مقاله انگلیسی باز ترکیب بیان شده با مخمر SARS-CoV-2 receptor binding domain RBD203-N1
Abstract
Keywords
Abbreviations
Introduction
Materials and methods
Results
Discussion
Conclusions
Author contributions
Declaration of Competing interest
Acknowledgments
Appendix A. Supplementary data
References
ABSTRACT
SARS-CoV-2 protein subunit vaccines are currently being evaluated by multiple manufacturers to address the global vaccine equity gap, and need for low-cost, easy to scale, safe, and effective COVID-19 vaccines. In this paper, we report on the generation of the receptor-binding domain RBD203-N1 yeast expression construct, which produces a recombinant protein capable of eliciting a robust immune response and protection in mice against SARS-CoV-2 challenge infections. The RBD203-N1 antigen was expressed in the yeast Pichia pastoris X33. After fermentation at the 5 L scale, the protein was purified by hydrophobic interaction chromatography followed by anion exchange chromatography. The purified protein was characterized biophysically and biochemically, and after its formulation, the immunogenicity was evaluated in mice. Sera were evaluated for their efficacy using a SARS-CoV-2 pseudovirus assay. The RBD203-N1 protein was expressed with a yield of 492.9 ± 3.0 mg/L of fermentation supernatant. A two-step purification process produced a >96% pure protein with a recovery rate of 55 ± 3% (total yield of purified protein: 270.5 ± 13.2 mg/L fermentation supernatant). The protein was characterized to be a homogeneous monomer that showed a well-defined secondary structure, was thermally stable, antigenic, and when adjuvanted on Alhydrogel in the presence of CpG it was immunogenic and induced high levels of neutralizing antibodies against SARS-CoV-2 pseudovirus. The characteristics of the RBD203-N1 proteinbased vaccine show that this candidate is another well suited RBD-based construct for technology transfer to manufacturing entities and feasibility of transition into the clinic to evaluate its immunogenicity and safety in humans.
Introduction
As of October 7th, 2021, more than 6.4 billion doses of coronavirus vaccines have been administered in over 180 countries. However, this impressive vaccination campaign has still left approximately 60% of the global population without access to efficient protection from COVID-19 [1]. According to a recent analysis, people in the highest-income countries are getting vaccinated more than 20 times faster than those living in poverty [2].