Recombinant Human Bone Morphogenetic Protein 9 (rhBMP9) Induced Osteoblastic Behaviour on a Collagen Membrane Compared With rhBMP2

BACKGROUND Bone morphogenetic protein 9 (BMP9) has previously been characterized as one of the most osteogenic growth factors of the BMP-family, however, up until now, these experiments have only been demonstrated using adenovirus-transfection experiments (gene therapy). With the recent development of recombinant human (rh)BMP9, the aim of the present study was to investigate its osteopromotive potential versus rhBMP2 when loaded onto a collagen membrane. METHODS ST2 stromal bone marrow cells were seeded onto 1)control; 2)rhBMP2-low(10ng/ml); 3)rhBMP2-high(100ng/ml); 4)rhBMP9-low(10ng/ml); and 5)rhBMP9-high(100ng/ml) porcine collagen membranes. Groups were then compared for cell adhesion at 8 hours, cell proliferation at 1, 3 and 5 days real-time PCR at 3 and 14 days for genes encoding Runx2, alkaline phosphatase(ALP) and bone sialoprotein(BSP) at 3 and 14 days and alizarin red staining at 14 days. RESULTS While rhBMP2 and rhBMP9 demonstrated little effects on cell attachment and proliferation, pronounced increases were observed on osteoblast differentiation. It was found that all groups significantly induced ALP mRNA levels at 3 days and BSP levels at 14 days, however rhBMP9-high demonstrated significantly higher values when compared to all other groups for ALP levels (5-fold increase at 3 days and 2-fold increase at 14 days). Alizarin red staining further revealed that both concentrations of rhBMP9 induced up to 3-fold more staining when compared to rhBMP2. CONCLUSION These results indicate that the combination of collagen membranes with rhBMP9 significantly induced significantly higher ALP mRNA expression and alizarin red staining when compared to rhBMP2. These findings suggest that rhBMP9 may be a suitable growth factor for future regenerative procedures in bone biology.

Use of Recombinant Virus Replicon Particles for Vaccination against Mycobacterium ulcerans Disease.

Buruli ulcer, caused by infection with Mycobacterium ulcerans, is a necrotizing disease of the skin and subcutaneous tissue, which is most prevalent in rural regions of West African countries. The majority of clinical presentations seen in patients are ulcers on limbs that can be treated by eight weeks of antibiotic therapy. Nevertheless, scarring and permanent disabilities occur frequently and Buruli ulcer still causes high morbidity. A vaccine against the disease is so far not available but would be of great benefit if used for prophylaxis as well as therapy. In the present study, vesicular stomatitis virus-based RNA replicon particles encoding the M. ulcerans proteins MUL2232 and MUL3720 were generated and the expression of the recombinant antigens characterized in vitro. Immunisation of mice with the recombinant replicon particles elicited antibodies that reacted with the endogenous antigens of M. ulcerans cells. A prime-boost immunization regimen with MUL2232-recombinant replicon particles and recombinant MUL2232 protein induced a strong immune response but only slightly reduced bacterial multiplication in a mouse model of M. ulcerans infection. We conclude that a monovalent vaccine based on the MUL2232 antigen will probably not sufficiently control M. ulcerans infection in humans.

Modulatory Effects of Eschscholzia californica Alkaloids on Recombinant GABAA Receptors.

The California poppy (Eschscholzia californica Cham.) contains a variety of natural compounds including several alkaloids found exclusively in this plant. Because of the sedative, anxiolytic, and analgesic effects, this herb is currently sold in pharmacies in many countries. However, our understanding of these biological effects at the molecular level is still lacking. Alkaloids detected in E. californica could be hypothesized to act at GABAA receptors, which are widely expressed in the brain mainly at the inhibitory interneurons. Electrophysiological studies on a recombinant α 1 β 2 γ 2 GABAA receptor showed no effect of N-methyllaurotetanine at concentrations lower than 30 μM. However, (S)-reticuline behaved as positive allosteric modulator at the α 3, α 5, and α 6 isoforms of GABAA receptors. The depressant properties of aerial parts of E. californica are assigned to chloride-current modulation by (S)-reticuline at the α 3 β 2 γ 2 and α 5 β 2 γ 2 GABAA receptors. Interestingly, α 1, α 3, and α 5 were not significantly affected by (R)-reticuline, 1,2-tetrahydroreticuline, codeine, and morphine-suspected (S)-reticuline metabolites in the rodent brain.

Description of the SAGhE Cohort: A Large European Study of Mortality and Cancer Incidence Risks after Childhood Treatment with Recombinant Growth Hormone.

BACKGROUND The long-term safety of growth hormone treatment is uncertain. Raised risks of death and certain cancers have been reported inconsistently, based on limited data or short-term follow-up by pharmaceutical companies. PATIENTS AND METHODS The SAGhE (Safety and Appropriateness of Growth Hormone Treatments in Europe) study assembled cohorts of patients treated in childhood with recombinant human growth hormone (r-hGH) in 8 European countries since the first use of this treatment in 1984 and followed them for cause-specific mortality and cancer incidence. Expected rates were obtained from national and local general population data. The cohort consisted of 24,232 patients, most commonly treated for isolated growth failure (53%), Turner syndrome (13%) and growth hormone deficiency linked to neoplasia (12%). This paper describes in detail the study design, methods and data collection and discusses the strengths, biases and weaknesses consequent on this. CONCLUSION The SAGhE cohort is the largest and longest follow-up cohort study of growth hormone-treated patients with follow-up and analysis independent of industry. It forms a major resource for investigating cancer and mortality risks in r-hGH patients. The interpretation of SAGhE results, however, will need to take account of the methods of cohort assembly and follow-up in each country.

Characterization of a shorter recombinant polypeptide chain of bone morphogenetic protein 2 on osteoblast behaviour

BACKGROUND Recombinant bone morphogenetic protein two (rhBMP2) has been utilised for a variety of clinical applications in orthopaedic surgery and dental procedures. Despite its widespread use, concerns have been raised regarding its short half-life and transient bioactivity in vivo. Recent investigation aimed at developing rhBMP2 synthesized from a shorter polypeptide chain (108 amino acids) has been undertaken. METHODS The osteopromotive properties of BMP2 were investigated on cell behaviour. Five concentrations of rhBMP2_108 including 10, 50, 100, 200 and 500 ng/ml were compared to a commercially available rhBMP2 (100 ng/ml). Each of the working concentrations of rhBMP2_108 were investigated on MC3T3-E1 osteoblasts for their ability to induce osteoblast recruitment, proliferation and differentiation as assessed by alkaline phosphatase (ALP) staining, alizarin red staining, and real-time PCR for genes encoding ALP, osteocalcin (OCN), collagen-1 (COL-1) and Runx2. RESULTS The results demonstrate that all concentrations of rhBMP2_108 significantly improved cell recruitment and proliferation of osteoblasts at 5 days post seeding. Furthermore, rhBMP2_108 had the most pronounced effects on osteoblast differentiation. It was found that rhBMP2_108 had over a four fold significant increase in ALP activity at seven and 14 days post-seeding and the concentrations ranging from 50 to 200 ng/ml demonstrated the most pronounced effects. Analysis of real-time PCR for genes encoding ALP, OCN, COL-1 and Runx2 further confirmed dose-dependant increases at 14 days post-seeding. Furthermore, alizarin red staining demonstrated a concentration dependant increase in staining at 14 days. CONCLUSION The results from the present study demonstrate that this shorter polypeptide chain of rhBMP2_108 is equally as bioactive as commercially available rhBMP2 for the recruitment of progenitor cells by facilitating their differentiation towards the osteoblast lineage. Future in vivo study are necessary to investigate its bioactivity.

Prevalence estimation of tick-borne encephalitis virus (TBEV) antibodies in dogs from Finland using novel dog anti-TBEV IgG MAb-capture and IgG immunofluorescence assay based on recombinant TBEV subviral particles

Tick-borne encephalitis (TBE) is one of the most dangerous human neurological infections occurring in Europe and Northern parts of Asia with thousands of cases and millions vaccinated against it. The risk of TBE might be assessed through analyses of the samples taken from wildlife or from animals which are in close contact with humans. Dogs have been shown to be a good sentinel species for these studies. Serological assays for diagnosis of TBE in dogs are mainly based on purified and inactivated TBEV antigens. Here we describe novel dog anti-TBEV IgG monoclonal antibody (MAb)-capture assay which is based on TBEV prME subviral particles expressed in mammalian cells from Semliki Forest virus (SFV) replicon as well as IgG immunofluorescence assay (IFA) which is based on Vero E6 cells transfected with the same SFV replicon. We further demonstrate their use in a small-scale TBEV seroprevalence study of dogs representing different regions of Finland. Altogether, 148 dog serum samples were tested by novel assays and results were compared to those obtained with a commercial IgG enzyme immunoassay (EIA), hemagglutination inhibition test and IgG IFA with TBEV infected cells. Compared to reference tests, the sensitivities of the developed assays were 90-100% and the specificities of the two assays were 100%. Analysis of the dog serum samples showed a seroprevalence of 40% on Åland Islands and 6% on Southwestern archipelago of Finland. In conclusion, a specific and sensitive EIA and IFA for the detection of IgG antibodies in canine sera were developed. Based on these assays the seroprevalence of IgG antibodies in dogs from different regions of Finland was assessed and was shown to parallel the known human disease burden as the Southwestern archipelago and Åland Islands in particular had considerable dog TBEV antibody prevalence and represent areas with high risk of TBE for humans.

Delivery of the p67 sporozoite antigen of Theileria parva by using recombinant Salmonella dublin: secretion of the product enhances specific antibody responses in cattle

The p67 sporozoite antigen of Theileria parva has been fused to the C-terminal secretion signal of Escherichia coli hemolysin and expressed in secreted form by attenuated Salmonella dublin aroA strain SL5631. The recombinant p67 antigen was detected in the supernatant of transformed bacterial cultures. Immunization trials in cattle revealed that SL5631 secreting the antigen provoked a 10-fold-higher antibody response to p67 than recombinant SL5631 expressing but not secreting p67. Immunized calves were challenged with a 80% lethal dose of T. parva sporozoites and monitored for the development of infection. Two of three calves immunized intramuscularly with the p67-secreting SL5631 strain were found to be protected, whereas only one of three animals immunized with the nonsecreting p67-expressing SL5631 strain was protected. This is the first demonstration that complete eukaryotic antigens fused to the C-terminal portion of E. coli hemolysin can be exported from attenuated Salmonella strains and that such exported antigens can protect cattle against subsequent parasite challenge.

Expression and biological activities of bovine interleukin 4: effects of recombinant bovine interleukin 4 on T cell proliferation and B cell differentiation and proliferation in vitro

Interleukin 4 (IL-4) is a pleotropic cytokine affecting a wide range of cell types in both the mouse and the human. These activities include regulation of the growth and differentiation of both T and B lymphocytes. The activities of IL-4 in nonprimate, nonmurine systems are not well established. Herein, we demonstrate in the bovine system that IL-4 upregulates production of IgM, IgG1, and IgE in the presence of a variety of costimulators including anti-IgM, Staphylococcus aureus cowan strain I, and pokeweed mitogen. IgE responses are potentiated by the addition of IL-2 to IL-4. Culture of bovine B lymphocytes with IL-4 in the absence of additional costimulators resulted in the increased surface expression of CD23 (low-affinity Fc epsilon RII), IgM, IL-2R, and MHC class II in a dose-dependent manner. IL-4 alone increased basal levels of proliferation of bulk peripheral blood mononuclear cells but in the presence of Con A inhibited proliferation. In contrast to the activities of IL-4 in the murine system, proliferation of TH1- and TH2-like clones was inhibited in a dose-dependent manner as assessed by antigen-or IL-2-driven in vitro proliferative responses. These observations are consistent with the role of IL-4 as a key player in regulation of both T and B cell responses.

Identification of two Th1 cell epitopes on the Babesia bovis-encoded 77-kilodalton merozoite protein (Bb-1) by use of truncated recombinant fusion proteins

Previous studies have demonstrated the serologic and T-cell immunogenicity for cattle of a recombinant form of the apical complex-associated 77-kDa merozite protein of Babesia bovis, designated Bb-1. The present study characterizes the immunogenic epitopes of the Bb-1 protein. A series of recombinant truncated fusion proteins spanning the majority of the Bb-1 protein were expressed in Escherichia coli, and their reactivities with bovine peripheral blood mononuclear cells and T-cell clones derived from B. bovis-immune cattle and with rabbit antibodies were determined. Lymphocytes from two immune cattle were preferentially stimulated by the N-terminal half of the Bb-1 protein (amino acids 23 to 266, termed Bb-1A), localizing the T-cell epitopes to the Bb-1A portion of the molecule. CD4+ T-cell clones derived by stimulation with the intact Bb-1 fusion protein were used to identify two T-cell epitopes in the Bb-1A protein, consisting of amino acids SVVLLSAFSGN VWANEAEVSQVVK and FSDVDKTKSTEKT (residues 23 to 46 and 82 to 94). In contrast, rabbit antiserum raised against the intact fusion protein reacted only with the C-terminal half of the protein (amino acids 267 to 499, termed Bb-1B), which contained 28 tandem repeats of the tetrapeptide PAEK or PAET. Biological assays and Northern (RNA) blot analyses for cytokines revealed that following activation with concanavalin A, T-cell clones reactive against the two Bb-1A epitopes produced interleukin-2, gamma interferon, and tumor necrosis factors beta and alpha, but not interleukin-4, suggesting that the Bb-1 antigen preferentially stimulates the Th1 subset of CD4+ T cells in cattle. The studies described here report for the first time the characterization, by cytokine production, of the Th1 subset of bovine T cells and show that, as in mice, protozoal antigens can induce Th1 cells in ruminants. This first demonstration of B. bovis-encoded Th1 cell epitopes provides a rationale for incorporation of all or part of the Bb-1 protein into a recombinant vaccine.