Vitamin C in the formulation of inactivated COVID-19 vaccine candidate induced Th1 pattern in the aged mice.
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Nika Asefi ,1 Parviz Pakzad ,2 Akbar Khorasani ,3 Mehdi Mahdavi ,4,*
1. Department of Microbiology, Faculty of Basic Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
2. Department of Microbiology, Faculty of Basic Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
3. 2. Department of FMD vaccine production, Razi Vaccine & Serum Research Institute, Agricultural Research, Education & Extension Organization (AREEO) Karaj, Iran
4. Recombinant Vaccine Research Center, Tehran University of Medical Sciences, Tehran, Iranو Immunotherapy Group, The Institute of Pharmaceutical Science (TIPS), Tehran University of Medical Science, Tehran, Iran
- Introduction: The morality rate of COVID-19 elevated in elderly people by 22%. Moreover, according to the reports, 90% and 80% of death in patients aged ≥60 years and ≥70 years have recorded. Aging is physiologically accompanied by a reduction in the function of the immune system, which there is a relationship between alteration in the immune system and susceptibility to infections.
IFN-γ has a crucial role in the defense against viruses. Since the production of IFN-γ declines in older adults. It may explain the reason of the susceptibility of the elderly to viral infectious diseases such as COVID-19. Studies show the potency of vitamin C in the improvement of immune responses of aged people. Here, we formulated inactivated COVID-19 vaccine in vitamin C and the potency of vaccine assessed in the aged and young mice.
- Methods: A SARS-CoV-2 strain was isolated from a patient and propagated in Vero cell line. The virus was inactivated using formalin and purified using column chromatography method and then quantified by Bradford. In order to formulate in Alum-based vaccine, 2µg of inactivated COVID-19 virus in PBS buffer was admixed with 200µg of Alum hydroxide adjuvant (for each dose of vaccine formulation) and shaked at 100 RPM for 60 minutes at room temperature and allowed that the viral particles to adsorb on the surface of Alum gel. And then vitamin C at concentration of 1 and 10mg/dose was added to the vaccine formulation. Young (6-8-week-old, N=32) and aged (16-20-month-old, N=32) male C57bl/6 mice were purchased from Pasteur Institute of Iran and grouped as below;
Group 1: Aged mice immunized with inactivated COVID-19-Alum.
Group 2: Aged mice immunized with inactivated COVID-19-Alum with1 mg vitamin C.
Group 3: Aged mice immunized with inactivated COVID-19-Alum with10 mg vitamin C.
Group 4: Aged mice immunized with PBS.
Group 5: Young mice immunized with inactivated COVID-19-Alum.
Group 6: Young mice immunized with inactivated COVID-19-Alum with1mg vitamin C.
Group 7: Young mice immunized with inactivated COVID-19-Alum with10mg vitamin C.
Group 8: Young mice immunized with PBS.
Experimental mice were immunized with 2µg of inactivated COVID-19 formulated vaccines subcutaneously on days 0 and 14 and two weeks after last shot IFN-γ and IL-4 cytokine were assessed with ELISA and specific IgG titer, IgG1/IgG2a isotypes determined with ELISA.
- Results: The results of IFN-γ and IL-4 cytokines in experimental groups demonstrated that injection of COVID-19 vaccine formulated with vitamin C in young and aged mice shows a significant increase as compared with the control and mere vaccine groups (P< 0.0401). In addition, specific total IgG and IgG1/IgG2a level improved in young and aged mice.
- Conclusion: It seems that vitamin C is useful in the improvement of specific immune responses against COVID-19 vaccine in young and aged people.
- Keywords: COVID-19 vaccine, vitamin C, Adjuvant, aging
