Lethal Infection Research Articles

Viral codon optimization on SARS-CoV-2 Spike boosts immunity in the development of COVID-19 mRNA vaccines.

Life-long persistent herpesviruses carry "trans-inducers" to overcome the unusual codon usage of their glycoproteins for efficient expression. Strikingly, this "trans-inducibility" can be achieved by simply changing the codon-usage of acute virus glycoproteins to that of persistent herpesvirus glycoproteins with herpesviral trans-inducer. Here, we apply the "persistent viral codon-usage-trans-inducer" principle to SARS-CoV-2 Spike mRNA vaccine platform, in which the codon-usage of Spike is changed to that of Herpes Simplex Virus-1 (HSV-1) glycoprotein B (gB) with its "trans-inducer" ICP27. The HSVgB-ICP27-codon-optimized Spike mRNA vaccine induced markedly high antigen expression and stability, total IgG, neutralizing antibody, and T cell response, ultimately enhancing protection against lethal SARS-CoV-2 challenge. Moreover, the HSVgB- codon-optimized Delta (B.1.617.2) strain Spike mRNA vaccine provided significant enhancements in antigen expression and long-term protection against SARS-CoV-2 challenge. Thus, we report a novel persistent viral codon-usage-trans-inducer mRNA vaccine platform for enhanced antigen expression and long-term protection against lethal viral infection.

A broad-based probe-free qPCR assay for detection and discrimination of three human herpes viruses

Primary infection or reactivation of latent human cytomegalovirus (HCMV) or herpes simplex viruses (HSV) 1 or 2 during pregnancy can transmit the virus in utero or during natural childbirth to the fetus. The majority of these infections are asymptomatic at birth but may present later with potentially lethal disseminated infection or meningitis (HSV), or long-term neurodevelopmental sequelae including sensorineural hearing loss or neurodevelopmental impairments (HCMV). Unfortunately, early signs and symptoms of disseminated viral infections may be misdiagnosed as bacterial sepsis. Therefore, immediate testing for viral etiologies may not be ordered or even considered by skilled clinicians. In asymptomatic HCMV infections, early detection is necessary to monitor for and treat future neurologic sequelae. In acutely ill-appearing infants, specific detection of viruses against other disease-causing agents is vital to inform correct patient management, including early administration of the correct antimicrobial(s). An ideal test should be rapid, inexpensive, require low sample volumes, and demonstrate efficacy in multiple tissue matrices to aid in timely clinical decision-making for neonatal infections. This work discusses the development of a rapid probe-free qPCR assay for HSV and HCMV that enables early and specific detection of these viruses in neonates. The assay’s probe free chemistry would allow easier extension to a broad-based multiplexed pathogenic panel as compared to assays utilizing sequence-specific probes or nested PCR.

Accessory gene regulators and virulence genes associated with the pathogenicity of Staphylococcus aureus from clinical and community settings in Lagos, Nigeria

Staphylococcus aureus is a prominent pathogen that causes serious community and hospital-acquired infections globally. Its pathogenicity is attributed to a variety of secreted and cell surface associated proteins that are modulated by the quorum-sensing accessory gene regulator (agr) system. In this study, we investigated the presence of toxin genes and agr involved with S. aureus from clinical samples and apparently healthy individuals. Unequivocal identification of the isolates was obtained with the Vitek 2 system. We screened 70 clinical (CL) and 22 community (C) S. aureus strains for the methicillin resistance (mecA) gene, agr and superantigens (SAg) (enterotoxins and toxic shock syndrome toxin-1) using PCR techniques. A total of 12 clinical isolates were classified as methicillin-resistant S. aureus (MRSA); 89 isolates belonged to one of the four agr groups (agr1-4), and 3 isolates were non-typeable. Of the agr groups, agr1 was the most prominent and mostly consisted of isolates from pus/wounds. The methicillin-susceptible S. aureus (MSSA) isolates were distributed within the four agr groups while MRSA strains were restricted to agr1 and agr3. The most common enterotoxin gene, sei, was likewise more prevalent in MSSA strains than in MRSA strains, where sea predominated. The co-existence of two or more enterotoxins was confirmed in 40% of the isolates. sea occurred through all the agr groups except agr3 and sei was not found in agr1 and agr4. The toxic shock toxin (tst) gene was detected in six MSSA. These findings suggest that MSSA may cause more lethal infections than MRSA because of the increased frequency of toxic genotypes seen in MSSA strains. Significance: Isolates in the agr1,3 groups had more SAg toxin genes, whereas isolates in the agr4 groups possessed more tst genes. The MSSA isolates contained higher proportions of virulence genes than MRSA. The clinical implications of this discovery include that MSSA may cause more lethal infections than MRSA due to the greater number of toxigenic genotypes discovered.

Multiple Brain Abscesses In A Child With Infective Endocarditis

Background: Infective endocarditis is a lethal infection affecting the endocardium of the heart and the valves.The causes are varied with staphylococcus aureus and streptococcus as the major causative agents.The triad of fever exceeding 38oc,vegetation in the heart and blood culture of the causative agents are the hallmarks of the diagnosis .The disease is known to be affect all ages with the very young age group, those with congenital heart disease and those on cardiac prosthesis as the most vulnerable. Septic emboli from the septic vegetation can spread to the brain, kidney, spleen, and lungs resulting in massive metastatic infections.It therefore has multisystemic manifestations and complications. Though neurological complications are common, brain abcess is known to be rare constituting only 1.0% of neurological complications. Objective: The study aimed at reporting occurrence of both cerebral and cerebellar micro- and macro-abscesses in a 3 year boy with infective endocarditis; a rare occurrence in the literature. Methods: This case report was carried out at University College Hospital Ibadan. Results: The boy presented with fever of 38oc for five weeks, convulsions and altered state of consciousness for ten days..In course of treatment patient however developed irritability and aggressive behaviour, which attracted the use of largactil to which he reacted with extrapyramidal signs and convulsions. Within the week he developed yellowness of the eyes and increase in abdominal girth. Patient had cranial computed tomography (CT) after plain skull X-rays and was referred to University College Hospital Ibadan as a result of the radiologically diagnosed brain abscess seen on CT images. child had grunting respiration with dyspnea, and the respiratory rate was 50/mm. However, the chest was clinically clear. In the cardiovascular system (CVS); the pulse was 140/mm, with moderate volume. The blood pressure (BP) was l60/110 mmHg. The first and second heart sounds were heard with a gallop rhythm. Cranial CT scan showed multiple ring enhancing hypodense lesions with surrounding hypodensity measuring 1cm in diameter and above with only a few measuring less than 1.0cm in both cerebral hemispheres and cerebelli in keeping with multiple cerebral and cerebellar abscesses. An echocardiography showed a brightly echogenic spot attached to the papillary muscle in the left ventricle suggesting vegetation consistent with an infective endocarditis. Retroviral test was negative for both type I and II.Blood culture — was negative, however urine culture yielded klebsiella sp. Serum urea, creatinine, Ca2+ and P04 were all elevated.The abdominal ultrasound scan confirmed the hepatosplenomegaly with decreased echogenicity but both kidneys appeared normal.There was no demonstrable ascitis. The boy was placed on antimicrobials; and had craniotomy for the drainage of the macroabscesses. He improved significantly. His renal and cardiac condition equally improved; he was subsequently discharged to continue treatment in the the paediaric outpatient. The infective endorcarditis still poses enormous challenge in management and the condition calls for multi disciplinary approach. It requires high index of suspicion for early detection; as well deployment of multiple imaging modalities by the cardiologists and radiologists to arrive at a more accurate diagnosis for effective patient management. This may save financial and material resources on part of the patients, care givers, the facility managers and the society at large.

An Ionizable Lipid Material with a Vitamin E Scaffold as an mRNA Vaccine Platform for Efficient Cytotoxic T Cell Responses.

RNA vaccines based on lipid nanoparticles (LNPs) with in vitro transcribed mRNA (IVT-mRNA) encapsulated are now a currently successful but still evolving modality of vaccines. One of the advantages of RNA vaccines is their ability to induce CD8+ T-cell-mediated cellular immunity that is indispensable for excluding pathogen-infected cells or cancer cells from the body. In this study, we report on the development of LNPs with an enhanced capability for inducing cellular immunity by using an ionizable lipid with a vitamin E scaffold. An RNA vaccine that contained this ionizable lipid and an IVT-mRNA encoding a model antigen ovalbumin (OVA) induced OVA-specific cytotoxic T cell responses and showed an antitumor effect against an E.G7-OVA tumor model. Vaccination with the LNPs conferred protection against lethal infection by Toxoplasma gondii using its antigen TgPF. The vitamin E scaffold-dependent type I interferon response was important for effector CD8+ T cell differentiation induced by the mRNA-LNPs. Our findings also revealed that conventional dendritic cells (cDCs) were essential for achieving CD8+ T cell responses induced by the mRNA-LNPs, while the XCR1-positive subset of cDCs, cDC1 specialized for antigen cross-presentation, was not required. Consistently, the mRNA-LNPs were found to selectively transfect another subset of cDCs, cDC2 that had migrated from the skin to lymph nodes, where they could make vaccine-antigen-dependent contacts with CD8+ T cells. The findings indicate that the activation of innate immune signaling by the adjuvant activity of the vitamin E scaffold and the expression of antigens in cDC2 are important for subsequent antigen presentation and the establishment of antigen-specific immune responses.

Live attenuated vaccines and layered defense strategies to combat infections caused by nonencapsulated Yersinia pestis

IntroductionPlague is an ancient disease caused by Yersinia pestis, a widely disseminated Tier 1 pathogen that poses significant public health and biothreat risks. The rapid course and high mortality of pneumonic plague limit the efficacy of antibiotic treatment and mandate the need for an effective, licensed, and readily available vaccine. New candidate vaccines are being developed; however, their efficacy in nonhuman primates, optimal vaccination schedule and immune response, duration of protection, and breadth of coverage against various virulent strains are inadequately understood. In the current work, we explored homologous and heterologous vaccination schemes using the sensitive BALB/c mouse models of bubonic and pneumonic plague challenged with Y. pestis strain C12. This strain, a derivative of the wild-type strain CO92, lacks the anti-phagocytic F1 capsule yet remains highly virulent. Protection against such nonencapsulated strains has been particularly elusive.MethodsWe tested the efficacy of live attenuated vaccine (LAV) derivatives of Y. pestis CO92 or C12 with a deletion of a type 3 secretion-associated gene (ΔyscN) or the pgm pigmentation locus, and they were cured of the pPst (PCP1) plasmid (CO92 pgm− pPst−). The LAVs were evaluated alone or accompanied by a dose of a protein subunit vaccine (rF1V or rV).ResultsThe most protective and immunogenic vaccination scheme, as tested under a variety of conditions in bubonic and pneumonic plague models, was heterologous vaccination with a LAV and the recombinant rF1V or rV protein subunit vaccine. Furthermore, in the heterologous scheme, different LAVs and subunit vaccines could be substituted, affording flexibility in vaccine component selection. We also evaluated a novel intervention strategy consisting of vaccination and post-exposure antibiotic treatment. The layering of vaccination with the LAVs and post-exposure treatment with streptomycin was synergistic, extending the time after the Y. pestis C12 challenge when treatment remained effective and affording a sparing of antibiotics.ConclusionThe current work defined effective and flexible vaccination and treatment interventions that successfully prevented lethal infection with virulent, nonencapsulated Y. pestis.

Mucormycosis in 2023: an update on pathogenesis and management.

Mucormycosis (MCR) is an emerging and frequently lethal fungal infection caused by the Mucorales family, with Rhizopus, Mucor, and Lichtheimia, accounting for > 90% of all cases. MCR is seen in patients with severe immunosuppression such as those with hematologic malignancy or transplantation, Diabetes Mellitus (DM) and diabetic ketoacidosis (DKA) and immunocompetent patients with severe wounds. The recent SARS COV2 epidemy in India has resulted in a tremendous increase in MCR cases, typically seen in the setting of uncontrolled DM and corticosteroid use. In addition to the diversity of affected hosts, MCR has pleiotropic clinical presentations, with rhino-orbital/rhino-cerebral, sino-pulmonary and necrotizing cutaneous forms being the predominant manifestations. Major insights in MCR pathogenesis have brought into focus the host receptors (GRP78) and signaling pathways (EGFR activation cascade) as well as the adhesins used by Mucorales for invasion. Furthermore, studies have expanded on the importance of iron availability and the complex regulation of iron homeostasis, as well as the pivotal role of mycotoxins as key factors for tissue invasion. The molecular toolbox to study Mucorales pathogenesis remains underdeveloped, but promise is brought by RNAi and CRISPR/Cas9 approaches. Important recent advancements have been made in early, culture-independent molecular diagnosis of MCR. However, development of new potent antifungals against Mucorales remains an unmet need. Therapy of MCR is multidisciplinary and requires a high index of suspicion for initiation of early Mucorales-active antifungals. Reversal of underlying immunosuppression, if feasible, rapid DKA correction and in selected patients, surgical debulking are crucial for improved outcomes.

Bcl-6 expression by CD4+ T cells determines concomitant immunity and host resistance across distinct parasitic infections

Cluster of differentiation (CD4+) T cells consist of multiple subtypes, defined by expression of lineage-specific transcription factors, that contribute to the control of infectious diseases by providing help to immune and nonimmune target cells. In the current study, we examined the role of B cell lymphoma (Bcl)-6, a transcriptional repressor and master regulator of T follicular helper cell differentiation, in T cell-mediated host defense against intestinal and systemic parasitic infections. We demonstrate that while Bcl-6 expression by CD4+ T cells is critical for antibody-mediated protective immunity against secondary infection with the nematode Heligmosoides polygyrus bakeri, it paradoxically compromises worm expulsion during primary infection by limiting the generation of interleukin-10 (IL-10)-producing Gata3+ T helper 2 cells. Enhanced worm expulsion in the absence of Bcl-6 expressing T cells was associated with amplified intestinal goblet cell differentiation and increased generation of alternatively activated macrophages, effects that were reversed by neutralization of IL-10 signals. An increase in IL-10 production by Bcl-6-deficient CD4+ T cells was also evident in the context of systemic Leishmania donovani infection, but in contrast to Heligmosoides polygyrus bakeri infection, compromised T helper 1-mediated liver macrophage activation and increased susceptibility to this distinct parasitic challenge. Collectively, our studies suggest that host defense pathways that protect against parasite superinfection and lethal systemic protozoal infections can be engaged at the cost of compromised primary resistance to well-tolerated helminths.

Active inoculation with an inactivated Coxsackievirus A2 vaccine induces neutralizing antibodies and protects mice against lethal infection

Coxsackievirus A2 (CVA2) is one of the causative agents of hand-foot-and-mouth disease (HFMD), which poses a great challenge for global public health. However, presently, there are no available commercial vaccines or antivirals to prevent CVA2 infection. Here, we present an inactivated Vero cell-based whole CVA2 vaccine candidate and evaluate its safety and efficacy in this study. Neonatal BALB/c mice were vaccinated at 5 and 7 days old, respectively, and then challenged with either homologous or heterologous strain of CVA2 at a lethal dose at 10 days old. The inactivated whole CVA2 vaccine candidate showed a high protective efficacy. Additionally, our inactivated vaccine stimulated the production of CVA2-specific IgG1 and IgG2a antibodies in vivo and high titers of neutralization antibodies (NtAbs) in the serum of immunized mice. Maternal immunization with the inactivated CVA2 vaccine provided full protection to pups against lethal infection. Compared with mice inoculated with only alum, the viral loads were decreased, and pathological changes were relieved in tissue samples of immunized mice. Moreover, the transcription levels of some genes related to cytokines (IFN-γ and TNF-α, MCP-1, IL-6, CXCL-10 etc.) were significantly reduced. The number of immune cells and levels of cytokines in peripheral blood of mice inoculated with only alum were higher than that of immunized mice. It is noteworthy that this vaccine showed a good cross-immunity efficacy against Enterovirus A71 (EVA71) challenge. In conclusion, our findings suggest that this experimental inactivated CVA2 vaccine is a promising component of polyvalent vaccines related to HFMD in the near future.

Evidence Based Optimal Dosing of Intravenous Artesunate in Children with Severe Falciparum Malaria.

The majority of deaths from malaria are in young African children. Parenteral artesunate (ARS) is the first-line treatment for severe falciparum malaria. Since 2015, the World Health Organization has recommended individual doses of 3 mg/kg for children weighing < 20 kg. Recently, the US Food and Drug Administration (FDA) has challenged this recommendation, based on a simulated pediatric population, and argued for a lower dose in younger children (2.4 mg/kg). In this study, we performed population pharmacokinetic (PK) modeling of plasma concentration data from 80 children with severe falciparum malaria in the Democratic Republic of Congo who were given 2.4 mg/kg of ARS intravenously. Bayesian hierarchical modeling and a two-compartment parent drug-metabolite PK model for ARS were used to describe the population PKs of ARS and its main biologically active metabolite dihydroartemisinin. We then generated a virtual population representative of the target population in which the drug is used and simulated the total first-dose exposures. Our study shows that the majority of younger children given the lower 2.4 mg/kg dose of intravenous ARS do not reach the same drug exposures as older children above 20 kg. This finding supports withdrawal of the FDA's recent lower ARS dose recommendation as parenteral ARS is an extremely safe and well-tolerated drug and there is potential for harm from underdosing in this rapidly lethal infection.

Broadly neutralizing antibodies derived from the earliest COVID-19 convalescents protect mice from SARS-CoV-2 variants challenge

Coronavirus disease 2019 (COVID-19) was first reported three years ago, when a group of individuals were infected with the original SARS-CoV-2 strain, based on which vaccines were developed. Here, we develop six human monoclonal antibodies (mAbs) from two elite convalescents in Wuhan and show that these mAbs recognize diverse epitopes on the receptor binding domain (RBD) and can inhibit the infection of SARS-CoV-2 original strain and variants of concern (VOCs) to varying degrees, including Omicron strains XBB and XBB.1.5. Of these mAbs, the two most broadly and potently neutralizing mAbs (7B3 and 14B1) exhibit prophylactic activity against SARS-CoV-2 WT infection and therapeutic effects against SARS-CoV-2 Delta variant challenge in K18-hACE2 KI mice. Furthermore, post-exposure treatment with 7B3 protects mice from lethal Omicron variants infection. Cryo-EM analysis of the spike trimer complexed with 14B1 or 7B3 reveals that these two mAbs bind partially overlapped epitopes onto the RBD of the spike, and sterically disrupt the binding of human angiotensin-converting enzyme 2 (hACE2) to RBD. Our results suggest that mAbs with broadly neutralizing activity against different SARS-CoV-2 variants are present in COVID-19 convalescents infected by the ancestral SARS-CoV-2 strain, indicating that people can benefit from former infections or vaccines despite the extensive immune escape of SARS-CoV-2.

Acute invasive fungal rhinosinusitis in post-COVID-19 patients in Vietnam

Acute invasive fungal rhinosinusitis (AIFR) is a potentially lethal infection commonly found in immunocompromised patients. It is considered the most aggressive subtype of fungal sinusitis and can lead to severe morbidity and mortality. There was a significant increase in the incidence of AIFR in post-COVID-19 patients compared to AIFR cases before the COVID-19 pandemic. This study aimed to describe the clinical presentation of AIFR associated with COVID-19 illness. A retrospective study included 22 patients diagnosed with AIFR with a recent COVID-19 infection. The most frequent disease associated with AIFR was diabetes mellitus (95.5%). The mycological analysis identified infection caused by Aspergillus species in 72.7% of patients. Along with stabilizing hemodynamic parameters and controlling any comorbidities, all patients in the present study underwent combined surgical debridement followed by antifungal medications. The overall survival rate was 72.7%. The chance of developing a fatal outcome was significantly higher if meningitis presented initially (odds ratio 35.63, p<0.05). The presence of meningitis upon initial diagnosis is related to a significantly higher chance of developing a fatal outcome and should be considered, especially in AIFR patients previously treated for COVID-19 infections. Early diagnosis, early use of antifungal agents, aggressive surgical debridement, and control of comorbid conditions remain crucial in managing AIFR.

Hemostasis defects underlying the hemorrhagic syndrome caused by mammarenaviruses in a cynomolgus macaque model

AbstractViral hemorrhagic fevers (HF) are a group of acute febrile diseases with high mortality rates. Although hemostatic dysfunction appears to be a major determinant of the severity of the disease, it is still unclear what pathogenic mechanisms lead to it. In clinical studies it is found that arenaviruses, such as Lassa, Machupo, and Guanarito viruses cause HF that vary in symptoms and biological alterations. In this study we aimed to characterize the hemostatic dysfunction induced by arenaviral HF to determine its implication in the severity of the disease and to elucidate the origin of this syndrome. We found that lethal infection with Machupo, Guanarito, and Lassa viruses is associated with cutaneomucosal, cerebral, digestive, and pulmonary hemorrhages. The affected animals developed a severe alteration of the coagulation system, which was concomitant with acute hepatitis, minor deficit of hepatic factor synthesis, presence of a plasmatic inhibitor of coagulation, and dysfunction of the fibrinolytic system. Despite signs of increased vascular permeability, endothelial cell infection was not a determinant factor of the hemorrhagic syndrome. There were also alterations of the primary hemostasis during lethal infection, with moderate to severe thrombocytopenia and platelet dysfunction. Finally, we show that lethal infection is accompanied by a reduced hematopoietic potential of the bone marrow. This study provides an unprecedented characterization of the hemostasis defects induced by several highly pathogenic arenaviruses.

Blaming the victim or structural conditioning? COVID‐19, obesity and the neoliberal diet

AbstractThe energy‐dense part of the neoliberal diet and obesity made for an explosive combination upon the arrival of the COVID‐19 pandemic. Energy‐dense foods lie at the root of comorbidities associated with complications of the COVID‐19 pandemic: overweight, obesity, diabetes, hypertension and so forth. Multiple medical studies have demonstrated the causal impact of overweight and obesity on more severe or lethal infections. Focusing on the case of Mexico, I will show that inequality strongly conditions what people can eat, so the issue is not simply a matter of personal choice or responsibility. My argument is twofold: (1) Mexico enjoyed its own ‘traditional’ diets through the mid‐1980s, which included widely accessible fruits and vegetables. But (2) the neoliberal turn in the form of trade liberalization and deepening inequality caused a substantial reshaping of the diet in favour of energy‐dense foods with lower nutritional value. The energy‐dense segment of ‘the neoliberal diet’ has turned a large portion of Mexicans into a vulnerable population. But this is a class‐differentiated diet with its healthy and nutritious components increasingly less accessible to the working classes. Recovering healthy diets in Mexico will require the recuperation of food sovereignty through the regeneration of its countryside and its peasantry. Agroecological methods of food production will also be needed to alleviate the climate change emergency.

Bacillus velezensis DSM 33864 reduces Clostridioides difficile colonization without disturbing commensal gut microbiota composition

Up to 25% of the US population harbor Clostridioides difficile in the gut. Following antibiotic disruption of the gut microbiota, C. difficile can act as an opportunistic pathogen and induce potentially lethal infections. Consequently, reducing the colonization of C. difficile in at-risk populations is warranted, prompting us to identify and characterize a probiotic candidate specifically targeting C. difficile colonization. We identified Bacillus velezensis DSM 33864 as a promising strain to reduce C. difficile levels in vitro. We further investigated the effects of B. velezensis DSM 33864 in an assay including human fecal medium and in healthy or clindamycin-treated mouse models of C. difficile colonization. The addition of B. velezensis DSM 33864 to human fecal samples was shown to reduce the colonization of C. difficile in vitro. This was supported in vivo where orally administered B. velezensis DSM 33864 spores reduced C. difficile levels in clindamycin-treated mice. The commensal microbiota composition or post-antibiotic reconstitution was not impacted by B. velezensis DSM 33864 in human fecal samples, short-, or long-term administration in mice. In conclusion, oral administration of B. velezensis DSM 33864 specifically reduced C. difficile colonization in vitro and in vivo without adversely impacting the commensal gut microbiota composition.

Refined semi-lethal aerosol H5N1 influenza model in cynomolgus macaques for evaluation of medical countermeasures

Highly pathogenic avian influenza A H5N1 viruses cause high mortality in humans and have pandemic potential. Effective vaccines and treatments against this threat are urgently needed. Here, we have refined our previously established model of lethal H5N1 infection in cynomolgus macaques. An inhaled aerosol virus dose of 5.1 log10 plaque-forming unit (pfu) induced a strong febrile response and acute respiratory disease, with four out of six macaques succumbing after challenge. Vaccination with three doses of adjuvanted seasonal quadrivalent influenza vaccine elicited low but detectable neutralizing antibody to H5N1. All six vaccinated macaques survived four times the 50% lethal dose of aerosolized H5N1, while four of six unvaccinated controls succumbed to disease. Although vaccination did not protect against severe influenza, vaccinees had reduced respiratory dysfunction and lower viral load in airways compared to controls. We anticipate that our macaque model will play a vital role in evaluating vaccines and antivirals against influenza pandemics.

CUR-N399, a PI4KB inhibitor, for the treatment of Enterovirus A71 infection

Over the years, the hand, foot and mouth disease (HFMD) has sparked epidemics across many countries which mainly affected young children. While symptoms are usually mild, severe complications may arise, and some even lead to death. Such concerns, coupled with the lack of approved vaccines and antivirals to date, create an urgency in the identification of safe therapeutics against HFMD. The disease is mainly transmitted by enteroviruses like enterovirus A71 (EV-A71). Essential for enterovirus replication is the host protein, PI4KB. In this study, we investigate the antiviral efficacy of a novel PI4KB inhibitor, CUR-N399. We found that CUR-N399 displayed broad-spectrum antiviral activity against picornaviruses in cell culture models. Using a suckling mouse model of lethal EV-A71 infection, CUR-N399 was found to be well-tolerated, promote survival and reduce viral titre in mice organs. Together, these support the discovery of CUR-N399 as an antiviral against EV-A71 and potentially other closely related viruses.

Synthetic 5-amino-6-D-ribitylaminouracil paired with inflammatory stimuli facilitates MAIT cell expansion in vivo.

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells, which mediate host immunity to microbial infection by recognizing metabolite antigens derived from microbial riboflavin synthesis presented by the MHC-I-related protein 1 (MR1). Namely, the potent MAIT cell antigens, 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU) and 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil (5-OE-RU), form via the condensation of the riboflavin precursor 5-amino-6-D-ribitylaminouracil (5-A-RU) with the reactive carbonyl species (RCS) methylglyoxal (MG) and glyoxal (G), respectively. Although MAIT cells are abundant in humans, they are rare in mice, and increasing their abundance using expansion protocols with antigen and adjuvant has been shown to facilitate their study in mouse models of infection and disease. Here, we outline three methods to increase the abundance of MAIT cells in C57BL/6 mice using a combination of inflammatory stimuli, 5-A-RU and MG. Our data demonstrate that the administration of synthetic 5-A-RU in combination with one of three different inflammatory stimuli is sufficient to increase the frequency and absolute numbers of MAIT cells in C57BL/6 mice. The resultant boosted MAIT cells are functional and can provide protection against a lethal infection of Legionella longbeachae. These results provide alternative methods for expanding MAIT cells with high doses of commercially available 5-A-RU (± MG) in the presence of various danger signals.

12 Prevention of terminal pathway activation improves survival in a lethal malarial infection mouse model associated with multiple organ failure

12 Prevention of terminal pathway activation improves survival in a lethal malarial infection mouse model associated with multiple organ failure

Design of a lipid nano-delivery system containing recombinant Candida albicans chitinase 3 as a potential vaccine against fungal infections

Opportunistic fungi cause lethal systemic infections and impose high medical costs to health systems. The World Health Organization has recognized the importance of fungal infections, including them in its global priority list guiding research, development, and discovery of new therapeutic approaches. Fungal vaccine development has been proposed as one of the treatment and prevention strategies in the last decade. In this study, we present the design of a lipid antigen delivery system based on Dioctadecyldimethylammonium bromide: Monoolein (DODAB: MO) containing recombinant Candida albicans Chitinase 3 (Cht3) for modulation the immune response against fungal infections. Several DODAB:MO liposomes containing Cht3 were prepared and those prepared by the incubation method and containing 5 µg/mL Cht3 were selected due to their favorable size, ζ-potential and stability, suited for antigen delivery applications. The encapsulation of Cht3 in these liposomes resulted in a significant increase in cellular uptake compared to empty liposomes, demonstrating their efficacy in delivering the antigen. Moreover, the liposomes proved to be safe for use in immunization procedures. Subcutaneous administration of Cht3 liposomes elicited a Th1/Th17 immune response profile, associated with the production of high levels of antibodies against Cht3. These antibodies recognized both the native and the recombinant forms of the protein, opsonizing mother-yeast at the cell scars, which has the potential to disrupt cell separation and hinder yeast growth. The findings suggest that the designed lipid antigen delivery system shows promise as a potential candidate for enhancing immune responses against fungal infections, offering a valuable strategy for future fungal vaccine development.