ABSTRACT
COVID-19 is a viral respiratory infection caused by SARS-CoV-2. The immune system plays a pivotal role in disease resolution but can also be detrimental to the clinical outcome in case of unbalanced immune activation. In this study, we have focused on the parallel expression of IL-6, a potent pro-inflammatory cytokine, and IL-10, an important regulator of the immune response, in COVID-19 patients. Using bead-based multiplex immunoassay technology we compared the serum levels of IL-6 and IL-10 in 47 COVID-19 patients with mild, moderate, or severe disease. The serum concentrations of both cytokines were significantly elevated in patients with severe COVID-19, and there was a significant positive correlation between IL-6 and IL-10 in the moderate and severe groups (R=0.6;p< 0.001). Our observations support that IL-6 is one of the driving forces for the cytokine release syndrome in COVID-19 while the immunosuppressive properties of IL-10 in severe disease act as a hindrance to viral clearance.
ABSTRACT
Neutralizing antibody (NAb) titer is a key biomarker of protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but point-of-care methods for assessing NAb titer are not widely available. Here, we present a lateral flow assay that captures SARS-CoV-2 receptor-binding domain (RBD) that has been neutralized from binding angiotensin-converting enzyme 2 (ACE2). Quantification of neutralized RBD in this assay correlates with NAb titer from vaccinated and convalescent patients. This methodology demonstrated superior performance in assessing NAb titer compared with either measurement of total anti-spike immunoglobulin G titer or quantification of the absolute reduction in binding between ACE2 and RBD. Our testing platform has the potential for mass deployment to aid in determining at population scale the degree of protective immunity individuals may have following SARS-CoV-2 vaccination or infection and can enable simple at-home assessment of NAb titer.