Descriptive epidemiology of rotavirus infection in a community in North India.

In India, rotavirus infections cause the death of 98621 children each year. In urban neighbourhoods in Delhi, children were followed up for 1 year to estimate the incidence of rotavirus gastroenteritis and common genotypes. Infants aged f1 week were enrolled in cohort 1 and infants aged 12 months (up to +14 days) in cohort 2. Fourteen percent (30/210) gastroenteritis episodes were positive for rotavirus. Incidence rates of rotavirus gastroenteritis episodes in the first and second year were 0.18 [95% confidence interval (CI) 0.10­0.27] and 0.14 (95% CI 0.07­0.21) episodes/child-year, respectively. The incidence rate of severe rotavirus gastroenteritis in the first year of life was 0.05 (95% CI 0.01­0.10) episodes/child-year. There were no cases in the second year. The common genotypes detected were G1P[8] (27%) and G9P[4] (23%). That severe rotavirus gastroenteritis is common in the first year of life is relevant for planning efficacy trials.

Comparison of the genome sequences and the phylogenetic analyses of the GP78 and the Vellore P20778 isolates of Japanese encephalitis virus from India.

The nucleotide sequence of the complete genomes of two Indian isolates of Japanese encephalitis virus were compared. One of these isolates, GP78 was obtained from northern India in 1978. The other, the Vellore P20778 isolate, was obtained from southern India in 1958. There was 4.40% nucleotide sequence divergence between the two Indian isolates that resulted in a 1.86% amino acid sequence divergence. Phylogenetic analyses showed that in evolutionary terms the north Indian GP78 isolate was close to the SA14 isolate from China whereas the south Indian Vellore P20778 isolate was close to the Beijing-1 isolate, also from China. The two Indian isolates, however, appear to have evolved independently.

Mov34 protein from mouse brain interacts with the 3' noncoding region of Japanese encephalitis virus.

The plus-sense RNA genome of Japanese encephalitis virus (JEV) contains noncoding regions (NCRs) of 95 and 585 bases at its 5' and 3' ends, respectively. The last 83 nucleotides of the 3'-NCR are predicted to form stable stem-loop (SL) structures. The shape of this 3'-SL structure is highly conserved among divergent flaviviruses even though only small stretches of nucleotide sequence contained within these structures are conserved. These SL structures have been predicted to function as cis-acting signals for RNA replication and as such may bind to viral and cellular proteins that may be involved in viral replication. We have studied the interaction of the JEV 3'-NCR RNA with host proteins using gel retardation assays. We show that the JEV 3'-SL structure RNA forms three complexes with proteins from the S100 cytoplasmic extract prepared from the neonatal mouse brain. These complexes could be obtained in the presence of 200 mM KCl, indicating that the RNA-protein interaction may be physiologically relevant. UV-induced cross-linking and Northwestern blotting analyses detected three proteins with apparent molecular masses of 32, 35, and 50 kDa that bound to the JEV 3'-SL structure RNA. Screening of the neonatal mouse brain cDNA library with the JEV 3'-SL structure RNA identified a 36-kDa Mov34 protein interacting with it. Competition experiments using the RNA extracted from JEV virions established that the 36-kDa Mov34 protein indeed bound to the JEV genome. Murine Mov34 belongs to a family of proteins whose members have been shown to be involved in RNA transcription and translation. It is, therefore, likely that the murine Mov34 interaction with JEV 3'-NCR has a role in RNA replication.

Complete nucleotide sequence of an Indian strain of Japanese encephalitis virus: sequence comparison with other strains and phylogenetic analysis.

The RNA genome of an Indian strain of Japanese encephalitis virus (JEV), GP78, was reverse transcribed and the cDNA fragments were cloned in bacterial plasmids. Nucleotide sequencing of the cDNA clones covering the entire genome of the virus established that the GP78 genome was 10,976 nucleotides long. An open reading frame of 10,296 bases, capable of coding for a 3,432 amino acid polyprotein, was flanked by 95- and 585-base long 5'- and 3'-non-coding regions, respectively. When compared with the nucleotide sequence of the JaOArS982 strain, the JEV GP78 genome had a number of nucleotide substitutions that were scattered throughout the genome except for the 5'-noncoding region, the sequence of which was fully conserved. Comparison of the complete genome sequences of different JEV isolates showed a 1.3-4.1% nucleotide sequence divergence among them, which resulted in 0.6-1.8% amino acid sequence divergence. Analysis based on the complete genome sequences of different JEV isolates showed that the GP78 isolate from India was phylogenetically closer to the Chinese SA14 isolate.

Molecular characterization of an Indian isolate of Japanese encephalitis virus that shows an extended lag phase during growth.

The biological properties of an Indian isolate (GP78) of Japanese encephalitis virus (JEV) were characterized in tissue-cultured cells and mice and these were compared with the JaOArS982 strain from Japan. The GP78 strain had a markedly extended lag phase during its growth in porcine stable kidney (PS) cells. There were no obvious defects in the penetration of GP78 into PS cells. However, viral RNA and protein synthesis were significantly delayed in GP78-infected PS cells. Fusion-from-within assays carried out in C6/36 cells indicated that GP78 was less fusogenic than the JaOArS982 strain of JEV. Moreover, maximum fusion in GP78-infected cells occurred at pH 5.5, whereas JaOArS982-infected cells showed maximum fusion at pH 6.0. These results suggested that there may be a lesion in the virus-cell fusion process. The GP78 strain also showed delayed growth in brains of 1-week-old BALB/c mice. Although JEV GP78 was as virulent as the JaOArS982 strain in these mice, the appearance of clinical symptoms of JEV infection was delayed by a day in mice infected with the GP78 strain and these animals showed an increased average survival time. Comparison of the nucleotide sequences of the GP78 and the JaOArS982 strains of JEV identified a number of amino acid substitutions in structural proteins. Of these, a Thr --> Met substitution at residue 76 of the envelope protein is predicted to be causally associated with the altered biology of the GP78 strain during growth.

Oral immunization with recombinant vaccina expressing cell-surface-anchored beta hCG induces anti-hCG antibodies and T-cell proliferative response in rats.

A vaccinia recombinant, VSS2, expressing cell-surface-anchored beta-subunit of human chorionic gonadotropin (beta hCG) has earlier been found to induce high titered anti-hCG antibodies in rats immunized by tail scarification. The immunogenicity of this recombinant was compared in rats which received the virus through different routes of inoculation: intradermal, intragastric, intrajejunal or by tail scarification. The recombinant virus induced high titers of anti-hCG antibodies in all instances although the titers were about one log lower when the recombinant virus was delivered orally. The recombinant was found to induce T-cell proliferative response in rats of all immunization groups.

Recombinant adenovirus synthesizing cell surface-anchored beta hCG induces bioneutralizing antibodies in rats.

A recombinant adenovirus (re-Ad) has been constructed that synthesizes a cell surface-anchored form of the beta-subunit of human chorionic gonadotropin (beta hCG). This was achieved by in-frame fusion of beta hCG cDNA at its C terminus with the gene sequences coding for the vesicular stomatitis virus glycoprotein (VSVg) transmembrane domain. The fusion protein gene was placed under the control of human cytomegalovirus (hCMV) immediate early promoter and this expression cassette was inserted into the E1 region of Ad type 5 by homologous recombination. In vitro experiments using re-Ad-infected 293 cells showed that beta hCG fusion protein was made as early as 6 h post infection and the protein was anchored to the cell membrane as seen by immunofluorescence staining. The re-Ad induced bioneutralizing antibodies (Ab) to hCG when inoculated in rats through intraperitoneal or intramuscular routes. The Ab were made in a dose-dependent manner. However, orally delivered re-Ad failed to generate any significant immune response.

The HSD-hCG vaccine prevents pregnancy in women: feasibility study of a reversible safe contraceptive vaccine.

PROBLEM: To develop a vaccine for reversible control of fertility in women. MATERIALS AND PROTOCOLS: Purified beta subunit of hCG annealed to purified alpha subunit of ovine LH linked chemically to tetanus toxoid (TT) and diphtheria (DT); vaccine employed at 300 micrograms gonadotropin equivalent per injection adsorbed on alhydrogel with 1 mg SPLPS added in the first injection; Phase I safety trials in 47 women with elective tubal ligation; Phase II efficacy studies in 148 proven fertile women (2 children), sexually active, desirous of family planning using IUD; IUD removed when anti-hCG titres exceed 50 ng/ml hCG bioneutralization capacity; boosters given to maintain above threshold antibody levels; post coital tests conducted in 8 volunteers; sera of protected women analysed for immuno-determinants recognized by competitive enzyme immunoassays employing a panel of monoclonal antibodies and by direct binding to synthetic peptides; recombinant vaccines expressing beta hCG as a secreted product or as a fused protein anchored on membrane. RESULTS: Immunization was well tolerated with no significant changes in endocrine, metabolic and hematological indices. Normal ovulatory cycles were maintained as indicated by menstrual regulation. The vaccine was highly effective in preventing pregnancy (1 pregnancy in 1224 cycles ) at and above antibody titres of 50 ng/ml. Antibodies declined in course of time in absence of boosters, with conceptions occurring below 35 ng/ml titres indicating regain of fertility. Ability of antibodies to prevent pregnancy was confirmed by post coital tests. High avidity (10(10) M-1) and other characteristics of antibodies generated by the vaccine are described and compared with those induced by two other hCG vaccines having undergone Phase I trials. The antibody response of the HSD vaccine in humans is characterized predominantly to an epitope recognized by the monoclonals 206 and P3W80. The antibodies had low or no reactivity with the carboxy terminal peptide and 38-57 region peptide. Live recombinant vaccines expressing beta hCG as a membrane anchored peptide generated antibody response to hCG in all animals following a single injection. CONCLUSIONS: Reversible fertility control is feasible with the HSD-hCG vaccine without impairment of ovulation or disturbance of menstrual regularity. Suggestions have been made for further optimization of the vaccine, which include replacement of TT and DT by a panel of T non B determinants communicating with the entire MHC spectrum and development of recombinant vaccine expressing beta hCG along with membrane anchored carrier.

Nucleotide sequence of ovine adenovirus tripartite leader sequence and homologues of the IVa2, DNA polymerase and terminal proteins.

Ovine adenovirus OAV287 was previously isolated from sheep in Western Australia. Here we describe a portion of its genome between map units 10.3 and 31.7 which includes major ORFs for homologues of the IVa2 polypeptide and the DNA replication proteins, Terminal protein and DNA polymerase, as well as the N-terminal portion of the 52/55-kDa polypeptide. In addition, as a prelude to possible adaptation of this virus as a vector we have mapped the elements which make up the tripartite leader sequence of late mRNAs, thereby defining the probable location of the OAV major late promoter. In other human and animal adenovirus genomes, one or two VA RNA genes are encoded between the ORFs for Terminal protein and 52/55-kDa polypeptides. In OAV, these ORFs overlap, suggesting that if VA RNA genes are present, they may lie elsewhere in the OAV genome.

Unique genome arrangement of an ovine adenovirus: identification of new proteins and proteinase cleavage sites.

The completed sequence and genome organization of OAV287, a serologically distinct ovine adenovirus, is described. The genome of 29,544 bp has inverted terminal repeats that are only 46 bp in length. Many OAV genes are identified by their homology with other adenovirus (Ad) sequences but three groups of reading frames show little homology. One group at the left-hand end of the genome probably represents the E1A/E1B regions. Two others, on the complementary strand at the right-hand end of the genome, are tentatively proposed as the E4 and E3 regions. They are separated by approximately 1 kb of A/T-rich sequence of unknown function with E3 being adjacent to the terminus. Structural proteins V and IX of human Ads are absent from the OAV genome but a new, processed, 28-kDa virion polypeptide is encoded on the strand complementary to the proposed E1A region. The coding sequences for two other structural proteins are unidentified. The OAV penton protein lacks the region containing an Arg/Gly/Asp sequence that, in human adenoviruses, is thought to interact with cellular integrins to facilitate virus entry. Analysis of proteins and peptides in purified OAV identified several cleavage sites utilized by the Ad proteinase. Some of these were previously identified in human Ad proteins, but new sites, some of which did not conform to the known specificity of the human Ad proteinase, were also identified. The data emphasize that this ovine virus differs significantly from other known human and animal adenoviruses.

Construction and transfection of ovine adenovirus genomic clones to rescue modified viruses.

The genome of ovine adenovirus OAV287 has an arrangement which is unique among known adenoviruses. To facilitate further experimentation on the structure and function of this genome, plasmids containing a complete clone of the genome were constructed. The cloned viral genome was released from plasmids by restriction enzyme digestion as an intact linear molecule with authentic 5' termini. Transfection of the linear DNA into cells which supported replication produced infectious virus. Mutation of a unique SalI site at the right-hand end of the genome disrupted reading frames of unknown function without affecting virus rescue, identifying this region as nonessential for replication in vitro. A 20-bp oligonucleotide was also inserted into the short intergenic region between the pVIII and the fiber sequences, identifying a second site for gene insertion. These studies will facilitate the development of OAV as a gene transfer vector.

Entry kinetics and mouse virulence of Ross River virus mutants altered in neutralization epitopes.

Previously we identified the locations of three neutralization epitopes (a, b1 and b2) of Ross River virus (RRV) by sequencing a number of variants resistant to monoclonal antibody neutralization which were found to have single amino acid substitutions in the E2 protein (S. Vrati, C.A. Fernon, L. Dalgarno, and R.C. Weir, Virology 162:346-353, 1988). We have now studied the biological properties of these variants in BHK cells and their virulence in mice. While variants altered in epitopes a and/or b1 showed no difference, variants altered in epitope b2, including a triple variant altered in epitopes a, b1, and b2, showed rapid penetration but retarded kinetics of growth and RNA and protein synthesis in BHK cells compared with RRV T48, the parent virus. Variants altered in epitopes a and/or b1 showed no change in mouse virulence. However, two of the six epitope b2 variants examined had attenuated mouse virulence. They had a four- to fivefold-higher 50% lethal dose (LD50), although no change in the average survival time of infected mice was observed. These variants grew to titers in mouse tissues similar to those of RRV T48. The ID50 of the triple variant was unchanged, but infected mice had an increased average survival time. This variant produced lower levels of viremia in infected mice. On the basis of these findings we propose that both the receptor binding site and neutralization epitopes of RRV are nearby or in the same domain of the E2 protein.

Sequence of ovine adenovirus homologs for 100K hexon assembly, 33K, pVIII, and fiber genes: early region E3 is not in the expected location.

Ovine adenovirus OAV287 was previously isolated from sheep in Western Australia. As a first step in characterizing the genome of this virus we have determined the sequence of its genome between map units 65 and 81. This region was expected to contain the nonessential E3 region which, in other adenoviruses, lies between the genes encoding the pVIII and fiber proteins, although its size and complexity varies. OAV287 genes coding for the hexon assembly, 33K, pVIII, and fiber proteins were identified by their homologies with human Ad2. These genes lie in the same relative positions in the OAV287 genome, but the intergenic region between the pVIII and the fiber genes is only 197 nucleotides and these appear to be incapable of coding for any protein. Thus, the ovine adenovirus E3 region is not present in the expected location. In addition, using cDNA synthesis, PCR amplification, and nucleotide sequencing we determined the location of splice junctions and transcription termination signals in mRNA species encoding these proteins. This showed that a family of variably spliced L4 RNAs is produced and that the region between the pVIII and the fiber genes contains several signals for RNA synthesis and processing. As the E3 region in human adenoviruses is nonessential for replication, in many instances it has been replaced with foreign DNA during the construction of recombinants. Because of this unexpected difference in the organization of the OAV287 genome further experimentation will be required to determine whether potential vaccine recombinants can be constructed for this adenovirus by making insertions into the pVIII/fiber intergenic region.

Characterisation of Australian ovine adenovirus isolates.

We have characterised two groups of adenoviruses isolated from sheep in Australia. Restriction endonuclease maps for enzymes BamHI, ClaI, SalI, SmaI and SphI have been determined for the genome of ovine adenoviruses related to bovine adenovirus serotype 7 (BAV 7) from sheep in Western Australia. Although previously serotyped as BAV 7 these isolates are different from bovine isolates of BAV 7 based on comparison with published restriction endonuclease profiles and maps of BAV 7 cattle isolates. Additional adenovirus isolates obtained from Victorian sheep have been serotyped as ovine adenovirus type 5 (OAV 5). On the basis of restriction endonuclease analysis these viruses are different from the sheep BAV 7 isolates. Following infection of sheep with ovine BAV 7 and OAV 5 isolates, virus was recovered from nasal and rectal swabs for several days. Antibodies detected by ELISA and serum neutralisation tests (SN) developed by 15 days after infection. Virus also spread from the infected sheep to an incontact control and one of ten sheep purchased for infection studies had SN antibodies to BAV 7 suggesting that BAV 7-like viruses naturally infect sheep in Victoria and Western Australia. With further development, these ovine adenoviruses may be suitable as vectors for the delivery of vaccine antigens to sheep and cattle.

An epidemic of non-A, non-B hepatitis in south Delhi: epidemiological studies and transmission of the disease to rhesus monkeys.

In November 1987 an epidemic of NANB-hepatitis broke out in a residential colony of South Delhi which lasted for nearly two months. The epidemic was caused due to the sewage contamination of the drinking water supply. Analysis of the epidemiological data showed that the disease was more common in the younger age group of 11-20 years and that both sexes were equally prone to the disease. The disease could be transmitted to rhesus monkeys by intravenous inoculation of the stool extracts from the patients. Experimentally infected monkeys showed elevated levels of serum aminotransferases and excreted the infectious agent in the stools. Hepatic lesions characteristic of enteric non-A, non-B hepatitis were observed in an infected monkey.

Serial passage of west-European sporadic non-A non-B hepatitis in rhesus monkeys by inoculation with fecal extracts.

An experimental model of sporadic non-A non-B hepatitis involving a Fab nonimmune binding activity in stools was established in the rhesus monkey. The first animal was inoculated intravenously with a stool extract from a French patient who had never left the country and in whom post-transfusion hepatitis was excluded. Four passages were performed, and the infection was transmitted by parenteral as well as the oral routes by inoculation of stools or liver extracts. Infection led in three monkeys to reversible hepatocyte injury manifested by a transitory increase in serum aminotransferases. The other three animals, in which persistently high levels of aminotransferases was observed, were sacrificed on day 60 after inoculation. The incubation period, as evidenced by elevation of aminotransferases was about 3 to 4 weeks. The infectious agent was transitorily present in the stools before aminotransferase elevation. The presence of the infectious agent in the stools was correlated with the nonimmune Fab binding activity.

Genetic stability of Ross River virus during epidemic spread in nonimmune humans.

We have examined the rate of evolution of Ross River virus, a mosquito-borne RNA virus, during epidemic spread through tens of thousands of nonimmune humans over a period of 10 months. Two regions of the Ross River virus genome were sequenced: the E2 gene (1.2 kb in length), which encodes the major neutralization determinant of the virus, and 0.4 kb of the 3'-untranslated region. In the E2 gene, a single nucleotide change was selected which led to a predicted amino acid change at residue 219. No changes were selected in the 3'-untranslated region. By comparison with rates of evolution reported for non-arthropod-borne RNA viruses, the rate for Ross River virus is surprisingly low. We identify three features of the Ross River virus replication and transmission cycle which may limit the rate of evolution of arthropod-borne viruses in the field.

Location of a major antigenic site involved in Ross River virus neutralization.

The location of a major antigenic domain involved in the neutralization of an alphavirus, Ross River virus, has been defined in terms of its position in the amino acid sequence of the E2 glycoprotein. The domain encompasses three topographically close epitopes which were identified using three E2-specific neutralizing monoclonal antibodies in competitive binding assays. Nucleotide sequencing of the structural protein genes of monoclonal antibody-selected antigenic variants showed that for each variant there was a single nucleotide change in the E2 gene leading to a nonconservative amino acid substitution in E2. Changes were at positions 216, 234, and 246-251 in the amino acid sequence. The epitopes are in a region of E2 which, though not strongly conserved as to sequence among Ross River virus, Semliki Forest virus, and Sindbis virus, is conserved in its hydropathy profile among the three alphaviruses. The epitopes lie between two asparagine-linked glycosylation sites (residues 200 and 262) in E2. They are conserved as to position between the mouse virulent T48 strain and the mouse avirulent NB5092 strain.

Ross River virus mutant with a deletion in the E2 gene: properties of the virion, virus-specific macromolecule synthesis, and attenuation of virulence for mice.

A mutant of RRV T48 the prototype strain of Ross River virus has been isolated with a 21-nucleotide deletion in the gene coding for the envelope glycoprotein E2. Direct sequencing of the 26 S subgenomic RNA, together with HaeIII and TaqI restriction digest analysis of cDNA to RNAs from cells infected with the mutant virus (RRV dE2) and with RRV T48, were consistent with the deletion being the only major alteration in the mutant genome. The E2 protein of RRV dE2 virions had a higher electrophoretic mobility than that of RRV T48 E2 protein. Neither RRV dE2 nor RRV T48 virions contained more than trace amounts of E3, the small envelope glycoprotein found in Semliki Forest virus. RRV dE2 generated small plaques on Vero cell monolayers; plaque formation was not temperature-sensitive between 32 and 41 degrees. By comparison with RRV T48 the infectivity of RRV dE2 virions was thermolabile at 50 degrees. In BHK cells RRV dE2 grew with similar kinetics to RRV T48. Rates of synthesis of 26 S RNA and 49 S RNA were higher in cells infected with RRV dE2 than in cells infected with RRV T48. Virus-specific protein synthesis and shut-down of host protein synthesis occurred 2-3 hr earlier in RRV dE2-infected cells than in cells infected with RRV T48. Minor differences between the two viruses were observed in the profiles of virus-specific proteins generated in infected cells. In day-old mice RRV dE2 induced less severe symptoms of hind leg paralysis than did RRV T48. A small increase in LD50 and average survival time was observed in RRV dE2-infected mice by comparison with RRV T48 infected mice. Peak titers reached by RRV dE2 in the hind leg muscle, brain, and blood of day-old mice were 3-4 log units less than the titers reached during infection with RRV T48. In week-old mice the differences in virulence between the two strains were magnified: RRV dE2 induced no detectable symptoms even when injected at high doses (8 X 10(6) PFU) whereas the LD50 and average survival time for RRV T48 were unchanged from those in day-old mice. Peak RRV dE2 titers in hind leg muscle, brain, and blood, respectively, were 2, 5, and 5 log units less than the corresponding titers for RRV T48. Peak muscle titers reached by RRV dE2 were similar (approximately 10(8) PFU/g tissue) in day-old mice where lethality was high and in week-old mice where the virus was avirulent.(ABSTRACT TRUNCATED AT 400 WORDS)