Proteome and immunogenicity differences in BCG Pasteur ATCC 35734 and its derivative, the vaccine candidate BCGΔBCG1419c during planktonic growth in 7H9 and Proskauer Beck media.

Bacillus Calmette-Guèrin (BCG) remains as the only vaccine employed to prevent tuberculosis (TB) during childhood. Among factors likely contributing to the variable efficacy of BCG is the modification in its antigenic repertoire that may arise from in vitro growth conditions. Our vaccine candidate, BCGΔBCG1419c, improved protection against TB in mice and guinea pigs with bacteria grown in either 7H9 OADC Tween 80 or in Proskauer Beck Tween 80 media in independent studies. Here, we compared the proteomes of planktonic cultures of BCG and BCGΔBCG1419c, grown in both media. Further to this, we compared systemic immunogenicity ex vivo elicited by both types of BCG strains and cultures when used to vaccinate BALB/c mice. Both the parental strain BCG Pasteur ATCC 35734, and its isogenic mutant BCGΔBCG1419c, had several medium-dependent changes. Moreover, ex vivo immune responses to a multiantigenic (PPD) or a single antigenic (Ag85A) stimulus were also medium-dependent. Then, not only the presence or absence of the BCG1419c gene in our strains under study affected the proteome produced in vitro but also that this was affected by culture medium, potentially leading to changes in the capacity to induce ex vivo immune responses.

In Vitro Antiviral Activity of Nordihydroguaiaretic Acid against SARS-CoV-2.

The coronavirus infectious disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has been spreading rapidly worldwide, creating a pandemic. This article describes the evaluation of the antiviral activity of nordihydroguaiaretic acid (NDGA), a molecule found in Creosote bush (Larrea tridentata) leaves, against SARS-CoV-2 in vitro. A 35 µM concentration of NDGA was not toxic to Vero cells and exhibited a remarkable inhibitory effect on the SARS-CoV-2 cytopathic effect, viral plaque formation, RNA replication, and expression of the SARS-CoV-2 spike glycoprotein. The 50% effective concentration for NDGA was as low as 16.97 µM. Our results show that NDGA could be a promising therapeutic candidate against SARS-CoV-2.

Exclusive circulation of canine parvovirus type 2c in the Guadalajara metropolitan area in western Mexico: a five-year study.

Canine parvovirus type 2 (CPV-2) infection in dogs is associated with severe gastroenteritis, bloody diarrhea, and vomiting, resulting in high rates of death, especially in unvaccinated puppies within the first months of age. There are three variants, called CPV-2a, CPV-2b, and CPV-2c, co-circulating worldwide. Our group previously reported that the only circulating CPV-2 variant in the Guadalajara metropolitan area in western Mexico was type 2c. Now, a five-year study was performed in order to investigate the possible dominance of CPV-2c in our region. Rectal swabs were collected from 146 dogs with clinical gastroenteritis from May 2014 to August 2019 at the Veterinary Hospital of the University of Guadalajara. Of these, 90 dogs tested positive for canine parvovirus by PCR. Most of the infected dogs with CPV-2 had a partial or incomplete vaccination status (n = 88, 97.8%). Approximately 65% (n = 59) of them were mixed-breed dogs, 77.8% (n = 70) were under 6 months of age, and 37.8% (n = 34) of them died from clinical complications. RFLP analysis of amplicons derived from the vp2 gene showed that all 90 DNA samples corresponded to CPV-2c, with no evidence of the presence of CPV-2a or CPV-2b variants. Twenty-nine of the 90 DNA samples were selected for amplification of a portion of the vp2 gene, and sequencing of these amplicons showed that all of them had the sequence GAA at codon 426, encoding the amino acid glutamic acid, which is characteristic of CPV-2c. Phylogenetic analysis showed that the CPV-2c sequences were related to those of viruses from Europe and South America. The present study indicates that CPV-2c is still the only variant circulating in the dog population of the Guadalajara metropolitan area.

Development of a Platform for Noncovalent Coupling of Full Antigens to Tobacco Etch Virus-Like Particles by Means of Coiled-Coil Oligomerization Motifs.

Virus-like particles are excellent inducers of the adaptive immune response of humans and are presently being used as scaffolds for the presentation of foreign peptides and antigens derived from infectious microorganisms for subunit vaccine development. The most common approaches for peptide and antigen presentation are translational fusions and chemical coupling, but some alternatives that seek to simplify the coupling process have been reported recently. In this work, an alternative platform for coupling full antigens to virus-like particles is presented. Heterodimerization motifs inserted in both Tobacco etch virus coat protein and green fluorescent protein directed the coupling process by simple mixing, and the obtained complexes were easily taken up by a macrophage cell line.

Updating zika diagnostic methods: the point-of-care approach

Abstract Zika virus (ZIKV) has gained great importance worldwide since the past epidemic that occurred in 2015 in Brazil. Early identification of ZIKV is critical to minimize transmission and prevents potentially devastating consequences, including microcephaly in neonates of infected women, congenital blindness, or Guillain-Barré Syndrome. However, this is not an easy task, considering that approximately 80% of ZIKV infection cases are asymptomatic or oligosymptomatic, there are diverse modes of transmission (vertical transmission is through vectors and horizontal transmission through blood, saliva, semen, and urine from infected people), and the fact that ZIKV has a high identity percentage with other cocirculating Flaviviruses such as dengue. Here, we review ZIKV diagnostic methods, with special emphasis on the development of point-of-care diagnostic assays, since these devices commonly have two important advantages: they provide prompt screening and are affordable.

Serum Analysis of Women with Early-Stage Breast Cancer Using a Mini-Array of Tumor-Associated Antigens.

Background: Several studies have shown that patients with cancer have antibodies in serum that react with cellular autoantigens, known as Tumor-Associated Antigens (TAA). The present work aimed to determine whether a mini-array comprising four recombinant TAA increases the detection of specific serum antibodies for the diagnosis of early-stage breast cancer. Methods: The mini-array included Alpha 1-AntiTrypsin (A1AT), TriosePhosphate Isomerase 1 (TPI1), Peptidyl-Prolyl cis-trans Isomerase A (PPIA), and PeroxiReDoXin 2 (PRDX2) full-length recombinant proteins. The proteins were produced after gene cloning, expression, and purification, and were verified by Western blot assays. Then, Dot-Blot was performed to find antibodies against the four TAA in 12 sera from women with early-stage breast cancer (stage II) and 12 sera from healthy women. Results: Antibody detection against individual TAA in early-stage breast cancer sera ranged from 58.3% to 83.3%. However, evaluation of the four TAA showed that there was a positive antibody reaction reaching a sensitivity of 100% and a specificity of 85% in early-stage breast cancer, suggesting that this mini-array must be evaluated as a clinical diagnostic tool for early-stage breast cancer in a larger sample size. Conclusion: Our results suggest that TAA mini-arrays may provide a promising and powerful method for improving the detection of breast cancer in Mexican women.

Updating Zika Diagnostic Methods: The Point-of-Care Approach.

Zika virus (ZIKV) has gained great importance worldwide since the past epidemic that occurred in 2015 in Brazil. Early identification of ZIKV is critical to minimize transmission and prevents potentially devastating consequences, including microcephaly in neonates of infected women, congenital blindness, or Guillain-Barré Syndrome. However, this is not an easy task, considering that approximately 80% of ZIKV infection cases are asymptomatic or oligosymptomatic, there are diverse modes of transmission (vertical transmission is through vectors and horizontal transmission through blood, saliva, semen, and urine from infected people), and the fact that ZIKV has a high identity percentage with other cocirculating Flaviviruses such as dengue. Here, we review ZIKV diagnostic methods, with special emphasis on the development of point-of-care diagnostic assays, since these devices commonly have two important advantages: they provide prompt screening and are affordable.

Regulatory SNP rs5743417 impairs constitutive expression of human ß-defensin 1 and has high frequency in Africans and Afro-Americans.

The prediction of regulatory single nucleotide polymorphisms (rSNPs) in proximal promoters of disease-related genes could be a useful tool for personalized medicine in both patient stratification and customized therapy. Using our previously reported method of rSNPs prediction (currently a software called SNPClinic v.1.0) as well as with PredictSNP tool, we performed in silico prediction of regulatory SNPs in the antimicrobial peptide human ß-defensin 1 gene in three human cell lines from 1,000 Genomes Project (1kGP), namely A549 (epithelial cell line), HL-60 (neutrophils) and TH 1 (lymphocytes). These predictions were run in a proximal pseudo-promoter comprising all common alleles on each polymorphic site according to the 1,000 Genomes Project data (1kGP: ALL). Plasmid vectors containing either the major or the minor allele of a putative rSNP rs5743417 (categorized as regulatory by SNPClinic and confirmed by PredictSNP) and a non-rSNP negative control were transfected to lung A549 human epithelial cell line. We assessed functionality of rSNPs by qPCR using the Pfaffl method. In A549 cells, minor allele of the SNP rs5743417 G→A showed a significant reduction in gene expression, diminishing DEFB1 transcription by 33% when compared with the G major allele (p-value = .03). SNP rs5743417 minor allele has high frequency in Gambians (8%, 1kGP population: GWD) and Afro-Americans (3.3%, 1kGP population: ASW). This SNP alters three transcription factors binding sites (TFBSs) comprising SREBP2 (sterols and haematopoietic pathways), CREB1 (cAMP, insulin and TNF pathways) and JUND (apoptosis, senescence and stress pathways) in the proximal promoter of DEFB1. Further in silico analysis reveals that this SNP also overlaps with GS1-24F4.2, a lincRNA gene complementary to the X Kell blood group related 5 (XKR5) mRNA. The potential clinical impact of the altered constitutive expression of DEFB1 caused by rSNP rs5743417 in DEFB1-associated diseases as tuberculosis, COPD, asthma, cystic fibrosis and cancer in African and Afro-American populations deserves further research.

Vector competence of Aedes aegypti and Culex quinquefasciatus from the metropolitan area of Guadalajara, Jalisco, Mexico for Zika virus.

Zika virus (ZIKV) is a mosquito-borne pathogen discovered in the late 40's in Uganda during a surveillance program for yellow fever. By 2014 the virus reached Eastern Island in the Americas, and two years later, the virus spread to almost all countries and territories of the Americas. The mosquito Aedes aegypti has been identified as the main vector of the disease, and several researchers have also studied the vector competence of Culex quinquefasciatus in virus transmission. The aim of the present study was to evaluate the vector competence of Ae. aegypti and Cx. quinquefasciatus in order to understand their roles in the transmission of ZIKV in Guadalajara, Jalisco, Mexico. In blood feeding laboratry experiments, we found that Ae. aegypti mosquitoes showed to be a competent vector able to transmit ZIKV in this area. On the other hand, we found that F0 Cx. quinquefasciatus mosquitoes are refractory to ZIKV infection, dissemination and transmission.

An Escherichia coli-Expressed Porcine Reproductive and Respiratory Syndrome Virus Chimeric Protein Induces a Specific Immunoglobulin G Response in Immunized Piglets.

Porcine reproductive and respiratory syndrome virus (PRRSV) still poses a threat to the swine industry worldwide. Currently, commercial vaccines against PRRSV, which consist of modified live or inactivated virus, reduce symptoms and viremia in immunized pigs, but efficacy against heterologous strains is variable. This has led to the development of subunit vaccines that contain viral antigens that show the highest variability. In this work, a chimeric protein comprising short amino acid sequences from glycoprotein 3 (GP3), glycoprotein 4 (GP4), glycoprotein 5 (GP5), and M (matrix protein) proteins of PRRSV was designed and expressed in Escherichia coli. This protein, designated as PRRSVchim, was purified by immobilized metal affinity chromatography and evaluated. PRRSVchim was identified by immunoglobulin G (IgG) presence in serum samples from PRRSV-positive pigs. Also, the protein probed to be antigenic in immunized mice and piglets and provided some degree of protection against challenge with a PRRSV field isolate. These results show the potential of PRRSVchim protein for both PRRSV diagnostic and immunoprophylaxis.

Development of essential oil-based phyto-formulations to control the cattle tick Rhipicephalus microplus using a mixture design approach.

The cattle tick Rhipicephalus (Boophilus) microplus is one of the most important ectoparasites for livestock in tropical and subtropical areas around the world. This tick economically impacts cattle production by reducing weight gain and milk production. Moreover, it is a vector of pathogens causing diseases such as babesiosis and anaplasmosis. Conventional tick control relies mainly on the use of chemical acaricides; however, their intensive use has led to the rapid appearance of resistant tick populations. It is therefore necessary to look for alternative tick control products. In that sense, plant extracts might represent a promising source of new acaricides. Previously, we reported a significant acaricide effect of essential oils from selected plant species. In the present study, we used a mixture design approach to develop phyto-formulations by combining individual essential oils. We produced several mixtures at 10% containing different proportions of individual essential oils (ranging from 0 to 1) from cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum) and allspice (Pimenta dioica) and tested their acaricidal activity against R. microplus ticks by means of larval packet test (LPT) and adult immersion test (AIT) assays. The optimal mixture predicted against R. microplus was composed of 66%, 17% and 17% of essential oils from C. zeylanicum, C. cyminum and P. dioica, respectively. We generated an estimated response surface contour plot that estimates 80%-100% acaricidal efficacy. In the optimal mixture 34 compounds were identified, which represent 98.65% of the total composition, with cinnamaldehyde (37.77%), ß-caryophyllene (13.92%), methyl eugenol (12.27%) and cuminaldehyde (8.99%) being the major components. Next, we developed emulsions by combining the optimal mixture with several surfactants and determined particle size, Zeta potential, stability and bioactivity. Emulsions containing 2% and 5% Tween 20 or Tween 80 remain stable after 14 days at 54 °C. Finally, optimized emulsion retained a high acaricidal activity against larval and adult R. microplus ticks. Taken together, our findings showed the usefulness of mixture design method for the development of essential oil mixtures with potent acaricidal activity. These formulations have the potential to successfully control tick infestations.

Functional Expression of Plant Lipases: The Case of CpLip1 from Carica papaya.

Carica papaya latex is one of the most studied sources of plant lipases. However, the complexity of the matrix composition makes it difficult to isolate and purify the lipolytic enzymes present in Carica papaya latex. Therefore, diverse strategies have been developed to study the catalytic properties of these enzymes.Recently the first lipase from Carica papaya latex (CpLip1) has been successfully cloned and expressed in order to study their catalytic properties. In order to improve the catalytic properties and increase the potential for its use at industrial scale.In this chapter, a practical protocol to recombinant CpLip1 lipase is given.

Porcine circovirus type 2 protective epitope densely carried by chimeric papaya ringspot virus-like particles expressed in Escherichia coli as a cost-effective vaccine manufacture alternative.

Porcine circovirus type 2 (PCV2) still represents a major problem to the swine industry worldwide, causing high mortality rates in infected animals. Virus-like particles (VLPs) have gained attention for vaccine development, serving both as scaffolds for epitope expression and immune response enhancers. The commercial subunit vaccines against PCV2 consist of VLPs formed by the self-assembly of PCV2 capsid protein (CP) expressed in the baculovirus vector system. In this work, a PCV2 protective epitope was inserted into three different regions of papaya ringspot virus (PRSV) CP, namely, the N- and C-termini and a predicted antigenic region located near the N-terminus. Wild-type and chimeric CPs were modeled in silico, expressed in Escherichia coli, purified, and visualized by transmission electron microscopy. This is the first report that shows the formation of chimeric VLPs using PRSV as epitope-presentation scaffold. Moreover, it was found that PCV2 epitope localization strongly influences VLP length. Also, the estimated yields of the chimeric VLPs at a small-scale level ranged between 65 and 80 mg/L of culture medium. Finally, the three chimeric VLPs induced high levels of immunoglobulin G against the PCV2 epitope in immunized BALB/c mice, suggesting that these chimeric VLPs can be used for swine immunoprophylaxis against PCV2.

Colostrum proinflammatory cytokines as biomarkers of bovine immune response to bovine tuberculosis (bTB).

Bovine colostrum contains compounds, which provide passive immune protection from mother to newborn calves. Little is known about cytokine levels and their role in bovine colostrum. Moreover, the capacity of bovine colostrum cells to mount specific immune responses after natural exposure to bovine tuberculosis (bTB) antigens in dairy herds has not been studied, thus far. The purpose of this study was to identify biomarkers for bTB infection measurable in bovine colostrum. The present study reveals that isolated-immune colostrum cells can mount a specific immune response against bTB antigens, by measuring the novo IFN-γ release in cell culture. We found that IFN-γ levels in the responders (Bov+) to bTB antigen were higher than in non-responders (Bov-). On the other hand, proinflammatory cytokines contained in colostrum's whey were tested in Tuberculin Skin Test (TST) reactor (TST+) and non-reactor (TST-) animals to assess their potential role as biomarker. We observed that IFN-γ levels were lower or undetectable, as opposed to IL4 levels were measurable, the TNF-α level was higher in TST- than TST+, while IL-6 levels showed the opposite reaction and with no statistical significance. Moreover, IL-1α mRNA expression levels were higher in colostrum mononuclear cells (CMC) in Bov+ cattle. Collectively, these data suggest that the differential expression of pro and anti-inflammatory cytokines could have relevant value to diagnose bTB in cattle.

Evaluation of the Immunogenicity of a Potyvirus-Like Particle as an Adjuvant of a Synthetic Peptide.

Improvement of current vaccines is highly necessary to increase immunogenicity levels and protection against several pathogens. Virus-like particles (VLPs) are promising approaches for vaccines because they emulate infectious virus structure, but lack any genetic material needed for replication. Plant viruses have emerged as a potential framework for VLP design, mainly because there is no preexisting immunity in mammals. In this study, we evaluated the scaffold of the papaya ringspot virus (PRSV) as a VLP adjuvant for a short synthetic peptide derived from the Hemagglutinin protein of AH1 N1 influenza virus-hemagglutinin (VLP-HA). Our results demonstrated that the adjuvant property of this VLP is highly similar to the trivalent influenza vaccine, showing comparable levels of IgG- and IgA-specific antibodies to HA-derived peptide in serum and feces of vaccinated mice, respectively. Furthermore, VLP-HA-immunized mice showed Th1-biased immune response as suggested by measuring IgG subclasses in comparison with the predominance of Th2-biased immune response in trivalent influenza vaccine dose-vaccinated mice. VLP-HA administration in mice induced comparable levels of activated CD4+- and CD8+-specific T lymphocytes for the HA-derived peptide. These results suggest the potential adjuvant capacity of the PRSV-VLP as a carrier for short synthetic peptides.

Self-assembly of hexahistidine-tagged tobacco etch virus capsid protein into microfilaments that induce IgG2-specific response against a soluble porcine reproductive and respiratory syndrome virus chimeric protein.

BACKGROUND: Assembly of recombinant capsid proteins into virus-like particles (VLPs) still represents an interesting challenge in virus-based nanotechnologies. The structure of VLPs has gained importance for the development and design of new adjuvants and antigen carriers. The potential of Tobacco etch virus capsid protein (TEV CP) as adjuvant has not been evaluated to date. FINDINGS: Two constructs for TEV CP expression in Escherichia coli were generated: a wild-type version (TEV-CP) and a C-terminal hexahistidine (His)-tagged version (His-TEV-CP). Although both versions were expressed in the soluble fraction of E. coli lysates, only His-TEV-CP self-assembled into micrometric flexuous filamentous VLPs. In addition, the His-tag enabled high yields and facilitated purification of TEV VLPs. These TEV VLPs elicited broader IgG2-specific antibody response against a novel porcine reproductive and respiratory syndrome virus (PRRSV) protein when compared to the potent IgG1 response induced by the protein alone. CONCLUSIONS: His-TEV CP was purified by immobilized metal affinity chromatography and assembled into VLPs, some of them reaching 2-µm length. TEV VLPs administered along with PRRSV chimeric protein changed the IgG2/IgG1 ratio against the chimeric protein, suggesting that TEV CP can modulate the immune response against a soluble antigen.

Identification of immunogenic proteins from ovarian tissue and recognized in larval extracts of Rhipicephalus (Boophilus) microplus, through an immunoproteomic approach.

Rhipicephalus (Boophilus) microplus ticks are obligatory hematophagous ectoparasites of cattle and act as vectors for disease-causing microorganisms. Conventional tick control is based on the use of chemical acaricides; however, their uncontrolled use has increased tSresistant tick populations, as well as food and environmental contamination. Alternative immunological tick control has shown to be partially effective. The only anti-tick vaccine commercially available at present in the world is based on intestinal Bm86 protein, and shows a variable effectiveness depending on tick strains or geographic isolates. Therefore, there is a need to characterize new antigens in order to improve immunological protection. The aim of this work was to identify immunogenic proteins from ovarian tissue extracts of R. microplus, after cattle immunization. Results showed that ovarian proteins complexed with the adjuvant Montanide ISA 50 V generated a strong humoral response on vaccinated cattle. IgG levels peaked at fourth post-immunization week and remained high until the end of the experiment. 1D and 2D SDS-PAGE-Western blot assays with sera from immunized cattle recognized several ovarian proteins. Reactive bands were cut and analyzed by LC-MS/MS. They were identified as Vitellogenin, Vitellogenin-2 precursor and Yolk Cathepsin. Our findings along with bioinformatic analysis indicate that R. microplus has several Vitellogenin members, which are proteolytically processed to generate multiple polypeptide fragments. This apparent complexity of vitellogenic tick molecular targets gives the opportunity to explore their potential usefulness as vaccine candidates but, at the same time, imposes a challenge on the selection of the appropriate set of antigens.

Detection of dengue, west Nile virus, rickettsiosis and leptospirosis by a new real-time PCR strategy.

Dengue virus (DENV) infection causes sudden fever along with several nonspecific signs and symptoms and in severe cases, death. DENV is transmitted to people by Aedes aegypti and Ae. albopictus mosquitoes, whose populations increase during rainy season. West Nile Virus (WNV), Rickettsia spp. and Leptospira spp. are fever-causing pathogens that share many of the initial symptoms of DENV infection and also thrive in the rainy season. Outbreaks in some regions may be due to any of these pathogens that can co-circulate. Plus, they are clinically indistinguishable until severe symptoms appear, even though these diseases should be treated differently. An effective differential diagnosis would help clinicians and vector control departments to make right decisions for control and treatment of these diseases. Therefore, we developed four different SYBR green (®) -based reverse transcription quantitative PCR (RT-qPCR) assays for simultaneous detection of DENV, WNV, Rickettsia spp. and Leptospira spp. The assay has been optimized to yield results in less than 1 h; and in order to reduce contamination risk, all reagents were premixed and lyophilized on 96 well plates and thus only requires the addition of water and total nucleic acids from the sample. Sensitivities of the assays were less than 100 copies of nucleic acid targeted for these four pathogens. Assays did not show cross reactivity with any of the four pathogens nor to human nucleic acids. We are presenting a sensitive and selective kit that detects four relevant pathogens from tropical regions, that is quick, cost-effective and easy to use.

Identification of immunodominant proteins from Mannheimia haemolytica and Histophilus somni by an immunoproteomic approach.

Mannheimia haemolytica and Histophilus somni are frequently isolated from diseased cattle with bovine respiratory disease (BRD). They compromise animal lung function and the immune responses generated are not sufficient to limit infection. Identification of specific immunogenic antigens for vaccine development represents a great challenge. Immunogenic proteins were identified by immunoproteomic approach with sera from cattle immunized with a commercial cellular vaccine of M. haemolytica and H. somni. Proteins of M. haemolytica were identified as solute ABC transporter, iron-binding protein, and hypothetical protein of capsular biosynthesis. Histophilus somni proteins correspond to porin, amino acid ABC transporter, hypothetical outer membrane protein, cysteine synthase, and outer membrane protein P6. Although these antigens share strong similarities with other proteins from animal pathogens, the ABC system proteins have been associated with virulence and these proteins could be considered as potential vaccine candidates for BRD.

Mannheimia haemolytica et Histophilus somni sont fréquemment isolées de bovins atteints de maladies respiratoires bovines (MRB). Ces agents compromettent la fonction pulmonaire et les réponses immunitaires générées ne permettent pas de limiter l'infection. L'identification d'antigènes spécifiques et immunogènes qui permettraient le développement de vaccins, représente un grand défi actuellement. Les protéines immunogènes ont été identifiées par une approche immunoproteomique en utilisant des sérums provenant de bovins immunisés par des vaccins commerciaux de M. haemolytica et H. somni. Les protéines de M. haemolytica ont été identifiées comme étant un transporteur ABC, une protéine de liaison du fer et une hypothétique protéine impliquée dans la biosynthèse de la capsule. Celles de H. somni correspondent à une porine, à un transporteur ABC d'acides aminés, à une hypothétique protéine de membrane externe, à la cystéine synthase et à la protéine membranaire P6. Bien que ces antigènes présentent une forte homologie avec des protéines provenant d'autres pathogènes d'animaux, les protéines du système ABC sont associées à la virulence et pourraient être considérées comme des candidats potentiels pour l'élaboration de vaccins contre les MBR.(Traduit par Docteur Patricia Dupre).

HRA2pl peptide: a fusion inhibitor for human metapneumovirus produced in tobacco plants by transient transformation.

MAIN CONCLUSION: The HRA2pl peptide expressed by transient transformation in N. tabacum plants is capable of inhibiting the binding of the human metapneumovirus to HEp-2 cells at the fusion stage. Human metapneumovirus (hMPV) is an agent responsible for acute respiratory infections that mainly affects children under 3 years, the elderly and immunocompromised patients. In children younger than 5 years, respiratory tract infections account for 20 % of deaths worldwide. However, there is currently no treatment or vaccine available against hMPV. The production of a safe, efficient and low cost treatment against this virus is a current challenge. Plants provide a system for recombinant protein production that is cost effective and is easier to scale up to an industrial level than other platforms; in addition, the plant tissue may be used as raw food, dried or, alternatively, proteins may be partially or fully purified and administered in aerosol or capsules as dry powder. In this study, we designed a gene expressing an antiviral peptide against hMPV based on the heptad repeat A domain of the F protein of the virus. We produced the recombinant peptide by a viral transient expression system (Magnifection(®)) in Nicotiana tabacum plants. The efficacy of this antiviral peptide was confirmed by in vitro assays in HEp-2 cell line. This is a promising result that can offer a prophylactic approach against hMPV.