Retroviruses assemble and bud from infected cells in an immature form and require proteolytic maturation for infectivity. The CA (capsid) domains of the Gag polyproteins assemble a protein lattice as a truncated sphere in the immature virion. Proteolytic cleavage of Gag induces dramatic structural rearrangements; a subset of cleaved CA subsequently assembles into the mature core, whose architecture varies among retroviruses. Murine leukemia virus (MLV) is the prototypical γ-retrovirus and serves as the basis of retroviral vectors, but the structure of the MLV CA layer is unknown. Here we have combined X-ray crystallography with cryoelectron tomography to determine the structures of immature and mature MLV CA layers within authentic viral particles. This reveals the structural changes associated with maturation, and, by comparison with HIV-1, uncovers conserved and variable features. In contrast to HIV-1, most MLV CA is used for assembly of the mature core, which adopts variable, multilayered morphologies and does not form a closed structure. Unlike in HIV-1, there is similarity between protein-protein interfaces in the immature MLV CA layer and those in the mature CA layer, and structural maturation of MLV could be achieved through domain rotations that largely maintain hexameric interactions. Nevertheless, the dramatic architectural change on maturation indicates that extensive disassembly and reassembly are required for mature core growth. The core morphology suggests that wrapping of the genome in CA sheets may be sufficient to protect the MLV ribonucleoprotein during cell entry.

• Klíčová slova
• capsid, cryoelectron tomography, maturation, murine leukemia virus, retrovirus,
• MeSH
• elektronová kryomikroskopie MeSH
• genové produkty gag chemie   genetika   ultrastruktura   MeSH
• HEK293 buňky MeSH
• HIV-1 chemie   genetika   ultrastruktura   MeSH
• kapsida chemie   ultrastruktura   MeSH
• krystalografie rentgenová MeSH
• kvarterní struktura proteinů MeSH
• lidé MeSH
• molekulární modely MeSH
• myši MeSH
• proteinové domény MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• tomografie elektronová MeSH
• virion chemie   genetika   ultrastruktura   MeSH
• virové plášťové proteiny chemie   genetika   ultrastruktura   MeSH
• virus myší leukemie chemie   genetika   ultrastruktura   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH
• srovnávací studie MeSH
• Názvy látek
• genové produkty gag MeSH
• virové plášťové proteiny MeSH

• MeSH
• biologie buňky * MeSH
• chromozomy MeSH
• embryo savčí MeSH
• experimentální sarkom * MeSH
• Gammaretrovirus * MeSH
• křečci praví MeSH
• krysa rodu Rattus MeSH
• kultivační techniky MeSH
• myši MeSH
• transplantace nádorů MeSH
• virus myší leukemie MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• krysa rodu Rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The present epidemiological study had the objective to establish whether and to what extent resident islander populations might be affected by the natural foci of murine typhus. To this end, 294 serum specimens were collected during summer and autumn of 1985 from the northern Dalmatian islanders, all of which were tested for anti-Rickettsia typhi (R. typhi) complement fixing (CF) antibodies. These were detected and confirmed at both stages of the screening, namely during the first stage, conducted on the northern Dalmatian islands, where 63.3% of the representative population had a titre of 1:4 or higher and during the second stage, carried out on the island of Vir, with 68.1% of the residents found R. typhi positive unlike in the former. The majority of positive sera were found in the 21-60-year group, peaking in the 21-30- and 31-40-year groups with fewer positive sera among the subjects over 60 and the fewest among the residents below 20 years of life. Thus, current differences in antibody rates in various age groups were shown to be statistically significant. Murine typhus immunity in resident islander populations could be detected from the age of 10 years on, and was shown to become almost equal to the adult population's positive sera levels in the 16-20-year age group. No differences were revealed with regard to the infective agent exposure between the male and female populations representative of the total population or in any of the age groups.

• MeSH
• dítě MeSH
• dospělí MeSH
• infekce přenášené vektorem MeSH
• lidé středního věku MeSH
• lidé MeSH
• tyfus endemický přenášený blechami epidemiologie   MeSH
• zdroje nemoci MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Jugoslávie epidemiologie   MeSH

The assembly of immature retroviral particles is initiated in the cytoplasm by the binding of the structural polyprotein precursor Gag with viral genomic RNA. The protein interactions necessary for assembly are mediated predominantly by the capsid (CA) and nucleocapsid (NC) domains, which have conserved structures. In contrast, the structural arrangement of the CA-NC connecting region differs between retroviral species. In HIV-1 and Rous sarcoma virus, this region forms a rod-like structure that separates the CA and NC domains, whereas in Mason-Pfizer monkey virus, this region is densely packed, thus holding the CA and NC domains in close proximity. Interestingly, the sequence connecting the CA and NC domains in gammaretroviruses, such as murine leukemia virus (MLV), is unique. The sequence is called a charged assembly helix (CAH) due to a high number of positively and negatively charged residues. Although both computational and deletion analyses suggested that the MLV CAH forms a helical conformation, no structural or biochemical data supporting this hypothesis have been published. Using an in vitro assembly assay, alanine scanning mutagenesis, and biophysical techniques (circular dichroism, NMR, microcalorimetry, and electrophoretic mobility shift assay), we have characterized the structure and function of the MLV CAH. We provide experimental evidence that the MLV CAH belongs to a group of charged, E(R/K)-rich, single α-helices. This is the first single α-helix motif identified in viral proteins.

• Klíčová slova
• capsid protein (CA), charged assembly helix (CAH), circular dichroism (CD), electron microscopy (EM), murine leukemia virus (MLV), nuclear magnetic resonance (NMR), retrovirus, single alpha-helix (SAH), spacer peptide (SP), virus assembly,
• MeSH
• mutageneze MeSH
• myši MeSH
• proteinové domény MeSH
• sekundární struktura proteinů MeSH
• virové plášťové proteiny chemie   genetika   MeSH
• virus myší leukemie chemie   genetika   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• virové plášťové proteiny MeSH

The use of nanoparticles as a delivery system for a specific antigen could solve many limitations of mucosal vaccine applications, such as low immunogenicity, or antigen protection and stabilization. In this study, we tested the ability of nasally administered chitosan nanoparticles loaded with glycoprotein B of murine cytomegalovirus to induce an immune response in an animal model. The choice of chitosan nanoparticle type was made by in vitro evaluation of sorption efficiency and antigen release. Three types of chitosan nanoparticles were prepared: crosslinked with tripolyphosphate, coated with hyaluronic acid, and in complex with polycaprolactone. The hydrodynamic size of the nanoparticles by dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, scanning electron microscopy, stability, loading efficiency, and release kinetics with ovalbumin were evaluated. Balb/c mice were immunized intranasally using the three-dose protocol with nanoparticles, gB, and adjuvants Poly(I:C) and CpG ODN. Subsequently, the humoral and cell-mediated antigen-specific immune response was determined. On the basis of the properties of the tested nanoparticles, the cross-linked nanoparticles were considered optimal for further investigation. The results show that nanoparticles with Poly(I:C) and with gB alone raised IgG antibody levels above the negative control. In the case of mucosal IgA, only gB alone weakly induced the production of IgA antibodies compared to saline-immunized mice. The number of activated cells increased slightly in mice immunized with nanoparticles and gB compared to those immunized with gB alone or to negative control. The results demonstrated that chitosan nanoparticles could have potential in the development of mucosal vaccines.

• Klíčová slova
• Nanoparticles, cytomegalovirus, murine, nasal administration, vaccine,
• MeSH
• adjuvancia imunologická MeSH
• aplikace intranazální MeSH
• chitosan * chemie   MeSH
• glykoproteiny MeSH
• imunizace MeSH
• imunoglobulin A MeSH
• Muromegalovirus * MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• nanočástice * chemie   MeSH
• slizniční imunita MeSH
• vakcíny * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adjuvancia imunologická MeSH
• chitosan * MeSH
• glykoproteiny MeSH
• imunoglobulin A MeSH
• vakcíny * MeSH

Murine herpesvirus 68 (MHV-68) is a natural pathogen that infects murid rodents, which serves as hosts for Ixodes ricinus ticks. For the first time, MHV-68 was detected in immature I. ricinus ticks feeding on Lacerta viridis lizards trapped in Slovakia, which supports the idea that ticks can acquire the virus from feeding on infected hosts. The recent discovery of MHV-68 infection and MHV-68 M3 gene transcripts in Dermacentor reticulatus ticks collected in Slovakia also supports this suggestion. Here, for the first time, we report MHV-68 infection, which was detected by nested PCR, in I. ricinus adults collected from the vegetation, and the viral load in infected ticks was determined by quantitative PCR. The viral incidence in ticks was 38.1% (21/55), and the viral load varied from 1.5 × 103 to 2.85 × 104 genome copies per tick. These results suggest that the I. ricinus ticks became infected with MHV-68 from biting infected rodents; thus, I. ricinus ticks may play a role in the spread of this virus in nature.

• Klíčová slova
• Ixodes ricinus, MHV-68 load, Murine herpesvirus 68, Slovakia, qPCR,
• MeSH
• arachnida jako vektory virologie   MeSH
• DNA virů genetika   MeSH
• hlodavci MeSH
• klíště virologie   MeSH
• Rhadinovirus izolace a purifikace   fyziologie   MeSH
• virová nálož MeSH
• virové geny genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Slovenská republika MeSH
• Názvy látek
• DNA virů MeSH

Immature retroviral particles are assembled by self-association of the structural polyprotein precursor Gag. During maturation the Gag polyprotein is proteolytically cleaved, yielding mature structural proteins, matrix (MA), capsid (CA), and nucleocapsid (NC), that reassemble into a mature viral particle. Proteolytic cleavage causes the N terminus of CA to fold back to form a β-hairpin, anchored by an internal salt bridge between the N-terminal proline and the inner aspartate. Using an in vitro assembly system of capsid-nucleocapsid protein (CANC), we studied the formation of virus-like particles (VLP) of a gammaretrovirus, the xenotropic murine leukemia virus (MLV)-related virus (XMRV). We show here that, unlike other retroviruses, XMRV CA and CANC do not assemble tubular particles characteristic of mature assembly. The prevention of β-hairpin formation by the deletion of either the N-terminal proline or 10 initial amino acids enabled the assembly of ΔProCANC or Δ10CANC into immature-like spherical particles. Detailed three-dimensional (3D) structural analysis of these particles revealed that below a disordered N-terminal CA layer, the C terminus of CA assembles a typical immature lattice, which is linked by rod-like densities with the RNP.

• MeSH
• DNA primery MeSH
• elektronová kryomikroskopie MeSH
• Escherichia coli ultrastruktura   virologie   MeSH
• Fourierova analýza MeSH
• molekulární sekvence - údaje MeSH
• polymerázová řetězová reakce MeSH
• proteolýza MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční homologie aminokyselin MeSH
• sestavení viru * MeSH
• transmisní elektronová mikroskopie MeSH
• virion fyziologie   MeSH
• virové proteiny chemie   metabolismus   MeSH
• virus myší leukemie fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• DNA primery MeSH
• virové proteiny MeSH

Mild microcytic anemia (without changes in mean corpuscular hemoglobin concentration, MCHC) was discovered 6-14 weeks after a single s.c. administration of 4 mg of particulate glucan to C57BL/10ScSnPh mice serologically positive for murine hepatitis (MHV). The anemia was associated with granulocytosis, decreased body weight and spleen hypertrophy. The overall intensity of erythropoiesis was measured by 59Fe-incorporation into the heme of erythropoietic organs. The localization of erythropoiesis became markedly redistributed--heme production was suppressed in the bone marrow while a several-fold increase was recorded for the spleen. A new steady state was also discovered in ferrokinetics: an iron pool localized away from the blood, erythropoietic organs and the liver was significantly elevated, and hypoferremia was detected. Anemia and wasting of mice were not observed in the same mouse strain free of MHV. A single administration of particulate glucan resulted in late impairment of red blood cell formation in the C57BL/10ScSnPh mouse strain infected with the mouse hepatitis virus. The anemia shares a number of features with those observed for the anemia of chronic diseases.

• MeSH
• adjuvancia imunologická toxicita   MeSH
• anemie etiologie   imunologie   metabolismus   MeSH
• glukany toxicita   MeSH
• hem metabolismus   MeSH
• hematopoéza MeSH
• kinetika MeSH
• koronavirové infekce komplikace   imunologie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• virová hepatitida u zvířat komplikace   imunologie   metabolismus   MeSH
• virus myší hepatitidy MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adjuvancia imunologická MeSH
• glukany MeSH
• hem MeSH
• železo MeSH

Murine cytomegalovirus (MCMV) has been reported from house mice (Mus musculus) worldwide, but only recently from Eastern house mice (M. m. musculus), of particular interest because they form a semi-permeable species barrier in Europe with Western house mice, M. m. domesticus. Here we report genome sequences of EastMCMV (from Eastern mice), and set these in the context of MCMV genomes from genus Mus hosts. We show EastMCMV and WestMCMV are genetically distinct. Phylogeny splitting analyses show a genome wide (94%) pattern consistent with no West-East introgression, the major exception (3.8%) being a genome-terminal region of duplicated genes involved in host immune system evasion. As expected from its function, this is a region of maintenance of ancestral polymorphism: The lack of clear splitting signal cannot be interpreted as evidence of introgression. The EastMCMV genome sequences reported here can therefore serve as a well-described resource for exploration of murid MCMV diversity.

• Klíčová slova
• Host-specificity, House mouse, Hybrid zone, Introgression, Murine cytomegalovirus, Mus musculus musculus,
• MeSH
• fylogeneze MeSH
• genetická variace * MeSH
• genom virový * MeSH
• hostitelská specificita * MeSH
• imunitní únik MeSH
• Muromegalovirus genetika   MeSH
• myši virologie   MeSH
• polymorfismus genetický MeSH
• zeměpis MeSH
• zvířata MeSH
• Check Tag
• myši virologie   MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

• MeSH
• antisérum * MeSH
• časové faktory MeSH
• experimentální sarkom imunologie   MeSH
• Gammaretrovirus imunologie   MeSH
• homologní transplantace MeSH
• myši MeSH
• nádorová transformace buněk MeSH
• protilátky MeSH
• techniky in vitro MeSH
• transplantace nádorů MeSH
• transplantační imunologie MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antisérum * MeSH
• protilátky MeSH