The severe COVID-19: A sepsis induced by viral infection? And its immunomodulatory therapy / 中华创伤杂志(英文版)

COVID-19 is known for its magical infectivity, fast transmission and high death toll based on the large number of infected people. From the perspective of the clinical manifestation, autopsy examination and pathophysiology, the essence of COVID-19 should be viewed as a sepsis induced by viral infection, and has the essential characteristics as sepsis induced by other pathogens. Therefore, in addition to etiological and supportive treatment, immunomodulatory therapy is also appropriate to severe COVID-19. Although there is still a lack of consensus on immunotherapy for sepsis so far, relatively rich experiences have been accumulated in the past decades, which will help us in the treatment of severe COVID-19. This article will elaborate immunotherapy of sepsis, though it may not be consistent.

Construction and application of a yeast expression system for thymosin a1

We want to construct a yeast expression system for thymosin a1 (Ta1) to make the orally administered Ta1 preparation possible. The whole Ta1 DNA fragment was obtained by PCR. After being digested with restriction enzymes, it was cloned into pYES2 vector. Sequencing was performed to identify the recombinant. The sequence of Ta1 in recombinant coincided with the original one reported in Genbank. When pYES2-Ta1 plasmid was transformed into yeast, galactose instead of glucose was used to induce Ta1 expression. Western blot was performed to identify the quality of the expressed Ta1. Dried yeast containing pYEST2-Ta1 was fed to Balb/c mice whose immunities were inhibited by cyclophosphamide in advance. Synthesized Ta1 peptide was used as positive control and empty yeast was used as negative control. Compared with the negative control group, both dried yeast containing pYEST2-Ta1 and synthesized Ta1 peptide can significantly increase the CD8+ level (22.74±1.09 and 18.77±4.72 vs 7.49±2.14, p<0.01), while both of them had little effect on the CD4+ lymphocytes (61.86±6.94 and 65.91±4.78 vs 57.93±10.40, p>0.05). We concluded that a high effective yeast expression system for Ta1 was constructed successfully and the Ta1 protein expressed by this system can improve CD8+ level in immune inhibited mice.