IMMUNOGENICITY AND TOXICITY OF COVID-19 VACCINE CANDIDATE PROTEIN SUBUNIT PLATFORM RRBD SPIKE SARS-COV-2 IN BALB/C MICE

• Main Author: Aghniya Safitri, Intan
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67667
• Institution: Institut Teknologi Bandung

The development of a safe and effective SARS-CoV-2 vaccine is continuing to help overcome the COVID-19 pandemic. Several platforms, including the viral protein subunit platform, have been developed. ITB’s merah putih vaccine team has developed a recombinant Receptor Binding Domain (RBD) protein in Escherichia coli BL21(DE3) as a candidate for the SARS-CoV-2 vaccine. SARS-CoV-2 RBD is one of the promising candidates for the SARS-CoV-2 vaccine because it is a viral facilitator for binding to host cell receptors with the specific and conserved epitope. The aims of this study are to investigate the humoral and cellular responses, as well as the toxicity, of ITB merah putih vaccine team’s SARS-CoV-2 spike rRBD COVID-19 vaccine candidate against Balb/c mice. The test was performed by administering a 1:1 (v:v) 10?g/mice rRBD SARS-CoV-2 with 1,3% Alhydrogel in comparison to the control group injected with PBS with 1,3% Alhydrogel in equal volume. The test material was administered intramuscularly with one priming and 2 boosters on days 21 and 42 after primary injection. Following the injection of the vaccine candidate, the formation of edema and erythema at the injection site was observed, as well as frequent measures of the mice’s body temperature and weight. Analysis of humoral immunity against SARS-CoV-2 rRBD was conducted by indirect ELISA, while cellular immunity by cytokine analysis was performed by ELISPOT assay. Toxicity evaluation of vaccine candidates was carried out by observing mice’s body weight and histological section from the heart, liver, and kidneys of Balb/c mice stained by Hematoxylin Eosin. There was no edema and erythema at the site of injection, no temperature increased, and no long-term weight loss in mice after injection of the vaccine candidate. In the mice control and treatment group's liver, kidneys, and heart, necrosis was found with mild severity. Mild inflammation was also found in the liver and kidney of mice in the control and treatment groups. There was no significant difference between the treatment and control groups except for renal inflammation score in male mice because the inflammation was only found in the treatment male group (P=0,0303). rRBD successfully induce humoral immunity, shown by male and female mice administered by the vaccine candidate had significantly higher IgM and IgG (P<0,0001) than control mice, injection of two boosters succeeded in increasing higher IgG (P<0,0001), as well as high level of IL-4 secreted by mice’s splenocyte in male mice (P=0,0018) dan female mice (<0,0001) were compared to controls. The ELISPOT results has showed that rRBD succeeded in inducing the cellular immunity shown by high level of IFN-? secreted by mice’s splenocyte in male mice (P=0,0166) and female mice (P=0,0007). Based on the findings in this study, it can be concluded that the SARS-CoV-2 rRBD vaccine candidate produced by the merah putih vaccine team ITB is not toxic and can induce humoral and cellular responses in Balb/c mice. The vaccine candidate evaluated on mice demonstrated mild toxicity to the heart, liver, and kidneys of mice administered by the SARS-CoV-2 rRBD protein subunit, similar to the control group.