CLIA COVID-19 RBD IgA

• Detection of IgA antibodies to Receptor-Binding Domain (RBD), a subunit of the Spike S1 protein of SARS-CoV-2
• Intended for human serum and plasma
• Recombinant antigen (rRBD), a subunit of the Spike S1 protein used

Coronaviruses belong to the family of enveloped RNA viruses. In humans, they cause diverse clinical pictures, from the common cold to severe respiratory syndromes (MERS, SARS, and COVID-19). SARS-CoV-2, the cause of COVID-19, is a respiratory virus discovered in 2019. It is primarily transmitted to an individual through close contact with an infected person, during which infectious droplets spread to the environment. Symptoms of COVID-19 are highly variable, ranging from none to life-threatening illness.

The SARS-CoV-2 virus contains four structural proteins: spike (S), nucleocapsid (N), envelope (E), and membrane (M) protein. Responding to the infection, the human immune system raises specific antibodies, starting with IgA and IgM. The IgG antibodies represent a later matured response. Serological tests play only a supporting role in COVID-19 diagnosis. However, they are effective in assessing the immune response of an individuum or population.

The used Receptor-Binding Domain (RBD) antigen, a subunit of the spike S1 protein, specifically binds to the angiotensin-converting enzyme 2 (ACE2) of the host cell. This bound highly correlates with the formation of neutralizing antibodies. In all vaccines developed so far, the spike protein is the antigenic substance (either as a protein or as an RNA / DNA sequence). Certainly, the anti-RBD antibodies are a valuable tool to monitor vaccination efficacy.