Archives of Virology

The genotypic relatedness of persistent baculovirus infections within UK populations of Mamestra brassicae was assessed by sequencing amplified regions from polyhedrin and ie1. Most populations harboured Mamestra brassicae (Mb) nucleopolyhedrosis virus (NPV) which showed very little genotypic variation between populations. However, one population harboured a virus that closely resembled a baculovirus found previously only in Pine Beauty Moth (Panolis flammea) populations in Scotland. Persistent baculoviruses that had emerged spontaneously as lethal, overt infections from two of the insect populations were compared with the type strain of MbNPV and a mixture of P. flammea (Pafl) NPV strains, isolated from a single host, by bioassay in virus-free Spodoptera exigua larvae. Reactivated baculoviruses were as pathogenic as the stock virus and showed phenotypic characteristics closest to the type strain they most resembled genetically. Sequence data from the insect host cytochrome oxidase genes were compared and showed a high degree of sequence conservation between populations and it was not possible to determine whether the persistent baculovirus infections had arisen on many occasions or whether they represented a single initial infection that had spread with the host. However, the presence of two distinct virus genotypes in separate M. brassicae populations suggests multiple colonisations of the host are a possibility.

A new badnavirus was sequenced from fragrant pandan grass (Pandanus amaryllifolius) displaying mosaic and chlorosis on the leaves. The complete genome sequence was determined by high-throughput sequencing. The new badnavirus was tentatively named "pandanus mosaic associated virus" (PMaV). Similar to those of other members of the genus Badnavirus, the genome of PMaV consists of a circular DNA molecule of 7,481 bp with three open reading frames (ORF) potentially coding for three proteins. ORF3 encodes a polyprotein with conserved protein domains including zinc finger, trimeric dUTPase, aspartic protease, reverse transcriptase (RT), and RNase H domains. Pairwise comparisons of the highly conserved RT + RNase H region revealed the highest nucleotide (nt) sequence identity (70.71%) to taro bacilliform CH virus-Et17 (MG017324). In addition to PMaV, viral sequences corresponding to orchid fleck dichorhavirus (OFV) were detected in the same plant sample. The complete sequence of the OFV coding region shared >98% nt sequence identity with other isolates of OFV available in the GenBank database. Disease symptoms could not be attributed exclusively to PMaV or OFV, as both viruses were present in the pandan grass exhibiting mosaic and chlorosis.

Increased peripheral blood mononuclear cell (PBMC) apoptosis during viral hepatitis has been suggested to cause impaired regulation of the immune response and maintenance of the infection. The purpose of this work was to study the expression of some apoptotic markers in chronic hepatitis B (CHB) and C (CHC) infections in order to understand the underlying mechanisms of immune failure and viral persistence. This study aims to evaluate the level of PBMC apoptosis and the expression of the apoptosis-related proteins Fas and Bcl-2 in CHB and CHC patients. This case control study was carried out on 38 cases (group I: 20 chronic HCV patients; group II: 18 chronic HBV patients) attending the Tropical Medicine Clinic, Mansoura University Hospital, in addition to 10 healthy controls. Morphological assessment of apoptosis of cultured PBMCs was done. The level of Fas and Bcl-2 expression by PBMCs was detected using flow cytometry. An increased level of apoptosis correlated with increased Fas expression, but no increase in Bcl-2 expression was found on the surface of PBMCs in CHC and CHB patients compared to controls. No significant difference in the level of apoptosis, Fas, or Bcl2 expression between CHC and CHB patients was detected. Modulation of apoptosis, particularly by manipulation of Fas receptor activation, may be of therapeutic benefit in chronic CHB and CHC.

Herpesviruses have been isolated from white-tailed, white-bearded and blue wildebeest, as well as from Jimela topi and Cape hartebeest. These animals are members of the sub-familyAlcelaphinae of the familyBovidae. Viruses isolated from wildebeest cause malignant catarrhal fever (MCF) in susceptible ruminant species. Alcelaphine herpesviruses (AHV) isolated from wildebeest replicate in both fetal aoudad sheep kidney (FAK) cells and bovine embryonic lung (BEL) cells. However, virus isolates from topi and hartebeest, which have not been linked to clinical MCF, replicate only in FAK cells. Buoyant density analysis by analytical ultracentrifugation, restriction endonuclease analysis and blot hybridization of virus genomic DNA from both alcelaphine herpesviruses as well as from bovine herpesviruses 1, 2, and 4 demonstrate that there are two types of alcelaphine herpesviruses, each distinct and different from the other bovine herpesviruses. Genomic size of both alcelaphine herpesviruses, estimated from DNA restriction fragments, is approximately 110 kilo-base pairs. Alcelaphine herpesvirus DNA resemblesHerpesvirus saimiri DNA during equilibrium sedimentation in that the majority of the DNA bands as a light (L) fraction with a minor heavy (H) component. Polyacrylamide gel analysis of virion proteins indicates that both viruses have distinct patterns, each consisting of 36 polypeptides ranging in molecular weight from 12,000 to 275,000. Virus isolates from wildebeest have been designated AHV-1, while viruses isolated from topi and hartebeest have been designated AHV-2.

Fifty-four harvests of 7 different strains of vaccinia virus present in calf lymph used as smallpox vaccine have been examined for virulence, antigenicity, and resistance to neutralizing antibody, and the results were compared with those of a similar examination of smallpox vaccines that had initiated postvaccinal encephalitis. In 3 of 6 cases of post vaccinal encephalitis, the antibody level was poor, and did not agree with the high antigenicity of the virus. In one case, a child that had been vaccinated with a vaccine of low antigenicity, vaccinia virus was recovered from the blood on the 15th day following vaccination. It is suggested, that individual factors may inhibit the production of neutralizing antibody, and in animal experiments, guanidin appeared to exert such an inhibitory effect, although slight and transient. A considerably higher antibody level was obtained when rabbits and children were revaccinated on the 7th day following primary vaccination, but then the virus could be recovered from the blood from the second to the eighth day following revaccination, which proves, that the virus is not rapidly inactived in spite of the high antibody level. Immunization experiments with heat-inactivated neurovaccinia, even when incorporated in vaseline and lanoline, were unsuccessfull, since the resistance to challenge with living neurovaccinia, particularly of the central nervous system, proved unsatisfactory, although antibodies had developed. Softened foci of the brain and encephalitis could be produced by intracerebral inoculation of rabbits with mixtures of neurovaccinia, vaccinia immune serum and brain tissue, but no demyelination was observed. Bovine protein, vaccinia virus grown on the chorioallantoic membrane of the chick-embryo, and bacteriologically sterile calf lymph failed to produce demyelination after repeated injection into rabbits. Only in one rabbit, that had been injected intracerebrally with calf lymph, and that received two subsequent intramuscular injections with the same material, developed a demyelinating encephalopathy, which, however, was not identical with the demyelinating lesions in human beings suffering from postvaccinal encephalitis. It is suggested, that the vaccinia virus may produce the inflammatory lesion in the wall of the blood vessels, but that the virus particle itself has no direct action on the myelin sheaths.

The complete genome of sweet potato latent virus (SPLV) was determined to be 10081 nucleotides long excluding the 3’ poly (A) tail. The genome contains a single large open reading frame encoding a polyprotein of 3247 amino acids. Its genomic organization is typical of potyviruses and contains motifs conserved in members of the genus Potyvirus. Pairwise comparisons show that SPLV shares identities of 50.0 %-56.3 % to other potyviruses at the genomic sequence level. Phylogenetic analysis shows that SPLV is closely related to four other sweet potato potyviruses in the sweet potato feathery mottle virus lineage, but it lacks the unique PISPO in the P1 region of those viruses. The genome analyses confirm that SPLV is a distinct sweet potato virus in the genus Potyvirus.

Porcine circovirus type 2 (PCV2) is an important pathogen in swine, and it is assumed that PCV2 replication is cell cycle dependent (especially during S phase). However, the cellular molecules that regulate PCV2 replication have not been fully identified. Here, we cloned the porcine cyclin A (CycA) and CDK2 genes, the major regulators of the S phase, and established CycA or CDK2 overexpression and lower-expression cell lines. The propagation efficiency of strains PCV2a/CL or PCV2b/YJ in these cell lines was investigated using a capture enzyme-linked immunosorbent assay (ELISA) or an immunoperoxidase monolayer assay (IPMA), and the cell cycle was analyzed by flow cytometry. The results showed that CycA overexpression suppressed PCV2 replication. In contrast, CycA down-regulation by shRNA induced increases during the S and G2/M phases and resulted in increased PCV2 propagation. In contrast, overexpression or lower expression of CDK2 exhibited no significant influence on PCV2 replication. Furthermore, the subcellular localization of the PCV2 replicase protein (Rep) and capsid protein (Cap), CycA, and CDK2 in PK-15 cells was analyzed by confocal microscopy. The results showed that overexpression of CycA, rather than CDK2, altered normal nuclear localization of PCV2-Rep, which was transferred to the cytoplasm. In conclusion, PCV2 replication is both S- and G2/M-phase dependent and CycA, is an important regulator of the PCV2 life cycle.

The complete genome sequence of Stellaria aquatica virus B (StAVB), a new member of the genus Polerovirus that infects Stellaria aquatica, was determined using high-throughput RNA sequencing with confirmation by Sanger sequencing. The complete StAVB genome (GenBank accession no. OP389993) is 5,900 nucleotide (nt) long with seven open reading frames (ORF0–5 and ORF3a) that encode putative proteins (P0–P5 and P3a) in a similar configuration to that of other typical poleroviruses. Pairwise sequence comparisons with other poleroviruses showed 38–50% nt sequence identity in the complete genome and 13–24%, 36–45%, 7–68%, and 6–50% amino acid sequence identity in (aa), for the P0, P1–2, P3, and P4 protein, respectively. These data, together with the results of phylogenetic analysis, indicate that StAVB should be classified as a new member of the genus Polerovirus, family Solemoviridae.

In this cross-sectional study, we evaluated the efficiency of the plasma of 38 antiretroviral-naïve HIV-1-infected children from northern India against a standard panel of pseudoviruses (3 clade C and 3 clade B) by TZM-bl assay. Neutralization potential was observed to a variable extent, with a potency ranging up to reciprocal ID50 titers of 1967. Cross-neutralization was observed in 28.9 % (11/38) of the children. There was a significant positive correlation between viremia and neutralization efficiency against two of the viruses studied (Du172 r = 0.49; p = 0.007 and RHPA r = 0.47; p = 0.01), suggesting that persistent antigenic stimulation is necessary for the generation of broadly neutralizing antibody responses in these children. Further mapping of the epitope specificities of the neutralization determinants in the polyclonal plasma would provide important information for immunogen design.