Understanding neutralising antibodies against SARS-CoV-2 and their implications in clinical practice

Abstract

SARS-CoV-2 is a newly identified member of the coronavirus family that has caused the Coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting SARS-CoV-2 has disrupted the lives and livelihoods of millions worldwide. As of 23 August 2021, a total of 211,373,303 COVID-19 cases have been confirmed globally with a death toll of 4,424,341. A strong understanding of the infection pathway of SARS-CoV-2, and how our immune system responds to the virus is highly pertinent for guiding the development and improvement of effective treatments. In this review, we discuss the current understanding of neutralising antibodies (NAbs) and their implications in clinical practice. The aspects include the pathophysiology of the immune response, particularly humoral adaptive immunity and the roles of NAbs from B cells in infection clearance. We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting—from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.

Comparison of the Anti-SARS-CoV-2 Surrogate Neutralization Assays by TECOmedical and DiaPROPH-Med with Samples from Vaccinated and Infected Individuals

“…Further, it was clear that the functionality of adaptive immunological components is more important than just sole quantity [5]. In line with this, it became evident that a diagnostic focus should be on the neutralizing the potency of detected anti-SARS-CoV-2-antibodies [6,7]. Correlations between the severity of clinical courses of COVID-19 disease and neutralizing antibody titers could be shown [8][9][10][11].…”

Overview of Neutralizing Antibodies and Their Potential in COVID-19

“…Regarding natural infection, Gozalbo-Rovira et al reported weak correlations between antibody levels and inflammatory biomarkers (ferritin, D-dimer, CRP, lactate dehydrogenase (LDH), and interleukin-6) [123,124]. These correlations could be explained by the relationship between the magnitude of antibody response with the hyperactivation of the immune system in patients with severe COVID-19.…”

Monoclonal antibody targeting the conserved region of the SARS-CoV-2 spike protein to overcome viral variants

“…However, we cannot rule out the possibility that Mab5-mediated neutralizing activity might be blocked through a yet unknown mechanism different from binding interference because a plurality of options allow SARS-CoV-2 entry during infection (43,44), such as the sequential endocytosis of SARS-CoV-2 infection observed in Vero E6 cells (45). The viral-antibody complex may prevent infections by interfering with virus binding to receptors, blocking uptake into cells, preventing uncoating of the genomes in endosomes, or causing virion aggregation (46). Most importantly, we determined that Mab5 indeed played a protective role in mitigating viral infection in live animal experiments (Figure 3-5), which makes our identified antibody a promising compound for therapeutic strategies.…”