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Background: The temperature upshift has been widely used as an induction system to produce recombinant proteins (RPs). However, thermoinduction could affect bacterial metabolism, RP production, and RP aggregation. Understanding the structure and functionality of those aggregates, known as inclusion bodies (IBs), is a research area of interest in bioprocesses being scarcely studied under thermoinduction. Here, we describe the effect of the thermoinduction (39°C or 42°C) on the production of the recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF) using Escherichia coli W3110 under the system kpL/cI857. Results: Results indicated that at 39°C, the production of biomass was almost doubled as well as the acetate accumulation compared to 42°C. Cultures thermoinduced at 42°C improved 1.5-fold the total protein over biomass yield and 1.25-fold the RP over total protein yield. Furthermore, 42°C accelerated the onset of IB formation, changing its architecture. Additionally, IBs formed at 42°C were less soluble and presented higher disorderly structures compared with IBs formed at 39°C, enriched in a-helix and amyloidal-like structures. Conclusions: This study highlights the observation that IBs attain different architecture in response to small changes in environmental conditions, such as the induction temperature, being this helpful information to improve thermoinduced bioprocesses. [ABSTRACT FROM AUTHOR]

Background: Developing countries have an estimate of ten times more approved biosimilars than developed countries. This disparity demands the need of an objective regulation that incorporates health policies according to the technological and economical capabilities of each country. One of the challenges lies on the establishment of comparability principles based on a physicochemical and biological characterization that should determine the extent of additional non-clinical and clinical studies. This is particularly relevant for licensed biosimilars in developing countries, which have an extensive clinical experience since their approval as generics, in some cases more than a decade. To exemplify the current status of biosimilars in Mexico, a characterization exercise was conducted on licensed filgrastim biosimilars using pharmacopeial and extended characterization methodologies. Results: Most of the evaluated products complied with the pharmacopeial criteria and showed comparability in their Critical Quality Attributes (CQAs) towards the reference product. These results were expected in accordance with their equivalent performance during their licensing as generics. Accordingly, a rational approval and registration renewal scheme for biosimilars is proposed, that considers the proper identification of CQAs and its thoroughly evaluation using selected techniques. Conclusions: This approach provides support to diminish uncertainty of exhibiting different pharmacological profiles and narrows or even avoids the necessity of comparative clinical studies. Ultimately, this proposal is intended to improve the accessibility to high quality biosimilars in Latin America and other developing countries. [ABSTRACT FROM AUTHOR]