Moreover, some patients transmit it even after disease recovery.1 Due to the potential zoonotic nature of this virus and its capability for transmission by aerosols or droplets, SARS-CoV-2 has been considered a strict BSL3 pathogen Gpr146 for research purposes.6 With attention to the importance of the subject, searching the neutralizing antibodies (Nabs) for CoV-2 is one method for treatment of this emerging disease. shown that ion-exchange chromatography could be a suitable technique for IgG purification. Conclusion: Herein, we presented a simple and cheap method for the purification of whole viral particles with relatively high quality. The results verified that these antigens could elicit a good immune response in the rat. The obtained pAbs showed a good specificity toward SARS-CoV-2 antigens. Accordingly, this study proposes a promising method for viral vaccine development. Keywords: ELISA, SARS-CoV-2, Polyethylene glycol, Western blotting, Sucrose cushion, Virus precipitation Introduction Among all known coronaviruses (CoVs), seven cases have the ability for human infection so far.1-3 Unlike four human CoVs (i.e. HCoV-OC43, HCoV-NL63, HCoV-229E, and HCoV-HKU1), MERS-CoV, SARS-CoV, and 2019-nCoV cause severe pneumonia or other organs failure and even death among the infected populations.2,4 The RG7800 novel coronavirus (as a causative agent of pneumonia), which was introduced as 2019 coronavirus disease (COVID-19 or 2019-nCoV) by the World Health Organization (WHO) has been rapidly distributed on the epidemic scale since its first emergence in Wuhan, China and, it has been affected over 247?968?227 million people (http://covid19.who.int/) by 5 November 2021.1,5,6 The International Committee on Taxonomy of Viruses (ICTV), nominated the novel coronavirus as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). On the 31st of January 2020, RG7800 WHO listed COVID-19 as PHEIC (Public Health Emergency of International RG7800 Concern); It means that this virus may cause a threat to various countries, therefore combat against it needs a coordinated international response.1,4,7 The RG7800 important note about this virus is its transmission to healthy people from asymptomatic persons. Moreover, some patients transmit it even after disease recovery.1 Due to the potential zoonotic nature of this virus and its capability for transmission by aerosols or droplets, SARS-CoV-2 has been considered a strict BSL3 pathogen for research purposes.6 With attention to the importance of the subject, searching the neutralizing antibodies (Nabs) for CoV-2 is one method for treatment of this emerging disease. Antibodies could work by two mechanisms: Direct neutralization of target viral antigen and effective indirect mechanisms (e.g., complement-dependent cytotoxicity [CDC] and antibody-dependent cell-mediated cytotoxicity [ADCC]).8 For the detection of various antigens, polyclonal antibodies (pAb) are widely used for diagnostics, therapeutics, and also research.9 Polyclonal sera (which include antibodies with different specificities for various immunogenic epitopes) are obtained from immunized animals such as rabbits, goats, and sheep. Depending on the immunized animal and immunization RG7800 quality, produced antibodies may be different from each other.10 When the goal is detection the antigen with various epitopes, pAbs are preferred to monoclonal antibodies (mAbs). Purification of these antibodies is useful for many kinds of diagnostic methods. They could be used as ligands for immunoaffinity-column preparation in biological and biochemical research. They are used for coating or labeling reagents in immunoassay tests (e.g., Enzyme-linked immunosorbent assay[ELISA], immunoradiometric assay, western blotting, radioimmunoassays), and other applications, too.11,12 With this regard, many attempts are doing for developing antibody-based tests to detection of SARS-CoV-2 by companies and laboratories (e.g., GeneTex, Cellex, etc).13 With attention to the mentioned subjects and due to the current situation caused by the distribution and mortality of SARS-CoV-2, the goal of this study was pAb production in response to concentrated antigen. Thereafter, the performance evaluation of produced antibody was performed by SDS-PAGE, ELISA, and western blot methods. Methods Virus isolation from cell culture Formalin inactivated (1:2000) SARS-CoV-2 virus strain (D614 mutant) with TCID50/mL ~6 and the cycle threshold (CT) value 12 in real-time PCR (ABI, USA) was prepared from a.
