Immunostimulation in the urinary bladder by local application of Nocardia rubra cell-wall skeletons (Rubratin) and bacillus Calmette-Guerin as therapy for superficial bladder cancer: a comparative study.
(1/25)
Twelve patients with superficial bladder cancer were treated with intravesical instillations of Rubratin (ASTA Pharma AG, Frankfurt, Germany), a cell-wall preparation of Nocardia rubra. The objective was to compare the immunostimulating effect of Rubratin with that of bacillus Calmette-Guerin (BCG). Local immunostimulation was determined by cytokine induction in serially collected urine samples during the first 24 h after each instillation, leukocyte influx into the urine, and phenotypic analysis of the lymphocyte fraction. Levels of Rubratin-induced interleukin (IL)-1 beta, IL-6, and tumor necrosis factor-alpha were significantly elevated compared with pretherapy levels. Rubratin induced leukocyte influx into the urine. T-cell activation (IL-2 receptor and human leukocyte antigen-DR expression) can be induced, and CD4:CD8 cell ratios can be increased. All parameters indicated that Rubratin-induced immunostimulation was less than that associated with BCG. In conclusion, although local Rubratin-induced immunostimulation occurs in a limited number of patients, the amount of immunocompetent cells attracted to the bladder seems to be less than that associated with BCG therapy, thus resulting in lower levels of cytokine production (which may reflect less clinical efficacy). (+info)
Maturation of human dendritic cells by cell wall skeleton of Mycobacterium bovis bacillus Calmette-Guerin: involvement of toll-like receptors.
(2/25)
The constituents of mycobacteria are an effective immune adjuvant, as observed with complete Freund's adjuvant. In this study, we demonstrated that the cell wall skeleton of Mycobacterium bovis bacillus Calmette-Guerin (BCG-CWS), a purified noninfectious material consisting of peptidoglycan, arabinogalactan, and mycolic acids, induces maturation of human dendritic cells (DC). Surface expression of CD40, CD80, CD83, and CD86 was increased by BCG-CWS on human immature DC, and the effect was similar to those of interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), heat-killed BCG, and viable BCG. BCG-CWS induced the secretion of TNF-alpha, IL-6, and IL-12 p40. CD83 expression was increased by a soluble factor secreted from BCG-CWS-treated DC and was completely inhibited by monoclonal antibodies against TNF-alpha. BCG-CWS-treated DC stimulated extensive allogeneic mixed lymphocyte reactions. The level of TNF-alpha secreted through BCG-CWS was partially suppressed in murine macrophages with no Toll-like receptor 2 (TLR 2) or TLR4 and was completely lost in TLR2 and TLR4 double-deficient macrophages. These results suggest that the BCG-CWS induces TNF-alpha secretion from DC via TLR2 and TLR4 and that the secreted TNF-alpha induces the maturation of DC per se. (+info)
Immunization with a polyprotein vaccine consisting of the T-Cell antigens thiol-specific antioxidant, Leishmania major stress-inducible protein 1, and Leishmania elongation initiation factor protects against leishmaniasis.
(3/25)
Development of an effective vaccine against Leishmania infection is a priority of tropical disease research. We have recently demonstrated protection against Leishmania major in the murine and nonhuman primate models with individual or combinations of purified leishmanial recombinant antigens delivered as plasmid DNA constructs or formulated with recombinant interleukin-12 (IL-12) as adjuvant. In the present study, we immunized BALB/c mice with a recombinant polyprotein comprising a tandem fusion of the leishmanial antigens thiol-specific antioxidant, L. major stress-inducible protein 1 (LmSTI1), and Leishmania elongation initiation factor (LeIF) delivered with adjuvants suitable for human use. Aspects of the safety, immunogenicity, and vaccine efficacy of formulations with each individual component, as well as the polyprotein referred to as Leish-111f, were assessed by using the L. major challenge model with BALB/c mice. No adverse reactions were observed when three subcutaneous injections of the Leish-111f polyprotein formulated with either MPL-squalene (SE) or Ribi 529-SE were given to BALB/c mice. A predominant Th1 immune response characterized by in vitro lymphocyte proliferation, gamma interferon production, and immunoglobulin G2A antibodies was observed with little, if any, IL-4. Moreover, Leish-111f formulated with MPL-SE conferred immunity to leishmaniasis for at least 3 months. These data demonstrate success at designing and developing a prophylactic leishmaniasis vaccine that proved effective in a preclinical model using multiple leishmanial antigens produced as a single protein delivered with a powerful Th1 adjuvant suitable for human use. (+info)
Effect of vaccination with refined components of the organism on infection of mice with Mycobacterium leprae.
(4/25)
Only native products of Mycobacterium leprae, whether cell wall, cytosol, or membrane derived, can confer protective immunity against challenge in the mouse footpad. Previously, recombinant proteins were shown to be ineffective. The cell wall skeleton-the mycolyl-arabinogalactan-peptidoglycan complex-devoid of proteins is not protective. (+info)
Mycobacterium bovis BCG cell wall-specific differentially expressed genes identified by differential display and cDNA subtraction in human macrophages.
(5/25)
We have analyzed the gene expression profile of monocytes in response to a highly purified cell wall fraction of Mycobacterium bovis BCG, a clinically approved adjuvant known as BCG cell wall skeleton (BCG-CWS). It is composed of mycolic acid, arabinogalactan, and peptidoglycan and confers Toll-like receptor 2 (TLR2)- and TLR4-dependent signaling that induces monocytes to differentiate into antigen-presenting cells (APCs). Here we report differential gene expression analysis with BCG-CWS-stimulated versus nonstimulated monocytes. BCG-CWS exerted massive induction of genes regulated by TLR signaling. Marked gene regulatory characteristics in BCG-CWS-stimulated cells compared to lipopolysaccharide (LPS)-stimulated cells follow. (i) Spliced mRNAs encoding soluble forms of TREM-1 and TREM-2 (recently discovered inflammatory-signal-amplifying receptors) were regulated by BCG-CWS, resulting in their differential expression. (ii) The genes for zinc-iron transporter protein (ZIP)-like family proteins HKE-1 and LIV-1 were induced exclusively by BCG-CWS. (iii) Interleukin-23 (IL-23), rather than IL-12p70, was induced by BCG-CWS, while interferon-inducible genes were induced only by LPS. By Northern and reverse transcription-PCR analyses, we confirmed the differential expression of more than 30 BCG-CWS regulatory genes, and their expression was compared with that of LPS and other known TLR ligands. A battery of genes responded rapidly and for a short time to LPS but for a long time to BCG-CWS. Structural analysis of the identified novel or hypothetical proteins revealed that some are potential candidates as signaling mediators or transcriptional regulators. Hence, BCG-CWS may profoundly modulate APC responses in a way distinct from that of LPS, leading to possible advantages for its adjuvant-active therapeutic potential. (+info)
The role of adjuvant on the regulatory effects of NK cells on B cell responses as revealed by a new model of NK cell deficiency.
(6/25)
We have utilized a novel method to generate transgenic mice that are deficient in NK cells. The strategy entails introduction of the H and L chain genes encoding PK136, an antibody shown to be effective in the in vivo elimination of NK cells, into the mouse genome. Since the introduced H chain gene does not contain sequences encoding membrane exons, the transgenic Ig is not expressed on the cell surface, but is secreted by activated B cells. We show that these animals are chronically depleted of NK cells, but not B, T or NKT cells. Therefore, they are compromised in their ability to mediate NK-mediated cytotoxicity. In addition, the deficiency in NK cells reduces the level of switching to various downstream isotypes in response to T-independent type II antigens. However, this reduction is only apparent when antigens are injected in the presence of adjuvant. Since NKT cells are not depleted, the effect cannot be attributed to this subpopulation. These results help to resolve differences in previous findings regarding the role of NK cells in antibody responses. (+info)
Protective immunity to vaccinia virus induced by vaccination with multiple recombinant outer membrane proteins of intracellular and extracellular virions.
(7/25)
Infectious intracellular and extracellular forms of vaccinia virus have different outer membrane proteins, presenting multiple targets to the immune system. We investigated the immunogenicity of soluble forms of L1, an outer membrane protein of the intracellular mature virus, and of A33 and B5, outer membrane proteins of the extracellular enveloped virus. The recombinant proteins, in 10-microg amounts mixed with a Ribi- or saponin-type adjuvant, were administered subcutaneously to mice. Antibody titers to each protein rose sharply after the first and second boosts, reaching levels that surpassed those induced by percutaneous immunization with live vaccinia virus. Immunoglobulin G1 (IgG1) antibody predominated after the protein immunizations, indicative of a T-helper cell type 2 response, whereas live vaccinia virus induced mainly IgG2a, indicative of a T-helper cell type 1 response. Mice immunized with any one of the recombinant proteins survived an intranasal challenge with 5 times the 50% lethal dose of the pathogenic WR strain of vaccinia virus. Measurements of weight loss indicated that the A33 immunization most effectively prevented disease. The superiority of protein combinations was demonstrated when the challenge virus dose was increased 20-fold. The best protection was obtained with a vaccine made by combining recombinant proteins of the outer membranes of intracellular and extracellular virus. Indeed, mice immunized with A33 plus B5 plus L1 or with A33 plus L1 were better protected than mice immunized with live vaccinia virus. Three immunizations with the three-protein combination were necessary and sufficient for complete protection. These studies suggest the feasibility of a multiprotein smallpox vaccine. (+info)
Evaluation of lipopolysaccharide and capsular polysaccharide as subunit vaccines against experimental melioidosis.
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Burkholderia pseudomallei is the causative agent of melioidosis, which is a major cause of morbidity and mortality in endemic regions. Currently there is no human vaccine against melioidosis. In this study, LPS or capsular polysaccharide was used to immunize BALB/c mice. The different polysaccharide antigens induced antibody responses. Mice vaccinated with LPS developed predominantly IgM and IgG3 responses. Contrastingly, mice vaccinated with capsular polysaccharide developed a predominantly IgG2b response. After immunization, mice were challenged by the intra-peritoneal route and an increased mean time to death was observed compared with unvaccinated controls. Immunization with LPS provided an optimal protective response. Mice challenged by the aerosol route showed a small increase in the mean time to death compared with the unvaccinated controls. The passive transfer of antigen from immunized into naive mice provided protection against a subsequent challenge. This study is the first time antigens protective by active immunization have been identified and suggests that polysaccharides have potential as vaccine candidates against melioidosis. (+info)