Investigation of the incidence of influenza A viraemia caused by virus strains circulating among children in 1968 - 1977.

Nineteen strains of Type A influenza virus isolated from the blood of small children in 1968--77 were studied. The investigation of the strains in HAIR with antisera to the antigenic components of the strains in HAIR with antisera to the antigenic components of the strains A/Hong-Kong/68,A/Anglia/72, A/Port Chalmers/73 and A/Victoria/75 made it possible to demonstrate antigenic "drive" of the haemagglutinin in the years 1968--1977 and to divide the strains into 4 varieties. A high sensitivity to inhibitors was observed in all the strains isolated. The study of pathogenicity and toxicity of the strains revealed viraemia in the strains isolated during the 1972--1973 epidemic and the subsequent epidemics with the absence of pathogenicity and toxicity for white mice. Regular finding of viraemia coincided in time with increased thermostablty of the haemagglutnin in the strains under study.     

The herald waves of influenza virus infections detected in Sendai and Yamagata cities in 1985-1990

The community surveillance of respiratory virus infections performed during 1985-1987 in Sendai and 1988-1990 in Yamagata has identified a total of five herald waves of influenza virus infections: A/H3N2 virus infections in 1985 and 1989, A/H1N1 virus infections in 1986 and 1988, and type B virus infections in 1989. To investigate the antigenic and genetic relationships between the herald wave and epidemic strains, influenza A/H1N1 viruses isolated during the 1986 and 1988 herald waves were compared with those isolated during the 1986-1987 and 1988-1989 epidemic seasons, respectively, utilizing hemagglutination inhibition tests with anti-hemagglutinin monoclonal antibodies and oligonucleotide mapping of total viral RNAs. The results showed that multiple variants differing in antigenic and genetic properties were cocirculating during the 1986 herald wave as well as during each of the two epidemics (only one strain was isolated in the 1988 herald wave). It was also observed that viruses which had the antigenic and/or genetic characteristics closely similar to those of the viruses circulating in the 1986 and 1988 herald waves, were isolated during the winters of 1986-1987 and 1988-1989, respectively.     

Analysis of a Viral Agent Isolated from Multiple Sclerosis Brain Tissue: Characterization as a Parainfluenzavirus Type 1

A virus originally isolated from cell cultures obtained by lysolecithin-induced fusion of human multiple sclerosis brain cells with CV-1 cells has been analyzed for its antigenic, RNA, and polypeptide compositions, and for selective biological properties. Our findings establish that this isolate, designated 6/94 virus, contains a 50S RNA genome and is, as yet, indistinguishable from Sendai virus in its antigenic and total polypeptide compositions. Despite these similarities, the 6/94 and Sendai viruses differ in certain phenotypic properties. 6/94 virus is markedly less cytocidal for chick fibroblasts, especially at 37 C and, after beta-propiolactone inactivation, it possesses a greater capacity for cell fusion and a lower toxicity than does comparably treated Sendai virus. In addition, 6/94 virus shows greater hemolytic activity.     

Results of virological and serological studies of three influenza A Hong-Kong epidemics in Leningrad.

An analysis of morbidity of the population in the course of 3 influenza A/Hong-Kong epidemics showed a pronounced decrease in influenza affection of adult population in the last epidemic in 1971--1972. Comparative studies of the diagnostic value of CFR and HIT demonstrated identical sensitivity of CFR as a method of influenza diagnostics in both the epidemic and interepidemic periods. HIT was suitable for the detection of influenza only in the epidemic period. In the interepidemic period, the percentage of influenza infection diagnosed by means of HIT ammounted to only 23--24 of all serologically confirmed cases of influenza. The highest percentage of virus isolation was observed when material from patients with serologically confirmed influenza was used. All strains of influenza A virus isolated in 1969 and 1970 were similar in their sensitivity to inhibitors of animal sera. During the last influenza epidemic, 2 of the 136 isolated strains were found to be resistant to gamma inhibitors and highly sensitive to the inhibitors showed their close relationship to gamma inhibitors. Antigenic analysis of the influenza A strains isolated during the 3 influenza epidemics revealed changes in the antigenic structure of the agents of the influenza epidemic in Leningrad in comparison with the standard strain A/Hong-Kong/I/68 (H3N2).     

Antigenic determinants of the 70,000 molecular weight glycoprotein of woolly monkey type C RNA virus.

The 70,000 molecular weight glycoprotein (gp70) of a type-C RNA virus originally isolated from a woolly monkey has been partially purified and immunologically characterized. Evidence that this viral protein is viral coded was derived from studies showing its antigenic properties to be unaltered by virus passage in cells of different species. A broadly reactive competition immunoassay was developed utilizing antiserum prepared against feline leukemia virus to precipitate 125I-labeled woolly monkey virus gp70. Gibbon and woolly viruses, as well as feline and several mouse type-C viruses, all reacted with equal efficiency in this assay. In contrast, an endogenous virus of the baboon failed to cross-react, suggesting that viruses of this latter group are less immunologically related to the others. In a homologous competition immunoassay for the woolly viral glycoprotein, the woolly virus was readily distingusihed from otherwise colsely related viruses of gibbon apes. These findings demonstrate the pronounced type-specific antigenic dterminants possessed by this viral protein. The antigenic determinants of gp70 responsible for neutralization have also been investigated.     

Isolation and characterization of four inhibitors from wheat flour which display differential inhibition specificities for human salivary and human pancreatic alpha-amylases

Four alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) inhibitors were isolated from an albumin fraction of wheat flour by ion-exchange and gel-filtration chromatography. The purified inhibitors were characterized according to their electrophoretic mobilities, molecular weights, carbohydrate, content, sulphydryl content, susceptibility to proteolytic digestion and specificities in inhibiting human salivary and pancreatic alpha-amylases. The properties of these inhibitors ae compared to similar proteins isolated by other workers.     

Nonspecific resistance of the organism and myxovirus inhibitors comparison of some antibacterial and antiviral mechanisms

There are three main lines of research on nonspecific resistance today: study of bactericidal and virocidal substances present in animal and human sera and tissues, study of early and delayed changes in resistance after heterologous infection or antigenic stimulation and study of cellular defence mechanisms (in particular of the reticuloendothelial system (RES) and interferon production). The authors discuss the existing situation in the classification of myxovirus inhibitors and draw attention to difficulties and errors. In the case of the beta-inhibitor of influenza viruses they draw attention to the similarity of the properties of this inhibitor and of bactericidal Gram-negative microorganisms. They cite some of the results of experiments in which they attempted to determine the origin of betainhibitors by immunizing mice, rats and guinea-pigs with their own food (mice), with their own enteric flora (guinea-pigs) and with salmonellae containing O or Vi antigen. As opposed to some of the data in the literature, they found that antibodies formed by rats immunized with influenza virus and reacting with O-or Visensitized erythrocytes were antibodies against the host's tissue present in the allantoic fluid.     

Phenotypic hypersusceptibility to multiple protease inhibitors and low replicative capacity in patients who are chronically infected with human immunodeficiency virus type 1

Increased susceptibility to the protease inhibitors saquinavir and amprenavir has been observed in human immunodeficiency virus type 1 (HIV-1) with specific mutations in protease (V82T and N88S). Increased susceptibility to ritonavir has also been described in some viruses from antiretroviral agent-naive patients with primary HIV-1 infection in association with combinations of amino acid changes at polymorphic sites in the protease. Many of the viruses displaying increased susceptibility to protease inhibitors also had low replication capacity. In this retrospective study, we analyze the drug susceptibility phenotype and the replication capacity of virus isolates obtained at the peaks of viremia during five consecutive structured treatment interruptions in 12 chronically HIV-1-infected patients. Ten out of 12 patients had at least one sample with protease inhibitor hypersusceptibility (change 相似文献   

The etiological structure of the morbidity from influenza and other ARDs on the territory of Russia in the season of 1997-1998

The antigenic properties of 51 strains of influenza virus A(H1N1), isolated in different cities of Russia during the epidemic of 1998, were studied. Most of these strains (49) proved to be similar to virus A/Bern/07/95 in the antigenic structure of hemagglutinin, but 2 strains isolated in Ulan-Ude were found to be closely related to new antigenic variants of this virus: A/Beijing/262/95 and A/Fukuoka/c7/98. The analysis of the antigenic structure of influenza-like diseases (ILD) in different cities of Russia revealed that adenoviruses causing up to 10.9-14.6% of all acute respiratory virus infections dominated at the pre- and post-epidemic periods. RS-viruses, parainfluenza viruses of types 2 and 3 circulated during the whole season (their proportion was 5.1-6.6%). The intensity of the circulation of influenza viruses A(H1N1) and A(H3N2) increased, starting from January, and continued till April 1998; its peak was observed in February-March in most of the cities of Russia (up to 37.5-41.6% according to the results of immunofluorescent diagnostics and 53-73% of ILD according to the results of the hemagglutination inhibition test). The occurrence of influenza B during this season was very low.     

Far‐eastern strains of bean common mosaic virus and methods of their immunodiagnostics

The paper presents data of investigation on the physico‐chemical and antigenic properties of capsid proteins of the Bean common mosaic virus isolated from Phaseolus plants in the Russian Far East (BCMV‐R) and from China (BCMV‐C). A method for isolation of the virus preparation was selected. The purified preparations of two isolates BCMV have been obtained. The presence of one polypeptide in structural proteins of virions was established and their molecular masses determined (BCMV‐R ‐ 31,6 kD; BCMV‐C ‐ 32,1 kD). Polyclonal antiserum was obtained with titre 1:12800 and the indirect and “sandwich"‐variants of ELISA were developed to detect this virus. The allied relationships were established with the bean yellow mosaic virus and with the type representative of the genus Potyvirus ‐ PVY. Based on the data of physico‐chemical and antigenic properties it was concluded that isolates BCMV‐R and BCMV‐C are two independent strains of this virus. The presence of strain‐, virus‐ and genusspecific epitopes of capsid proteine was revealed as a result of comparison of antigenic characteristics of the Russian Far Eastern and Chinese strains of BCMV. A high antigenic activity of capsid protein of the Russian Far Eastern strain was observed.     

Distinct glycoprotein inhibitors of influenza A virus in different animal sera.

Normal horse and guinea pig sera contain the glycoprotein inhibitor alpha 2-macroglobulin, which inhibits the infectivity and hemagglutinating activity of influenza A viruses of the H2 and H3 subtypes. In the current study, the presence of inhibitors of influenza A virus in pig and rabbit sera was investigated. Variants of influenza virus type A/Los Angeles/2/87(H3N2) that were resistant to horse, pig, or rabbit serum were isolated. Analysis of the variant viruses with anti-hemagglutinin (HA) monoclonal antibodies revealed that antigenic changes occurred with the development of serum inhibitor resistance. Characterization of the inhibitors in pig and rabbit sera by using periodate and receptor-destroying enzyme demonstrated that carbohydrate is an important constituent of the active portion of both inhibitor molecules and that sialic acid is involved in the interaction of the inhibitors with influenza virus HA. Nucleotide sequence analysis of the HA molecule revealed that the serum-resistant variants each acquired a different set of amino acid alterations. The multiply resistant variants maintained the original amino acid changes and acquired additional changes. Sequence modifications in the HA involved the conserved amino acids within the receptor binding site (RBS) at position 137 and the second-shell RBS residues at positions 155 and 186. Amino acid changes also occurred within antigenic site A (position 145) and directly behind the receptor binding pocket (position 220). Amino acid alterations resulted in the acquisition of a potential glycosylation site at position 128 and the loss of potential glycosylation sites at positions 246 and 248. The localization of the amino acid changes in HA1 to the region of the RBS supports the concept of serum inhibitors as receptor analogs. The unique set of mutations acquired by the serum inhibitor-resistant variants strongly suggests that horse, pig, and rabbit sera each contain distinct glycoprotein inhibitors of influenza A virus.     

Monoclonal antibodies of African swine fever virus: antigenic differences among field virus isolates and viruses passaged in cell culture.

An analysis of the binding properties of a collection of monoclonal antibodies to African swine fever virus particles showed that virus field isolates passaged in porcine macrophages changed antigenically more than a strain of a cell-adapted virus passaged in Vero cells. From seven clones isolated from the spleen of a field-infected pig, we found four clones that had the same antigenic properties, one clone that had large changes in proteins p150 and p27 and small changes in proteins p37 and p14, and two clones that had minor changes in proteins p150 and p27, respectively. An analysis of the binding properties of the monoclonal antibodies to 23 field isolates from Africa, Europe, and America showed that the African isolates differed among themselves more than the European and the American isolates; in this study we found changes in 8 of the 10 virus proteins tested. The most variable proteins in the African isolates were p150, p27, p14, and p12. In contrast to the African isolates, protein p12 from the non-African viruses did not change. The clustering of the field virus isolates in six antigenic homology groups indicated the existence of a complex variety of African swine fever virus serotypes.     

Clinical resistance to enfuvirtide does not affect susceptibility of human immunodeficiency virus type 1 to other classes of entry inhibitors

The clinical use of the human immunodeficiency virus (HIV) fusion inhibitor enfuvirtide (ENF) can select for drug-resistant HIV-1 strains bearing mutations in the HR1 region of the viral envelope (Env) protein. We analyzed the properties of multiple Env proteins isolated from five patients who experienced an initial decline in viral load after ENF therapy followed by subsequent rebound due to emergence of ENF-resistant HIV-1. Prior to ENF therapy, each patient harbored genetically and phenotypically diverse Env proteins that used CCR5 and/or CXCR4 to elicit membrane fusion. Coreceptor usage patterns of the Envs isolated from two patients underwent homogenization following ENF therapy, whereas in the other three patients, recombination appeared to allow the introduction of a single HR1 sequence with ENF resistance mutations into phenotypically distinct Env proteins. Analysis of individual Env clones also revealed that prior to ENF therapy, there was sometimes marked heterogeneity in the susceptibility of individual Env proteins to coreceptor inhibitors. After virologic failure, all Envs acquired resistance to ENF but exhibited no consistent change in their sensitivity to the fusion inhibitor T-1249 or to coreceptor inhibitors. In summary, using patient-derived Env proteins, we found that ENF failure was associated with emergence of high-level resistance to ENF due largely to mutations in HR1 but that susceptibility to other entry inhibitors was unaffected, that in these late-stage patients there was greater clonal variability to coreceptor than to fusion inhibitors, and that recombination events in vivo could sometimes restore Env genotypic and phenotypic heterogeneity by introducing drug-resistant gp41 sequences into heterologous gp120 backgrounds.     

Immunochemical study of bovine spleen thiol proteinases: cathepsinS B, H and L

Rabbit antisera were prepared against three highly purified enzymes from bovine spleen: proteinase I (cathepsin L), proteinase II (cathepsin H), and cathepsin B. The Ouchterlony double diffusion test shows that each antiserum specifically reacts with the corresponding antigen and does not cross react with other proteinases. These data provide evidence that the three proteinases are distinct with respect to their antigenic properties. Using specific antisera, the identity of two preparations of proteinase I isolated by different methods was demonstrated. Analysis of the fractions obtained in the course of isolation procedure revealed a component reacting with antisera against proteinase I. It had a greater molecular mass than proteinase I (30 000-40 000), was richer in antigenic respect and had a lower proteolytic activity as compared with proteinase I. The effect of various inhibitors and denaturation conditions on antigenic properties of proteinases was also studied.     

Antigenic stability of foot-and-mouth disease virus variants on serial passage in cell culture.

Two neutralizing monoclonal antibody (MAb)-resistant variants selected from an isolate of foot-and-mouth disease virus (FMDV) type A5 were repeatedly passaged in cell culture and monitored for susceptibility to neutralization by the selecting MAb. A variant isolated with a MAb to a conformational epitope (1-OG2) lost resistance in 20 passages, while a variant isolated with a MAb to a linear epitope (1-HA6) persisted for 30 passages. In both cases, the virus population emerging after passage was antigenically and genetically indistinguishable from the original wild-type parental virus (FMDV A5 Spain-86). Coinfection assays with the wild type and each variant, and between the variants, showed rapid conversion to a homogeneous population. Wild-type virus prevailed over the variants and for coinfection between the variants, the linear epitope variant 1-HA6. While both variants arose from a single nucleotide substitution and reversion to wild type occurred for each, it appears that the variant based on the continuous epitope (1-HA6) was more stable. We discuss the implications of these results for the antigenic diversity of FMDV and its relationship to virus evolution.     

Characterization of the H5N1 influenza virus isolated during an outbreak among wild birds in Russia (Tuva Republic) in 2010

The study of basic biological properties of H5N1 subtype strain isolated during an outbreak among wild birds in Russia in 2010 was presented. The study was carried out using conventional methods according to the WHO recommendations. H5N1 influenza virus isolated in Siberia belonged to clade 2.3.2 of the hemagglutinin gene; the phylogenetic analysis was performed. The antigenic characteristics and the basic genetic markers of biological properties were studied. It was shown that all strains were highly pathogenic for chickens and white mice. Thus, it was shown that in Russia in the 2010 H5N1 virus phylogenetically closely related to Asian variants caused epizootic among wild birds. The potential danger of this variant of the virus for humans was confirmed by different methods. We discussed the possibility of formation of H5N1 influenza natural focus.     

Changing selective pressure during antigenic changes in human influenza H3

The rapid evolution of influenza viruses presents difficulties in maintaining the optimal efficiency of vaccines. Amino acid substitutions result in antigenic drift, a process whereby antisera raised in response to one virus have reduced effectiveness against future viruses. Interestingly, while amino acid substitutions occur at a relatively constant rate, the antigenic properties of H3 move in a discontinuous, step-wise manner. It is not clear why this punctuated evolution occurs, whether this represents simply the fact that some substitutions affect these properties more than others, or if this is indicative of a changing relationship between the virus and the host. In addition, the role of changing glycosylation of the haemagglutinin in these shifts in antigenic properties is unknown. We analysed the antigenic drift of HA1 from human influenza H3 using a model of sequence change that allows for variation in selective pressure at different locations in the sequence, as well as at different parts of the phylogenetic tree. We detect significant changes in selective pressure that occur preferentially during major changes in antigenic properties. Despite the large increase in glycosylation during the past 40 years, changes in glycosylation did not correlate either with changes in antigenic properties or with significantly more rapid changes in selective pressure. The locations that undergo changes in selective pressure are largely in places undergoing adaptive evolution, in antigenic locations, and in locations or near locations undergoing substitutions that characterise the change in antigenicity of the virus. Our results suggest that the relationship of the virus to the host changes with time, with the shifts in antigenic properties representing changes in this relationship. This suggests that the virus and host immune system are evolving different methods to counter each other. While we are able to characterise the rapid increase in glycosylation of the haemagglutinin during time in human influenza H3, an increase not present in influenza in birds, this increase seems unrelated to the observed changes in antigenic properties.     

Characterization of a highly evolved vaccine-derived poliovirus type 3 isolated from sewage in Estonia

Two types of vaccine-derived polioviruses have been recently designated to emphasize the different origins of the evolved viruses: circulating vaccine-derived polioviruses (cVDPV) associated with outbreaks of paralytic disease and strains isolated from chronically infected immunodeficient individuals (iVDPV). We describe here a type 3 VDPV (PV3/EST/02/E252; later E252) isolated from sewage collected in Tallinn, Estonia, in October 2002. Due to aberrant properties in subtyping, the virus was subjected to detailed characterization. Partial genomic sequencing suggested that the closest relative was the oral vaccine strain PV3/Sabin, but the two virus strains shared only 86.7% of the 900 nucleotides (nt) coding for the capsid protein VP1. Phylogenetic analysis of the nearly complete genome [nt 19 to poly(A)] revealed multiple nucleotide substitutions throughout the genome and a possible Sabin 3/Sabin 1-recombination junction site in the 2C coding region. A calculation based on the estimated mutation frequency of the P1 region of polioviruses suggested that the E252 virus might have replicated in one or more individuals for approximately 10 years. No persons chronically excreting poliovirus are known in Estonia. Amino acid substitutions were seen in all known antigenic sites, which was consistent with the observed aberrant antigenic properties of the virus demonstrated by both monoclonal antibodies and human sera from vaccinated children. In spite of the apparent transmission potential, no evidence was obtained for circulation of the virus in the Estonian population.     

Structural Proteins of Mammalian Oncogenic RNA Viruses: Immunological Characterization of the p15 Polypeptide of Rauscher Murine Virus

The immunological properties of the purified 15,000-dalton protein of Rauscher murine type-C virus were analyzed by radioimmunoassay. The majority of the antigenic determinants of this protein were found to be remarkably specific to Rauscher and Friend virus and to a lesser extent to Moloney virus. Determinants reactive with other murine viruses (group-specific) or type-C viruses of other species (interspecies) were also demonstrated but were minor components of the total antigenic specificities of the protein. The results provide evidence that the antigenic properties of this protein specify the Friend-Moloney-Rauscher subgroup of type-C viruses.