First performance report of QIAreach™ Anti-SARS-CoV-2 Total Test, an innovative nanoparticle fluorescence digital detection platform.

In 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic. Disease diagnosis, appropriate clinical management and infection control are all important factors in controlling the spread of SARS-CoV-2. The QIAreach™ Anti-SARS-CoV-2 Total Test (Anti-CoV2) is a rapid, qualitative serological test, using proprietary nanoparticle fluorescence technology to detect total antibody (IgA, IgM, and IgG) against SARS-CoV-2. Here we report the results of the US Food and Drug Administration (FDA) clinical agreement study. Thirty positive plasma or serum samples were taken from consenting individuals with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection ≥14 days from symptom onset. Seventy-five samples from before the believed circulation of SARS-CoV-2 (November 1, 2019) were used to assess specificity. Positive percent agreement (PPA) and negative percent agreement (NPA) were calculated along with the corresponding exact two-sided 95 % confidence intervals (CI) using an FDA Emergency Use Authorized PCR test as the reference method. Anti-CoV2 was shown to have 100 % sensitivity (PPA; 95 % CI 88.4-100 %) and 100 % specificity (NPA; 95 % CI 95.2-100 %). Against 157 pre-pandemic samples, no cross-reactivity was observed with seasonal coronaviruses or other respiratory pathogens tested. Additionally, no interference was observed when samples were spiked with: conjugated bilirubin 0.4 mg/ml; unconjugated bilirubin 0.4 mg/ml; hemoglobin 5 mg/ml; prednisolone 0.12 mg/ml; triglycerides 15 mg/ml. In conclusion, Anti-CoV2 provides accurate qualitative detection of total antibodies against SARS-CoV-2.

Histone H3 lysine 4 methylation signature associated with human undernutrition.

Chronically undernourished children become stunted during their first 2 years and thereafter bear burdens of ill health for the rest of their lives. Contributors to stunting include poor nutrition and exposure to pathogens, and parental history may also play a role. However, the epigenetic impact of a poor environment on young children is largely unknown. Here we show the unfolding pattern of histone H3 lysine 4 trimethylation (H3K4me3) in children and mothers living in an urban slum in Dhaka, Bangladesh. A pattern of chromatin modification in blood cells of stunted children emerges over time and involves a global decrease in methylation at canonical locations near gene start sites and increased methylation at ectopic sites throughout the genome. This redistribution occurs at metabolic and immune genes and was specific for H3K4me3, as it was not observed for histone H3 lysine 27 acetylation in the same samples. Methylation changes in stunting globally resemble changes that occur in vitro in response to altered methylation capacity, suggesting that reduced levels of one-carbon nutrients in the diet play a key role in stunting in this population. A network of differentially expressed genes in stunted children reveals effects on chromatin modification machinery, including turnover of H3K4me3, as well as posttranscriptional gene regulation affecting immune response pathways and lipid metabolism. Consistent with these changes, reduced expression of the endocytic receptor gene LDL receptor 1 (LRP1) is a driver of stunting in a mouse model, suggesting a target for intervention.

MyD88-mediated TLR signaling protects against acute rotavirus infection while inflammasome cytokines direct Ab response.

Rotavirus (RV) infects small intestinal epithelial cells, inducing severe diarrhea in children, resulting in over 500,000 deaths annually. Relatively little is known about how innate immunity contains acute infection and drives adaptive immune responses that afford complete clearance of RV and protection against future infection. Hence, we examined the consequence of the absence of MyD88, known to be central to innate immunity, in a mouse model of RV infection. The absence of MyD88, but not combined blockade of IL-1ß and IL-18 signaling, resulted in greater infectivity, as reflected by levels of RV in feces, intestinal lysates and viremia. Such increased RV levels correlated with an increase in incidence and duration of diarrhea. Loss of MyD88 also impaired humoral immunity to RV. Specifically, MyD88 knockout generated less RV-specific IgA and exhibited profoundly reduced RV-specific IgG2c/IgG1 ratios suggesting that MyD88 signaling drives RV-induced Th1 responses. A study of MyD88 bone marrow chimeras indicated that MyD88-dependent control of acute RV infection was mediated by both hemopoietic and non-hemopoietic cells, while generation of RV-specific humoral immunity was driven by MyD88 signaling in hemopoietic cells, which reflected the loss of IL-1ß and IL-18 expression by these cells. Thus, TLR signaling and inflammasome cytokines drive innate and adaptive immunity to RV.

Viral infection. Prevention and cure of rotavirus infection via TLR5/NLRC4-mediated production of IL-22 and IL-18.

Activators of innate immunity may have the potential to combat a broad range of infectious agents. We report that treatment with bacterial flagellin prevented rotavirus (RV) infection in mice and cured chronically RV-infected mice. Protection was independent of adaptive immunity and interferon (IFN, type I and II) and required flagellin receptors Toll-like receptor 5 (TLR5) and NOD-like receptor C4 (NLRC4). Flagellin-induced activation of TLR5 on dendritic cells elicited production of the cytokine interleukin-22 (IL-22), which induced a protective gene expression program in intestinal epithelial cells. Flagellin also induced NLRC4-dependent production of IL-18 and immediate elimination of RV-infected cells. Administration of IL-22 and IL-18 to mice fully recapitulated the capacity of flagellin to prevent or eliminate RV infection and thus holds promise as a broad-spectrum antiviral agent.

Antibiotic treatment suppresses rotavirus infection and enhances specific humoral immunity.

BACKGROUND: Rotavirus causes 500 000 deaths and millions of physician visits and hospitalizations per year, with worse outcomes and reduced vaccine efficacy in developing countries. We hypothesized that the gut microbiota might modulate rotavirus infection and/or antibody response and thus potentially play a role in such regional differences. METHODS: The microbiota was ablated via germ-free or antibiotic approaches. Enhanced exposure to microbiota was achieved via low-dose dextran sodium sulfate (DSS) treatment. Rotavirus infection and replication was assessed by enzyme-linked immunosorbent assay (ELISA) and quantitative reverse-transcription polymerase chain reaction. Diarrhea was scored visually. Humoral responses to rotavirus were measured by ELISA and enzyme-linked immunosorbent spot assay. RESULTS: Microbiota elimination delayed infection and reduced infectivity by 42%. Antibiotics did not alter ratios of positive-sense to negative-sense strands, suggesting that entry rather than replication was influenced. Antibiotics reduced the diarrhea incidence and duration, indicating that the reduction in the level of rotavirus antigen was biologically significant. Despite lowered antigen level, antibiotics resulted in a more durable rotavirus mucosal/systemic humoral response. Increased rotavirus antibody response durability correlated with increased small intestinal rotavirus-specific, immunoglobulin A-producing antibody-secreting cell concentration in antibiotic-treated mice. Conversely, DSS treatment impaired generation of rotavirus-specific antibodies. CONCLUSIONS: Microbiota ablation resulted in reduced rotavirus infection/diarrhea and a more durable rotavirus antibody response, suggesting that antibiotic administration before rotavirus vaccination could raise low seroconversion rates that correlate with the vaccine's inefficacy in developing regions.