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Viral-like particles are assembled from capsid protein structural subunits of different viruses and have ability to establish research in biomedicals, like construction of novel safety vaccines, gene therapy vectors by delivering systems for nucleic acids, small biomolecules and diagnostics. Papaya Mosaic Viral nanoparticals can provide as a vaccine candidate helps to increase the immunity by fusing the epitope based peptide antigen. Capripox viruses are the genus comprises Lymphy skin-disease, Sheep and Goat pox Viruses are notified by The World Animal Health Organization (OIE) based on their economic impotence act as a transboundary animal diseases viruses of sheep, goat, and cattle’s respectively. Plant viral based innovative vaccines have been emerged ineffective vaccine development. This research describes the engineering and development of a new vaccine candidate by display immunogenic peptide using the carrier capsid protein of Papaya Mosaic Virus. The Capripox virus P32 immunogenic protein is homologous of the vaccinia virus H3L gene displayed PapMV CP. The antigenicity of P32 protein epitope lowest score among epitopes C-terminally docked epitopes are EP6 > EP3 > EP8 as well the lowest score among epitopes N-terminally docked epitopes are EP8 > EP3 > EP6 presented on the N-terminus of PMV CP region which are found to be suitable for epitope display. And these modelled immunogenic peptide could be used to develop a viral like particles. Epitope based Antibody developed against immunogenic epitopic regions can contribute to a novel and robust protection from infection. As well might be used for developing cost effective detection kits for Transboundary animal disease viruses.

Background Flexuous rod-shaped nanoparticles made of the coat protein (CP) of papaya mosaic virus (PapMV) have been shown to trigger innate immunity through engagement of toll-like receptor 7 (TLR7). PapMV nanoparticles can also serve as a vaccine platform as they can increase the immune response to fused peptide antigens. Although this approach shows great potential, fusion of antigens directly to the CP open reading frame (ORF) is challenging because the fused peptides can alter the structure of the CP and its capacity to self assemble into nanoparticles—a property essential for triggering an efficient immune response to the peptide. This represents a serious limitation to the utility of this approach as fusion of small peptides only is tolerated. Results We have developed a novel approach in which peptides are fused directly to pre-formed PapMV nanoparticles. This approach is based on the use of a bacterial transpeptidase (sortase A; SrtA) that can attach the peptide directly to the nanoparticle. An engineered PapMV CP harbouring the SrtA recognition motif allows efficient coupling. To refine our engineering, and to predict the efficacy of coupling with SrtA, we modeled the PapMV structure based on the known structure of PapMV CP and on recent reports revealing the structure of two closely related potexviruses: pepino mosaic virus (PepMV) and bamboo mosaic virus (BaMV). We show that SrtA can allow the attachment of long peptides [Influenza M2e peptide (26 amino acids) and the HIV-1 T20 peptide (39 amino acids)] to PapMV nanoparticles. Consistent with our PapMV structural model, we show that around 30% of PapMV CP subunits in each nanoparticle can be fused to the peptide antigen. As predicted, engineered nanoparticles were capable of inducing a strong antibody response to the fused antigen. Finally, in a challenge study with influenza virus, we show that mice vaccinated with PapMV-M2e are protected from infection. Conclusions This technology will allow the development of vaccines harbouring long peptides containing several B and/or T cell epitopes that can contribute to a broad and robust protection from infection. The design can be fast, versatile and can be adapted to the development of vaccines for many infectious diseases as well as cancer vaccines. Electronic supplementary material The online version of this article (doi:10.1186/s12951-017-0289-y) contains supplementary material, which is available to authorized users.

Background The addition of an adjuvant to a vaccine is a promising approach to increasing strength and immunogenicity towards antigens. Despite the fact that adjuvants have been used in vaccines for decades, their mechanisms of action and their influence on the kinetics of the immune response are still not very well understood. The use of papaya mosaic virus (PapMV) nanoparticles-a novel TLR7 agonist-was recently shown to improve and broaden the immune response directed to trivalent inactivated flu vaccine (TIV) in mice and ferrets. Results We investigated the capacity of PapMV nanoparticles to increase the speed of the immune response toward TIV. PapMV nanoparticles induced a faster and stronger humoral response to TIV that was measured as early as 5 days post-immunization. The addition of PapMV nanoparticles was shown to speed up the differentiation of B-cells into early plasma cells, and increased the growth of germinal centers in a CD4+ dependent manner. TIV vaccination with PapMV nanoparticles as an adjuvant protected mice against a lethal infection as early as 10 days post-immunization. Conclusion In conclusion, PapMV nanoparticles are able to accelerate a broad humoral response to TIV. This property is of the utmost importance in the field of vaccination, especially in the case of pandemics, where populations need to be protected as soon as possible after vaccination. Electronic supplementary material The online version of this article (doi:10.1186/s12951-016-0200-2) contains supplementary material, which is available to authorized users.

A potexvirus was isolated from creeping phlox (Phlox stolonifera) plants from a commercial nursery in Pennsylvania. The virus was serologically related to clover yellow mosaic virus, plantain virus X, potato virus X, and potato aucuba mosaic virus, and was most closely related to papaya mosaic virus (PapMV). The sequence of a PCR fragment obtained with potexvirus group-specific primers was distinct from that of PapMV; the coat protein (CP) gene and 3' untranslated region (UTR) were closely related to Alternanthera mosaic virus (AltMV), previously reported only from Australia. The host range was similar to that of the Australian isolate (AltMV-Au), and the phlox isolate reacted strongly with antiserum to AltMV-Au. The full sequence of the phlox isolate was more closely related to PapMV throughout the genome than to any potexvirus other than AltMV-Au, for which only the CP and 3'UTR sequences are available. The phlox isolate was therefore named AltMV-PA (for Pennsylvania), and the full 6607 nt sequence is presented(1). Additional AltMV isolates from creeping phlox (AltMV-BR and AltMV-SP) and trailing portulaca (Portulaca grandiflora; AltMV-Po) were also isolated, suggesting that AltMV may be widespread, and may have been mis-diagnosed in the past as PapMV. AltMV has the potential to spread to other ornamental crops.

The complete nucleotide sequence of a strain of Cactus virus X (CVX-Hu) isolated from Hylocereus undatus (Cactaceae) has been determined. Excluding the poly(A) tail, the sequence is 6614 nucleotides in length and contains seven open reading frames (ORFs). The genome organization of CVX is similar to that of other potexviruses. ORF1 encodes the putative viral replicase with conserved methyltransferase, helicase, and polymerase motifs. Within ORF1, two other ORFs were located separately in the +2 reading frame, we call these ORF6 and ORF7. ORF2, 3, and 4, which form the "triple gene block" characteristic of the potexviruses, encode proteins with molecular mass of 25, 12, and 7 KDa, respectively. ORF5 encodes the coat protein with an estimated molecular mass of 24 KDa. Sequence analysis indicated that proteins encoded by ORF1-5 display certain degree of homology to the corresponding proteins of other potexviruses. Putative product of ORF6, however, shows no significant similarity to those of other potexviruses. Phylogenetic analyses based on the replicase (the methyltransferase, helicase, and polymerase domains) and coat protein demonstrated a closer relationship of CVX with Bamboo mosaic virus, Cassava common mosaic virus, Foxtail mosaic virus, Papaya mosaic virus, and Plantago asiatica mosaic virus.

We have isolated a previously undescribed potexvirus from Alternanthera pungens (Amaranthaceae) in southern Queensland, Australia. This virus was shown to have a moderately wide experimental host range, infecting plants in nine of the twelve families tested. Using specific antibodies, a plate trapped antigen ELISA was developed, allowing detection of virions down to 0.8 microgram/ml of leaf extract. Virions averaged 554 nm long and had a capsid protein with a M(r) of 23.1 x 10(3). A portion of the genome containing the capsid protein ORF and 3' untranslated region was cloned and sequenced. From both serological and amino acid sequence comparisons, the virus was shown to be closely related to papaya mosaic potexvirus (PMV). To determine the taxonomic status of the virus, we assessed variation in the amino acid sequence of capsid proteins of distinct species within the potexvirus genus, as well as variation between strains of the same virus. When the core region of the capsid proteins were compared, distinct species had a maximum of 62.2% sequence identity, whereas strains had a minimum of 88.8% identity. By comparison, the core region of the capsid proteins of the Alternanthera virus and PMV had 79.8% identity. We have concluded that the Alternanthera virus is a different species from PMV, and its relationship with PMV resembles that of potyvirus subgroup members.

The presence of an acetyl blocking group at the N-terminus of the coat protein of papaya mosaic virus has been identified by FAB mass spectrometry. Furthermore, we have found that the N-terminal sequence of the protein is four amino-acid residues (AC-Ser-Lys-Ser-Ser-) longer than that previously reported, while Glu instead of Gln is the C-terminal residue. The present paper shows that PMV-protein is made up of 215 amino acid residues, with a molecular mass of 22,960 Da.