Purification Methodology Supports COVID-19 Severity Study

Scientists worldwide have been grappling with understanding why COVID-19 patients display such wide variation in the severity of disease symptoms they experience. While a great deal has been learned about the virus in the past year, knowledge is still scarce on why some patients seem predisposed to severe disease.

In a study recently published in the journal Glycobiology ^[1]  scientists have pooled the expertise and resources of several different European research institutes to examine how the modification of protein activity via glycosylation (the addition of various carbohydrate groups) may be a way to predict COVID-19 severity.

Research has shown that some COVID-19 patients become extremely ill due to over-activation of their immune systems. Since the activity of immune proteins is linked to their glycosylation state, the research group decided to take a closer look at glycan groups associated with IgG (the most common type of antibody found in humans). Previous studies have shown that IgG variability from person-to-person may be linked to clinical variability in immune response.

To carry out their study, the researchers obtained plasma samples from 166 COVID-19 patients with severe disease, and 167 patients with mild disease symptoms. IgG was isolated from each sample via standard antibody purification, with plasma samples being pipetted into a 96-well protein purification plate connected to a Pall vacuum manifold and vacuum pump to accommodate the washing steps. Following IgG purification, N-glycan groups were enzymatically stripped from the IgG molecules.

To prepare the glycan samples for analysis, the scientists first labelled the glycans with a fluorescent tag, then purified the samples using AcroPrep 0.2 μm Supor 96-well filter plates as the stationary phase.

Pall’s AcroPrep filter plates are available in a range of formats, from 384-well plates suitable for 80 μL samples, through to 24-well plates that can accommodate sample volumes of up to 7 mLs. AcroPrep filter plates are also offered in a variety of membrane types and size cutoffs, to accommodate diverse research applications.

Following purification, distinct glycan groups were separated out by liquid chromatography, and results from different patient samples were compared to look for statistical differences in the type and frequency of glycan groups present. The researchers observed significant differences in IgG glycan modification between severe and mild COVID-19 patients. The most notable difference was a decrease in one form of a particular carbohydrate group known as N-acetylglucosamine (GlcNAc).

Protein modification factors, including glycosylation, are known to be associated with aging, as well as disease states such as diabetes. The authors believe that this important finding will lead to a better understanding of what drives COVID-19 vulnerability, and how those at the greatest risk can be protected.

Pall wholeheartedly supports biomedical research focused on fighting COVID-19. For more information on our COVID-19 workflow solutions, please visit our COVID-19 solutions information.

Reference:

1. Petrovic T., et al. Composition of the immunoglobulin G glycome associates with the severity of COVID-19. Glycobiology. Nov 2020.