Severe acute respiratory syndrome coronavirus 2 immunoglobulin G (SARS-CoV-2 IgG) (SARS-CoV-2 IgG)

Severe acute respiratory syndrome coronavirus 2 immunoglobulin G (SARS-CoV-2 IgG) is a class of specialized immune proteins produced by B lymphocytes following exposure to the SARS-CoV-2 virus or vaccination (CDC, 2021). These antibodies are critical components of the adaptive immune system, specifically the humoral response, and are primarily directed against the viral Spike (S) protein or Nucleocapsid (N) protein (Nature Communications, 2020). By binding to the receptor-binding domain (RBD) of the Spike protein, IgG antibodies can neutralize the virus, effectively blocking its ability to bind to the human angiotensin-converting enzyme 2 (ACE2) receptor and infect host cells (NIH, 2021). In addition to neutralization, IgG facilitates the clearance of viral particles through opsonization and the activation of the classical complement pathway (PubMed, 2020). Clinically, the detection and quantification of SARS-CoV-2 IgG serve as vital biomarkers for assessing individual and population-level immunity, as well as the efficacy of COVID-19 vaccines (WHO, 2021). Furthermore, recombinant monoclonal IgG antibodies, such as Casirivimab and Imdevimab, have been developed as therapeutic interventions to provide immediate passive immunity to infected individuals at high risk of progressing to severe disease (FDA, 2020). However, the therapeutic utility of these antibodies is continually challenged by the emergence of viral variants with mutations in the Spike protein that can lead to immune evasion (Science, 2021).

Other names

Anti-SARS-CoV-2 IgGCOVID-19 IgG antibodySARS-CoV-2 S-IgGSARS-CoV-2 N-IgGAnti-Spike IgG

Neutralization of the SARS-CoV-2 virus by binding to the receptor-binding domain (RBD) of the Spike protein, preventing its interaction with the host cell ACE2 receptor and subsequent viral entry (NIH, 2021).