27 research outputs found

    High Yield Production Process for Shigella Outer Membrane Particles

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    Gram-negative bacteria naturally shed particles that consist of outer membrane lipids, outer membrane proteins, and soluble periplasmic components. These particles have been proposed for use as vaccines but the yield has been problematic. We developed a high yielding production process of genetically derived outer membrane particles from the human pathogen Shigella sonnei. Yields of approximately 100 milligrams of membrane-associated proteins per liter of fermentation were obtained from cultures of S. sonnei ΔtolR ΔgalU at optical densities of 30–45 in a 5 L fermenter. Proteomic analysis of the purified particles showed the preparation to primarily contain predicted outer membrane and periplasmic proteins. These were highly immunogenic in mice. The production of these outer membrane particles from high density cultivation of bacteria supports the feasibility of scaling up this approach as an affordable manufacturing process. Furthermore, we demonstrate the feasibility of using this process with other genetic manipulations e.g. abolition of O antigen synthesis and modification of the lipopolysaccharide structure in order to modify the immunogenicity or reactogenicity of the particles. This work provides the basis for a large scale manufacturing process of Generalized Modules of Membrane Antigens (GMMA) for production of vaccines from Gram-negative bacteria

    Correlation of securin and Ki67 in invasive breast carcinoma

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    Aims. To identify the role of securin (PTTG) as a prognostic marker in invasive breast carcinoma and its possible relation to ki67 and to evaluate the use of ImmunoRatio® as a tool for calculating ki67 and securin labelling indices. Methods. Securin and ki67 immunohistochemical staining were performed on tissue microarray sections representative of 118 patients diagnosed with invasive breast carcinoma from 2005 to 2011. Assessment of immunohistochemical staining was carried out using both visual counting and ImmunoRatio®. The 118 cases were categorized into 2 groups according to their clinical outcome; the first group (G1) (n=77) comprised patients who were disease-free while the second group (G2) (n=41) included patients who developed either recurrence and/or metastasis at the end of 24 months follow-up duration. Results. Both securin and ki67 labelling indices (LIs) obtained by visual counting were significantly higher in G2, while only securin LIs acquired by ImmunoRatio® were significantly higher in G2. Securin assessment by visual counting was the most accurate (AUC=0.775) in identifying patients who will likely suffer from recurrence and/or distant metastasis. Pearson correlation showed r=0.638, p<0.001 for Ki67 and r=0.671, p<0.001 for securin. Linear regression analysis showed a significant correlation between ki67 and securin, B=1.75, p<0.001. Conclusion. The present results suggest that securin may add to the prognostic value of ki67 in highlighting intra-tumoural heterogeneity in invasive breast carcinoma patients with poor clinical outcome. In addition, the study showed that since securin has a visual counting cutoff with more than 1%, making it easier to use as a breast cancer biomarker in conjunction with ki67 to predict the outcome of the cases more accurately than using only ki67. However, a multivariate analysis on a larger cohort of patients is mandatory to test its potential prognostic value
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