Expression of bovine cytokines in Escherichia coli.
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Glutathione S-transferase fusion proteins of bovine interleukin-2 (IL-2), IL-4, IL-6 and interferon-gamma (IFN-gamma) were expressed in Escherichia coli. Complementary DNA (cDNA) for open reading frame of each cytokine without signal peptide encoding region was amplified by reverse transcriptional polymerase chain reaction method and was subcloned into pGEX-5X-1. In result, IL-6 and IFN-gamma fusion proteins in bacteria were soluble, but IL-2 and IL-4 fusion proteins were insoluble. The insoluble IL-2 fusion protein successfully refolded by urea became soluble. The recombinant IL-2, IL-6 and IFN-gamma could be obtained by the batch method using Glutathione Sepharose 4B and Factor Xa digestion, which may be useful for preparation of antisera as antigens and functional studies. (+info)
Comparative study of the in vitro behavior of cord blood subpopulations after short-term cytokine exposure.
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We investigated the effect of short-term cytokine exposure on defined cord blood subpopulations. CD34+Thy1+, CD34+Thy1-, CD34+38-, CD34+38+, CD34+DR+, CD34+DR-, CD34+Rhodamine123 (Rh123)- and CD34+Rh123+ cells were incubated for 7 days in IMDM + 10% FCS + IL3 + IL6 + G-CSF + SCF (36GS) + flt3L. We evaluated LTHC-IC, immunophenotype and nucleated cell count for each cell population before and after cytokine exposure. Short-term exposure of CD34+38+, CD34+Thy1-, CD34+DR+, CD34+DR- and CD34+Rh123+ cells to 36GS causes a significant increase in cell number, whereas CD34+38-, CD34+Thy1+, and CD34+Rh123- cells show only a limited increase. CD34 status post cytokine incubation shows that CD34+38+, CD34+Thy1-, CD34+DR+, and CD34+Rh123+ fractions have a lower proportion of cells remaining CD34+ than CD34+38- CD34+Thy1+, CD34+DR- and CD34+Rh123- fractions. LTHC-IC analyses among input subpopulations show a higher frequency among CD34+38+, CD34+Thy1-, CD34+DR+, CD34+DR- and CD34+Rh123+ cells as compared with CD34+38-, CD34+Thy1+ and CD34+Rh123- cells. However, when LTHC-IC were evaluated after cytokine exposure, CD34+38-, CD34+Thy1+, and CD34+Rh123- cells showed a higher frequency of LTHC-IC as compared with other subpopulations. Addition of flt3L to 36GS doubled the numbers in all subpopulations without altering the proportion of CD34+ cells. Results suggest that CD34+38-, CD34+Thy1+ and CD34+Rh123- cells have a limited proliferative response to cytokines, the stem cell component of these populations is largely maintained and that expansion is derived from mature cell populations. (+info)
Localization of ubiquitin and ubiquitin cross-reactive protein in human and baboon endometrium and decidua during the menstrual cycle and early pregnancy.
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We have examined the distribution of ubiquitin and the related ubiquitin cross-reactive protein (UCRP) in paraffin-embedded sections of human and baboon endometrium and decidua by immunoperoxidase or immunofluorescence cytochemistry with antibodies raised against ubiquitin, UCRP, CD45, and insulin-like growth factor-binding protein-1. Anti-ubiquitin immunoreactivity was present in the nonpregnant endometrium, particularly in the glandular epithelial cells, and up-regulated in endometrial stromal cells as they decidualized at the beginning of pregnancy. Anti-UCRP immunoreactivity was absent from nonpregnant tissue but accumulated to high levels in decidual cells during pregnancy. Western blotting indicated that immunoreactivity was primarily due to the presence of ubiquitin and UCRP conjugated to other proteins, and that although levels of ubiquitin-protein conjugates do not change substantially during pregnancy, decidualization is accompanied by the appearance of conjugates of UCRP. Baboon uterine tissues demonstrated a similar distribution of the two proteins, which indicates that the baboon may be a useful model for study of the role of the ubiquitin system and UCRP in the establishment of pregnancy in humans. (+info)
The p47(phox-/-) mouse model of chronic granulomatous disease has normal granuloma formation and cytokine responses to Mycobacterium avium and Schistosoma mansoni eggs.
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Chronic granulomatous disease (CGD) is a genetic disorder of NADPH oxidase in which phagocytes are defective in generating reactive oxidants. CGD patients suffer from recurrent infections and exuberant and persistent tissue granuloma formation. We hypothesized that abnormal granulomata in CGD may result from aberrant T-cell-mediated cytokine responses. To assess Th-1-type cytokine responses and granulomata, we challenged p47(phox-/-) and wild-type mice with avirulent (SmD) or virulent (SmT) variants of Mycobacterium avium 2-151. To assess Th-2-type cytokine responses and granulomata, we used Schistosoma mansoni eggs (SME). Mononuclear cells were harvested, and cytokine responses were determined by enzyme-linked immunosorbent assay or reverse transcriptase PCR. Following SmD or SmT challenge, splenocytes from p47(phox-/-) and wild-type mice generated similar polar Th-1 responses (increased levels of gamma interferon and basal levels of interleukin 4 [IL-4] and IL-5). By 8 weeks after SmT challenge, exuberant splenic granulomata developed in p47(phox-/-) and wild-type mice. After SME challenge, thoracic lymph node mononuclear cells from p47(phox-/-) and wild-type mice generated similar mixed Th-1 and Th-2 cytokine responses to SME antigen and concanavalin A. Peak lung granuloma sizes and rates of regression were similar in p47(phox-/-) and wild-type mice. These results suggest that exuberant granulomatous inflammation in CGD is probably not the result of skewing of T-cell responses toward the Th-1 or Th-2 pole. Appropriate regression of established tissue granulomata in p47(phox-/-) mice challenged with SME suggests that abnormal granuloma formation in CGD is stimulus dependent and is not an invariant feature of the disease. (+info)
Differential protective efficacy of DNA vaccines expressing secreted proteins of Mycobacterium tuberculosis.
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The development of more-effective antituberculosis vaccines would assist in the control of the global problem of infection with Mycobacterium tuberculosis. One recently devised vaccination strategy is immunization with DNA plasmids encoding individual microbial genes. Using the genes for the M. tuberculosis secreted proteins MPT64 (23 kDa), Ag85B (30 kDa), and ESAT-6 (6 kDa) as candidate antigens, DNA vaccines were prepared and tested for immunogenicity and protective efficacy in a murine model of aerosolized tuberculosis (TB). Intramuscular immunization with DNA-64 or DNA-85B resulted in the activation of CD4(+) T cells, which produce gamma interferon (IFN-gamma), and high titers of specific immunoglobulin G antibodies. Further, DNA-64 induced major histocompatibility complex class I-restricted CD8(+) cytotoxic T cells. The addition of a eukaryotic leader sequence to mpt64 did not significantly increase the T-cell or antibody response. Each of the three DNA vectors stimulated a significant reduction in the level of M. tuberculosis infection in the lungs of mice challenged 4 weeks after immunization, but not to the levels resulting after immunization with Mycobacterium bovis BCG. The vaccines showed a consistent hierarchy of protection, with the most effective being Ag85B, followed by ESAT-6 and then MPT64. Coimmunization with the three vectors resulted in a greater degree of protection than that induced by any single vector. This protective efficacy was associated with the emergence of IFN-gamma-secreting T cells earlier than in infected animals immunized with a control vector. The efficacy of these DNA vaccines suggests that multisubunit vaccination may contribute to future vaccine strategies against TB. (+info)
Role of gamma interferon in cellular immune response against murine Encephalitozoon cuniculi infection.
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Microsporidia are obligate intracellular protozoan parasites that cause a wide variety of opportunistic infection in patients with AIDS. Because it is able to grow in vitro, Encephalitozoon cuniculi is currently the best-studied microsporidian. T cells mediate protective immunity against this parasite. Splenocytes obtained from infected mice proliferate in vitro in response to irradiated parasites. A transient state of hyporesponsiveness to parasite antigen and mitogen was observed at day 17 postinfection. This downregulatory response could be partially reversed by addition of nitric oxide (NO) antagonist to the culture. Mice infected with E. cuniculi secrete significant levels of gamma interferon (IFN-gamma). Treatment with antibody to IFN-gamma or interleukin-2 (IL-12) was able to neutralize the resistance to the parasite. Mutant animals lacking the IFN-gamma or IL-12 gene were highly susceptible to infection. However, mice unable to secrete NO withstood high doses of parasite challenge, similar to normal wild-type animals. These studies describe an IFN-gamma-mediated protection against E. cuniculi infection that is independent of NO production. (+info)
Middle ear fluid cytokine and inflammatory cell kinetics in the chinchilla otitis media model.
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Streptococcus pneumoniae is the most frequent microbe causing middle ear infection. The pathophysiology of pneumococcal otitis media has been characterized by measurement of local inflammatory mediators such as inflammatory cells, lysozyme, oxidative metabolic products, and inflammatory cytokines. The role of cytokines in bacterial infection has been elucidated with animal models, and interleukin (IL)-1beta, IL-6, and IL-8 and tumor necrosis factor alpha (TNF-alpha) are recognized as being important local mediators in acute inflammation. We characterized middle ear inflammatory responses in the chinchilla otitis media model after injecting a very small number of viable pneumococci into the middle ear, similar to the natural course of infection. Middle ear fluid (MEF) concentrations of IL-1beta, IL-6, IL-8, and TNF-alpha were measured by using anti-human cytokine enzyme-linked immunosorbent assay reagents. IL-1beta showed the earliest peak, at 6 h after inoculation, whereas IL-6, IL-8, and TNF-alpha concentrations were increasing 72 h after pneumococcal inoculation. IL-6, IL-8, and TNF-alpha but not IL-1beta concentrations correlated significantly with total inflammatory cell numbers in MEF, and all four cytokines correlated significantly with MEF neutrophil concentration. Several intercytokine correlations were significant. Cytokines, therefore, participate in the early middle ear inflammatory response to S. pneumoniae. (+info)
TWEAK induces angiogenesis and proliferation of endothelial cells.
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TWEAK is a recently described member of the Tumor Necrosis Factor (TNF) ligand family whose transcripts are present in a wide variety of human tissues (Chicheportiche, Y., Bourdon, P. R., Xu, H., Hsu Y. M., Scott, H., Hession, C., Garcia, I., and Browning, J. L. (1997) J. Biol. Chem. 272, 32401-32410). TWEAK is a weak inducer of apoptosis in transformed cells when administered with interferon-gamma or cycloheximide (Chicheportiche, Y., Bourdon, P. R., Xu, H., Hsu Y. M., Scott, H., Hession, C., Garcia, I., and Browning, J. L. (1997) J. Biol. Chem. 272, 32401-32410; Masters, S. A., Sheridan, J. P., Pitti, R. M., Brush, A. G., and Ashkenazi, A. (1998) Curr. Biol. 8, 525-528) and also promotes IL-8 secretion in cultured cells. We report here that picomolar concentrations of recombinant soluble TWEAK induce proliferation in a variety of normal human endothelial cells and in aortic smooth muscle cells and reduce culture requirements for serum and growth factors. Blocking antibodies to Vascular Endothelial Growth Factor (VEGF) do not significantly inhibit TWEAK-induced proliferation, indicating that TWEAK does not function indirectly through up-regulation of VEGF. Pellets containing TWEAK induce a strong angiogenic response when implanted in rat corneas, suggesting a role for TWEAK in vasculature formation in vivo. (+info)