Development of a Gold Nanoparticle-Based ELISA for Detection of PCV2

In this new methodology, plasmonic ELISA (pELISA) was used to detect Circovirus porcine2 (PCV2) in serum samples without the need for plate reading equipment. This process occurs by adapting the conventional ELISA test with gold nanoparticles (AuNPs) to promote a color change on the plate and quickly identify this difference with the naked eye, generating a dark purple-gray hue when the samples are positive and red when the samples are negative. The technique demonstrated high efficiency in detecting samples with a viral load ≥ 5 log10 copies/mL. Plasmonic ELISA offers user-friendly, cost-effective, and reliable characteristics, making it a valuable tool for PCV2 diagnosis and potentially adaptable for other pathogen detection applications.

Inflammatory cytokines and chemokines in obese adolescents with antibody against to adenovirus 36

Obesity in adolescents has reached epidemic proportions and is associated with the inflammatory response and viral infections. The aim of this study was to understand the profile of inflammatory cytokines and chemokines associated with the inflammatory response and metabolic syndrome (MetS) in obese adolescents with positive serology for adenovirus 36 (ADV36). Thirty-six overweight, 36 obese, and 25 severe obesity adolescents aged 10 to 16 years were included in the study. The following variables were analyzed: sex, age, body mass index (BMI), blood pressure, total cholesterol and fractions, triglycerides, glucose, serum cytokine concentrations, and ADV36 antibodies. Cytokines and chemokines were quantified by cytometry and ADV36 serology was determined by enzyme-linked immunosorbent assay (ELISA). The results showed higher levels of the cytokines interleukin-1beta (IL-1β), IL-6, IL-10 and of the chemokine interferon-gamma-inducible protein 10 (IP-10) in severe obesity adolescents compared to the obese and overweight groups, as well as in the group with MetS compared to the group without this syndrome. The frequency of ADV36-positive individuals did not differ between groups. The findings revealed differences in BMI between the obese and severe obesity groups versus the overweight group in the presence of positivity for ADV36, suggesting an association with weight gain and possibly MetS installation.

Fast and reliable detection of SARS-CoV-2 antibodies based on surface plasmon resonance

Researchers worldwide have been studying alternatives to detect SARS-CoV-2 (COVID-19), and accurate and timely diagnosis is crucial for controlling the outbreaks of the disease. Surface plasmon resonance (SPR) is an effective strategy based on antibodies, and it can be used for simple and fast detection of antibodies due to COVID-19 infection. Accordingly, this paper reports on the highly sensitive and specific detection of antibody responses to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in COVID-19 patients. In this methodology, spike (S) and nucleocapsid (N) proteins belonging to the coronavirus genome were immobilized on the surface of a gold sensor using self-assembled monolayers. Previously, serum from COVID-19 patients was screened by immunochromatography-based COVID-19 IgG rapid test and/or ELISA in house to determine the presence of IgG titers. Serum from COVID-19-positive patients presenting with IgG were added on the surface and, at the time they bound to proteins, they caused refractive changes in the SPR angle. The antibody detection limit was determined through successive injections into the SPR apparatus - these injections ranged from pure (without dilution) to 1 : 200 μL. The system has shown good reproducibility between runs after coated surface regeneration with 0.1 M glycine-HCl solution (pH 3.0); all experiments were tested in triplicate. The antibodies targeted both S and N fragments and gave a high assay sensitivity by identifying 19 out of 20 COVID-19-positive patients. Most importantly, the assay time took less than 10 min. The results of this study indicate that the proposed simple strategy demonstrates high sensitivity and time-saving in the detection of SARS-CoV-2 response antibodies.

Identification of large genetic variations in the equine infectious anemia virus tat-gag genomic region

The aetiological agent of equine infectious anaemia (EIA) is the retrovirus equine infectious anemia virus (EIAV) that infects all members of the Equidae family. The EIA is widely disseminated in the Brazilian territory with a high seroprevalence in the Brazilian Pantanal and is mainly diagnosed using agar gel immunodiffusion (AGID). There are few complete EIAV genome sequences available in GenBank, which had an impact on molecular detection studies. In this study, we conducted molecular detection and sequencing of EIAV proviral DNA from Brazilian horses. We analysed the genomic region from exon 1 of tat to gag (tat-gag). Comparative serological tests, comprising AGID and two enzyme-linked immunosorbent assays (ELISAs), were also conducted. Of the 133 samples, 58 were positive in the tat-gag PCR, and 49 nucleotide sequences of 272 bp were obtained. Using this developed tat-gag PCR EIAV proviral DNA was detected in 7% of the AGID-negative samples and 26% of the AGID-negative samples were positive in at least one of the ELISA tests used. Using phylogenetic analysis, the Brazilian Pantanal EIAV sequences grouped in a different clade of EIAV sequences from other countries. Thus, the EIAV sequences can contribute to the knowledge of the tat-gag genomic region in the circulating viruses in the Brazilian Pantanal, in addition to providing new information about the genetic diversity. In addition, the serological results demonstrate the greater sensitivity of the ELISAs used in this study compared to AGID for EIA diagnosis.