Açaí (Euterpe oleracea Mart.) Seed Oil and Its Nanoemulsion: Chemical Characterisation, Toxicity Evaluation, Antioxidant and Anticancer Activities.

This study explores a nanoemulsion formulated with açaí seed oil, known for its rich fatty acid composition and diverse biological activities. This study aimed to characterise a nanoemulsion formulated with açaí seed oil and explore its cytotoxic effects on HeLa and SiHa cervical cancer cell lines, alongside assessing its antioxidant and toxicity properties both in vitro and in vivo. Extracted from fruits sourced in Brazil, the oil underwent thorough chemical characterization using gas chromatography-mass spectrometry. The resulting nanoemulsion was prepared and evaluated for stability, particle size, and antioxidant properties. The nanoemulsion exhibited translucency, fluidity, and stability post centrifugation and temperature tests, with a droplet size of 238.37, PDI -9.59, pH 7, and turbidity 0.267. In vitro assessments on cervical cancer cell lines revealed antitumour effects, including inhibition of cell proliferation, migration, and colony formation. Toxicity tests conducted in cell cultures and female Swiss mice demonstrated no adverse effects of both açaí seed oil and nanoemulsion. Overall, açaí seed oil, particularly when formulated into a nanoemulsion, presents potential for cancer treatment due to its bioactive properties and safety profile.

Prophylactic use of standardized extract of propolis of Apis mellifera (EPP-AF®) reduces lung inflammation and improves survival in experimental lethal sepsis.

ETHNOPHARMACOLOGICAL RELEVANCE: Sepsis poses one of the biggest public health problems, necessitating the search for new therapeutic alternatives. For centuries, propolis has been widely used in folk medicine to treat various inflammatory and infectious diseases. Given its extensive use, it has excellent potential as an adjuvant treatment for patients with sepsis. OBJECTIVE: This study evaluated prophylactic treatment with standardized propolis extract (EPP-AF®) and followed the prognosis of sepsis induced by ligation and cecal ligation and puncture (CLP). METHODS: Initially, for survival assessment, Swiss mice were separated into five groups: Sham (false operated), control (PBS), ATB (received antibiotic, 8 mg/kg), P10 (received EPP-AF®, 10 mg/kg), and P100 (received EPP-AF®, 100 mg/kg). The animals received PBS, antibiotic, or EPP-AF® by the subcutaneous route 6 h before the CLP procedure. Animal survival was assessed every 12 h for five days when all of them were euthanized. RESULTS: We show that the treatment with EPP-AF® significantly increased the life expectancy of animals with sepsis compared to the control group. Interestingly, prophylactic treatment with EPP-AF® showed no effect on the number of colony-forming units in the peritoneum, blood, or lung. However, there was a decrease in cellular influx in the peritoneum. This alteration was unrelated to the number of bone marrow cells or the differential counting of peripheral blood cells. The coagulogram remained unchanged, including the number of platelets and prothrombin time-activated partial thromboplastin time. However, the inflammatory infiltrate and bleeding in the lung tissue were lower in the animals that received EPP-AF®. CONCLUSION: Thus, it was possible to conclude that prophylactic treatment with EPP-AF® preserved the lung parenchyma, resulting in an increased lifespan of mice with sepsis. It can be a helpful adjuvant in prophylactic treatment with antibiotics in presurgical conditions.

Effects of blood flow restriction therapy in patients with knee osteoarthritis: protocol for an overview of systematic reviews.

Background: Osteoarthritis (OA) is the most common and prevalent musculoskeletal disease associated with population aging, negatively impacting function and quality of life. A consequence of knee OA is quadriceps muscle weakness. Musculoskeletal rehabilitation using low load exercises, associated with Blood Flow Restriction (BFR) may be a useful alternative to high load exercises when those cannot be tolerated. Several systematic reviews have reported inconclusive results due to discrepancies in study findings, heterogeneity of results, evaluated time points, and research questions explored. Objective: To perform an overview of systematic reviews with meta-analyses, synthesizing the most recent evidence on the effects of muscle strength training with BFR for knee OA. Methodology: Systematic reviews that include primary controlled and randomized clinical trials will be considered for inclusion. Articles will be considered only if they present a clear and reproducible methodological structure, and when they clearly demonstrate that a critical analysis of the evidence was carried out using instrumented analysis. Narrative reviews, other types of review, overviews of systematic reviews, and diagnostic, prognostic and economic evaluation studies will be excluded. Studies must include adults aged 40 years and older with a diagnosis of knee OA. Two authors will perform an electronic search with guidance from an experienced librarian. The following databases will be searched: PubMed via MEDLINE, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), PEDro, Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host, Web of Science, and the gray literature. The search strategy used in the databases will follow the acronym PICOS (population, intervention, comparison, outcome, and study design). Screening (i.e., titles and abstracts) of studies identified by the search strategy will be selected using Rayyan (http://rayyan.qcri.org). The quality assessment will be performed using the "Assessment of Multiple Systematic Reviews" (AMSTAR-2) tool. Systematic Review Registration: PROSPERO, CRD42022367209.

Long-term recruitment of peripheral immune cells to brain scars after a neonatal insult.

Although brain scars in adults have been extensively studied, there is less data available regarding scar formation during the neonatal period, and the involvement of peripheral immune cells in this process remains unexplored in neonates. Using a murine model of neonatal hypoxic-ischemic encephalopathy (HIE) and confocal microscopy, we characterized the scarring process and examined the recruitment of peripheral immune cells to cortical and hippocampal scars for up to 1 year post-insult. Regional differences in scar formation were observed, including the presence of reticular fibrotic networks in the cortex and perivascular fibrosis in the hippocampus. We identified chemokines with chronically elevated levels in both regions and demonstrated, through a parabiosis-based strategy, the recruitment of lymphocytes, neutrophils, and monocyte-derived macrophages to the scars several weeks after the neonatal insult. After 1 year, however, neutrophils and lymphocytes were absent from the scars. Our data indicate that peripheral immune cells are transient components of HIE-induced brain scars, opening up new possibilities for late therapeutic interventions.

MIR-376A-2-5P as a potential prognostic marker for advanced penile squamous cell carcinomas trough HPV-dependent pathways.

Penile cancer (PeCa) is a rare tumor, generally associated with socioeconomic conditions in low-income countries. Hence, a delay in diagnosis and treatment leads in more advanced tumors, to higher comorbidity, and mortality. Human papillomavirus (HPV) infection has been identified as one of the major risk factors for PeCa. In addition, viral integration sites have been related to copy number alterations, impacting miRNAs/mRNA interactions and, consequently, the molecular pathways related to them. Nonetheless, studies on differentially expressed miRNAs (miRDEs) in PeCa are still scarce, especially in PeCa associated with high-risk HPV (hrHPV). To investigate the role of these gene regulators in PeCa progression, 827 miRNAs (Nanostring Technologies™, Seattle, WA, USA) were evaluated in 22 hrHPV-associated penile squamous cell carcinomas and five non-tumor penile tissues. For functions of miRNAs/target genes and relationship with HPV we conducted an integrated analysis by Diana Tools, KEGG, HPVbase, and InterSPPI-HVPPI platforms. We found that 25 miRNAs of the most differentially expressed impact 43 top molecular pathways, of which the fatty acid biosynthesis pathway, prions, miRNAs in cancer and hippo signaling (P<1.0-325, for each) were the most statistically significant. Notably, 23 out of 25 are located at HPV integration sites (HPVis). MiR-1206, miR-376b-3p and miR-495-3p were downregulated and associated with perineural invasion. In addition, a comparison between advanced and early diseases revealed 143 miRDEs. ROC analysis of a single (miR-376a-2-5p), paired (miR-376a-2-5p, miR-551b-3p) or combination of five miRDEs (miR-99a-5p, miR-150-5p, miR-155-5p, let-7c-5p, miR-342-3p) showed robust discriminatory power (AUC = 0.9; P = 0.0114, for each). Strikingly, miR-376a-2-5p exhibited the highest values of sensitivity and specificity, with 100% and 83.3%, respectively, indicating this miRNA as a potential prognostic marker in hrHPV-penile carcinogenesis.

Oligosymptomatic long-term carriers of SARS-CoV-2 display impaired innate resistance but increased high-affinity anti-spike antibodies.

The vast spectrum of clinical features of COVID-19 keeps challenging scientists and clinicians. Low resistance to infection might result in long-term viral persistence, but the underlying mechanisms remain unclear. Here, we studied the immune response of immunocompetent COVID-19 patients with prolonged SARS-CoV-2 infection by immunophenotyping, cytokine and serological analysis. Despite viral loads and symptoms comparable to regular mildly symptomatic patients, long-term carriers displayed weaker systemic IFN-I responses and fewer circulating pDCs and NK cells at disease onset. Type 1 cytokines remained low, while type-3 cytokines were in turn enhanced. Of interest, we observed no defects in antigen-specific cytotoxic T cell responses, and circulating antibodies displayed higher affinity against different variants of SARS-CoV-2 Spike protein in these patients. The identification of distinct immune responses in long-term carriers adds up to our understanding of essential host protective mechanisms to ensure tissue damage control despite prolonged viral infection.

The Immunomodulatory Activity of Punica granatum L. Peel Extract Increases the Lifespan of Mice with Lethal Sepsis.

Sepsis is an organ dysfunction syndrome associated with high mortality. To date, no effective treatment is available to combat this disease. Punica granatum L. is a potential alternative treatment due to its anti-inflammatory, antimicrobial, and antioxidant properties. Thus, this study aimed to evaluate the effects of a hydroalcoholic crude extract from the peels of P. granatum (HCEPg) in mice with lethal sepsis. Lethal polymicrobial sepsis was induced in female Swiss mice via cecal ligation and puncture (CLP). Initially, the animals were divided into three groups: Sham (false-operated), CLP-control (phosphate-buffered saline), and CLP-HCEPg (single dose, 5 mg/kg, subcutaneous administration). Treatment was initiated immediately after the induction of sepsis, and survival was evaluated every 12 hr for 5 days. Those who survived were euthanized. Serum cytokine levels were measured using a cytometric bead array Mouse Inflammatory Cytokine Kit. The number of colony-forming units, as well as the number of cells in the lymphoid organs and their activation markers, were analyzed. Results showed that treatment with HCEPg increased lifespan and reduced bacterial counts in the peritoneum, bloodstream, and spleen. HCEPg also decreased hydrogen peroxide secretion by phagocytes and augmented serum IL-10 levels, indicating its systemic anti-inflammatory effects. Additionally, treatment with HCEPg attenuated infection-induced lung hemorrhage. Overall, P. granatum extract improved the lifespan of septic mice, possibly due to its antimicrobial, anti-inflammatory, and immunomodulatory effects, thereby regulating bacterial load and translocation, as well as controlling the systemic inflammation induced by sepsis.

Antitumor Effect of Açaí (Euterpe oleracea Mart.) Seed Extract in LNCaP Cells and in the Solid Ehrlich Carcinoma Model.

Euterpe oleracea (açaí) fruit has approximately 15% pulp, which is partly edible and commercialized, and 85% seeds. Although açaí seeds are rich in catechins-polyphenolic compounds with antioxidant, anti-inflammatory, and antitumor effects-almost 935,000 tons/year of seeds are discarded as industrial waste. This work evaluated the antitumor properties of E. oleracea in vitro and in vivo in a solid Ehrlich tumor in mice. The seed extract presented 86.26 ± 0.189 mg of catechin/g of extract. The palm and pulp extracts did not exhibit in vitro antitumor activity, while the fruit and seed extracts showed cytotoxic effects on the LNCaP prostate cancer cell line, inducing mitochondrial and nuclear alterations. Oral treatments were performed daily at 100, 200, and 400 mg/kg of E. oleracea seed extract. The tumor development and histology were evaluated, along with immunological and toxicological parameters. Treatment at 400 mg/kg reduced the tumor size, nuclear pleomorphism, and mitosis figures, increasing tumor necrosis. Treated groups showed cellularity of lymphoid organs comparable to the untreated group, suggesting less infiltration in the lymph node and spleen and preservation of the bone marrow. The highest doses reduced IL-6 and induced IFN-γ, suggesting antitumor and immunomodulatory effects. Thus, açaí seeds can be an important source of compounds with antitumor and immunoprotective properties.

High mobility group box 1, ATP, lipid mediators, and tissue factor are elevated in COVID-19 patients: HMGB1 as a biomarker of worst prognosis.

The severe acute respiratory syndrome coronavirus 2, the agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic, has spread worldwide since it was first identified in November 2019 in Wuhan, China. Since then, progress in pathogenesis linked severity of this systemic disease to the hyperactivation of network of cytokine-driven pro-inflammatory cascades. Here, we aimed to identify molecular biomarkers of disease severity by measuring the serum levels of inflammatory mediators in a Brazilian cohort of patients with COVID-19 and healthy controls (HCs). Critically ill patients in the intensive care unit were defined as such by dependence on oxygen supplementation (93% intubated and 7% face mask), and computed tomography profiles showing ground-glass opacity pneumonia associated to and high levels of D-dimer. Our panel of mediators included HMGB1, ATP, tissue factor, PGE2 , LTB4 , and cys-LTs. Follow-up studies showed increased serum levels of every inflammatory mediator in patients with COVID-19 as compared to HCs. Originally acting as a transcription factor, HMGB1 acquires pro-inflammatory functions following secretion by activated leukocytes or necrotic tissues. Serum levels of HMGB1 were positively correlated with cys-LTs, D-dimer, aspartate aminotransferase, and alanine aminotransferase. Notably, the levels of the classical alarmin HMGB1 were higher in deceased patients, allowing their discrimination from patients that had been discharged at the early pulmonary and hyperinflammatory phase of COVID-19. In particular, we verified that HMGB1 levels above 125.4 ng/ml is the cutoff that distinguishes patients that are at higher risk of death. In conclusion, we propose the use of serum levels of HMGB1 as a biomarker of severe prognosis of COVID-19.

Unusual dimeric flavonoids (brachydins) induce ultrastructural membrane alterations associated with antitumor activity in cancer cell lines.

Notwithstanding the advances in molecular target-based drugs, chemotherapy remains the most common cancer treatment, despite its high toxicity. Consequently, effective anticancer therapies with fewer adverse effects are needed. Therefore, this study aimed to determine the anticancer activity of the dichloromethane fraction (DCMF) isolated from Arrabidae brachypoda roots, whose components are three unusual dimeric flavonoids. The toxicity of DCMF was investigated in breast (MCF-7), prostate (DU145), and cervical (HeLa) tumor cells, as well as non-tumor cells (PNT2), using sulforhodamine B (cell viability), Comet (genotoxicity), clonogenicity (reproductive capacity) and wound healing (cell migration) assays, and atomic force microscopy (AFM) for ultrastructural cell membrane alterations. Molecular docking revealed affinity between albumin and each rare flavonoid, supporting the impact of fetal bovine serum in DCMF antitumor activity. The IC50 values for MCF7, HeLa, and DU145 were 2.77, 2.46, and 2.51 µg/mL, respectively, and 4.08 µg/mL for PNT2. DCFM was not genotoxic to tumor or normal cells when exposed to twice the IC50 for up to 24 h, but it inhibited tumor cell migration and reproduction compared to normal cells. Additionally, AFM revealed alterations in the ultrastructure of tumor nuclear membrane surfaces, with a positive correlation between DCMF concentration and tumor cell roughness. Finally, we found a negative correlation between roughness and the ability of DCMF-treated tumor cells to migrate and form colonies with more than 50 cells. These findings suggest that DCFM acts by causing ultrastructural changes in tumor cell membranes while having fewer toxicological effects on normal cells.

Perfil Funcional e Clínico durante o Pré e o Pós-Cirúrgico de Pacientes Oncológicos de Cabeça e Pescoço / Pre and Post-Surgical Functional and Clinical Profile of Patients with Head and Neck Cancer / Perfil Funcional y Clínico durante el Período Pre y Post Quirúrgico de Pacientes con Cáncer de Cabeza y Cuello

Introdução: O câncer de cabeça e pescoço ocupa o sexto lugar das neoplasias mais predominantes no mundo. Pela localização anatômica, essas neoplasias podem promover alterações funcionais importantes, relacionadas à alimentação, respiração e comunicação, afetando a interação social. Objetivo: Caracterizar o perfil funcional e clínico de pacientes com neoplasias malignas de cabeça e pescoço. Método: Estudo transversal, descritivo, quali-quantitativo. Foram avaliadas a goniometria e a dinamometria dos membros superiores, e utilizados a Intensive Care Unit Mobility Scale (ICUMS) para avaliar a mobilidade, o índice de performance de Karnofsky (KPS) e a Eastern Cooperative Oncology Group Performance Scale (PS-ECOG), em um hospital público terciário. A coleta ocorreu entre agosto e novembro de 2022. Resultados: Participaram do estudo 39 pacientes do sexo feminino (61,54%) com idade média de 51,51 anos (±16,05). Os fatores de risco mais comuns foram: histórico familiar (53,85%), incidência em Regiões com desigualdade de distribuição de renda (17,95%), em Ceilândia (Região Administrativa do Distrito Federal), e tendo concluído o apenas o ensino fundamental (48,72%). O tumor primário com maior prevalência foi o de tireoide (61,54%), estadiamento T4 (33,33%). No pós-cirúrgico, 10 apresentavam paralisia facial, 11, trismo, 27, escápula alada. A mobilidade no pós-operatório foi mantida durante a internação com ICUMS 10, KPS 90% e PS-ECOG 0-1. Conclusão: A predisposição e o perfil clínico e funcional se correlacionaram com os problemas respiratórios, trismo, paralisia facial, escápula alada e amplitude reduzida de membro superior, como as repercussões mais frequentes, possivelmente decorrentes do tumor ou do tratamento. Entretanto, a mobilidade e a performance pós-cirúrgica não sofreram alterações consideráveis.

Introduction: Head and neck cancer is the sixth most prevalent neoplasm in the world. Due to their anatomical location, these cancers can promote important functional changes related to eating, breathing and communication, affecting social interaction. Objective: To characterize the functional and clinical profile of patients with head and neck cancer. Method: Cross-sectional, descriptive, quanti-qualitative study. Goniometry and dynamometry of the upper limbs, the Intensive Care Mobility Scale (ICUMS) to evaluate mobility, the Karnofsky performance scale (KPS) and the Eastern Cooperative Oncology Group Performance Scale (PS-ECOG) were utilized in a tertiary public hospital. Data collection occurred between August and November 2022. Results: There were 39 female patients (61.54%) enrolled in the study with mean age of 51.51(±16.05). The most common risk factors were: family history (53.85%), incidence in social and economically underserved regions (17.95%), in Ceilândia (Administrative Region of the Federal District), and education up to elementary school (48.72%). The primary tumor with the highest prevalence was thyroid (61.54%), staging T4 (33.33%). In the postoperative period, 10 presented facial paralysis, 11, trismus and 27, winged scapula. Postoperative mobility was maintained during hospitalization with ICUMS 10, KPS 90% and PS-ECOG between 0-1. Conclusion: The predisposition and the clinical and functional profile were correlated with respiratory problems, trismus, facial paralysis, winged scapula and reduced upper limb amplitude, as the most frequent repercussions, possibly resulting from the tumor or the treatment. However, post-surgical mobility and performance did not change considerably.

Introducción: El cáncer de cabeza y cuello ocupa el sexto lugar de las neoplasias más prevalentes en el mundo. Por su ubicación anatómica, estos cánceres pueden promover cambios funcionales importantes relacionados con la alimentación, la respiración y la comunicación, afectando la interacción social. Objetivo: Caracterizar el perfil funcional y clínico de los pacientes con cáncer de cabeza y cuello. Método: Estudio transversal, descriptivo, cuali-cuantitativo. En un hospital público de tercer nivel se evaluó la goniometría y dinamometría de miembros superiores, utilizando la Intensive Care Unit Mobility Scale (IUMS) para evaluar la movilidad, el índice de desempeño de Karnofsky (KPS) y la Eastern Cooperative Oncology Group Performance Scale (PS-ECOG). La recolección de datos se realizó entre agosto y noviembre de 2022. Resultados: Participaron en el estudio 39 pacientes de sexo femenino (61,54%) con una edad promedio de 51,51 años (±16,05). Los factores de riesgo más comunes fueron: antecedentes familiares (53,85%), incidencia en regiones con distribución desigual de la renta (17,95%), en Ceilândia (Región Administrativa del Distrito Federal) y escolaridad hasta la enseñanza básica (48,72%). El tumor primario con mayor prevalencia fue el de tiroides (61,54%), categoría de estadificación T4 (33,33%). En el postoperatorio 10 presentaron parálisis facial, 11 trismo, 27 omóplato alado. La movilidad postoperatoria se mantuvo durante la hospitalización con ICUMS 10, KPS 90% y PS-ECOG 0-1. Conclusión: La predisposición y el perfil clínico y funcional se correlacionaron con los problemas respiratorios, trismo, parálisis facial, omóplato alado y la amplitud reducida del miembro superior como las más frecuentes repercusiones, posiblemente debidas al tumor o al tratamiento. Sin embargo, la movi

Humoral response in Leishmaniasis.

Leishmaniasis presents different types of clinical manifestations that can be divided into cutaneous leishmaniasis and visceral leishmaniasis. The host's immune system, associated with genetic and nutritional factors, is strongly involved in the evolution of the disease or parasite escape. Humoral immunity is characterized by the production of antibodies capable of promoting neutralization, opsonization, and activation of the complement system. In this scenario, B lymphocytes produce antibodies that play an important role in Leishmania infection although neglected for a long time. Thus, relevant aspects in the establishment of Leishmania infection will be addressed, highlighting the importance of humoral immunity during the entire process of Leishmania infection.

Schinus terebinthifolius Leaf Lectin (SteLL) Reduces the Bacterial and Inflammatory Burden of Wounds Infected by Staphylococcus aureus Promoting Skin Repair.

Staphylococcus aureus is commonly found in wound infections where this pathogen impairs skin repair. The lectin isolated from leaves of Schinus terebinthifolius (named SteLL) has antimicrobial and antivirulence action against S. aureus. This study evaluated the effects of topical administration of SteLL on mice wounds infected by S. aureus. Seventy-two C57/BL6 mice (6−8 weeks old) were allocated into four groups: (i) uninfected wounds; (ii) infected wounds, (iii) infected wounds treated with 32 µg/mL SteLL solution; (iv) infected wounds treated with 64 µg/mL SteLL solution. The excisional wounds (64 mm2) were induced on the dorsum and infected by S. aureus 432170 (4.0 × 106 CFU/wound). The daily treatment started 1-day post-infection (dpi). The topical application of both SteLL concentrations significantly accelerated the healing of S. aureus-infected wounds until the 7th dpi, when compared to untreated infected lesions (reductions of 1.95−4.55-fold and 1.79−2.90-fold for SteLL at 32 µg/mL and 64 µg/mL, respectively). The SteLL-based treatment also amended the severity of wound infection and reduced the bacterial load (12-fold to 72-fold for 32 µg/mL, and 14-fold to 282-fold for 64 µg/mL). SteLL-treated wounds show higher collagen deposition and restoration of skin structure than other groups. The bacterial load and the levels of inflammatory markers (IL-6, MCP-1, TNF-α, and VEGF) were also reduced by both SteLL concentrations. These results corroborate the reported anti-infective properties of SteLL, making this lectin a lead candidate for developing alternative agents for the treatment of S. aureus-infected skin lesions.

The major role of junctional diversity in the horse antibody repertoire.

The antibody repertoire (Rep-seq) sequencing revolutionized the diversity of antigen B cell receptor studies, allowing deep and quantitative analysis to decipher the role of adaptive immunity in health and disease. Particularly, horse (Equus caballus) polyclonal antibodies have been produced and used since the century XIX to treat and prophylaxis diphtheria, tuberculosis, tetanus, pneumonia, and, more recently, COVID-19. However, our knowledge about the horse B cell receptors repertories is minimal. We present a deep horse antibody heavy chain repertoire (IGH) characterization of non-infected horses using NGS (Next generation sequencing). This study obtained a mean of 248,169 unique IgM clones and 66,141 unique IgG clones from four domestic adult horses. Rarefaction analysis showed sequence coverage was between 52 % and 82 % in IgM and IgG isotypes. We observed that besides horses antibody can use all functional IGHV genes, around 80 % of their antibodies use only three IGHV gene segments, and around 55 % use only one IGHJ gene segment. This limited VJ diversity seems to be compensated by the junctional diversity of these antibodies. We observed that the junctional diversity in horse antibodies is widespread, present in more than 90 % of horse antibodies. Besides this, the length of this region seems to be higher in horse antibodies than in other species. N1 and N2 nucleotides addition range from 0 to 111 nucleotides. In addition, around 45 % of the antibody clones have more than ten nucleotides in both the N1 and N2 junction regions. This diversity mechanism may be one of the most important in providing variability to the equine antibody repertoire. This study provides new insights regarding horse antibody composition, diversity generation, and particularities compared to other species, such as the frequency and length of N nucleotide addition. This study also points out the urgent need to better characterize TdT in horses and other species to better understand antibody repertoire characteristics.

COVID-19 diverse outcomes: Aggravated reinfection, type I interferons and antibodies.

SARS-CoV-2 infection intrigued medicine with diverse outcomes ranging from asymptomatic to severe acute respiratory syndrome (SARS) and death. After more than two years of pandemic, reports of reinfection concern researchers and physicists. Here, we will discuss potential mechanisms that can explain reinfections, including the aggravated ones. The major topics of this hypothesis paper are the disbalance between interferon and antibodies responses, HLA heterogeneity among the affected population, and increased proportion of cytotoxic CD4+ T cells polarization in relation to T follicular cells (Tfh) subtypes. These features affect antibody levels and hamper the humoral immunity necessary to prevent or minimize the viral burden in the case of reinfections.

Intradermal Immunization of SARS-CoV-2 Original Strain Trimeric Spike Protein Associated to CpG and AddaS03 Adjuvants, but Not MPL, Provide Strong Humoral and Cellular Response in Mice.

Despite the intramuscular route being the most used vaccination strategy against SARS-CoV-2, the intradermal route has been studied around the globe as a strong candidate for immunization against SARS-CoV-2. Adjuvants have shown to be essential vaccine components that are capable of driving robust immune responses and increasing the vaccination efficacy. In this work, our group aimed to develop a vaccination strategy for SARS-CoV-2 using a trimeric spike protein, by testing the best route with formulations containing the adjuvants AddaS03, CpG, MPL, Alum, or a combination of two of them. Our results showed that formulations that were made with AddaS03 or CpG alone or AddaS03 combined with CpG were able to induce high levels of IgG, IgG1, and IgG2a; high titers of neutralizing antibodies against SARS-CoV-2 original strain; and also induced high hypersensitivity during the challenge with Spike protein and a high level of IFN-γ producing CD4+ T-cells in mice. Altogether, those data indicate that AddaS03, CpG, or both combined may be used as adjuvants in vaccines for COVID-19.

From a recombinant key antigen to an accurate, affordable serological test: Lessons learnt from COVID-19 for future pandemics.

Serological tests detect antibodies generated by infection or vaccination, and are indispensable tools along different phases of a pandemic, from early monitoring of pathogen spread up to seroepidemiological studies supporting immunization policies. This work discusses the development of an accurate and affordable COVID-19 antibody test, from production of a recombinant protein antigen up to test validation and economic analysis. We first developed a cost-effective, scalable technology to produce SARS-COV-2 spike protein and then used this antigen to develop an enzyme-linked immunosorbent assay (ELISA). A receiver operator characteristic (ROC) analysis allowed optimizing the cut-off and confirmed the high accuracy of the test: 98.6% specificity and 95% sensitivity for 11+ days after symptoms onset. We further showed that dried blood spots collected by finger pricking on simple test strips could replace conventional plasma/serum samples. A cost estimate was performed and revealed a final retail price in the range of one US dollar, reflecting the low cost of the ELISA test platform and the elimination of the need for venous blood sampling and refrigerated sample handling in clinical laboratories. The presented workflow can be completed in 4 months from first antigen expression to final test validation. It can be applied to other pathogens and in future pandemics, facilitating reliable and affordable seroepidemiological surveillance also in remote areas and in low-income countries.

Plasma and memory antibody responses to Gamma SARS-CoV-2 provide limited cross-protection to other variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to be a global problem in part because of the emergence of variants of concern that evade neutralization by antibodies elicited by prior infection or vaccination. Here we report on human neutralizing antibody and memory responses to the Gamma variant in a cohort of hospitalized individuals. Plasma from infected individuals potently neutralized viruses pseudotyped with Gamma SARS-CoV-2 spike protein, but neutralizing activity against Wuhan-Hu-1-1, Beta, Delta, or Omicron was significantly lower. Monoclonal antibodies from memory B cells also neutralized Gamma and Beta pseudoviruses more effectively than Wuhan-Hu-1. 69% and 34% of Gamma-neutralizing antibodies failed to neutralize Delta or Wuhan-Hu-1. Although Class 1 and 2 antibodies dominate the response to Wuhan-Hu-1 or Beta, 54% of antibodies elicited by Gamma infection recognized Class 3 epitopes. The results have implications for variant-specific vaccines and infections, suggesting that exposure to variants generally provides more limited protection to other variants.

Immunogenicity of SARS-CoV-2 Trimeric Spike Protein Associated to Poly(I:C) Plus Alum.

The SARS-CoV-2 pandemic has had a social and economic impact worldwide, and vaccination is an efficient strategy for diminishing those damages. New adjuvant formulations are required for the high vaccine demands, especially adjuvant formulations that induce a Th1 phenotype. Herein we assess a vaccination strategy using a combination of Alum and polyinosinic:polycytidylic acid [Poly(I:C)] adjuvants plus the SARS-CoV-2 spike protein in a prefusion trimeric conformation by an intradermal (ID) route. We found high levels of IgG anti-spike antibodies in the serum by enzyme linked immunosorbent assay (ELISA) and high neutralizing titers against SARS-CoV-2 in vitro by neutralization assay, after two or three immunizations. By evaluating the production of IgG subtypes, as expected, we found that formulations containing Poly(I:C) induced IgG2a whereas Alum did not. The combination of these two adjuvants induced high levels of both IgG1 and IgG2a. In addition, cellular immune responses of CD4+ and CD8+ T cells producing interferon-gamma were equivalent, demonstrating that the Alum + Poly(I:C) combination supported a Th1 profile. Based on the high neutralizing titers, we evaluated B cells in the germinal centers, which are specific for receptor-binding domain (RBD) and spike, and observed that more positive B cells were induced upon the Alum + Poly(I:C) combination. Moreover, these B cells produced antibodies against both RBD and non-RBD sites. We also studied the impact of this vaccination preparation [spike protein with Alum + Poly(I:C)] in the lungs of mice challenged with inactivated SARS-CoV-2 virus. We found a production of IgG, but not IgA, and a reduction in neutrophil recruitment in the bronchoalveolar lavage fluid (BALF) of mice, suggesting that our immunization scheme reduced lung inflammation. Altogether, our data suggest that Alum and Poly(I:C) together is a possible adjuvant combination for vaccines against SARS-CoV-2 by the intradermal route.

Mature Naive B Cells Regulate the Outcome of Murine Acute Graft-versus-Host Disease in an IL-10-Independent Manner.

Graft-versus-host disease (GVHD) is the main complication of bone marrow transplantation (BMT). CD4+ T lymphocytes are the main effector cells for disease development, but other cell types can determine disease outcome through cytokine production and antigen presentation. B cells are abundant in BMT products and are involved in chronic GVHD immunopathogenesis. However, their role in acute GVHD is still unclear. Here we studied the role of donor resting B cells in a model of acute GVHD. Animals receiving transplants depleted of B cells developed more severe disease, indicating a protective role for B cells. Mice undergoing transplantation with IL-10 knockout B cells developed GVHD as severe as those receiving wild-type B cells. Moreover, mice that received MHC II-deficient B cells, and thus were unable to present antigen to CD4+ T cells, developed as severe GVHD as animals receiving transplants without B cells. This result suggests that the protection provided by mature naive B cells depends on antigen presentation and not on IL-10 production by B cells. Mice who underwent transplantation in the absence of donor B cells exhibited disorganized lymphoid splenic tissue. In addition, donor B cell depletion diminished the follicular T (Tfh)/effector T (Teff) cell ratio, suggesting that protection was correlated with a shift to Tfh differentiation, reducing the number of Teff cells. Importantly, the Tfh/Teff shift impacts disease outcome, with observed proinflammatory cytokine levels and tissue damage in target organs consistent with disease protection. The role of transplanted B cells in the outcome of BMT and the development of acute GVHD merits careful study, given that these cells are abundant in BMT products and are potent modulator and effector cells in the allogeneic response.