Antibody Responses against Enterovirus Proteases are Potential Markers for an Acute Infection

Abstract

Background: Enteroviruses are a group of common non-enveloped RNA viruses that cause symptoms ranging from mild respiratory infections to paralysis. Due to the abundance of enterovirus infections it is hard to distinguish between on-going and previous infections using immunological assays unless the IgM fraction is studied. Methods: In this study we show using Indirect ELISA and capture IgM ELISA that an IgG antibody response against the nonstructural enteroviral proteins 2A and 3C can be used to distinguish between IgM positive (n = 22) and IgM negative (n = 20) human patients with 83% accuracy and a diagnostic odds ratio of 30. Using a mouse model, we establish that the antibody response to the proteases is short-lived compared to the antibody response to the structural proteins in. As such, the protease antibody response serves as a potential marker for an acute infection. Conclusions: Antibody responses against enterovirus proteases are shorter-lived than against structural proteins and can differentiate between IgM positive and negative patients, and therefore they are a potential marker for acute infections.

Multiplexed High-Throughput Serological Assay for Human Enteroviruses

“…We compared the antibody responses between the different adult groups based on their previous capture IgM assay results [ 19 ] ( Figure 3 A) as well as between adults and children ( Figure 3 B). Non-characterized adult serum samples collected from healthy individuals from Tampere biobank collection were included in the analysis as representatives of population background.…”

“…Serum samples from patients with confirmed acute enterovirus infection ( n = 20) were obtained from Turku University Hospital [ 19 ]. Control samples ( n = 22) were collected from healthy individuals [ 19 ].…”

“…Serum samples from patients with confirmed acute enterovirus infection ( n = 20) were obtained from Turku University Hospital [ 19 ]. Control samples ( n = 22) were collected from healthy individuals [ 19 ]. Another serum sample collection was obtained from the Diabetes prediction and prevention (DIPP) consortium [ 28 ], total of 88 serum samples, with partially known enterovirus histories [ 15 ].…”

“…After the production of each antigen and confirming their functionality individually in traditional ELISA following the same protocol used previously [ 19 ], we biotinylated the antigens, added unique U-PLEX linkers to them, pooled them prior to coating and followed the protocol outlined in Figure 1 . After confirming with a limited sample set, including Nanogam, that we obtained reasonable signals for each of the antigens, we ran a more comprehensive set of samples.…”

“…We set out to see if a panel of VP1-proteins from representatives of all human infecting enterovirus species could be used to make an assay that can identify antibody responses to enteroviruses on a species level. To this panel of species-specific antigens, we added conserved non-structural enterovirus proteins that we have shown in a previous study to act as markers for an acute enterovirus infection in adults [ 19 ].…”