Virucidal activity of a new hand disinfectant with reduced ethanol content: comparison with other alcohol-based formulations

A new formula with reduced ethanol content (55%) in combination with 10% propan-1-ol, 5.9% propan-1.2-diol, 5.7% butan-1.3-diol and 0.7% phosphoric acid exhibited a broad spectrum of virucidal activity. In quantitative suspension tests, with and without protein load, this formulation reduced the infectivity titre of seven enveloped (influenza A and B, herpes simplex 1 and 2, bovine corona, respiratory syncytial, vaccinia, hepatitis B, bovine viral diarrhoea) and four non-enveloped (hepatitis A, polio, rota, feline calici) viruses >10(3)-fold within 30s. In comparative testing, only 95% ethanol showed similar levels of activity. In fingerpad tests, the formulation produced a log10 reduction factor of the titre of poliovirus type 1 (Sabin) of 3.04 in 30s compared with 1.32 by 60% propan-2-ol. Testing against feline calicivirus produced a log10 reduction factor of 2.38 by the test formulation; in contrast, the log10 reduction factors with 70% ethanol and 70% propan-1-ol were 0.68 and 0.70, respectively.

Rapid identification of subgenera of human adenovirus by serological and PCR assays

Bacterially expressed recombinant protein IX (pIX) of human adenovirus serotype 2 (Ad2) and 3 (Ad3) was evaluated for use as a subgenus-specific antigen by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Patients sera positive by ELISA for the genus-specific adenovirus hexon antigen recognized the recombinant pIX of Ad2 and Ad3 in a subgenus-specific manner by both assays. Polyclonal rabbit serum raised against the recombinant Ad2pIX reacted strongly by indirect immunofluorescence assay, with Adl, 2 and 5 (subgenus C) but not with serotypes representing other subgenera. In a similar way, anti-Ad3pIX reacted with Ad3, 7, 11 and 14 (subgenus B), but not with serotypes representing other subgenera. A polymerase chain reaction showed that the complete pIX gene could be amplified in a subgenus specific fashion using primers specific for Ad3 (subgenus B), Ad2 (subgenus C), or Ad40/41 (subgenus F). The pIX gene from the available isolates of subgenus A, D and E was not amplified with these primers. The use of pIX-based serological assays is useful for subgenotyping as a primary screen of anti-Ad sera. It is much more rapid than the currently used neutralization assay or hemagglutination inhibition test. The application of anti-pIX sera by immunofluorescence and a pIX gene-based PCR are rapid methods which will improve subgenus identification of adenoviruses.

Adenovirus-receptor interaction with human lymphocytes

Lymphocytes play a key role in cell-mediated immunity and are host cells for several viral and bacterial pathogens. Their importance in adenovirus (Ad) infections is not yet fully understood. The initial event, the attachment of Ad to lymphocytes and their subsets, was examined using flow cytometry. The study included analysis of stimulated T cells in binding assays with FITC-labeled Ad fiber. The results confirm that native peripheral lymphocytes express very small amounts of Ad receptors. Stimulation with PHA and interleukin 2 induced the expression. The presence of Ad DNA as a sign of internalization in stimulated cells was demonstrated using the polymerase chain reaction. The findings suggest that lymphocytes after stimulation can turn into target cells for Ad. This is particularly important if there are indications for persistence of Ad, and in the case of immunocompromised patients severe, life-threatening diseases can develop.

Inhibition of cell adhesion to the virus by synthetic peptides of fiber knob of human adenovirus serotypes 2 and 3 and virus neutralisation by anti-peptide antibodies

The fiber knob of adenovirus (Ad) causes the first step in the interaction of adenovirus with cell membrane receptors. To obtain information on the receptor binding site(s) several synthetic peptides derived from Ad2 and Ad3 fiber head sequences and their antisera were tested for interference with virus attachment to HeLa and FL cells and cell adhesion to viruses. The anti-peptide sera were also evaluated in ELISA and virus neutralisation test. Ad2 (of subgroup C) and Ad3 (of subgroup B) attachment was not significantly inhibited by peptides corresponding to the amino acid residues 535-554, 555-573, 562-582 of Ad2 fiber or 210-225, 267-283, 291-306 and 300-319 of Ad3 fiber. However, microplate pre-adsorbed Ad3 fiber residues 210-225 and 267-283 could bind FL and HeLa cells, and 1 mg/ml of Ad3 fiber residues 267-283 inhibited the cell adhesion to Ad3 virus to approximately 90%. This peptide may participate in the receptor binding site of Ad3 fiber. ELISA reactive anti-peptide antibodies against the homologous peptide and virus did not significantly reduce the cell adhesion to the immobilised virus or the virus attachment to cells, but in the neutralisation assay antibodies raised to Ad2 fiber residues 555-573 and 562-582 and Ad3 fiber residues 210-225 caused neutralisation of the homologous virus at serum dilutions of 1:500 and 1:32, respectively. The corresponding peptides and one further peptide of Ad2 fiber and two of Ad3 fiber seem to contain neutralisation epitopes.

Antigenic and molecular analysis of influenza A(H3N2) virus strains isolated in 1985 in open and closed communities of northern Germany

Antigenic and molecular analyses of influenza A(H3N2) virus strains isolated in 1985 during outbreaks in open and closed communities of North Germany were carried out. The data obtained have shown that 11 strains isolated in a closed orphanage were antigenically similar to each other. The electrophoretic mobilities of either HA, NP, M1 and NS1 polypeptides or of double stranded RNA segments were indistinguishable. Analysis of viruses isolated at the same time from open communities has revealed that they contained at least three groups of strains differing in homology of 3-5 RNA segments. These data support the idea that an outbreak of influenza in a community is caused by single virus strain, from which their slightly different variants of the virus arise during circulation among sensitive persons.

Intraepidemic variants of influenza virus H3 hemagglutinin differing in the number of carbohydrate side chains

During the epidemic outbreak in the region of Greifswald in the winter 1974/75, we found influenza virus variants which showed differences in the electrophoretic mobility of HA. Among the 25 isolates 13 were of slower and 12 of higher mobility. HA1 of 6 isolates was studied by determining the number of the carbohydrate side chains and by direct sequencing of vRNA. Evidence is presented that variants showing a slower electrophoretic mobility of HA1 had consistently acquired a seventh carbohydrate side chain at Asn 126 in epitope A. All the isolates differed from the reference strain A/Port Chalmers/1/73 by the loss of the oligosaccharide at Asn 81. The field strain A/Dresden/3/71 possessed only 5 oligosaccharides in HA1. These results suggest that changes in glycosylation are an important mechanism in the structural variation underlying antigenic drift of HA.

Further studies on cold adapted variants of human influenza virus A/Krasnodar/101/59 (H2N2) with special reference to genetic stability of attenuation markers

A previously described cold adapted (ca) attenuated virus, K/25, derived from parent strain A/Krasnodar/101/59 (H2N2), was further modified by 35 additional passages in chick embryos at suboptimal temperature. The virus obtained had retained a distinct ts and ca phenotype and some other markers of attenuation but differed from formerly isolated ca variants by its higher genetic stability connected with an increased growth capacity in chick embryos.

[The selection of cold-adapted variants of the influenza viruses H1N1 and H3N2 and their antigenic and genetic characteristics]

As a result of serial passages (42 passages) at low temperatures (26 degrees--28 degrees C) of two influenza H1N1 and H3N2 virus strains stable cold-adapted (ca) variants were produced. Investigations of them showed the ca A/USSR/03/84 (H1N1) variant to have ts-mutations in genes 1, 2, 4, 5, 7, and 8 and the ca A/USSR/215/79 (H3N2) to have ts-mutations in genes 1, 3, 4, 5, 7 and 8. These ca-variants may be recommended as attenuation donors to be used in recombination experiments with epidemic influenza viruses in order to obtain attenuated reassortant candidate vaccine strains.

[Virologic research at the Institute of Medical Microbiology at the Greifswald Ernst-Moritz-Arndt University]

A short review of the virological research at the former Institute of Hygiene and of one of its followers, the Institute of medical microbiology of the Ernst-Moritz-Arndt-University Greifswald is given.

Effects of norakin on respiratory syncytial virus in tissue culture and in mice

Norakin at 1 microgram/ml inhibits the reproduction of respiratory syncytial virus (RSV) in Vero cells to 50% and at 5 micrograms/ml to 90%. The development of lung lesions in RSV-infected BALB/c mice was suppressed by 70% when the animals were treated with two doses (25 mg/kg each) of norakin, 30 min before and 4 hr post infection. (p.i.), respectively.

Antigenic reactivity of matrix protein and nucleoprotein of influenza virus as detected by EIA after dissociation with different detergents

Solid phase enzyme-immunoassay (EIA) was employed to assess the antigenic reactivity of matrix protein (M) and nucleoprotein (NP) of influenza A virus adsorbed to polystyrene in the presence of different detergents such as beta-octaglucoside (OG), Triton X-100, Tween-20, sodium dodecylsulphate (SDS), sodium deoxycholate (Doch-Na), Nonidet P-40 (NP-40), and sarcosyl at concentrations ranging from 0 to 2%. The antigenic reactivity of NP was the highest in the absence of detergents. For M protein, Doch-Na, SDS, NP-40 and sarcosyl of 0.05-0.1% enhanced the chromatophoric response in EIA 1.5-2 times. In contrast, the antigenic reactivity of M protein remained unchanged after OG or Triton X-100 treatments, and it decreased in the presence of Tween-20.

Differences of nucleoproteins of human and avian influenza A virus strains shown by polyacrylamide gel electrophoresis and by the peptide mapping technique

Electrophoretic mobility differences in polyacrylamide gels were detected between (35S)-methionine-labelled nucleoproteins (NPs) induced in monolayer cells by 15 human and 4 avian reference strains of influenza viruses. The (35S)-methionine-labelled tryptic peptides of nucleoproteins of these strains were also analyzed by peptide mapping technique. Based on several detectable hydrophilic peptides the NPs could be arranged in 7 clearly differentiable groups. After radioiodination of NPs from 4 human and 3 avian reference strains the tryptic peptide patterns showed one clear difference between human and avian strains.

Variation of influenza A (H3N2) viruses isolated in the G.D.R. during 1969-1980 epidemics

A collection of 39 influenza A virus strains of the subtype H3N2 isolated in G.D.R. and of six reference strains were analysed with regard to the antigenic structure of their surface proteins haemagglutinin (HA) and neuraminidase (NA) as well as regarding their polypeptide variations. For the field strains during the drift period from spring 1969 to spring 1980 seven main variations resulted from eight polyclonal sera with the haemagglutination inhibition test, and five main variations from six polyclonal sera with the neuraminidase inhibition test. Using the polyacrylamide gel electrophoresis polypeptide variations in HA, nonstructural proteins NS1, NS2 and nucleoprotein (NP) were detected. It could be shown that, even during one epidemic, strains circulated with different polypeptide composition. With the help of peptide mapping further variations of NP and NS1 were registered. The mechanisms leading to the emergence of new epidemic strains are discussed.

The variability of genes of influenza A (H3N2) virus strains isolated in the G.D.R. during the 1970-1978 epidemic seasons

Gene variability of all influenza A virus strains (H3N2) isolated in the G.D.R. during the epidemic seasons of 1970-1978 was investigated by cRNA:vRNA hybridization. From 1970 through 1975 a gradual smooth variability of the majority of genes and moderate heterogeneity in gene homology of the isolates were observed. From 1975 through 1977 the genome variability was more profound and the isolates differed from one another in gene homology. In 1978 the variability became less pronounced again. Quantitative evaluation of the variability for individual genes gave the following results: 0.4% nucleotides per year for genes, 1, 2, 3 (P proteins), 1.4% for gene 4 (HA), 0.1% for gene 5 (NP), 1.0% for gene 6 (NA), 0.1% for gene 7 (M) and 0.4 for gene 8 (NS).

Genome analysis of epidemic influenza virus strains isolated in 1979-1983

Comparative studies on the electrophoretic mobility of double-stranded RNA segments constructed of the genome of isolates under study and of reference influenza virus strains of respective serotypes are suggestive for the evolution of majority of the genes of both A and B influenza viruses, including their genes coding for non-glycosylated proteins. Among influenza A and B virus strains which were circulating during the same epidemic, there were variants differing from each other in a number of genes including those coding for virion internal proteins. A recombinant (reassortant) detected among the influenza virus strains, which circulated in Moscow in 1979, contained the genes 4, 6, 7 and 8 identical with those of the reference H1N1 strain, and the genes 1, 2, 3 and 5 identical with those of the reference H3N2 strain. Comparative analysis of reference influenza virus strains, both the H3N2 serotype (being isolated from 1968 to 1979) and the H1N1 serotype (being isolated from 1977 to 1980) differing in the antigenic specificity of their haemagglutinin (HA) suggested the increasing variability of either genes coding for glycoproteins as well as for non-glycosylated proteins.

Ts mutations in the genome of cold-adapted variants of human influenza virus A/Krasnodar/101/59 (H2N2) at different passage levels and their reproduction in lungs of hamsters

Human influenza virus A/Krasnodar/101/59 (H2N2) was passaged in chick fibroblast cultures in the presence of trypsin at suboptimal temperature. The virus which underwent 16 passages at 28 degrees C possessed cold-adapted (ca) and temperature sensitive (ts) phenotypes and formed larger plaques at the optimal temperature (33 degrees C). Its reproduction in the lungs of hamsters was decreased as evidenced by approximately 2.5 log10 lower titres; only one of 9 virus isolates from the lungs of hamsters acquired the ts +/- phenotype, although it had retained a ca phenotype. Recombination of this variant with ts mutants of fowl plague virus (FPV) revealed a ts mutation only in gene 4 of this variant coding for haemagglutinin (HA). The virus which had had 25 passages at 28 degrees C possessed the same properties as the previous variant, but all eight virus isolates from the lungs of hamsters retained the ts phenotype; the genome of this variant contained ts mutations in genes 1, 3, 4, 5 and 6. The mutation found in gene 8 was not a ts mutation. The virus, which underwent 25 passages at 28 degrees C and additional 15 passages at 27 degrees C, formed large plaques and alike to the previous variants it possessed the ca and ts phenotypes; however, its reproduction in the lungs of hamsters was decreased by 4.0 log10 and occurred in the lungs only of 4 out 16 infected animals. This variant contained ts mutations in genes 1, 3, 4, 5, 6 and 7 and a non-ts mutation in gene 8.

Role of genes 4 and 6 for the expression of some biological properties of influenza virus A/PR/8/34

Genetic composition and biological properties of influenza virus recombinants A/PR/8/34 (H1N1) and A/Greifswald/6/74 (H3N2) were analysed. The haemagglutinin (HA) gene of the strain A/PR/8/34 was shown an important part of the gene complex determining the virulence for mice, the yield of HA and the plaque forming capacity. The exchange of the HA gene with that of an another strain led to a drastic reduction of these properties. On the other hand, the introduction of the HA gene of A/PR/8/34 strain into the genome of an another strain, did not render the latter virulent for mice. The production of H3 HA proceeded at an about 5-fold higher extent when the H3-gene was cooperating with the genes of A/PR/8/34 in contrast to the genes of A/Greifswald/6/74.

[Production and properties of inhibitor-resistant mutants of influenza A virus recombinants]

Inhibitor-resistant (Ir) mutants could be selected from recombinants between influenza virus A/PR8/34 (H1N1) and A/Greifswald 6/74, A/Greifswald, 1/76, A/Erfurt 8/77 (all (H3N2)). Spontaneous mutants were selected by cultivation on chorioallantoic membrane fragments in roller tubes, in the presence of 10% inactivated rabbit serum. The Ir-mutants thus obtained were cloned during two successive plaque-to-plaque passages. The appearance of resistance to heat-stable rabbit serum inhibitors was concomitant with the development of resistance to inhibitors contained in guinea pig, horse and human sera. There was, however, no significant change in the resistance to calf serum inhibitors. Ir-mutants caused larger plaques in primary chick embryo fibroblasts, as compared with the initial inhibitor-sensitive (Is) recombinants. The yield in the infected chick embryo allantoic fluid (established by the hemagglutination test) was significantly higher in 2 out of 8 Ir-strains, as against the initial Is-strains. Hemagglutinins from three Ir/Is pairs were investigated by a bidimensional peptide-mapping technique. In one case there was a difference in the tryptic peptides of the Ir-mutant in comparison with those of the Is parental strain.

Differentiation of influenza A virus nucleoproteins in enzyme-linked immunosorbent assay

The serum antibody titre to the nucleoprotein (NP) of the influenza virus recombinant MRC-11 was determined in virus strains A/USSA/5/80 (H3N2), A/Hong Kong/8/64 (H3N2), A/duck/Ukraine/63 (Hav7Neq2) and in a recombinant strain between A/tern/Frunse/334/78(Hav4Nav1) and A/PR/8/34(H0N1) using the enzyme-linked immunosorbent assay (ELISA). Significant differences between the NP of these strains were found proving the usefulness for ELISA for such investigations.

Studies on some genetic properties of antigenic recombinants of influenza viruses

Two groups of antigenic recombinants Hav4N1 were obtained by recombination of human influenza virus H0N1 with two avian influenza viruses isolated from ducks in 1956 and terns in 1978 and possessing the same surface antigen Hav4 Nav1. Recombinants obtained by crossing A/PR/8/34 and A/duck/CSSR/56 viruses showed a lower ability to reproduce at optimal and lowered temperatures and differed in the thermosensitivity of haemagglutinin and neuraminidase. An analysis of virus-specific proteins of the recombinants revealed different combinations of genes coding for internal (Pl, NP) and nonstructural (NS1) proteins. Recombinants obtained by crossing A/PR/8/34 and A/tern/Frunze/334/78 viruses possessed a thermostable haemagglutinin; they produced plaques of a size characteristic of avian influenza but, as distinct from the latter, they were practically not eluted from fowl erythrocytes. Polypeptide analysis of these recombinants showed that the genes coding for NP, M and NS1 proteins were inherited from the A/tern/Frunze/334/78 strain.

Genome analysis of influenza A virus strains isolated during an epidemic of 1979-1980

The genome and polypeptides of influenza A virus H3N2 strains isolated during the epidemic of 1979-1980 in the U.S.S.R. and G.D.R. have been analysed. Five varieties of H3N2 strains differing in a number of genes have been found. The isolates of the first group was similar to the A/Texas/1/77 strain in all the genes; the isolates of the second group were similar to the A/Bangkok/1/79 strain in all the genes; the strain representative of the third variety, contained all the genes except gene 4 close to those of the A/Bangkok/1/79 strain; the isolates of the fourth group contained genes 7 and 8 similar to those of the A/Bangkok/1/79 strain while the other genes corresponded to those of no strains under comparison; the viruses of the fifth group contained gene 3 similar to that of A/Moscow/406/76 strain, gene 7 was similar to that of A/Texas/1/77 strain and the other genes differed from all other strains compared. The data obtained indicate that during an influenza epidemic occurring in certain region several influenza virus varieties of the same serotype can circulate simultaneously, differing not only in the antigenic specificity of the haemagglutinin, but also in other genes.

Untersuchungen zur Beseitigung von Inhibitoren und Heteroagglutininen bei der Durchführung des HAH-Testes mit Parainfluenzaviren

A hemagglutination inhibition test is described in which the removal of nonspecific inhibitors and heteroagglutinins is affected by a combined treatment of sera with heparin-MnCl₂and stabilized erythrocytes of guinea pigs. The usefulness of the test is proved.

Über eine Methode zur schnellen Bestimmung plaquebildender Einheiten von Parainfluenzaviren der Typen 2 und 3

A plaque test for parainfluenza viruses types 2 and 3 is described which yields results within 4 and 2 days, respectively. Infectious centers forming under a semisolid layer of agarose are developed by hemadsorption followed by a benzidine reaction.

Der Nachweis von Adenovirus-Antikörpern mit Hilfe der einfachen radialen Inimunodiffusion

Simple radial immunodiffusion technique proved well suited for serological diagnosis of adenovirus infections. The technique permitted quantative determinations of antibodies and was shown to be superior to determinations made with complement fixation. Qualitative differences with respect to the distribution of antibodies were observed when immunodiffusion and complement fixation were compared.