuclear leukocyte counts (by 119%). Infiltrated pleural neutrophil counts in G-CSF-treated rats (G-CSF-r) 5h after the intrapleural injection of zymosanactivated serum were significantly higher (by 155%) than those in control rats (Vehicle-r). In carrageenin-induced pleurisy, counts of infiltrated pleural neutrophils in G-CSF-r 5 and 7h after carrageenin were significantly higher (by 119% and 116%) than those in Vehicle-r. G-CSF treatment increased the volume of pleural exudate and the plasma exudation rate by 122% and 226%, compared to values in Vehicle-r 5h after carrageenin. Cobra venom factor (75 g/kg, i.v.) significantly reduced pleural neutrophil migration in G-CSF-r (by 53%) and Vehicle-r (by 49%). Bromelain (10 mg/kg, i.v.) and aspirin (100 mg/kg, p.o.) reduced pleural neutrophil migration and reduced exudate volume and plasma exudation. Intrapleural bradykinin-(1–5) and prostaglandin E₂ levels were significantly higher in G-CSF-r than in Vehicle-r. The increased neutrophil migration in G-CSF-r may be atributed to enhanced activation of the complement system facilitated by increased plasma exudation due to bradykinin and prostaglandins.accepted by M. J. Parnham     

Natural antibodies against the immunoglobulin F(ab′)2 fragment cause elimination of antigens recognized by the F(ab′)2 from the circulation

A humanized monoclonal IgG1 antibody, designated hC4G1, recognizes the fibrinogen receptor glycoprotein (GP)IIb/IIIa on platelets and inhibits platelet aggregation. When the F(ab′)₂ fragment of hC4G1 (F(ab′)₂ hC4G1) was administered to cynomolgus monkeys, all the monkeys showed inhibition of platelet aggregation ex vivo. Unexpectedly, a significant decrease in platelet count was observed in 5 of 18 monkeys. Antibodies against F(ab′)₂ hC4G1 were detected in the plasma of these monkeys by ELISA. Antibody activity in the plasma of these monkeys was significantly correlated with the intensity of platelet decrease (r = 0.84). The natural monkey antibodies to F(ab′)₂ hC4G1 were directed against the C-terminal region of F(ab′)₂ fragment common to all human and humanized IgG antibodies. Natural homo-reactive antibodies were also detected in human plasma from 15 of 40 healthy volunteers. Specificity was closely similar to that of the monkey antibodies. Affinity-purified human homo-reactive antibodies enhanced phagocytosis of platelets treated with the F(ab′)₂ hC4G1. Monkey plasma with high homo-reactive antibody activity was confirmed to decrease platelet count when administered together with F(ab′)₂ hC4G1 to a monkey with low antibody activity. These results suggest that F(ab′)₂ of humanized and human antibodies causes elimination of the corresponding antigens from the circulation by homo-reactive antibodies.     

Changes of endogenous ganglioside composition in mouse cerebrum primary cultures following long-term exposure to phorbol ester.

Changes in endogenous gangliosides caused by phorbol 12-myristate 13-acetate (PMA, 162 nM) were examined using mouse cerebrum primary cultures. The total ganglioside content was significantly decreased by 25% and 40% in PMA-treated cultures compared to control cultures on days 1 and 8, respectively. In addition, changes in the pattern of ganglioside composition were also observed in which the percentage of GM1 and GD3 in total gangliosides was significantly increased and, in contrast, the percentage of GD1a and GT1b was reduced. Treatment of neurons with PMA induced the change of morphology. These results suggest that the decrease in the total ganglioside content and changes in ganglioside composition produced by long-term exposure to PMA are related to the appearance of neuronal cell aggregation and neurite fasciculation.     

Serotype-specific amplification of Rickettsia tsutsugamushi DNA by nested polymerase chain reaction.

Polymerase chain reaction (PCR) with nested primer pairs was used to diagnose scrub typhus and identify the Rickettsia tsutsugamushi serotype. The primer pairs used for PCR were designed on the basis of the nucleotide sequence of the gene that encodes the 56-kDa antigen. Serotype-specific primers were used in the second PCR amplification. Five serovariants, the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of R. tsutsugamushi, were identified by nested PCR. In addition, the serotype identified by PCR with DNA from blood clots was the same as that of the strain isolated from five patients with scrub typhus. These findings indicate that this method is useful for diagnosis and identification of the rickettsial serotype in infected patients.