Characterization of excretory/secretory products of the Taenia crassiceps cysticercus involved in the induction of regulatory T cells in vivo.

The ability to modulate the host immune response has allowed some parasites to establish themselves in the tissues of an immunocompetent organism. While some parasite excretion/secretion products (ESPs) were recently reported to induce differentiation of regulatory T cells (Tregs), their identity is not known. This work is aimed to identify and characterize ESPs of Taenia crassiceps cysticerci linked with Treg induction in vivo. ESPs were obtained from cultures of T. crassiceps cysticerci and inoculated in mice, measuring Treg levels by flow cytometry. Proteins in ESPs were analyzed by electrophoresis; then, ESPs were classified as either differential or conserved. Differentially included proteins were MS-sequenced and functionally characterized. Only 4 of 10 ESPs induced Tregs. Proteins with catalytic activity and those involved in immunological processes predominated, supporting the idea that these molecules could play an important role in the induction of Tregs.

Development and validation of a laboratory-based risk score to predict the occurrence of critical illness in hospitalized patients with COVID-19.

BACKGROUND: Early identification of patients with COVID-19 who may develop critical illness is of great importance. METHODS: In this study a retrospective cohort of 264 COVID-19 cases admitted at Macarena University was used for development and internal validation of a risk score to predict the occurrence of critical illness in hospitalized patients with COVID-19. Backward stepwise logistic regression was used to derive the model, including clinical and laboratory variables predictive of critical illness. Internal validation of the final model used bootstrapped samples and the model scoring derived from the coefficients. External validation was performed in a cohort of 154 cases admitted at Valme and Virgen del Rocio University Hospital. RESULTS: A total of 62 (23.5%) patients developed a critical illness during their hospitalization stay, 21 (8.0%) patients needed invasive ventilation, 34 (12.9%) were admitted at the ICU and the overall mortality was of 14.8% (39 cases). 5 variables were included in the final model: age >59.5 years (OR: 3.11;95%CI 1.39-6.97), abnormal CRP results (OR: 5.76;95%CI 2.32-14.30), abnormal lymphocytes count (OR: 3.252;95%CI 1.56-6.77), abnormal CK results (OR: 3.38;95%CI 1.59-7.20) and abnormal creatinine (OR: 3.30;95%CI 1.42-7.68). The AUC of this model was 0.850 with sensitivity of 65% and specificity of 87% and the IDI and NRI were 0.1744 and 0.2785, respectively. The validation indicated a good discrimination for the external population. CONCLUSIONS: Biomarkers add prognostic information in COVID-19 patients. Our risk-score provides an easy to use tool to identify patients who are likely to develop critical illness during their hospital stay.

Antigenic Fingerprinting of Respiratory Syncytial Virus (RSV)-A-Infected Hematopoietic Cell Transplant Recipients Reveals Importance of Mucosal Anti-RSV G Antibodies in Control of RSV Infection in Humans.

BACKGROUND: Respiratory syncytial virus (RSV) infection causes significant morbidity in hematopoietic cell transplant (HCT) recipients. However, antibody responses that correlate with recovery from RSV disease are not fully understood. METHODS: In this study, antibody repertoire in paired serum and nasal wash samples from acutely RSV-A-infected HCT recipients who recovered early (<14 days of RSV shedding) were compared with late-recovered patients (≥14 days of shedding) using gene fragment phage display libraries and surface plasmon resonance. RESULTS: Anti-F serum responses were similar between these 2 groups for antibody repertoires, neutralization titers, anti-F binding antibodies (prefusion and postfusion proteins), antibody avidity, and binding to specific antigenic sites. In contrast, nasal washes from early-recovered individuals demonstrated higher binding to F peptide containing p27. While the serum RSV G antibody repertoires in the 2 groups were similar, the strongest difference between early-recovered and late-recovered patients was observed in the titers of nasal wash antibodies, especially binding to the central conserved domain. Most importantly, a significantly higher antibody affinity to RSV G was observed in nasal washes from early-recovered individuals compared with late-recovered HCT recipients. CONCLUSIONS: These findings highlight the importance of mucosal antibodies in resolution of RSV-A infection in the upper respiratory tract.

Antibody Repertoire of Human Polyclonal Antibodies Against Ebola Virus Glycoprotein Generated After Deoxyribonucleic Acid and Protein Vaccination of Transchromosomal Bovines.

Several Ebola vaccines and therapeutics are under clinical development. However, limited knowledge exists on the quality of antibody response generated by different Ebola vaccines. In this study, antibody repertoire induced by vaccination of transchromosomal bovine (TcB) with Ebola virus (EBOV) glycoprotein ([GP]; recombinant GP [rGP]) encoded by either deoxyribonucleic acid (DNA) or nanoparticle-based vaccine platform was analyzed using EBOV genome fragment phage display library and surface plasmon resonance (SPR)-based real-time kinetics assay to measure antibody affinity maturation to both native and partially denatured Ebola GP as well as GP containing the receptor binding domain but lacking the mucin-like domain. Immunoglobulin (IgG) obtained from rGP nanoparticle-vaccinated TcB demonstrated ~4-fold higher binding affinity compared with DNA-vaccinated TcB-induced IgG against the native rGP's. The rGP nanoparticle vaccine generated a more robust and diverse antibody immune response to the native EBOV-GP compared with the DNA vaccine, which may explain the protective efficacy observed for these antibody preparations.

Antigenic Fingerprinting following Primary RSV Infection in Young Children Identifies Novel Antigenic Sites and Reveals Unlinked Evolution of Human Antibody Repertoires to Fusion and Attachment Glycoproteins.

Respiratory Syncytial Virus (RSV) is the major cause of pneumonia among infants. Here we elucidated the antibody repertoire following primary RSV infection and traced its evolution through adolescence and adulthood. Whole genome-fragment phage display libraries (GFPDL) expressing linear and conformational epitopes in the RSV fusion protein (F) and attachment protein (G) were used for unbiased epitope profiling of infant sera prior to and following RSV infection. F-GFPDL analyses demonstrated modest changes in the anti-F epitope repertoires post-RSV infection, while G-GFPDL analyses revealed 100-fold increase in number of bound phages. The G-reactive epitopes spanned the N- and C-terminus of the G ectodomain, along with increased reactivity to the central conserved domain (CCD). Panels of F and G antigenic sites were synthesized to evaluate sera from young children (<2 yr), adolescents (14-18 yr) and adults (30-45 yr) in SPR real-time kinetics assays. A steady increase in RSV-F epitope repertoires from young children to adults was observed using peptides and F proteins. Importantly, several novel epitopes were identified in pre-fusion F and an immunodominant epitope in the F-p27. In all age groups, antibody binding to pre-fusion F was 2-3 folds higher than to post-fusion form. For RSV-G, antibody responses were high following early RSV infection in children, but declined significantly in adults, using either G proteins or peptides. This study identified unlinked evolution of anti-F and anti G responses and supportive evidence for immune pressure driven evolution of RSV-G. These findings could help development of effective countermeasures including vaccines.

Treatment-Resistant Human Extraparenchymal Neurocysticercosis: An Immune-Inflammatory Approach to Cysticidal Treatment Outcome.

OBJECTIVE: The aim of this study is to analyze the immune-endocrine profile in neurocysticercosis (NC) patients resistant to cysticidal treatment. METHODS: The inflammatory and regulatory responses of 8 resistant NC patients with extraparenchymal parasites and 5 healthy controls were evaluated through flow cytometry. Serum interleukin levels were measured by ELISA and catecholamines levels by high performance liquid chromatography. RESULTS: Higher percentages of Tr1, CD4+CD25+FOXP3+CD127- and CD4+CD45RO+FOXP3HI were found in NC patients compared with healthy controls, but no difference was found in catecholamine levels. Antigen-specific proliferative immune response was observed in NC patients. Neither anti-inflammatory nor pro-inflammatory cytokines showed differences between patients and controls, but IL-6 levels were lower in treatment-resistant NC patients. In addition, TGFß showed a significant negative correlation with dopamine. CONCLUSIONS: Altogether, these results may point to a modulation of the neuroinflammation in these patients that could indirectly favor cysticercal survival in CNS microenvironment.

Type II integral membrane protein, TM of J paramyxovirus promotes cell-to-cell fusion.

Paramyxoviruses include many important animal and human pathogens. Most paramyxoviruses have two integral membrane proteins: fusion protein (F) and attachment proteins hemagglutinin, hemagglutinin-neuraminidase, or glycoprotein (G), which are critical for viral entry into cells. J paramyxovirus (JPV) encodes four integral membrane proteins: F, G, SH, and transmembrane (TM). The function of TM is not known. In this work, we have generated a viable JPV lacking TM (JPV∆TM). JPV∆TM formed opaque plaques compared with JPV. Quantitative syncytia assays showed that JPV∆TM was defective in promoting cell-to-cell fusion (i.e., syncytia formation) compared with JPV. Furthermore, cells separately expressing F, G, TM, or F plus G did not form syncytia whereas cells expressing F plus TM formed some syncytia. However, syncytia formation was much greater with coexpression of F, G, and TM. Biochemical analysis indicates that F, G, and TM interact with each other. A small hydrophobic region in the TM ectodomain from amino acid residues 118 to 132, the hydrophobic loop (HL), was important for syncytial promotion, suggesting that the TM HL region plays a critical role in cell-to-cell fusion.

Nonglycosylated G-Protein Vaccine Protects against Homologous and Heterologous Respiratory Syncytial Virus (RSV) Challenge, while Glycosylated G Enhances RSV Lung Pathology and Cytokine Levels.

UNLABELLED: New efforts are under way to develop a vaccine against respiratory syncytial virus (RSV) that will provide protective immunity without the potential for vaccine-associated disease enhancement such as that observed in infants following vaccination with formalin-inactivated RSV vaccine. In addition to the F fusion protein, the G attachment surface protein is a target for neutralizing antibodies and thus represents an important vaccine candidate. However, glycosylated G protein expressed in mammalian cells has been shown to induce pulmonary eosinophilia upon RSV infection in a mouse model. In the current study, we evaluated in parallel the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain (amino acids 67 to 298) expressed in Escherichia coli (REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model. Vaccination with REG generated neutralizing antibodies against RSV A2 in 7/11 BALB/c mice, while RMG did not elicit neutralizing antibodies. Total serum binding antibodies against the recombinant proteins (both REG and RMG) were measured by surface plasmon resonance (SPR) and were found to be >10-fold higher for REG- than for RMG-vaccinated animals. Reduction of lung viral loads to undetectable levels after homologous (RSV-A2) and heterologous (RSV-B1) viral challenge was observed in 7/8 animals vaccinated with REG but not in RMG-vaccinated animals. Furthermore, enhanced lung pathology and elevated Th2 cytokines/chemokines were observed exclusively in animals vaccinated with RMG (but not in those vaccinated with REG or phosphate-buffered saline [PBS]) after homologous or heterologous RSV challenge. This study suggests that bacterially produced unglycosylated G protein could be developed alone or as a component of a protective vaccine against RSV disease. IMPORTANCE: New efforts are under way to develop vaccines against RSV that will provide protective immunity without the potential for disease enhancement. The G attachment protein represents an important candidate for inclusion in an effective RSV vaccine. In the current study, we evaluated the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain produced in E. coli (REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model (strains A2 and B1). The unglycosylated G generated high protective immunity and no lung pathology, even in animals that lacked anti-RSV neutralizing antibodies prior to RSV challenge. Control of viral loads correlated with antibody binding to the G protein. In contrast, the glycosylated G protein provided poor protection and enhanced lung pathology after RSV challenge. Therefore, bacterially produced unglycosylated G protein holds promise as an economical approach to a protective vaccine against RSV.

Simultaneous Second Harmonic Generation and Multiphoton Excited Photoluminescence in Samarium-Doped BaTiO3 Nanoparticles Functionalized with Poly(ethylene glycol).

In this work, samarium-doped BaTiO3 (BT:Sm) nanoparticles (NPs) were prepared and coated with poly(ethylene glycol) (PEG) to investigate their optical characteristics and compatibility with biological systems. The structure, particle morphology, optical properties, and biological compatibility of the NPs were assessed. The results demonstrated the formation of BT:Sm and [(BT:Sm)-PEG]. The relative intensities and positions of peaks in the X-ray diffraction (XRD) are consistent with an average crystallite size of ∼75 nm. The Raman spectra showed that Sm doping produced the typical tetragonal peaks at around 306 and 715 cm-1, and Fourier transform infrared (FTIR) spectroscopy showed that the PEGylation process was effective. Also, our investigation demonstrates the potential of these NPs as very temperature-sensitive nanosensors with a resolution exceeding 0.5 °C, which is achievable through optical excitation. We also analyze their emission properties. Finally, we present a study related with the mitochondrial activity of naked and PEG-coated NPs. The results indicate that neither naked nor PEG-coated NPs exhibit changes in mitochondrial metabolism, as indicated by quantitative cell viability and morphological visualization. The PEG-coated NPs prevented the formation of aggregates in cell culture compared to naked NPs, demonstrating the significance of PEG as a stabilizing agent.

The V protein of mumps virus plays a critical role in pathogenesis.

Mumps virus (MuV) causes an acute infection in humans characterized by a wide array of symptoms ranging from relatively mild manifestations, such as parotitis, to more-severe complications, such as meningitis and encephalitis. Widespread mumps vaccination has reduced mumps incidence dramatically; however, outbreaks still occur in vaccinated populations. The V protein of MuV, when expressed in cell culture, blocks interferon (IFN) expression and signaling and interleukin-6 (IL-6) signaling. In this work, we generated a recombinant MuV incapable of expressing the V protein (rMuVΔV). The rescued MuV was derived from a clinical wild-type isolate from a recent outbreak in the United States (MuV(Iowa/US/06), G genotype). Analysis of the virus confirmed the roles of V protein in blocking IFN expression and signaling and IL-6 signaling. We also found that the rMuV(Iowa/US/06)ΔV virus induced high levels of IL-6 expression in vitro, suggesting that V plays a role in reducing IL-6 expression. In vivo, the rMuV(Iowa/US/06)ΔV virus was highly attenuated, indicating that the V protein plays an essential role in viral virulence.

Circulating myeloid-derived suppressor cells may be a useful biomarker in the follow-up of unvaccinated COVID-19 patients after hospitalization.

SARS-CoV-2 infection is the cause of the disease named COVID-19, a major public health challenge worldwide. Differences in the severity, complications and outcomes of the COVID-19 are intriguing and, patients with similar baseline clinical conditions may have very different evolution. Myeloid-derived suppressor cells (MDSCs) have been previously found to be recruited by the SARS-CoV-2 infection and may be a marker of clinical evolution in these patients. We have studied 90 consecutive patients admitted in the hospital before the vaccination program started in the general population, to measure MDSCs and lymphocyte subpopulations at admission and one week after to assess the possible association with unfavorable outcomes (dead or Intensive Care Unit admission). We analyzed MDSCs and lymphocyte subpopulations by flow cytometry. In the 72 patients discharged from the hospital, there were significant decreases in the monocytic and total MDSC populations measured in peripheral blood after one week but, most importantly, the number of MDSCs (total and both monocytic and granulocytic subsets) were much higher in the 18 patients with unfavorable outcome. In conclusion, the number of circulating MDSCs may be a good marker of evolution in the follow-up of unvaccinated patients admitted in the hospital with the diagnosis of COVID-19.

Function of the small hydrophobic protein of J paramyxovirus.

At 18,954 nucleotides, the J paramyxovirus (JPV) genome is one of the largest in the family Paramyxoviridae, consisting of eight genes in the order 3'-N-P/V/C-M-F-SH-TM-G-L-5'. To study the function of novel paramyxovirus genes in JPV, a plasmid containing a full-length cDNA clone of the genome of JPV was constructed. In this study, the function of the small hydrophobic (SH) protein of JPV was examined by generating a recombinant JPV lacking the coding sequence of the SH protein (rJPVΔSH). rJPVΔSH was viable and had no growth defect in tissue culture cells. However, more tumor necrosis factor alpha (TNF-α) was produced during rJPVΔSH infection, suggesting that SH plays a role in inhibiting TNF-α production. rJPVΔSH induced more apoptosis in tissue culture cells than rJPV. Virus-induced apoptosis was inhibited by neutralizing antibody against TNF-α, suggesting that TNF-α contributes to JPV-induced apoptosis in vitro. The expression of JPV SH protein inhibited TNF-α-induced NF-κB activation in a reporter gene assay, suggesting that JPV SH protein can inhibit TNF-α signaling in vitro. Furthermore, infection of mice with rJPVΔSH induced more TNF-α expression, indicating that SH plays a role in blocking TNF-α expression in vivo.

Review on Sol-Gel Synthesis of Perovskite and Oxide Nanomaterials.

Sol-Gel is a low cost, well-established and flexible synthetic route to produce a wide range of micro- and nanostructures. Small variations in pH, temperature, precursors, time, pressure, atmosphere, among others, can lead to a wide family of compounds that share the same molecular structures. In this work, we present a general review of the synthesis of LaMnO3, SrTiO3, BaTiO3 perovskites and zinc vanadium oxides nanostructures based on Sol-Gel method. We discuss how small changes in the parameters of the synthesis can modify the morphology, shape, size, homogeneity, aggregation, among others, of the products. We also discuss the different precursors, solvents, working temperature, reaction times used throughout the synthesis. In the last section, we present novel uses of Sol-Gel with organic materials with emphasis on carbon-based compounds. All with a perspective to improve the method for future applications in different technological fields.

Phylogenetic relationships, origin and historical biogeography of the genus Sprattus (Clupeiformes: Clupeidae).

The genus Sprattus comprises five species of marine pelagic fishes distributed worldwide in antitropical, temperate waters. Their distribution suggests an ancient origin during a cold period of the earth's history. In this study, we evaluated this hypothesis and corroborated the non-monophyly of the genus Sprattus, using a phylogenetic approach based on DNA sequences of five mitochondrial genome regions. Sprattus sprattus is more closely related to members of the genus Clupea than to other Sprattus species. We also investigated the historical biogeography of the genus, with the phylogenetic tree showing two well-supported clades corresponding to the species distribution in each hemisphere. Time-calibrated phylogenetic analyses showed that an ancient divergence between Northern and Southern Hemispheres occurred at 55.8 MYBP, followed by a diversification in the Oligocene epoch in the Northern Hemisphere clade (33.8 MYBP) and a more recent diversification in the Southern Hemisphere clade (34.2 MYBP). Historical biogeography analyses indicated that the most recent common ancestor (MRCA) likely inhabited the Atlantic Ocean in the Southern Hemisphere. These results suggest that the ancestral population of the MRCA diverged in two populations, one was dispersed to the Northern Hemisphere and the other across the Southern Hemisphere. Given that the Eocene was the warmest epoch since the Paleogene, the ancestral populations would have crossed the tropics through deeper cooler waters, as proposed by the isothermal submergence hypothesis. The non-monophyly confirmed for the genus Sprattus indicates that its systematics should be re-evaluated.

Low Levels of Granulocytic Myeloid-Derived Suppressor Cells May Be a Good Marker of Survival in the Follow-Up of Patients With Severe COVID-19.

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a disease (coronavirus disease 2019, COVID-19) that may develop into a systemic disease with immunosuppression and death in its severe form. Myeloid-derived suppressive cells (MDSCs) are inhibitory cells that contribute to immunosuppression in patients with cancer and infection. Increased levels of MDSCs have been found in COVID-19 patients, although their role in the pathogenesis of severe COVID-19 has not been clarified. For this reason, we raised the question whether MDSCs could be useful in the follow-up of patients with severe COVID-19 in the intensive care unit (ICU). Thus, we monitored the immunological cells, including MDSCs, in 80 patients admitted into the ICU. After 1, 2, and 3 weeks, we examined for a possible association with mortality (40 patients). Although the basal levels of circulating MDSCs did not discriminate between the two groups of patients, the last measurement before the endpoint (death or ICU discharge) showed that patients discharged alive from the ICU had lower levels of granulocytic MDSCs (G-MDSCs), higher levels of activated lymphocytes, and lower levels of exhausted lymphocytes compared with patients who had a bad evolution (death). In conclusion, a steady increase of G-MDSCs during the follow-up of patients with severe COVID-19 was found in those who eventually died.

A novel, sequencing-free strategy for the functional characterization of Taenia solium proteomic fingerprint.

The flatworm Taenia solium causes human and pig cysticercosis. When cysticerci are established in the human central nervous system, they cause neurocysticercosis, a potentially fatal disease. Neurocysticercosis is a persisting public health problem in rural regions of Mexico and other developing countries of Latin America, Asia, and Africa, where the infection is endemic. The great variability observed in the phenotypic and genotypic traits of cysticerci result in a great heterogeneity in the patterns of molecules secreted by them within their host. This work is aimed to identify and characterize cysticercal secretion proteins of T. solium cysticerci obtained from 5 naturally infected pigs from Guerrero, Mexico, using 2D-PAGE proteomic analysis. The isoelectric point (IP) and molecular weight (MW) of the spots were identified using the software ImageMaster 2D Platinum v.7.0. Since most secreted proteins are impossible to identify by mass spectrometry (MS) due to their low concentration in the sample, a novel strategy to predict their sequence was applied. In total, 108 conserved and 186 differential proteins were identified in five cysticercus cultures. Interestingly, we predicted the sequence of 14 proteins that were common in four out of five cysticercus cultures, which could be used to design vaccines or diagnostic methods for neurocysticercosis. A functional characterization of all sequences was performed using the algorithms SecretomeP, SignalP, and BlastKOALA. We found a possible link between signal transduction pathways in parasite cells and human cancer due to deregulation in signal transduction pathways. Bioinformatics analysis also demonstrated that the parasite release proteins by an exosome-like mechanism, which could be of biological interest.

Regulatory T Cells as an Escape Mechanism to the Immune Response in Taenia crassiceps Infection.

Murine cysticercosis by Taenia crassiceps is a model for human neurocysticercosis. Genetic and/or immune differences may underlie the higher susceptibility to infection in BALB/cAnN with respect to C57BL/6 mice. T regulatory cells (Tregs) could mediate the escape of T. crassiceps from the host immunity. This study is aimed to investigate the role of Tregs in T. crassiceps establishment in susceptible and non-susceptible mouse strains. Treg and effector cells were quantified in lymphoid organs before infection and 5, 30, 90, and 130 days post-infection. The proliferative response post-infection was characterized in vitro. The expression of regulatory and inflammatory molecules was assessed on days 5 and 30 post-infection. Depletion assays were performed to assess Treg functionality. Significantly higher Treg percentages were observed in BALB/cAnN mice, while increased percentages of activated CD127+ cells were found in C57BL/6 mice. The proliferative response was suppressed in susceptible mice, and Treg proliferation occurred only in susceptible mice. Treg-mediated suppression mechanisms may include IL-10 and TGFß secretion, granzyme- and perforin-mediated cytolysis, metabolic disruption, and cell-to-cell contact. Tregs are functional in BALB/cAnN mice. Therefore Tregs could be allowing parasite establishment and survival in susceptible mice but could play a homeostatic role in non-susceptible strains.

Genome Analysis and Replication Studies of the African Green Monkey Simian Foamy Virus Serotype 3 Strain FV2014.

African green monkey (AGM) spumaretroviruses have been less well-studied than other simian foamy viruses (SFVs). We report the biological and genomic characterization of SFVcae_FV2014, which was the first foamy virus isolated from an African green monkey (AGM) and was found to be serotype 3. Infectivity studies in various cell lines from different species (mouse, dog, rhesus monkey, AGM, and human) indicated that like other SFVs, SFVcae_FV2014 had broad species and cell tropism, and in vitro cell culture infection resulted in cytopathic effect (CPE). In Mus dunni (a wild mouse fibroblast cell line), MDCK (Madin-Darby canine kidney cell line), FRhK-4 (a fetal rhesus kidney cell line), and MRC-5 (a human fetal lung cell line), SFVcae_FV2014 infection was productive resulting in CPE, and had delayed or similar replication kinetics compared with SFVmcy_FV21 and SFVmcy_FV34[RF], which are two Taiwanese macaque isolates, designated as serotypes 1 and 2, respectively. However, in Vero (AGM kidney cell line) and A549 (a human lung carcinoma cell line), the replication kinetics of SFVcae_FV2014 and the SFVmcy viruses were discordant: In Vero, SFVcae_FV2014 showed rapid replication kinetics and extensive CPE, and a persistent infection was seen in A549, with delayed, low CPE, which did not progress even upon extended culture (day 55). Nucleotide sequence analysis of the assembled SFVcae_FV2014 genome, obtained by high-throughput sequencing, indicated an overall 80-90% nucleotide sequence identity with SFVcae_LK3, the only available full-length genome sequence of an AGM SFV, and was distinct phylogenetically from other AGM spumaretroviruses, corroborating previous results based on analysis of partial env sequences. Our study confirmed that SFVcae_FV2014 and SFVcae_LK3 are genetically distinct AGM foamy virus (FV) isolates. Furthermore, comparative infectivity studies of SFVcae_FV2014 and SFVmcy isolates showed that although SFVs have a wide host range and cell tropism, regulation of virus replication is complex and depends on the virus strain and cell-specific factors.

Human Antibody Repertoire following Ebola Virus Infection and Vaccination.

Limited knowledge exists on the quality of polyclonal antibody response generated following Ebola virus (EBOV) infection compared with vaccination. Polyclonal antibody repertoire in plasma following EBOV infection in survivors was compared with ChAd3-MVA prime-boost human vaccination. Higher antibody binding and affinity to GP was observed in survivors compared with vaccinated plasma that correlated with EBOV neutralization. Surprisingly, a predominant IgM response was generated after prime-boost vaccination, whereas survivors demonstrated IgG-dominant antibody response. EBOV infection induced more diverse antibody epitope repertoire compared with vaccination. A strong binding to antigenic sites in the fusion peptide and another in the highly conserved GP2-HR2 domain was preferentially recognized by EBOV survivors than vaccinated individuals that correlated strongly with EBOV neutralization titers. These findings will help development and evaluation of effective Ebola countermeasures including therapeutics and vaccines.

Akt plays a critical role in replication of nonsegmented negative-stranded RNA viruses.

The order Mononegavirales (comprised of nonsegmented negative-stranded RNA viruses or NNSVs) contains many important pathogens. Parainfluenza virus 5 (PIV5), formerly known as simian virus 5, is a prototypical paramyxovirus and encodes a V protein, which has a cysteine-rich C terminus that is conserved among all paramyxoviruses. The V protein of PIV5, like that of many other paramyxoviruses, plays an important role in regulating viral RNA synthesis. In this work, we show that V interacts with Akt, a serine/threonine kinase, also known as protein kinase B. Both pharmacological inhibitors and small interfering RNA against Akt1 reduced PIV5 replication, indicating that Akt plays a critical role in PIV5 replication. Furthermore, treatment with Akt inhibitors also reduced the replication of several other paramyxoviruses, as well as vesicular stomatitis virus, the prototypical rhabdovirus, indicating that Akt may play a more universal role in NNSV replication. The phosphoproteins (P proteins) of NNSVs are essential cofactors for the viral RNA polymerase complex and require heavy phosphorylation for their activity. Inhibition of Akt activity reduced the level of P phosphorylation, suggesting that Akt is involved in regulating viral RNA synthesis. In addition, Akt1 phosphorylated a recombinant P protein of PIV5 purified from bacteria. The finding that Akt plays a critical role in replication of NNSV will lead to a better understanding of how these viruses replicate, as well as novel strategies to treat infectious diseases caused by NNSVs.