A novel S2-derived peptide-based ELISA for broad detection of antibody against infectious bronchitis virus

Simultaneous detection and partial molecular characterization of five RNA viruses associated with enteric disease in chickens: chicken astrovirus, avian nephritis virus, infectious bronchitis virus, avian rotavirus a and avian orthoreovirus, via multiplex RT-qPCR

In the poultry industry, intestinal diseases can lead to significant economic losses due to diarrhea, weight loss and mortality, often linked to viral infections. Chicken astrovirus (CAstV), avian nephritis virus (ANV), infection bronchitis virus (IBV), avian rotavirus A (AvRVA) and avian orthoreovirus (ARV) are key pathogens on this disease including feed malabsorption and runting-stunting syndrome (RSS). This study proposes a multiplex RT-qPCR assay for the simultaneous detection of these five viruses in chickens with enteritis in Ecuador. Primers and hydrolysis probes were designed for the five viruses, along with a synthetic gBlock as a positive control. The method was evaluated for sensitivity, repeatability, and specificity, and 200 jejunal samples were tested. Genome regions of each virus were sequenced, and a phylogenetic analysis confirmed their presence in the samples. The optimized RT-qPCR assay showed efficiency between 98.8-105.9%, with a detection limit of 1 copy/μL. It specifically amplified the five target viruses without cross-reactivity. Among 200 chickens tested, 97% were positive for at least one virus, with ANV (89%) and CAstV (53%) being the most prevalent. Coinfections were common, especially between CAstV and ANV, with three samples positive for all viruses. Sequencing and phylogenetic analysis confirmed the circulation of multiple strains in chickens with enteric disease in Ecuador. This study describes a multiplex RT-qPCR assay for detecting key enteric viruses in Ecuadorian poultry highlighting the high prevalence of astroviruses, emphasizing the impact of coinfections, its possible role in the disease and the importance of improving disease control strategies.

A Blood Test for the Diagnosis of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune chronic disease characterized by inflammation and demyelination of the central nervous system (CNS). Despite numerous studies conducted, valid biomarkers enabling a definitive diagnosis of MS are not yet available. The aim of our study was to identify a marker from a blood sample to ease the diagnosis of MS. In this study, since there is evidence connecting the serotonin pathway to MS, we used an ELISA (Enzyme-Linked Immunosorbent Assay) to detect serum MS-specific auto-antibodies (auto-Ab) against the extracellular loop 1 (ECL-1) of the 5-hydroxytryptamine (5-HT) receptor subtype 2A (5-HT2A). We utilized an ELISA format employing poly-D-lysine as a pre-coating agent. The binding of 208 serum samples from controls, both healthy and pathological, and of 104 serum samples from relapsing-remitting MS (RRMS) patients was tested. We observed that the serum-binding activity in control cohort sera, including those with autoimmune and neurological diseases, was ten times lower compared to the RRMS patient cohort (p = 1.2 × 10-47), with a sensitivity and a specificity of 98% and 100%, respectively. These results show that in the serum of patients with MS there are auto-Ab against the serotonin receptor type 2A which can be successfully used in the diagnosis of MS due to their high sensitivity and specificity.

Comparative Study of SERS-Spectra of NQ21 Peptide on Silver Particles and in Gold-Coated "Nanovoids"

The NQ21 peptide has relatively recently attracted attention in the biomedical sphere due to its prospects for facilitating the engineering of the HIV1 vaccine and ELISA test. Today, there is still a need for a reliable and fast methodology that reveals the secondary structure of this analyte at the low concentrations conventionally used in vaccines and immunological assays. The present research determined the differences between the surface-enhanced Raman scattering (SERS) spectra of NQ21 peptide molecules adsorbed on solid SERS-active substrates depending on their geometry and composition. The ultimate goal of our research was to propose an algorithm and SERS-active material for structural analysis of peptides. Phosphate buffer solutions of the 30 µg/mL NQ21 peptide at different pH levels were used for the SERS measurements, with silver particles on mesoporous silicon and gold-coated "nanovoids" in macroporous silicon. The SERS analysis of the NQ21 peptide was carried out by collecting the SERS spectra maps. The map assessment with an originally developed algorithm resulted in defining the effect of the substrate on the secondary structure of the analyte molecules. Silver particles are recommended for peptide detection if it is not urgent to precisely reveal all the characteristic bands, because they provide greater enhancement but are accompanied by analyte destruction. If the goal is to carefully study the secondary structure and composition of the peptide, it is better to use SERS-active gold-coated "nanovoids". Objective results can be obtained by collecting at least three 15 × 15 maps of the SERS spectra of a given peptide on substrates from different batches.