Yamilet Rabasa

Center of Molecular Immunology, La Habana, Ciudad de La Habana, Cuba

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Publications (7)9.42 Total impact

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    ABSTRACT: AbstractBackground
    Vaccine 05/2014; 32(24):2851-2858. · 3.49 Impact Factor
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    ABSTRACT: The development of safe, effective, and affordable vaccines has become a global effort due to its vast impact on overall world health conditions. A brief overview of vaccine characterization techniques, especially in the area of high-resolution mass spectrometry, is presented. It is highly conceivable that the proper use of advanced technologies such as high-resolution mass spectrometry, along with the appropriate chemical and physical property evaluations, will yield tremendous in-depth scientific understanding for the characterization of vaccines in various stages of vaccine development. This work presents the physicochemical and biological characterization of cancer vaccine Racotumomab/alumina, a murine anti-idiotypic antibody that mimics N-glycolyl-GM3 gangliosides. This antibody has been tested as an anti-idiotypic cancer vaccine, adjuvated in Al(OH)3, in several clinical trials for melanoma, breast, and lung cancer. Racotumomab was obtained from ascites fluid, transferred to fermentation in stirred tank at 10L and followed to a scale up to 41L. The mass spectrometry was used for the determination of intact molecule, light and heavy chains masses; amino acids sequence analysis, N- and C-terminal, glycosylation and posttranslational modifications. Also we used the DLS for the size distribution and zeta potential analysis. The biological analyses were performed in mice and chickens. We observed differences in glycosylation pattern, charge heterogeneity and structural stability between in vivo-produced and bioreactor-obtained Racotumomab products. Interestingly, these modifications had no significant impact on the immune responses elicited in two different animal models. We are demonstrated that this approach could potentially be more efficient and effective for supporting vaccine research and development.
    Vaccine 03/2014; · 3.77 Impact Factor
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    ABSTRACT: 1E10 monoclonal antibody is a murine anti-idiotypic antibody that mimics N-glycolyl-GM3 gangliosides. This antibody has been tested as an anti-idiotypic cancer vaccine, adjuvated in Al(OH)3, in several clinical trials for melanoma, breast, and lung cancer. During early clinical development this mAb was obtained in vivo from mice ascites fluid. Currently, the production process of 1E10 is being transferred from the in vivo to a bioreactor-based method. Here, we present a comprehensive molecular and immunological characterization of 1E10 produced by the two different production processes in order to determine the impact of the manufacturing process in vaccine performance. We observed differences in glycosylation pattern, charge heterogeneity and structural stability between in vivo-produced 1E10 and bioreactor-obtained 1E10. Interestingly, these modifications had no significant impact on the immune responses elicited in two different animal models. Changes in 1E10 primary structure like glycosylation; asparagine deamidation and oxidation affected 1E10 structural stability but did not affect the immune response elicited in mice and chickens when compared to 1E10 produced in mice.
    BMC Biotechnology 11/2011; 11:112. · 2.17 Impact Factor
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    ABSTRACT: Although continuous cultures (CC) studies has been recognized as the standard method for cell line characterization, thorough and precise studies makes its use prohibitively costly. Batch cultures have also been used for this purpose due to its simplicity, but because of the constantly changing environment results obtained are reliable only for non limited growth phase.
    01/2010;
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    ABSTRACT: In this work several clones of a recombinant myeloma NS0 cell that were isolated in protein-free medium and selected by an integrated methodology that takes in account specific production and growth rates, stability of expression and resistance to apoptosis induced by nutrient limitation were characterized by two-dimensional gel electrophoresis in the pH range of 3–10. We have determined a group of 5 spots that correlated well with the values of selection indexes calculated for different clones.
    01/2007;
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    ABSTRACT: When developing cell culture processes based on recombinant mammalian cell lines, researchers faces very often problems related with early selection of that clone, which could better fit with the requirements needed for the future scale-up. Among desired characteristics for newly selected clones are high level and stable expression of desired protein and capability to reach high cell density in protein free-medium, in many cases under nutrient or oxygen limitations. In this work an integrated methodology was developed for the final cell line/culture medium selection. For this aim kinetic parameters were determined in batch cultures and expression stability was studied during long term cultures. An integral multiparametric coefficient was calculated for each clone and five of twelve clones were pre-selected based on this value. The final selection was done based on resistance to apoptosis induction when these cell lines reached limiting conditions at the end of exponential growth phase.
    12/2004: pages 505-507;
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    ABSTRACT: Semicontinuous cultures are a powerful tool for cell characterization. However, it is hard to be established at small scale due to the far more complex experimental configuration required. In this work, the use of semicontinuous culture in spinner flasks was explored with daily feeds and extractions, considering that metabolic and growth rates are lower in animal cells under continuous culture regimes. Relatively stabilized conditions were established, char- acterized by small fluctuations in the concentration of the different metabolic species (glucose, lactate, etc.) at the dilution rates evaluated, and the kinetic parameters (μ, qp, qGlu) were calculated as a function of the dilution rate for each phase. Results obtained were equivalent to those expected for a continuous culture, the semicontinuous operation mode being a much simpler variant. Up to now there are only scarce reports on using semicontinuous cultures as a feasible alternative to simulate the kinetic behavior at stationary states. Finally, the antibody produc- tion pattern was confirmed as growth independent, with glutamine as the limiting substrate in the medium. The results were validated by an statistical homogeneity of variance test (ANOVA) and with normally distributed data as evidenced by a Students t test.