Showing papers in "Journal of General Virology in 1983"

The biology of coronaviruses.

Abstract: Introduction. The Coronaviridae is a monogeneric family comprising 11 viruses which infect vertebrates. Members of the group are responsible for diseases of clinical and economic importance, in particular respiratory and gastrointestinal disorders (Table 1). The group was originally recognized on the basis of a characteristic virion morphology (Tyrrell et al., 1968), but can now be defined by biological and molecular criteria. Various aspects of coronavirus biology have been dealt with in recent reviews (Robb & Bond, 1979; Siddell et al., 1982; Wege et al., 1982). Structure. Morphology. Coronavirions are pleomorphic, although generally spherical, 60 to 220 nm in diameter and bear widely spaced, club-shaped surface projections about 20 nm in length. Complete virions have a density in sucrose of about 1.18 g/ml. In thin sections the virion envelope may be visualized as inner and outer shells separated by a translucent space. In negatively stained preparations of avian infectious bronchitis virus (IBV) an inner tongue-shaped membrane is visible (Bingham & Almeida, 1977; Fig. 1).

Genomic and biological variation among commonly used lymphocytic choriomeningitis virus strains.

Abstract: Six commonly used strains of lymphocytic choriomeningitis virus (LCMV) [Armstrong (Arm) CA 1371, Arm E-350, WE, UBC, Traub and Pasteur C1PV 76001] were examined for distinctive genetic and biological properties. Agarose gel electrophoresis yielded no detectable differences among the L or S RNAs of these six strains. The RNase T1 fingerprint patterns of LCMV Arm CA 1371 and E-350 RNAs were similar, but in contrast, those of the WE, UBC, Traub and Pasteur strains differed from each other and from the pattern of LCMV Arm CA 1371 and E-350. There were also differences among LCMV strains in their biological properties. LCMV Arm CA 1371, E-350 and Pasteur caused severe vasculitis and focal necrotizing hepatitis in the livers of neonatally infected BALB/WEHI mice in contrast to LCMV WE which caused minimal lesions. LCMV Arm CA 1371 and E-350 were lethal for neonatal C3H/St mice. In contrast, LCMV WE, Traub and Pasteur induced persistent infections in C3H/St mice. Adult guinea-pigs resisted infection by Arm CA 1371, E-350, Traub and Pasteur but succumbed to WE and UBC LCMV strains. Our results show a wide variation in the RNA genomes of LCMV strains commonly used in research laboratories, and these genomic differences are accompanied by variations in the biological properties of LCMV strains.

Molecular Characterization of Rotaviruses with Distinct Group Antigens

Abstract: Summary Comparative serological and nucleic acid studies were carried out on rotavirus isolates, with and without the original group antigen. Indirect immunofluorescence allowed the atypical isolates to be divided into two groups each with its own distinct group antigen hence giving a total of at least three distinct rotavirus groups. Genome profile analysis of the atypical isolates again divided them into two groups which corresponded with those obtained by immunofluorescence and within which the overall pattern of genome segments was similar. A more rigorous examination of the degree of difference between the three virus groups was carried out using single-dimension terminal fingerprint analysis. This indicated that the viruses in the three groups did not carry any genome segments in common with each other. Therefore, experimental criteria have been established which allow the division of rotaviruses into three groups. Analysis of further atypical isolates, as they become available, will establish whether the division of rotaviruses into a number of separate groups, of the type seen in influenza virus, is justified.

Gene coding assignments for growth restriction, neutralization and subgroup specificities of the W and DS-1 strains of human rotavirus.

Abstract: Gene coding assignments for growth restriction, neutralization and subgroup specificities were determined for two human rotavirus strains, DS-1 and W, which represent two distinct serotypes. The 4th gene segment of both viruses was associated with restriction of growth in cell culture. The 9th gene segment of W virus and 8th segment of DS-1 were associated with serotype specificity, while the 6th gene segment of W virus was associated with subgroup specificity.

Antigenic sites on the CVS rabies virus glycoprotein: analysis with monoclonal antibodies.

Abstract: Antigenic variation in the glycoprotein of rabies (CVS-11) virus was studied. Neutralization-resistant variant viruses were isolated in vitro at high frequency (10(-4) to 10(-5)) in the presence of anti-glycoprotein monoclonal antibody. Analysis of these variants identified at least three functionally independent antigenic sites, based on the grouping of variants that were no longer neutralized by one or more of a panel of 24 monoclonal antibodies. Competition radioimmunoassay suggested that one of these three antigenic sites was topologically distinct, with the other two in close proximity. In addition, it was shown that most (but not all) neutralization-resistant variants failed to bind the relevant monoclonal antibody. Viruses with altered antigenicity were shown to accumulate in virus stocks following several passages in vitro in the absence of antibody. In addition, variants were isolated in vivo following treatment of mice with monoclonal antibody.

Coronavirus IBV: structural characterization of the spike protein.

Abstract: Summary The spike protein (S; surface projection) of avian infectious bronchitis virus (IBV) strain M41 comprises two glycopolypeptides, S1 (mol. wt. 90 × 103) and S2 (mol. wt. 84 × 103), in equimolar proportions. The apparent mol. wt. of S was calculated as 354 (±17) × 103 following co-sedimentation with catalase in sucrose gradients. Incubation of radiolabelled IBV with urea resulted in the removal of most S1, but none of S2, from the virus particle. A similar result was obtained using low concentrations of SDS, although some nucleocapsid, but not matrix, protein was also released. 2% SDS alone was as effective as 2% SDS plus 2% 2-mercaptoethanol for the separation of S1 and S2 prior to SDS-polyacrylamide gel electrophoresis. Dithiothreitol did not remove S from virions but did decrease the buoyant density of the virus from 1.18 g/ml to 1.16 g/ml, and changed the configuration of S. It is concluded that IBV S protein is an oligomer comprising two copies of each of S1 and S2, although the possibility that there are three copies of each glycopolypeptide cannot be discounted. S is attached to the membrane by S2, while S1 has little or no contact with the membrane and may form the major part of the bulbous end of S. Interpeptide disulphide bonds do not occur in S, and the association of S1 and S2 is weak.

Analyses of the Antigenicity of Influenza Haemagglutinin at the pH Optimum for Virus-mediated Membrane Fusion

Abstract: Summary At the pH optimum for membrane fusion the haemagglutinin glycoprotein (HA) of the influenza virus membrane which is implicated in the fusion activity undergoes a conformational change. We have analysed the effects of this change on the antigenicity of the haemagglutinin by reacting the molecule with monoclonal antibodies of defined specificity. The results obtained indicate that specific changes in antigenicity occur in antigenic sites B and D and are interpreted in terms of the three-dimensional structure of the molecule and the effects of low pH incubation on it. Our results also provide evidence for the antigenic significance of amino acid sequence changes in site B of the HAs of natural isolates and allow clear delineation of this site into two regions.

Protection of mice from fatal herpes simplex virus type 1 infection by adoptive transfer of cloned virus-specific and H-2-restricted cytotoxic T lymphocytes.

Abstract: Summary A cloned culture of secondary anti-herpes simplex virus (anti-HSV) cytotoxic T lymphocytes (CTL) generated in vitro when adoptively transferred to intact or cyclophosphamide (CP) pretreated syngeneic mice protected the recipients from death following intraperitoneal infection with HSV-1. This in vivo protective effect conferred by anti-HSV CTL was virus-specific and H-2K/D-restricted. Twenty-four h after HSV-1 infection of BALB/c mice (intact or CP-pretreated) relatively high levels of serum interferon-γ were observed in the recipients of syngeneic anti-HSV CTL and this event may explain, at least in part, the CTL-mediated protective effect.

Persistent, tolerant or subacute infection in Borna disease virus-infected rats.

Abstract: Summary The rabbit-adapted Borna disease (BD) virus strain V was passaged by intracerebral infection of 1-day-old Wistar rats. Infectivity titres reached 108 infectious units per gram of brain 4 weeks after infection. No clinical signs were evident. The persistent infection could be induced with adapted or field strains of BD virus. Strains were identified by neutralization tests. The virulence of the rabbit-adapted BD virus for the rat increased with rat passages. The 5th passage induced clinical symptoms in animals infected at 1 week of age or older. Between 20% and 50% of diseased rats died. Virus-specific antigen was detectable immunohistologically in neurons of rats infected at all ages. Animals inoculated at 1 or 2 months of age, but not the neonatal rats, showed signs of inflammation in the brain. Infected rats produced specific antibodies. In the older groups (infected at ages of 1 or 2 months), and especially in surviving animals, occasionally, neutralizing antibodies with high titres were found. Transfer of primed spleen cells resulted in subacute disease. These findings demonstrate that neonatal rats can acquire a persistent, tolerant infection and that expression of disease is mediated by immunological factors.

Isolation of influenza C virus from pigs and experimental infection of pigs with influenza C virus

Abstract: Summary Fifteen strains of influenza C virus were isolated from abattoir pigs in China in 1981 and antibody against influenza C virus was found in pig sera. Virus survey also showed seasonal activity of influenza C virus in pigs. Additionally, experimental infection of pigs with influenza C virus demonstrated that Chinese domestic pigs could be infected by influenza C virus and that the virus could be transmitted from pig to pig. These results indicate that, like influenza A, influenza C virus can cause natural infection in pigs. To our knowledge, this is the first report of such a finding.

Purification and Partial Characterization of a New Enveloped RNA Virus (Berne Virus)

Abstract: In Berne (Switzerland), a virus was isolated from a horse which was found to be serologically unrelated to known equine viruses. Its growth was unaffected by iododeoxyuridine and it was inactivated by organic solvents. A purification procedure involving ammonium sulphate precipitation and sucrose gradient equilibrium centrifugation was developed and viral activities were monitored using infectivity and enzyme-linked immunosorbent assays. Purified virions of density 1.16 g/ml were shown by negative staining electron microscopy to be roughly spherical and to measure 120 to 140 nm in diameter; projections (peplomers, about 20 nm long) were identified on the virion surface. In thin sections, an envelope and an elongated core structure could be distinguished. The core, measuring about 23 nm across and 104 nm in length, appears to assume a rod-, crescent- or open ring-shape within the envelope. It has a tubular structure and shows a transverse striation (periodicity 4.5 nm). Binding at the plasma membrane was observed. Berne virus is considered as a representative of a hitherto undefined family of widespread animal viruses serologically related to recent bovine isolates in Ames, Iowa (U.S.A.) and Lyon (France).

Antibodies to Respiratory Syncytial Virus Polypeptides and their Significance in Human Infection

Abstract: The human antibody response to respiratory syncytial (RS) virus infection was investigated using radioimmunoprecipitation analysis (RIPA). A total of nine RS virus-specific proteins, VP200, VGP95, VP68, VGP48, VPN41, VP35, VP27, VP23 and VGP20 were identified by comparing 35S- or 3H-labelled extracts of infected and uninfected HEp-2 cells, and by radioimmunoprecipitation using a hyperimmune human serum. Three glycopeptides, VGP95, VGP48 and VGP20, were identified by incorporation of [3H]glucosamine, and two of these (VGP48 and VGP20) were assumed to be part of a single disulphide-bonded polypeptide since they were precipitated by a monoclonal antibody raised against a surface protein. Human serum antibodies to three major RS virus proteins, VGP95, VGP48/VGP20 and VPN41 were measured by RIPA using radioiodinated RS virus antigens. Sera from a group of mothers whose babies escaped RS virus infection during a local epidemic showed increased antibody levels to VPN41 when compared to sera from mothers whose babies had become infected with RS virus within the first 6 months of life. In infants who remained uninfected with RS virus during the first 12 months of life the maternal gift of antibody decayed to about 50% at 3 months with traces of antibodies detected in a few sera at 12 months. The antibody levels detected in the sera of infants less than 3 months old convalescent from primary RS virus infection did not exceed the mean levels present in the serum of uninfected babies. Infants between the ages of 6 and 12 months were able to mount an IgG response to VPN41 and VGP48 but, unlike adults and older children, a particularly striking finding was their failure to produce antibodies to VGP95.

Ribonucleotide reductase induced by herpes simplex virus has a virus-specified constituent.

Abstract: Ribonucleotide reductase, an enzyme found in all prokaryotic and eukaryotic cells that synthesize DNA, is induced by herpes simplex virus (HSV). In this study the effect of anti-HSV antiserum on the induced ribonucleotide reductase has been examined and the ability of different temperature-sensitive (ts) mutants of HSV-1 to induce the enzyme has been investigated. The HSV-1-induced ribonucleotide reductase was inhibited by antiserum raised against infected cell lysates but not by preimmune serum. The wild-type (ts+) virus induced similar levels of ribonucleotide reductase at 31 degrees C and 38.5 degrees C (the permissive and non-permissive temperatures respectively for the ts mutants). All ts mutants induced approximately wild-type levels of the enzyme at 31 degrees C. At 38.5 degrees C, two of the four ts mutants studied also induced wild-type levels of enzyme but ts G failed to induce any activity while ts K induced variable but low levels. The enzyme activity induced by ts G at 31 degrees C was thermolabile both in vivo and in vitro. These results provide the first strong evidence that the induced ribonucleotide reductase activity is at least partially virus-coded.

Location and orientation of homologous sequences in the genomes of five herpesviruses.

Abstract: Molecular hybridization experiments were carried out to investigate homologous regions in the genomes of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), equid herpesvirus 1 (EHV-1), pseudorabies virus (PRV) and varicella-zoster virus (VZV). Virion DNA probes from EHV-1, PRV and VZV hybridized to similar regions of the HSV genome, and the use of cloned DNA probes allowed heterologous genomes to be oriented with respect to homologous regions. The HSV-1 and HSV-2 genomes are colinear, the EHV-1 and VZV genomes are colinear with the IL or ISL genome arrangement of HSV, and the PRV genome is essentially colinear with the IL genome arrangement of HSV except that the region 0.1 to 0.4 fractional genome units appears to be inverted. A detailed analysis of sequences in the HSV-2 and PRV genomes to which the HSV-1 major capsid protein gene hybridized was carried out in order to demonstrate the application of molecular hybridization to the location of genes in heterologous genomes. The lesion in a DNA-positive temperature-sensitive mutant of PRV was mapped within the putative PRV major capsid protein gene. We conclude that the herpesviruses we have studied possess several highly conserved genes, and propose that they are similar in genetic organization despite presumably separate evolutionary histories.

Recurrent Herpes Simplex in the Mouse: Inflammation in the Skin and Activation of Virus in the Ganglia Following Peripheral Stimulation

Abstract: Summary The originally infected ear of mice latently infected in the cervical ganglia with herpes simplex virus (HSV) was treated with one of five stimuli: stripping with cellophane tape, irradiation with u.v. light, or the application of xylene, dimethyl sulphoxide (DMSO) or retinoic acid. Each of these stimuli induced the appearance of infectious virus in the ganglia 1 to 5 days later, most frequently after 1 to 3 days. Virus was also isolated from the treated ears, most frequently 3 to 5 days after stimulation. In a proportion of mice treated with cellophane tape stripping, xylene, retinoic acid or DMSO, clinical recurrent disease was observed, although in the case of DMSO this proportion was low. Some of the physiological changes induced in the skin by the five stimuli were studied. Treatment with DMSO, cellophane tape stripping or xylene induced almost immediate inflammation in the skin as judged by extravasation of Evans blue dye. Studies with inhibitors suggested that this was mediated by a neurogenic factor together with histamine or 5-hydroxytryptamine, or both of these. In addition, with the exception of mice treated with DMSO, the levels of prostaglandins of the E and F classes in the skin of the ear were elevated 1 to 3 days after treatment. These results are discussed with reference to the mechanisms by which recurrent herpetic disease develops.

The proteins of morbilliviruses.

Abstract: Introduction. The study of proteins in the virions of the morbilliviruses such as measles virus (MV), canine distemper (CDV), rinderpest (RPV) and peste-des-petits ruminants (PPR) viruses and proteins induced by these viruses in infected cells has been stimulated greatly over the past 5 years because of the involvement of these viruses in chronic diseases in their natural hosts (Appel et al., 1981). MV has been associated with acute and subacute sclerosing panencephalitis (SSPE) and CDV induces chronic distemper encephalitis and old dog encephalitis (ODE). Persistent infections with morbilliviruses have been reviewed recently by ter Meulen & Carter (1982). Neurological diseases involving RPV and PPR viruses have not been described so far, but a case of bovine sporadic meningoencephalitis has been associated with a morbillivirus (Lu-107) by Bachmann et al. (1975). However, no biochemical studies have appeared on PPR and Lu-107 viruses.

Characterization of the genome of the agent of erythrocyte aplasia permits its classification as a human parvovirus.

Abstract: Summary It has recently been established that infection with a virus is the most common cause of transient arrest of erythrocyte production in the bone marrow, leading to aplastic crisis, in persons suffering chronic haemolytic anaemias. The physical characteristics of this human virus have suggested that it may be a member of the Parvoviridae. We report here that extraction of nucleic acid from this virus under annealing conditions yielded a single species of double-stranded DNA 5.5 kb in length. Treatment with heat or alkali converted this DNA into a rapidly migrating form sensitive to the single-strand-specific nuclease S1. Extraction of the virion DNA under conditions of low ionic strength where annealing would not be expected to occur yielded DNA which comigrated with the 5.5 kb single-stranded molecule. The results indicate that this virus packages equal numbers of complementary DNA strands into separate virions. It is suggested that this virus can be classified as a member of the genus parvovirus.

Sheep pulmonary adenomatosis: demonstration of a protein which cross-reacts with the major core proteins of Mason-Pfizer monkey virus and mouse mammary tumour virus.

Abstract: Summary A retrovirus that causes pulmonary adenomatosis, a contagious lung tumour of sheep, contains a 25000 mol. wt. polypeptide which cross-reacts with the major core protein (p27) of Mason-Pfizer monkey virus and mouse mammary tumour virus.

Characterization of Monoclonal Antibodies to Potato Virus Y and Their Use for Virus Detection

Abstract: Summary Cultures of hybrid cells secreting monoclonal antibodies to potato virus Y (PVY) were produced by fusing a non-secreting FO myeloma cell line with spleen cells from BALB/c mice immunized with an isolate of the tobacco veinal necrosis strain group (PVY n 605). Monoclonal antibodies were obtained which reacted with common antigenic determinants of 24 isolates belonging to the homologous (PVY n ), common (PVY o ) and stipple streak (PVY c ) strain groups of PVY. Other antibodies were either strictly specific to PVY n isolates or of intermediate specificity. In enzyme-linked immunosorbent assay (ELISA) for the detection of PVY viruses, a preparation of monoclonal antibody to a common antigenic determinant gave more uniform reactions than polyclonal antibodies from rabbit serum. Enzyme conjugates of monoclonal antibody preparations could be used highly diluted without loss of activity in ELISA, thereby decreasing the background caused by non-specific reactions.

Bunyavirus nucleoprotein, N, and a non-structural protein, NSS, are coded by overlapping reading frames in the S RNA.

Abstract: It has been shown previously, by sequence analysis of the S RNA segment of snowshoe hare (SSH) bunyavirus, that two overlapping open reading frames in the viral complementary sequence code for proteins with molecular weights of 26.8 X 10(3) and 10.5 X 10(3) respectively. In addition to the viral nucleocapsid (N) protein, which is coded by the S RNA, analyses of parental and reassortant bunyavirus-infected cell extracts have shown that the viral S RNA and M RNA species each code for non-structural proteins (NSS and NSM, respectively). In the present report, in vitro translation analyses of the S mRNA species recovered from virus-infected cells indicate that a single size class of mRNA directs the synthesis of N and NSS. Compositional analyses of selected tryptic peptides of N and NSS have provided proof that N is the product of the first open reading frame, and NSS the product of the second.

Antigenic Drift in Visna: Virus Variation During Long-term Infection of Icelandic Sheep

Abstract: A group of 20 Icelandic sheep were infected intracerebrally with visna virus strain 1514, and 209 virus isolates were obtained from the blood, cerebrospinal fluid, and central nervous system (CNS) over a period of 7 years, during which eight animals developed clinical signs of visna necessitating sacrifice. (i) Using type-specific antisera, it was found that 12 (16%) of 76 isolates tested escaped neutralization. These 12 variant viruses were distributed randomly among animals and over time, and did not replace the infecting strain even though all sheep developed homotypic antibody within 3 months of infection. The one exception was sheep no. 1557 (an animal without clinical visna), where the last six isolates were variants. (ii) A total of 35 blood and CNS isolates from seven of these sheep (including five with clinical visna) were tested against serial samples of their own sera. Autologous antisera neutralized all isolates tested with the exception of isolates from sheep 1557. None of the isolates obtained at sacrifice from the five sheep with clinical visna escaped neutralization with autologous antisera. These data suggest that although variant viruses are encountered at considerable frequency during long-term infection of Icelandic sheep, the variants usually do not replace the infecting strain. Antigenic drift does not appear to be essential for virus persistence or for the development of clinically evident CNS lesions.

Bacteriophage distribution in human faeces: continuous survey of healthy subjects and patients with internal and leukaemic diseases.

Abstract: Summary In order to elucidate the ecological role of bacteriophages in the human intestine, we analysed the numbers of coliphages and of coliphage strains present in faecal samples collected from healthy individuals and from patients with certain intestinal diseases. The isolated phages were grouped according to their serological properties. The samples with low phage titres, observed in both healthy subjects and patients, contained mainly temperate phages (many were related to o80 and λ), and those with higher titres, observed in patients, contained virulent phages. From successive surveys of coliphages and their host, Escherichia coli, in faecal samples of each subject, it was concluded that temperate phages are maintained in the human intestine through spontaneous induction of lysogenic bacteria. Qualitative and quantitative differences existed between phages isolated from faecal samples from healthy subjects and from patients. Simultaneous changes in the distribution patterns of coliphages and of the clinical symptoms were observed in a continuous survey of a leukaemic patient in a protective environmental ward.

Coronavirus JHM: coding assignments of subgenomic mRNAs.

Abstract: Protein synthesis in the murine hepatitis virus JHM-infected cells was temporarily inhibited by hypertonic shock. When the cells were returned to isotonic medium the synthesis of six virus-specific polypeptides, 150K, 65K, 60K, 30K, 23K and 14K was reinitiated simultaneously. Polyadenylated RNA isolated from the cytoplasm or polysomes of infected cells was translated in vitro and the products included polypeptides with molecular weights (mol. wt.) of 120,000, 60,000, 30,000, 23,000 and 14,000. Immunoprecipitation and fingerprinting of [35S]methionine-containing tryptic peptides showed that the 60,000 and 23,000 mol. wt. products were identical to the 60K and 23K polypeptides found in infected cells; the 120,000 mol. wt. product showed identity with the 150K intracellular polypeptide and a virus-specific 120K polypeptide synthesized in tunicamycin-treated cells. Two-dimensional polyacrylamide gel electrophoresis strongly suggested that the 30,000 and 14,000 mol. wt. products are equivalent to virus-specific 30K and 14K intracellular polypeptides. [3H]Uridine-labelled polyadenylated virus RNA was isolated from infected cells and sedimented in sucrose gradients containing formamide. The distribution in the gradient of each of the previously identified virus RNAs was determined by gel electrophoresis and gradient fractions enriched for each RNA were translated in vitro. The 120,000, 60,000, 30,000, 23,000 and 14,000 mol. wt. polypeptides were found to be encoded by mRNAs 3, 7, 2, 6, and 4 or 5 respectively. These results demonstrate that the virus-specific polypeptides in JHM-infected cells are encoded in separate subgenomic mRNAs and are translated independently. The assignment of coding functions and the known sequence relationships of JHM RNAs permitted a gene order to be deduced.

Characterization of abnormal thymidine kinases induced by drug-resistant strains of herpes simplex virus type 1.

Abstract: Two TK+ acyclovir-resistant variants of herpes simplex virus (HSV) (S1 and Tr7) and one TK+ BVdU-resistant variant (B3) induce abnormal thymidine kinases with impaired ability to phosphorylate the drugs used in their isolation. These enzymes have been purified and their properties compared with those of the wild-type (wt) parent, SC16. The enzyme induced by S1 differed markedly from the other three in both its responses to salt and to pH. B3 TK recognized the enzyme's natural substrates, thymidine, deoxycytidine, dTMP and ATP as well as the wt enzyme. In contrast, Tr7 and S1 TKs failed to bind deoxycytidine and bind thymidine less well than wt. Tr7 and S1 TKs had affinities for dTMP similar to those of B3 and the wt enzymes. ATP binding to wt, Tr7 and B3 enzymes was similar but this substrate bound only weakly to S1 TK. Each mutant displayed a characteristically distinct pattern of affinities for a range of nucleoside analogue substrates, suggesting that they will show some cross-resistance to drugs which have a similar mechanism of action to acyclovir and BVdU.

Neutralizing and non-neutralizing monoclonal antibodies to the E2 glycoprotein of Semliki Forest virus can protect mice from lethal encephalitis.

Abstract: Summary Two monoclonal antibodies (UM 42 and UM 51) directed against the glycoprotein E2 of Semliki Forest virus (SFV) are described; both belong to the IgG2a isotype but are of different idiotype Analysis employing isoelectric focusing resulted in different focusing patterns for both monoclonals (UM 42, pI 8; UM 51, pI 72) They further differed in their ability to neutralize virus The UM 42 antibodies were inactive in neutralization, while the UM 51 antibodies exceeded conventional mouse hyperimmune serum in this respect Both monoclonal antibodies, however, were able to protect mice passively from a lethal infection with SFV Based on the amount of protein, the UM 51 antibodies were 100-fold more effective than the UM 42 antibodies in mouse protection tests

Respiratory syncytial virus polypeptides. III. The envelope-associated proteins.

Abstract: Summary Four proteins, GP1, VGP48, GP26 and VPM27, are associated with the envelope of respiratory syncytial (RS) virus. The status of GP1 has been uncertain, because a cellular glycoprotein migrates at the same position when Laemmli's discontinuous buffer system is used for PAGE, and because BSC-1 cells infected with the RSN-2 strain of RS virus appear not to contain GP1. However, additional evidence suggests that GP1 is a viral structural protein. (i) It is removed from cells by trypsin, while the cellular glycoprotein is not; (ii) it is separated from the cellular glycoprotein when the infected cells are analysed by neutral SDS-PAGE; (iii) it is present in the purified RSN-2 strain of RS virus produced by BSC-1 cells; (iv) it is also present in the purified Long strain of RS virus produced by either human or monkey cells. When purified Long strain virus is analysed by PAGE under non-reducing conditions, the glycoproteins VGP48 and GP26 migrate together, and VPM27 separates into two proteins, which one-dimensional peptide mapping suggests are not different proteins. These observations suggest that VGP48 and GP26 exist in the virion as a single molecule joined by disulphide bonds, and so resemble a paramyxovirus fusion protein, and that probably there are two forms of VPM27 which differ in either position or number of disulphide bonds.

Rabies subunit vaccines.

Abstract: Conclusions The secondary and tertiary structures of the rabies virus spike G protein are important for its ability to induce VN antibodies and confer immunity to the host. For a subunit peptide vaccine to be as effective as the native spike G protein, it would appear that the amino acid sequence comprising the antigenic determinant for VN antibody binding must be made to fold properly even when deprived of its native support structure. Since CNBr peptides have retained at least some of their antigenicity for binding antibodies from hyperimmune serum but not monoclonal VN antibodies, and their immunogenicity, then synthetic peptides containing corresponding sequences should show similar activities. Additionally, determinants that might be necessary for stimulating T lymphocytes would have to be built into the synthetic peptide preparation. It would also appear that a properly folded peptide might have to be aggregated into suitably large particles for it to achieve its full protective effect. Adjuvants may serve in this capacity to enhance the immune response to relevant peptides and thus improve the immunogenicity of a subunit vaccine that ultimately protects animals and humans against rabies virus infection.

Genome Differences among Varicella-Zoster Virus Isolates

Abstract: Summary The DNAs of 17 isolates of varicella-zoster virus (VZV) were analysed by restriction endonuclease cleavage and agarose gel electrophoresis. By comparing gel patterns of DNAs cleaved with only a few enzymes, all epidemiologically distinct isolates were shown to be unique. Two isolates recovered from members of a family infected in a common-source outbreak were identical to each other (4/4 enzymes) but distinct from the other strains. In addition, three isolates recovered at different times during the course of a single episode of zoster in another individual were identical by endonuclease analysis (4/4 enzymes) but once again were distinct from all other isolates. The differences that have been recognized in cleavage profiles of all VZV strains reported thus far map into four regions of the viral genome. Two of these variable regions lie within the long unique sequences while the other differences appear to map in each of the inverted repeat sequences.

Coronavirus IBV: further evidence that the surface projections are associated with two glycopolypeptides

Abstract: The surface projections (peplomers) of avian infectious bronchitis virus (IBV) strain M41 have been separated from the nucleocapsid (N) and matrix (M) proteins by sedimentation in a sucrose gradient after virus disruption by the non-ionic detergent Nonidet P40. The peplomers comprised two glycopolypeptides of mol. wt. 90 X 10(3) (90K; S1) and 84K (S2), shown by analysis of differentially radiolabelled virus to be present in equimolar proportions. Polypeptides of 75K and 110K, which were detected by Coomassie Brilliant Blue staining in similar amounts to S1 and S2 in some unlabelled virus preparations, were absent from peplomer preparations and are probably host cell polypeptides. The S1:S2:N:M polypeptide molar ratio for IBV-M41 was approximately 1:1:6:15.

Organization of the herpes simplex virus type 1 transcription unit encoding two early proteins with molecular weights of 140000 and 40000.

Abstract: Summary The 5′ ends of two early herpes simplex virus type 1 mRNAs have been identified by nuclease S1 and exonuclease VII analysis using cloned virus DNA probes. These mRNAs (5.0 kb and 1.2 kb), located within the genome region between map coordinates 0.56 and 0.60, are unspliced and share a 3′ terminus. Genomic DNA at the 5′ ends has been sequenced and the 5′ termini have been located on the virus DNA sequence. The DNA sequence has revealed signals involved in the initiation of transcription of both mRNAs, and the 5′ end of the 1.2 kb mRNA is encoded within the internal sequences of the 5.0 kb mRNA. The probable translational initiation codons for the polypeptides specified by these mRNAs have been identified, and the results indicate that the coding regions of the two mRNAs do not overlap.