ABSTRACT
To evaluate the immune protection of recombinant SARS-CoV-2 S1 and S protein vaccine. Methods;Recombinant SARS-CoV-2 S1 or S protein combined with aluminum hydroxide adjuvant was inoculated at different doses of 0.1 μg, 1 μg, 5 μg and 10 μg per mouse for 6-8 weeks. Serum IgG antibody liters were detected by enzyme linked immunosorbent assay (ELISA) after second immunization. The serum neutralizing antibody titers of the immunized mice against pseudotype SARS-CoV-2-Fluc WT, B. 1.1. 7, P. 1, B. 1.617.2, B. 1.621, 501Y. V2-1 strains were compared by pseudovirus neutralization test. The cellular immune levels of sera were detected by enzyme-linked immunospot assay (ELISpot). Results;Both SARS-CoV-2 S and S1 proteins could induce strong IgG antibody levels in mouse model. The sera of mice immunized with S1 protein showed obvious neutralization activity against SARS-CoV-2-Fluc WT, B. 1. 1.7 and P. 1. The sera of mice immunized with the recombinant S protein also showed obvious neutralization activity against SARS-CoV-2-Fluc B. 1.617.2 in addition to SARS-CoV-2-Fluc WT, B. 1. 1.7 and P. 1. The serum of mice immunized with two kinds of proteins had the strongest neutralizing effect on SARS-CoV-2-Fluc WT. Mouse spleen cells immunized with S protein could significantly induce the production of interferon-γ (IFN--γ) and interleukin-4 (IL-4). The levels of IgG antibody, neutralizing antibody and cellular immunity induced by S protein were higher than those of S1. Conclusion;Recombinant SARS-CoV-2 S protein vaccine can induce protective immune responses. © 2022, China Biotechnology. All rights reserved.
ABSTRACT
To investigate the effect of Fufang yinhua jiedu (FFYH) granules against coronavirus and its potential mechanism, we used Huh7, Huh7.5, H460, and C3A cell lines as in vitro models to evaluate the cytotoxicity and antiviral activity of FFYH by observation of cell pathogenic effect (CPE);and then the inhibitory effect of FFYH on the transcription expression of coronavirus RNA and inflammatory factor mRNA were evaluated by quantitive reverse transcription PCR (qRT-PCR);finally, the inhibitory effect of FFYH on the expression of coronavirus protein and its underlying mechanism against coronavirus were investigated by Western blot and immunofluorescence. Our results indicated that 50% toxic concentration (TC50) FFYH on Huh7, Huh7.5, H460, and C3A cells were 2 035.21, 5 245.69, 2 935.28 and 520 µg·mL-1, respectively;50% inhibitory concentration (IC50) of FFYH on HCoV-229E in Huh7 and Huh7.5 cells were 438.16 and 238.54 µg·mL-1 with safety index (SI) of 4.64 and 21.99, respectively;IC50 of FFYH on HCoV-OC43 in H460 cells was 165.13 µg·mL-1 with SI of 17.78. Moreover, FFYH not only could inhibit the replication of coronaviruses (HCoV-OC43 and HCoV-229E) through inhibiting the transcription of viral RNA and the expression of viral protein, but also effectively suppress the expression of inflammatory factors interleukin-6 (IL-6), tumor necrosis factor α (TNF-α) and interleukin-8 (IL-8) at mRNA level caused by coronaviruses, which might be associated with the inhibitory effect of FFYH on mitogen-activated protein kinase (MAPK) pathway and the nuclear translocation of nuclear transcription factor-κB (NF-κB). In summary, our results demonstrated that FFYH exhibited a good in vitro anti-coronavirus effect, which provides a theoretical basis for its clinical use in the treatment of anti-coronavirus pneumonia.