Resumo

SERRANO-DIAZ, Anabel et al. Production of a human papillomavirus type 18-His-tag-L1 protein by a working cell bank of Escherichia coli BL21 (DE-3). Rev. CENIC Cienc. Biol [online]. 2021, vol.52, n.1, pp. 11-17.  Epub 01-Jun-2021. ISSN 2221-2450.

The infection with Human Papilloma viruses (HPV) is the most common sexually transmitted disease worldwide. The HPV 16 and 18 types are responsible for around 70% of cervical cancer cases globally. In Cuba, this is the second cancer in incidence and mortality on women between 15 to 44 years old. The viral capsid is formed by 72 capsomeres, composed by L1 and L2 proteins, being L1 the major protein. The available preventive vaccines are based on virus-like particles (VLPs) assembled from L1 protein produced in eukaryotic hosts and they have high prices, which has hindered their deployment in middle- and low-income countries. The bacterium Escherichia coli has been used as an alternative cheaper host for second-generation HPV vaccine production. The aims of this study were to prepare a working cell bank (WCB) of E. coli BL21 (DE3) harboring the HPV18-His-tag-L1-pET28a plasmid, which encodes the HPV18-L1 protein fused to a six-histidine-Tag; as well as to evaluate L1 protein´s production and solubility under isopropyl-β-D-1-thiogalactopyranoside (IPTG) induction and on auto-inducing conditions, as the first step to tackle L1 purification. The highest L1 levels were detected on terrific broth (TB)-grown cultures induced for 4h or 16h with low-IPTG-concentrations (30 and 60 µmolL-1) or with a lactose/glucose mixture for 16 hours. In both conditions, the protein was mainly detected in the insoluble fraction, so its purification will be carried out under denaturing conditions. The available WCB will allow maintaining the constant quality and homogeneity of the initial inoculum during L1 production to develop a robust purification process.

Palavras-chave : human papillomavirus; Escherichia coli; L1 protein; HPV18.

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