Hepatitis B surface antigen fusions delivered by DNA vaccination elicit CTL responses to human papillomavirus oncoproteins associated with tumor protection.

We describe the construction and evaluation of a recombinant hepatitis B surface antigen (HBsAg)-vectored DNA vaccine encoding the E7 and E6 tumor-associated oncoproteins of human papillomavirus (HPV) type 16. We show the induction of effector and memory cytotoxic T lymphocyte responses to E7 and E6 class I-restricted epitopes after a single immunization, which were associated with tumor prevention and therapy. The findings vindicate the use of a HBsAg-based DNA vaccine as a vehicle to elicit responses to co-encoded tumor antigens, and have specific implications for the development of a therapeutic vaccine for HPV-associated squamous carcinomas.

Deduced amino acid sequences surrounding the fusion glycoprotein cleavage site and of the carboxyl-terminus of haemagglutinin-neuraminidase protein of the avirulent thermostable vaccine strain I-2 of Newcastle disease virus.

A single-tube RT-PCR technique generated a 387 bp or 300 bp cDNA amplicon covering the F(0) cleavage site or the carboxyl (C)-terminus of the HN gene, respectively, of Newcastle disease virus (NDV) strain I-2. Sequence analysis was used to deduce the amino acid sequences of the cleavage site of F protein and the C-terminus of HN protein, which were then compared with sequences for other NDV strains. The cleavage site of NDV strain I-2 had a sequence motif of (112) RKQGRLIG(119), consistent with an avirulent phenotype. Nucleotide sequencing and deduction of amino acids at the C-terminus of HN revealed that strain I-2 had a 7-amino-acid extension (VEILKDGVREARSSR. This differs from the virulent viruses that caused outbreaks of Newcastle disease in Australia in the 1930s and 1990s, which have HN extensions of 0 and 9 amino acids, respectively. Amino acid sequence analyses of the F and HN genes of strain I-2 confirmed its avirulent nature and its Australian origin.

Genetic diversity of bluetongue viruses in south east Asia.

Bluetongue viruses (BTV) were isolated from sentinel cattle in Malaysia and at two sites in Indonesia. We identified eight serotypes some of which appeared to have a wide distribution throughout this region, while others were only isolated in Malaysia or Australia. Nearly half of the 24 known BTV serotypes have now been identified in Asia. Further, we investigated the genetic diversity of their RNA segments 3 and 10. Using partial nucleotide sequences of the RNA segment 3 (540 bp) which codes for the conserved core protein (VP3), the BTV isolates were found to be unique to the previously defined Australasian topotype and could be further subdivided into four distinct clades or genotypes. Certain of these genotypes appeared to be geographically restricted while others were distributed widely throughout the region. Similarly, the complete nucleotide sequences of the RNA segment 10 (822 bp), coding for the non-structural protein (NS3/3A), were also conserved and grouped into the five genotypes; the BTV isolates could be grouped into three Asian genotypes and two Nth American/Sth African genotypes.

Virulent Newcastle disease in Australia: molecular epidemiological analysis of viruses isolated prior to and during the outbreaks of 1998-2000.

Gene sequence analysis of fusion (F) gene cleavage motifs and haemagglutinin-neuraminidase (HN) carboxyl-terminal extension sequences was used to analyse Newcastle disease viruses (NDV) associated with virulent outbreaks of the disease which occurred in New South Wales, Australia in 1998-2000. PCR fragments were amplified directly from diseased tissue or allantoic fluids and sequence analyses used for phylogenetic comparisons between these viruses and Australian reference NDV. F and HN gene sequence comparison showed a strong relationship to sequences derived from endemic Australian NDV rather than those of overseas viruses or wild bird isolates. Prior to notification of the 1998 outbreak, an NDV was isolated from chickens suffering respiratory disease that appeared to be the progenitor virus from which the virulent virus originated. In turn, these viruses are closely related to two previously isolated 'ancestor' viruses that have the same unique HN extension sequence.

First isolation of an aquatic birnavirus from farmed and wild fish species in Australia.

During routine sampling and testing, as part of a systematic surveillance program (the Tasmanian Salmonid Health Surveillance Program), an aquatic birnavirus was isolated from 'pin-head' (fish exhibiting deficient acclimatisation on transfer to saltwater) Atlantic salmon Salmo salar, approximately 18 mo old, farmed in net-pens located in Macquarie Harbour on the west coast of Tasmania, Australia. The isolate grows readily in a range of fish cell lines including CHSE-214, RTG-2 and BF-2 and is neutralised by a pan-specific rabbit antiserum raised against infectious pancreatic necrosis virus (IPNV) Ab strain and by a commercial pan-specific IPNV-neutralising monoclonal antibody. Presence of the virus was not associated with gross clinical signs. Histopathological examination revealed a range of lesions particularly in pancreatic tissue. The virus was localised in pancreas sections by immunoperoxidase staining using the polyclonal antiserum and by electron microscopy. Examination by electron microscopy demonstrated that the virus isolated in cell culture (1) belongs to the family Birnaviridae, genus Aquabirnaviridae; (2) was ultrastructurally and antigenically similar to virus identified in the index fish; (3) is related to IPNV. Western blot analysis using the polyclonal rabbit antiserum confirmed the cross-reactions between various aquatic birnavirus isolates. In addition, PCR analysis of isolated viral nucleic acid from the index case indicated that the virus is more closely related to IPNV fr21 and N1 isolates than to other birnavirus isolates available for comparison. Sampling of other fish species within Macquarie Harbour has demonstrated that the virus is present in several other species of fish including farmed rainbow trout Oncorhynchus mykiss, wild flounder Rhombosolea tapirina, cod Pseudophycis sp., spiked dogfish Squalus megalops and ling Genypterus blacodes.

The complete nucleotide sequence of rabbit haemorrhagic disease virus (Czech strain V351): use of the polymerase chain reaction to detect replication in Australian vertebrates and analysis of viral population sequence variation.

The complete nucleotide sequence of the Czech strain of rabbit haemorrhagic disease virus (RHDV) was determined to be 7437 nucleotides in length with a 5-terminal non-coding region of 9 nucleotides and a 3'-terminal non-coding region of 59 nucleotides. Two open reading frames (ORFs) were found within this sequence coding for polypeptides of 2344 (nucleotides 10-7044) and 117 amino acids (nucleotides 7025-7378). The sequence of this isolate was approximately 1% different from that reported by Meyers et al., having 78 nucleotide changes which resulted in 30 amino acid differences, the majority of these clustering in the N-terminus of the large ORF and the middle of the viral coat protein. Only a single conservative amino acid change was seen in the smaller 3'-terminal ORF. Since the virus cannot at present be propagated in tissue culture, but isolated only after replication in rabbits, the reported sequence must be considered as a consensus sequence from the viral population. To gain some understanding of the possible sequence diversity within this virus population, 97 clones were sequenced from a polymerase chain reaction (PCR) fragment to determine the sequence diversity of the virus population. Four major classes of variant were described with mutations generally in the third base position of codons. A nested reverse transcriptase (RT) PCR (using sequence derived for the coat protein of RHDV) was used to determine the presence or absence of RHDV inoculated into non-host animal species. No replication of the virus was detected in 28 different vertebrate species other than rabbits. PCR tests on both mosquitoes and fleas feeding on RHDV infected rabbits were positive. The RT-PCR test was more sensitive when compared with an antigen capture ELISA to detect the presence of genomic RNA/or virus in infected rabbits.