A flow cytometry-based assay to measure neutralizing antibodies against SARS-CoV-2 virus.

The COVID-19 pandemic caused by the SARS-CoV-2 virus has highlighted the need for serological assays that can accurately evaluate the neutralizing efficiency of antibodies produced during infection or induced by vaccines. However, conventional assays often require the manipulation of live viruses on a level-three biosafety (BSL3) facility, which presents practical and safety challenges. Here, we present a novel, alternative assay that measures neutralizing antibodies (NAbs) against SARS-CoV-2 in plasma using flow cytometry. This assay is based on antibody binding to the S protein and has demonstrated precision in both intra- and inter-assay measurements at a dilution of 1:50. The cut-off was determined using Receiver Operating Characteristic (ROC) analysis and the value of 36.01% has shown high sensitivity and specificity in distinguishing between pre-pandemic sera, COVID-19 patients, and vaccinated individuals. The efficiency significantly correlates with the gold standard test, PRNT. Our new assay offers a safe and efficient alternative to conventional assays for evaluating NAbs against SARS-CoV-2.

Hemograms and serial hemogram-derived ratios in survivors and non-survivors of COVID-19 in Campinas, Brazil.

Introduction: The hemogram and hemogram-derivative ratios (HDRs) are becoming markers of the severity and mortality of COVID-19. We evaluated the hemograms and serial weekly HDRs [neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), platelet-lymphocyte ratio (PLR), neutrophil-platelet ratio (NPR) and systemic immune-inflammatory index (SII)] in the survivors and non-survivors of COVID-19. Methods: We retrospectively reviewed the medical notes and serial hemograms of real-time reverse-transcription polymerase chain reaction (RT-PCR)-confirmed COVID-19 adults hospitalized from April 2020 to March 2021 from the time of diagnosis to the 3rd week of diagnosis. Results: Of the 320 adults, 257 (80.3%) were survivors and had a lower mean age than the non-survivors (57.73 vs. 64.65 years, p < 0.001). At diagnosis, the non-survivors had lower lymphocyte (p = 0.002) and basophil (p = 0.049) counts and the hematocrit showed a p-value (Is this what you meant???) of 0.021); higher NLR (p < 0.001), PLR (p = 0.047), NPR (p = 0.022) and SII (p = 0.022). Using general linear models, the survivors and non-survivors showed significant variations with weekly lymphocyte count (p < 0.001), neutrophil count (p = 0.005), NLR (p = 0.009), MLR (p = 0.010) and PLR (p = 0.035). All HDRs remained higher in the non-survivors in the 2nd week and 3rd week of diagnosis and the HDRs were higher in the intubated patients than in the non-intubated patients. The NLR and SII were more efficient predictors of mortality in COVID-19 patients. Conclusions: This study shows that serial lymphocyte and neutrophil counts, NLR, PLR, MLR, NPR and SII could serve as good and easily accessible markers of severity and predictors of outcomes in COVID-19 patients and should be used for the monitoring of treatment response.

Outer Membrane Vesicles from Neisseria Meningitidis (Proteossome) Used for Nanostructured Zika Virus Vaccine Production.

The increase of Zika virus (ZIKV) infections in Brazil in the last two years leaves a prophylactic measures on alert for this new and emerging pathogen. Concerning of our positive experience, we developed a new prototype using Neisseria meningitidis outer membrane vesicles (OMV) on ZIKV cell growth in a fusion of OMV in the envelope of virus particles. The fusion of nanoparticles resulting from outer membrane vesicles of N. meningitidis with infected C6/36 cells line were analyzed by Nano tracking analysis (NTA), zeta potential, differential light scattering (DLS), scan and scanning transmission eletronic microscopy (SEM and STEM) and high resolution mass spectometry (HRMS) for nanostructure characterization. Also, the vaccination effects were viewed by immune response in mice protocols immunization (ELISA and inflammatory chemokines) confirmed by Zika virus soroneutralization test. The results of immunizations in mice showed that antibody production had a titer greater than 1:160 as compared to unvaccinated mice. The immune response of the adjuvant and non-adjuvant formulation activated the cellular immune response TH1 and TH2. In addition, the serum neutralization was able to prevent infection of virus particles in the glial tumor cell model (M059J). This research shows efficient strategies without recombinant technology or DNA vaccines.

Correlation between Helicobacter pylori infection, gastric diseases and life habits among patients treated at a university hospital in Southeast Brazil.

Helicobacter pylori is considered a significant agent in the development of various gastric diseases. However, the diseases caused by this bacterium are known as being multi-factorial, with the genotype, immune system and life habits of the host playing important roles in the establishment of the clinical outcome. Also, H. pylori exhibit a high degree of genetic variability, contributing to the complexity of the host-pathogen relationship. These observations, considered together with the widely-varying origins and social habits of the Brazilian population, lead us to speculate about the influence of these life habits on H. pylori infection and the clinical outcome. Therefore, in this study we evaluated the relationship between H. pylori infection and certain diseases in 172 patients treated at the Hospital das Clínicas of Ribeirão Preto (HCRP), Brazil, taking into account their different life habits, such as non-steroidal anti-inflammatory drugs and alcohol ingestion, and smoking habit. Our analysis indicated that H. pylori infection is not affected by any of the life habits evaluated but is associated with the development of peptic ulcers (gastric and duodenal ulcer) and inverse correlate with gastroesophageal reflux disease (GERD). No correlation was found between the infection with this bacterium and gastritis or intestinal metaplasia. However, gastritis and erosive gastritis were directly correlated with non-steroidal anti-inflammatory drugs (NSAID) ingestion. Moreover, ingestion of alcohol beverages exhibited a protective effect on gastritis development in men. Our data also indicated that to achieve reliable detection of this bacterium in biopsies, two or three detection methods should be used.

Correlation between Helicobacter pylori infection, gastric diseases and life habits among patients treated at a university hospital in Southeast Brazil

Helicobacter pylori is considered a significant agent in the development of various gastric diseases. However, the diseases caused by this bacterium are known as being multi-factorial, with the genotype, immune system and life habits of the host playing important roles in the establishment of the clinical outcome. Also, H. pylori exhibit a high degree of genetic variability, contributing to the complexity of the host-pathogen relationship. These observations, considered together with the widely-varying origins and social habits of the Brazilian population, lead us to speculate about the influence of these life habits on H. pylori infection and the clinical outcome. Therefore, in this study we evaluated the relationship between H. pylori infection and certain diseases in 172 patients treated at the Hospital das Clínicas of Ribeirão Preto (HCRP), Brazil, taking into account their different life habits, such as non-steroidal anti-inflammatory drugs and alcohol ingestion, and smoking habit. Our analysis indicated that H. pylori infection is not affected by any of the life habits evaluated but is associated with the development of peptic ulcers (gastric and duodenal ulcer) and inverse correlate with gastroesophageal reflux disease (GERD). No correlation was found between the infection with this bacterium and gastritis or intestinal metaplasia. However, gastritis and erosive gastritis were directly correlated with non-steroidal anti-inflammatory drugs (NSAID) ingestion. Moreover, ingestion of alcohol beverages exhibited a protective effect on gastritis development in men. Our data also indicated that to achieve reliable detection of this bacterium in biopsies, two or three detection methods should be used.

Prevalence of Helicobacter pylori cagA, iceA and babA2 alleles in Brazilian patients with upper gastrointestinal diseases.

Helicobacter pylori is an important human pathogen associated with gastrointestinal diseases such as gastritis, gastric and duodenal ulcer (peptic ulcer disease, PUD), and gastric cancer. A number of pathogenic factors have been described for this bacterium, and some of them have been proposed as markers for the prediction of the clinical outcome. However, with the exception of the cag and vacA status, there is no universal consensus regarding the importance of the other virulence factors. Therefore, the aim of this study was to investigate the status of H. pylori strains regarding the babA and iceA alleles, as well as the cagA genotype, to reveal any association between these genotypes and clinical outcomes in Brazilian patients. The great majority (92.6%) of the strains were typed as iceA1, while 40.4% were found to possess the babA2 allele. The cagA gene was detected in 73.4% of the strains. The iceA2 and cagA genotypes were associated with PUD, while iceA1 was negatively correlated with PUD. However, considering the high percentage of strains typed as iceA1, these associations must be treated with caution. No clinical entity was associated with the babA2 allele. These results suggest that iceA1 is not a good marker for the diseases associated with H. pylori infection in Brazil. Further studies are needed in order to elucidate the relevance of the babA status, because other studies performed in Brazil have associated the babA2 allele with clinical outcomes. These results also indicate the existence of regional differences in the H. pylori genotypes and their association with clinical outcomes.