Immunogenicity and protection efficacy of a COVID-19 DNA vaccine encoding spike protein with D614G mutation and optimization of large-scale DNA vaccine production.

Severe acute respiratory syndrome coronavirus 2 had devastating consequences for human health. Despite the introduction of several vaccines, COVID-19 continues to pose a serious health risk due to emerging variants of concern. DNA vaccines gained importance during the pandemic due to their advantages such as induction of both arms of immune response, rapid development, stability, and safety profiles. Here, we report the immunogenicity and protective efficacy of a DNA vaccine encoding spike protein with D614G mutation (named pcoSpikeD614G) and define a large-scale production process. According to the in vitro studies, pcoSpikeD614G expressed abundant spike protein in HEK293T cells. After the administration of pcoSpikeD614G to BALB/c mice through intramuscular (IM) route and intradermal route using an electroporation device (ID + EP), it induced high level of anti-S1 IgG and neutralizing antibodies (P < 0.0001), strong Th1-biased immune response as shown by IgG2a polarization (P < 0.01), increase in IFN-γ levels (P < 0.01), and increment in the ratio of IFN-γ secreting CD4+ (3.78-10.19%) and CD8+ (5.24-12.51%) T cells. Challenging K18-hACE2 transgenic mice showed that pcoSpikeD614G administered through IM and ID + EP routes conferred 90-100% protection and there was no sign of pneumonia. Subsequently, pcoSpikeD614G was evaluated as a promising DNA vaccine candidate and scale-up studies were performed. Accordingly, a large-scale production process was described, including a 36 h fermentation process of E. coli DH5α cells containing pcoSpikeD614G resulting in a wet cell weight of 242 g/L and a three-step chromatography for purification of the pcoSpikeD614G DNA vaccine.

Therapeutic Effect of C-Vx Substance in K18-hACE2 Transgenic Mice Infected with SARS-CoV-2.

C-Vx is a bioprotective product designed to boost the immune system. This study aimed to determine the antiviral activity of the C-Vx substance against SARS-CoV-2 infection. The effect of C-Vx in K18-hACE2 transgenic mice against the SARS-CoV-2 virus was investigated. For this purpose, ten mice were separated into experimental and control groups. Animals were infected with SARS-CoV-2 prior to the administration of the product to determine whether the product has a therapeutic effect similar to that demonstrated in previous human studies, at a histopathological and molecular level. C-Vx-treated mice survived the challenge, whereas the control mice became ill and/or died. The cytokine-chemokine panel with blood samples taken during the critical days of the disease revealed detailed immune responses. Our findings showed that C-Vx presented 90% protection against the SARS-CoV-2 virus-infected mice. The challenge results and cytokine responses of K18-hACE2 transgenic mice matched previous scientific studies, demonstrating the C-Vx's antiviral efficiency.

Investigation of the Antiviral Effects of Saussurea lappa Root Extract against SARS-CoV-2 Virus.

SCOPE: The purpose of this study was to look into the antiviral activity of a plant extract derived from the roots of the Saussurea lappa as a food supplement against SARS-CoV-2 infection. METHODS AND RESULTS: Vero E6 cells are employed in the study to test the neutralizing effect of Saussurea lappa extract against the SARS-CoV-2 virus. For anti-viral activity detection, a sensitive real-time cell analyzer (xCELLigence RTCA) with a high repetition rate is used. A challenge experiment in mice is planned as a result of the in vitro analysis. A challenge test against SARS-CoV-2 is performed with 10 adult female K18-hACE2 transgenic mice in each group for this purpose. The mice in the S. lappa Group are gavaged 2 days before the virus is administered intranasally (i.n.). The control group received PBS instead of the extract. SARS-CoV-2 virus is administered i.n. under anesthesia for the first 3 days of the experiment, and S. lappa extract was administered by gavage in the afternoon. On the 10th day, mice in the S. lappa group survived the study, whereas animals in the control group grew ill and/or died. In this study, the extract protects the mice against the SARS-CoV-2 virus in 90% of the cases. CONCLUSIONS: This study demonstrates that the Saussurea plant has antiviral effects against SARS-CoV-2 in vitro and in animal models.

Process development for an effective COVID-19 vaccine candidate harboring recombinant SARS-CoV-2 delta plus receptor binding domain produced by Pichia pastoris.

Recombinant protein-based SARS-CoV-2 vaccines are needed to fill the vaccine equity gap. Because protein-subunit based vaccines are easier and cheaper to produce and do not require special storage/transportation conditions, they are suitable for low-/middle-income countries. Here, we report our vaccine development studies with the receptor binding domain of the SARS-CoV-2 Delta Plus strain (RBD-DP) which caused increased hospitalizations compared to other variants. First, we expressed RBD-DP in the Pichia pastoris yeast system and upscaled it to a 5-L fermenter for production. After three-step purification, we obtained RBD-DP with > 95% purity from a protein yield of > 1 g/L of supernatant. Several biophysical and biochemical characterizations were performed to confirm its identity, stability, and functionality. Then, it was formulated in different contents with Alum and CpG for mice immunization. After three doses of immunization, IgG titers from sera reached to > 106 and most importantly it showed high T-cell responses which are required for an effective vaccine to prevent severe COVID-19 disease. A live neutralization test was performed with both the Wuhan strain (B.1.1.7) and Delta strain (B.1.617.2) and it showed high neutralization antibody content for both strains. A challenge study with SARS-CoV-2 infected K18-hACE2 transgenic mice showed good immunoprotective activity with no viruses in the lungs and no lung inflammation for all immunized mice.

Antioxidant, Cytotoxicity, Apoptotic Properties of Extracts of Andricus sternlichti galls and Their Phenolic Characterisation by HPLC.

Quercus L. galls have been used in Western and Eastern cultures for various diseases in traditional medicine. Galls are also used in the East for many purposes, including consumption as food, commercial inks, leather tanning. In the current study, Andricus sternlichti Bellido, Pujade-Villar & Melika, 2003 galls were extracted in different solvents. The possible antioxidant effects of gall extracts were determined using 7 different methods (ß-carotene-linoleic acid assay, Phosphomolybdenum assay, DPPH and ABTS radical scavenging activity, CUPRAC and FRAP assay, Metal Chelating activity) to support each other. Total phenolic, flavonoid and tannin amounts of extracts are calculated by using standard curves. In addition, HPLC method used to characterize the phenolic component with 15 different standards. The MIA PaCa-2 cell lines was preferred to identify possible cytotoxic activities of galls. Expression of some genes (Bax, Bcl-2, FAS, BID, caspase-3, caspase-8, caspase-9, caspase-10, FADD, TRADD) role in the apoptosis was determined to investigate apoptotic effects of extracts. According the results, the gall extracts of A. sternlichti may be considered as a potential source of biological agents for their antioxidant capacity and rich bioactive compounds. The gall extracts exhibit antiproliferative activity via regulating expressions of apoptotic genes.

Antioxidant activity, phytochemical composition of Andricus tomentosus and its antiproliferative effect on Mia-Paca2 cell line.

Plant derived products are widely used in cancer treatment. Gall species has been preferred for treatment various diseases in folk medicine, but there are few studies on the anticancer effects of gall species. The present study reports the antioxidant activity and total secondary metabolites of extracts of A. tomentosus galls. The antioxidant potency of galls was carried out using different in-vitro model systems. Their cytotoxic efficacy on Mia-Paca cell line was also explored. Gall extract was found to contain a large amount of phenolic acids. The extract potently scavenged free radicals including DPPH (IC50 9.56 ± 1.08 µg/mL), ABTS (IC50 18.51 ± 0.25 µg/mL). It can be seen as a potential source of antioxidants according to ß-carotene/linoleic acid method (%92.58 ± 0.92) and Phosphomolybdenum assays (104.36 ± 4.95 mgAE/g). Gall extract also posses ability of metal chelating (%40.07 ± 2.30) and Fe3+ (184.01 ± 2.83 mgTE/g) and Cu2+ (89.81 ± 0.96 mgTE/g) reducing activity. According to total secondary metabolites tests, gall extract showed high total phenolic, total flavonoid and total tannin amount. HPLC analysis of the extract suggested it to contain caffeic acid (424.068.479 µg/g), ellagic acid (187.696.132 µg/g). XTT assay revealed gall extract to enhance percent survival of Mia-Paca2 cell line exposed A. tomentosus extracts. The best cytotoxic effect was determined in acetone extracts (IC50: 124.7 µM). Expression of some genes (Bax, Bcl-2, FAS, BID, caspase-3, caspase-8, caspase-9, caspase-10, FADD, TRADD) in the apoptosis pathway was determined to invastigate apoptosis inducing activity. These results indicate that A. tomentosus galls possess potent antioxidant activity, when tested both in chemical as well as biological models.