Maria Tutukina from Skoltech has become the first author of the paper “IgG Antibodies Develop to Spike but Not to the Nucleocapsid Viral Protein in Many Asymptomatic and Light COVID-19 Cases” that has been recently published in Viruses journal. The researchers studied the levels of IgG antibodies to receptor-binding domain of spike protein (S) protein and to nucleocapsid (N) protein of SARS-CoV-2. Further they measured the serum neutralization capabilities in a cohort of patients with different levels of COVID-19 severity. They found that IgG neutralizing the spike protein were present in the absolute majority of patients irrespective of the severity, while IgG neutralizing N protein were detected in all patients with moderate or severe symptoms and nearly half of asymtomatic or light COVID-19 patients. Moreover, severe lung lesions correlated with a respectively higher level of antibodies to N protein. Importantly, IgG to N protein is the main target in many modern test systems. The scientists suggest that the anti-RBD/anti-N antibody ratio may serve as an indicator of the disease severity. Interestingly, anti-RBD IgG remained detectable after a year or more since the infection, even with a slight tendency to raise over time. Full text of the paper is available here.