A comparison between different chemical fractionation methods for immunoglobulin preparation.

Background: Application of antibodies in therapeutics and diagnostics are growing Continually. Herein, we aimed to find the most qualified immunoglobulin (Ig) chemical preparation method.

Methods: A rabbit was immunized against recombinant SARS-CoV-2 nucleocapsid (NP) and reactive polyclonal antibodies were prepared using the ammonium sulfate (AS), caprylic acid (CA), polyethylene glycol (PEG), and caprylic acid/ammonium sulfate (CA/AS) methods.

Recombinant highly antigenic truncated fusion-based protein as a diagnostic antigen for anti-SARS-CoV-2 nucleocapsid antibody ELISA.

Among the main structural protein of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), nucleocapsid phosphoprotein (NP) exhibits high immunogenicity and is the most abundant viral protein produced and shed during infection. Detection of antibodies against NP may help assess the number of individuals exposed to SARS-COV-2 or vaccinated against it. Based on these findings and other structural and antigenic evaluations, we designed a recombinant truncated fusion NP-based protein for application in an immunoassay for detecting immunoglobulins in patients who have recovered from COVID-19.