Heterologous DNA Prime- Subunit Protein Boost with Chikungunya Virus E2 Induces Neutralizing Antibodies and Cellular-Mediated Immunity.

Chikungunya virus (CHIKV) has become a significant public health concern due to the increasing number of outbreaks worldwide and the associated comorbidities. Despite substantial efforts, there is no specific treatment or licensed vaccine against CHIKV to date. The E2 glycoprotein of CHIKV is a promising vaccine candidate as it is a major target of neutralizing antibodies during infection. In this study, we evaluated the immunogenicity of two DNA vaccines (a non-targeted and a dendritic cell-targeted vaccine) encoding a consensus sequence of E2CHIKV and a recombinant protein (E2*CHIKV). Mice were immunized with different homologous and heterologous DNAprime-E2* protein boost strategies, and the specific humoral and cellular immune responses were accessed. We found that mice immunized with heterologous non-targeted DNA prime- E2*CHIKV protein boost developed high levels of neutralizing antibodies, as well as specific IFN-γ producing cells and polyfunctional CD4+ and CD8+ T cells. We also identified 14 potential epitopes along the E2CHIKV protein. Furthermore, immunization with recombinant E2*CHIKV combined with the adjuvant AS03 presented the highest humoral response with neutralizing capacity. Finally, we show that the heterologous prime-boost strategy with the non-targeted pVAX-E2 DNA vaccine as the prime followed by E2* protein + AS03 boost is a promising combination to elicit a broad humoral and cellular immune response. Together, our data highlights the importance of E2CHIKV for the development of a CHIKV vaccine.

Robust specific RBD responses and neutralizing antibodies after ChAdOx1 nCoV-19 and CoronaVac vaccination in SARS-CoV-2- seropositive individuals.

Background: The pandemic unleashed by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 500 million people worldwide and caused more than 6 million deaths. Cellular and humoral immunity induced by infection or immunization are key factors in controlling the viral burden and avoiding the recurrence of coronavirus disease. The duration and effectiveness of immunity after infection is relevant to pandemic policy interventions, including the timing of vaccine boosters. Objectives: We sought to evaluate longitudinal binding and functional antibodies against SARS-CoV-2 receptor-binding domain in police officers and health care workers with a history of coronavirus disease 2019 and compare with SARS-CoV-2-naive individuals after vaccination with adenovirus-based ChAdOx1 nCoV-19 (AstraZeneca-Fiocruz) or the inactivated CoronaVac vaccine (Sinovac-Butantan Institute). Methods: A total of 208 participants were vaccinated. Of these, 126 (60.57%) received the ChAdOx1 nCoV-19 vaccine and 82 (39.42%) received the CoronaVac vaccine. Prevaccination and postvaccination blood was collected, and the amount of anti-SARS-CoV-2 IgG and the neutralizing ability of the antibodies to block the interaction between angiotensin-converting enzyme 2 and receptor-binding domain were determined. Results: Subjects with preexisting SARS-CoV-2 immunity and who received a single dose of ChAdOx1 nCoV-19 or CoronaVac have similar or superior antibody levels when compared with levels in seronegative individuals even after 2 doses of the vaccine. Neutralizing antibody titers of seropositive individuals were higher with a single dose of either ChAdOx1 nCoV-19 or CoronaVac compared with those of seronegative individuals. After 2 doses, both groups reached a plateau response. Conclusions: Our data reinforce the importance of vaccine boosters to increase specific binding and neutralizing SARS-CoV-2 antibodies.

Time-dependent contraction of the SARS-CoV-2-specific T-cell responses in convalescent individuals.

Background: Adaptive immunity in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is decisive for disease control. Delayed activation of T cells is associated with a worse outcome in coronavirus disease 2019 (COVID-19). Although convalescent individuals exhibit solid T-cell immunity, to date, long-term immunity to SARS-CoV-2 is still under investigation. Objectives: We aimed to characterize the specific T-cell response on the basis of the in vitro recall of IFN-γ-producing cells to in silico-predicted peptides in samples from SARS-CoV-2 convalescent individuals. Methods: The sequence of the SARS-CoV-2 genome was screened, leading to the identification of specific and promiscuous peptides predicted to be recognized by CD4+ and CD8+ T cells. Next, we performed an in vitro recall of specific T cells from PBMC samples from the participants. The results were analyzed according to clinical features of the cohort and HLA diversity. Results: Our results indicated heterogeneous T-cell responsiveness among the participants. Compared with patients who exhibited mild symptoms, hospitalized patients had a significantly higher magnitude of response. In addition, male and older patients showed a lower number of IFN-γ-producing cells. Analysis of samples collected after 180 days revealed a reduction in the number of specific circulating IFN-γ-producing T cells, suggesting decreased immunity against viral peptides. Conclusion: Our data are evidence that in silico-predicted peptides are highly recognized by T cells from convalescent individuals, suggesting a possible application for vaccine design. However, the number of specific T cells decreases 180 days after infection, which might be associated with reduced protection against reinfection over time.

Dual-pool, three-phase kinetic model of anaerobic digestion in batch mode.

The ability of anaerobic digestion to create value from waste gives it an important role in reducing greenhouse gas emissions and in the transition to a circular economy. For a better understanding of the digestion process and in order to reduce the number of time-consuming batch tests, an analytical model was developed to describe the kinetics of biogas production. Assuming that the organic fraction of the substrate has different degradation rates, the whole process was modelled as two groups of 1st order reactions. The model was tested with published data and showed an excellent performance in reproducing the experimental information. Moreover, its kinetic constants provided a useful insight into the internal processes of anaerobic digestion and the substrate characteristics. Given its accuracy in fitting the data, the model can be used as an auxiliary tool to determine the biogas potential, presenting itself as the most complete empirical model currently available.

Recurrence of COVID-19 associated with reduced T-cell responses in a monozygotic twin pair.

Recurrence of COVID-19 in recovered patients has been increasingly reported. However, the immune mechanisms behind the recurrence have not been thoroughly investigated. The presence of neutralizing antibodies (nAbs) in recurrence/reinfection cases suggests that other types of immune response are involved in protection against recurrence. Here, we investigated the innate type I/III interferon (IFN) response, binding and nAb assays and T-cell responses to severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) with IFN gamma (IFNγ) enzyme-linked spot assay (ELISPOT) in three pairs of young adult monozygotic (MZ) twins with previous confirmed COVID-19, one of them presenting a severe recurrence four months after the initial infection. Twin studies have been of paramount importance to comprehend the immunogenetics of infectious diseases. Each MZ twin pair was previously exposed to SARS-CoV-2, as seen by clinical reports. The six individuals presented similar overall recovered immune responses except for the recurrence case, who presented a drastically reduced number of recognized SARS-CoV-2 T-cell epitopes on ELISPOT as compared to her twin sister and the other twin pairs. Our results suggest that the lack of a broad T-cell response to initial infection may have led to recurrence, emphasizing that an effective SARS-CoV-2-specific T-cell immune response is key for complete viral control and avoidance of clinical recurrence of COVID-19.

Oxygen saturation as a predictor of inflammation in obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is a chronic sleep disorder, and its prevalence is increasing worldwide. This disorder has been consistently associated with several comorbidities. Although it is clear that obstructive sleep apnea severity is associated with inflammation, the trigger for this phenomenon continues to puzzle scientists. Here, we investigated the relationship between obstructive sleep apnea severity and immune parameters. METHODS: In this cross-sectional epidemiological research, we analyzed the immune profile of 461 adults according to OSA severity (mild, moderate, and severe) and oxygen saturation. RESULTS: The hallmark of OSA severity - the apnea-hypopnea index (AHI) - weakly correlated with an inflammatory profile. However, individuals who experienced lower oxygen saturation were more likely to exhibit higher total leukocyte and neutrophil counts, a higher neutrophil-lymphocyte ratio (NLR), and an increased concentration of C-reactive protein. CONCLUSION: Our findings indicated that oxygen saturation is a predictor of inflammation during OSA and should be considered crucial in disease diagnostic and treatment strategies.

Correlation between Electronic Configuration and Magnetic Stability in Dysprosium Single Atom Magnets.

Single atom magnets offer the possibility of magnetic information storage in the most fundamental unit of matter. Identifying the parameters that control the stability of their magnetic states is crucial to design novel quantum magnets with tailored properties. Here, we use X-ray absorption spectroscopy to show that the electronic configuration of dysprosium atoms on MgO(100) thin films can be tuned by the proximity of the metal Ag(100) substrate onto which the MgO films are grown. Increasing the MgO thickness from 2.5 to 9 monolayers induces a change in the dysprosium electronic configuration from 4f9 to 4f10. Hysteresis loops indicate long magnetic lifetimes for both configurations, however, with a different field-dependent magnetic stability. Combining these measurements with scanning tunneling microscopy, density functional theory, and multiplet calculations unveils the role of the adsorption site and charge transfer to the substrate in determining the stability of quantum states in dysprosium single atom magnets.

Zika virus-an update on the current efforts for vaccine development.

In 2015, the world witnessed the resurgence and global spread of Zika virus (ZIKV). This arbovirus infection is associated with Guillain-Barré syndrome in adults and with devastating congenital malformations during pregnancy. Despite scientific efforts, the development of a vaccine capable of inducing long-term protection has been challenging. Without a safe and efficacious licensed vaccine, control of virus transmission is based on vector control, but this strategy has been shown to be inefficient. An effective and protective vaccine relies on several requirements, which include: (i) induction of specific immune response against immunodominant antigens; (ii) selection of adjuvant-antigen formulation; and (iii) assessment of safety, effectiveness, and long-term protection. In this commentary, we provide a brief overview about the current efforts for the development of an efficacious ZIKV vaccine, covering the most important preclinical trials up to the formulations that are now being evaluated in clinical trials.

Prime-boost with Chikungunya virus E2 envelope protein combined with Poly (I:C) induces specific humoral and cellular immune responses.

Chikungunya virus (CHIKV) is an arbovirus transmitted to humans mainly by the bite of infected Aedes aegypti and Aedes albopictus mosquitoes. CHIKV illness is characterized by fever and long-lasting arthritic symptoms, and in some cases it is a deadly disease. The CHIKV envelope E2 (E2CHIKV) glycoprotein is crucial for virus attachment to the cell. Furthermore, E2CHIKV is the immunodominant protein and the main target of neutralizing antibodies. To date, there is no available prophylactic vaccine or specific treatment against CHIKV infection. Here, we designed and produced a DNA vaccine and a recombinant protein containing a consensus sequence of E2CHIKV. C57BL/6 mice immunized twice with the E2CHIKV recombinant protein in the presence of the adjuvant Poly (I:C) induced the highest E2CHIKV-specific humoral and cellular immune responses, while the immunization with the homologous DNA vaccine pVAX-E2CHIKV was able to induce specific IFN-γ producing cells. The heterologous prime-boost strategy was also able to induce specific cellular and humoral immune responses that were, in general, lower than the responses induced by the homologous E2CHIKV recombinant protein immunization. Furthermore, recombinant E2CHIKV induced the highest titers of neutralizing antibodies. Collectively, we believe this is the first report to analyze E2CHIKV-specific humoral and cellular immune responses after immunization with E2CHIKV recombinant protein and DNA pVAX-E2CHIKV vaccine platforms.

Sleep Disturbance during Infection Compromises Tfh Differentiation and Impacts Host Immunity.

Although the influence of sleep quality on the immune system is well documented, the mechanisms behind its impact on natural host immunity remain unclear. Meanwhile, it has been suggested that neuroimmune interactions play an important role in this phenomenon. To evaluate the impact of stress-induced sleep disturbance on host immunity, we used a murine model of rapid eye movement sleep deprivation (RSD) integrated with a model of malaria blood-stage infection. We demonstrate that sleep disturbance compromises the differentiation of T follicular helper cells, increasing host susceptibility to the parasite. Chemical inhibition of glucocorticoid (Glcs) synthesis showed that abnormal Glcs production compromised the transcription of Tfh-associated genes resulting in impaired germinal center formation and humoral immune response. Our data demonstrate that RSD-induced abnormal activation of the hypothalamic-pituitary-adrenal axis drives host susceptibility to infection. Understanding the impact of sleep quality in natural resistance to infection may provide insights for disease management.

Invariant Natural Killer T cells resilience to paradoxical sleep deprivation-associated stress.

Although several studies demonstrate that stressful situations, such as sleep disturbances, negatively impact the innate and adaptive arms of the immune system, their influence on invariant Natural Killer T (iNKT) cells remains unclear. iNKT cells are CD1d-restricted innate T cells that recognize glycolipid antigens and rapidly produce polarizing cytokines being key players in several immune responses, and a potential target for immunotherapy. iNKT cells differ in several aspects from conventional T lymphocytes, including a unique dependence on CD1d-expressing double-positive (DP) thymocytes for intrathymic maturation. As a consequence of stress, DP thymocytes undergo glucocorticoid-induced apoptosis, which might compromise iNKT developmental pathway. Therefore, we used a paradoxical sleep deprivation (SD) model to determine the impact of sleep disturbance on iNKT cell biology. After 72 h of SD, C57Bl/6 mice exhibited a significant increase in systemic glucocorticoid levels and thymus atrophy. Despite marked decrease in the number of DP thymocytes, the ratio CD1d+/CD1d- was higher in SD mice, and the number of thymic iNKT cells remained unaltered, suggesting that SD did not compromise the iNKT developmental pathway. In contrast, SD reduced hepatic IFN-γ, but not, IL-4-producing iNKT cells, without further effect in the spleen. Despite this fact, SD did not affect stimulation of IFN-γ production by iNKT cells, or cytokine release, in response to α-galactosylceramide, a specific antigen. Furthermore, although SD impaired splenic NK cells activity against tumor cells, it did not affect iNKT cell-specific cytotoxicity. Thus, our study shows that SD-induced stress did not impair the iNKT cells' responses to a cognate antigen.

Homologous prime-boost with Zika virus envelope protein and poly (I:C) induces robust specific humoral and cellular immune responses.

The recent outbreaks of Zika virus (ZIKV) infection and the potential association with Guillain-Barré syndrome in adults and with congenital abnormalities have highlighted the urgency for an effective vaccine. The ZIKV Envelope glycoprotein (EZIKV) is the most abundant protein on the virus surface, and has been evaluated together with the pre-membrane protein (prM) of the viral coat as a vaccine candidate in clinical trials. In this study, we performed a head-to-head comparison of the immune response induced by different EZIKV-based vaccine candidates in mice. We compared different platforms (DNA, recombinant protein), adjuvants (poly (I:C), CpG ODN 1826) and immunization strategies (homologous, heterologous). The hierarchy of adjuvant potency showed that poly (I:C) was a superior adjuvant than CpG ODN. While poly (I:C) assisted immunization reached a plateau in antibody titers after two doses, the CpG ODN group required an extra immunization dose. Besides, the administration of poly (I:C) induced higher EZIKV-specific cellular immune responses than CpG ODN. We also show that immunization with homologous prime-boost EZIKV protein + poly (I:C) regimen induced a more robust humoral response than homologous DNA (pVAX-EZIKV) or heterologous regimens (DNA/protein or protein/DNA). A detailed analysis of cellular immune responses revealed that homologous (EZIKV + poly (I:C)) and heterologous (pVAX-EZIKV/EZIKV + poly (I:C)) prime-boost regimens induced the highest magnitude of IFN-γ secreting cells and cytokine-producing CD4+ T cells. Overall, our data demonstrate that homologous EZIKV + poly (I:C) prime-boost immunization is sufficient to induce more robust specific-EZIKV humoral and cellular immune responses than the other strategies that contemplate homologous DNA (pVAX-EZIKV) or heterologous (pVAX-EZIKV/EZIKV + poly (I:C), and vice-versa) immunizations.

Sleep deprivation predisposes allergic mice to neutrophilic lung inflammation.

BACKGROUND: Although different studies associated sleep deprivation (SD) with systemic inflammatory changes, the effect of sleep duration on the pathology of allergic chronic diseases is poorly understood. OBJECTIVE: We sought to evaluate the influence of SD on allergen-induced pulmonary inflammation. METHODS: Ovalbumin (OVA)-sensitized C57BL/6 mice were exposed to a first set of intranasal OVA challenge under SD or healthy sleep (HS) conditions, followed by a second OVA challenge, 1 week apart. Some groups were subjected to corticosteroid treatment with dexamethasone. RESULTS: OVA-sensitized mice with SD had more severe airway inflammation than the allergic group with HS. Analysis of lung parenchyma revealed that the inflammation in allergic mice with SD was marked by an influx of neutrophils (mainly) and eosinophils and secretion of IL-6, TNF-α, and IL-17 in contrast to the eosinophilic inflammation and IL-4 production observed in allergic mice with HS. The same cytokine profile was observed in ex vivo culture of cervical lymph node cells and splenocytes, indicating that in allergic mice SD favors immune responses toward a proinflammatory TH17 profile. This idea is supported by the fact that disruption of IL-17 signaling (IL-17 receptor A-/-) prevented airway neutrophilia in allergic mice with SD. Furthermore, allergic mice with SD became refractory to corticosteroid treatment in contrast to the allergic group with HS. CONCLUSION: Collectively, our data show that sleep quality participates in the progression of allergen-induced eosinophilic lung inflammation to corticosteroid-refractory neutrophilic manifestation.

Temperature-dependent self-assembly of NC-Ph5-CN molecules on Cu(111).

We present the results of temperature-dependent self-assembly of dicarbonitrile-pentaphenyl molecules (NC-Ph5-CN) on Cu(111). Our low-temperature scanning tunneling microscopy study reveals the formation of metal-organic and purely organic structures, depending on the substrate temperature during deposition (160-300 K), which determines the availability of Cu adatoms at the surface. We use tip functionalization with CO to obtain submolecular resolution and image the coordination atoms, enabling unequivocal identification of metal-coordinated nodes and purely organic ones. Moreover, we discuss the somewhat surprising structure obtained for deposition and measurement at 300 K.