In a recent study led by the Barcelona Institute for Global Health (ISGlobal) researchers identified the C-terminal region of the nucleocapsid protein (N) of SARS-CoV-2 as being specific to the new coronavirus (and different from the common cold coronaviruses). This could serve to improve the current techniques of diagnosis and seroprevalence studies since, together with the Spike (S) protein, they are the targets used for the detection of antibodies against the COVID-19 virus.
Analyses of samples of healthy people from before the pandemic, samples of health personnel and samples of COVID-19 patients, they verified that there is some cross-reactivity with the common cold coronaviruses. As a consequence, the presence of other viruses that cause the cold could interfere with the diagnosis and the antibody tests for SARS-CoV-2 infection.
“This calls into question the utility of using the entire N protein in seroprevalence studies”
Carlota Dobaño, lead author of the study (ISGlobal)
Now, with the discovery of a fragment of the N protein (the C-terminal region) that is specific to the new coronavirus, the authors suggest that more studies should be done to verify the immunity generated by this protein region and assess its possible inclusion in the future vaccine design.
Dobaño C, Santano R, Jiménez A et al. Immunogenicity and crossreactivity of antibodies to the nucleocapsid protein of SARS-CoV-2: utility and limitations in seroprevalence and immunity studies. Translational Research.