Studies with a cold-recombinant A/Victoria/3/75 (H3N2) virus. II. Evaluation in adult volunteers

A cold-recombinant influenza A virus, CR 22, derived from A/Ann Arbor/6/60 (H2N2) cold-adapted virus and A/Victoria/3/75 (H3N2) wild-type virus, was tested in adult volunteers. CR 22 induced only low-grade clinical reactions in volunteers who had low titers of serum antibodies. Virus could be reisolated from about one-third of the volunteers, but only at low titers. No revertant viruses were found, and there was no evidence for transmission of virus to unvaccinated volunteers housed in the close contact with the vaccinees. A high proportion of the volunteers seroconverted, and the mean titers of serum antibody after immunization suggest that a high degree of protection is induced by vaccination with liver CR 22 virus.

[Efficacy of Vaccination Against Tick-Borne Encephalitis]

Since 1973 blood samples have been investigated at random for the presence of antibodies to tick-borne encephalitis (TBE) virus in persons vaccinated with the Austrian TBE vaccine. The immunization schedule was to doses given 1 to 3 months apart and a third dose injected 9 to 12 months later. This resulted in a seroconversion rate of 96% (n=444) in the haemagglutination-inhibition (HI) test and of 99% in the ELISA. The vaccine also induced high titres of complement-fixing anti-bodies. Antibody formation did not depend significantly on the age of the vaccinees. After three years, 66% (n=321) of those vaccinated still possessed antibodies in the HI test and 87% in the ELISA. Moreover, antibodies were still found in the sera of some persons at the end of the observation period (i.e. 6 years). Persons who had become seronegative still responded positively to a booster dose of vaccine. In a large number of persons it was evident that the intervals between injection of the single doses of vaccine can be extended considerably without jeopardizing the success of vaccination. The protection rate is larger than 99%.

Formation of polymeric glycoprotein complexes from a flavivirus: tick-borne encephalitis virus

Treatment of tick-borne encephalitis (TBE) virus with Triton X-100 (TX-100), octylglucoside (OG) or cetyltrimethylammonium bromide (CTAB) caused dissociation of the virus envelope into dimers or monomers of the glycoprotein V3. By centrifugation into detergent-free sucrose density gradients, these subunits were found to reassociate and to form haemagglutinating homogeneous glycoprotein complexes sedimenting at 15 to 16, 16 to 18 and 11 to 23S after TX-100, OG and CTAB treatment, respectively. Glycoprotein complexes obtained after TX-100 solubilization contained less than 1% lipid and detergent by weight.

Replication of TBE and Langat viruses in cells from immune individuals

The replication of TBE virus and Langat virus in cells of immune and non-immune individuals was compared in phytohemagglutinin (PHA)-stimulated and non-PHA-stimulated cultures and also following infection with low and high infection multiplicity. Following infection of spleen cells from Langat-immune mice with Langat virus having a high infection multiplicity, higher virus replication rates than in non-immune cells were found to be present. Replication of Langat virus was generally superior to that of TBE virus. Virus replication was generally reduced by PHA stimulation of spleen cells. Langat virus did not replicate in human peripheral leukocytes. TBE virus replicated equally well in cells from a patient with TBE history and in cells from a non-immune person.

[Hepatitis A: antibody conversion under gamma globulin (author's transl)]

55 soldiers of the Austrian UNO contingent to the Near East, stationed on the Golan Heights for 6 months were examined before and after their period of duty for hepatitis A antibodies and the liver specific enzymes GOT, GTP and gamma-GT were determined. All received prophylactic gamma globulin to prevent infectious hepatitis at a dosage of 0.05 ml/kg body weight before flying out and after three months. No cases of hepatitis occurred, but 4 sero-negative subjects displayed antibody conversion. No concomitant changes in the liver enzyme values were recorded, however. These findings are discussed.

Chemical crosslinking of tick-borne encephalitis virus and its subunits

Tick-borne encephalitis (TBE) virus was crosslinked by dimethylsuberimidate (DMS) and the cleavable dimetyl 3,3'-dithiobispropionimidate (DTBP). Analysis by SDS-PAGE revealed polymers of the virus core protein V2 and the glyco protein V3 in continuously decreasing amounts. The formation of higher order complexes was not favoured over the formation of lower order complexes. This is consistent with an even distribution of V3 molecules on the surface of the virion and of V2 in the core. The formation of polymers was completely abolished by SDS, whereas crosslinking of TBE virus disrupted with a large excess of mild detergents (Triton X-100, octylglucoside, Na-deoxycholate) still yielded V3 dimers but only negligible amounts of higher polymers. This indicates that in the presence of these detergents the basic subunit of the TBE virus envelope is composed of two V3 molecules, probably associated with V1. Using two-dimensional PAGE analysis of DTBP crosslinked complete virions or cores, no heterocomplexes between different virus proteins could be found which were small enough to penetrate a 5% gel. Crosslinking between V3 molecules only and V2 molecules only was therefore highly favoured over other reactions.

Immunogenicity and reactogenicity of a highly purified vaccine against tick-borne encephalitis

Immunogenicity and reactogenicity of a vaccine containing inactivated tick-borne encephalitis virus prepared by continuous flow zonal ultracentrifugation were compared with those of a previously used, less purified vaccine. Antibody response as measured by hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) was 93% after two vaccinations and 100% after a third dose. The zonally purified vaccine impressively reduced the incidence of side reactions. Pyrexia (greater than 37.3 degrees C) was recorded in only 4--10% of the vaccinees almost exclusively after first vaccinations compared to 17--68% with the old type of vaccine. When these results are evaluated according to criteria commonly used in the United States (ie, pyrexia greater than 100 degrees F = 37.8 degrees C), almost no fewer would be recorded. The frequency of systemic side reactions was even lower (statistically significant) after second and third vaccination. This highly purified vaccine therefore represents an effective and well-tolerated means for the immunoprophylaxis of TBE.

Studies in man with cold-recombinant influenza virus (H1N1) live vaccines

Two cold-recombinant influenza A (H1N1) viruses were tested in several groups of human volunteers. Only minor clinical symptoms were seen and no febrile reactions occurred. With serologically primed individuals virus shedding was low, but a high proportion showed rises in serum antibody levels after vaccination and mean titres were high. With serologically unprimed volunteers shedding was high, about 75% yielding viruses but only at low titres and for a short duration. No revertant viruses were found and there was no evidence of transmission to potentially susceptible individuals housed in close contact to the vaccinees. Serum antibody responses with unprimed volunteers were, however, low. Only about one half showed increases in serum antibody titres after vaccination and mean titres were low. Nevertheless, challenge with live attenuated virus indicated a high degree of protection based on virological evidence of infection.

Preparation of a highly purified vaccine against tick-borne encephalitis by continuous flow zonal ultracentrifugation

By the use of continuous-flow zonal ultracentrifugation, a highly purified, inactivated tick-borne encephalitis (TBE) virus vaccine was prepared tht contained almost exclusively TBE virus particles. The purity of this preparation was 90- to 100-fold higher than that of a previously used partially purified vaccine. A mean protein content of 3-5 microgram/ml in the final vaccine represents 20 mouse protective doses50 in a mouse challenge potency test. This high degree of purity resulted in a strong reduction of side reactions observed with the less purified vaccine.

Isolation of dimeric glycoprotein subunits from tick-borne encephalitis virus

Crosslinking of tick-borne encephalitis virus with dimethylsuberimidate followed by SDS-PAGE analysis yielded polymers of the core protein V2 and the viral glycoprotein V3, both in continuously decreasing amounts. As the two structural entities of flaviviruses - cores and viral envelope - are apparently crosslinked independently from one another, we employed this property to study the action of different detergents at various concentrations on either the viral envelope or core. Triton X-100 and octylglucoside had no influence on the core but did dissociate the envelope into a V3-dimer. Centrifugation in density gradients containing these detergents yielded a 5-6S lipid-free hemagglutinating subunit which most probably represents a V3-dimer. In the presence of Triton X-100 this complex contains V1 in addition to V3.

Protease treatment and chemical crosslinking of a flavivirus: tick borne encephalitis virus

Tick-borne encephalitis virus was treated with pronase or thermolysin. The resulting particles were banded in sucrose gradients and analyzed for polypeptide composition. Both enzymes caused a reduction in particle density from 1.19 to 1.15--1.16 g/cm3. No loss of viral lipid or nucleic acid could be observed. SDS-polyacrylamidegel electrophoresis showed that only the core protein V2 was unchanged whereas the envelope proteins V3 and V1 had disappeared from their original positions in the PAGE profile. Instead a new peptide(s) with molecular weight of 4000--6000 was found in which hydrophobic amino-acids were enriched. Crosslinking by dimethyl-3.3'-dithiobispropionimidate (DTBP) made the virus resistent to solubilization of the envelope proteins by TX-100. This could be interpreted by the formation of a dense envelope protein network around the nucleocapsid preventing its liberation by TX-100. Some data however indicate that direct crosslinking of at least one of the envelope proteins with the core cannot be excluded.

Dissociation of tick-borne encephalitis virus by Triton X-100 and cetyltrimethylammonium bromide

The uses of the nonionic detergent Triton X-100 (TX-100) and the cationic cetyltrimethylammonium bromide (CTAB) for the production of tick-borne encephalitis (TBE) virus subunits were compared. TX-100 splitted the virus into haemagglutinating envelope components which contain the virion proteins V3 and V1 and into a lipid-free nucleoprotein composed of RNA and V2. The lipid content of the released envelope fragments decreased with increasing detergent concentration. By the use of CTAB, the viral glycoprotein V3 could be prepared in electrophoretically pure and active, i.e. haemagglutinating form.

[The incidence of antibodies to hepatitis A virus in people from Vienna and certain Austrian provinces (author's transl)]

The prevalence of antibodies to hepatitis A virus was measured by solid-phase radioimmunoassay in sera of 651 persons from Vienna, Lower Austria, Upper Austria, Carinthia and Burgenland. On subdivision of the subjects according to age groups, a curve resulted which showed a steep rise in persons between 20 and 40 years. In the age groups over 40 more than 80% of the test-persons possessed the specific antibody. In all age groups the population of Vienna showed a higher incidence of hepatitis A antibody than the people from rural areas.

Immunoglobulins to tick-borne encephalitis in the cerebrospinal fluid of man

Antibodies of IgM and IgG type were detected in the CSF of patients with recent tick-borne encephalitis (TBE) by means of ELISA. No false-positive results were obtained with CSF specimens from patients suffering from meningitis or other illnesses. The ratio of the antibodies in serum to CSF clearly indicated that both IgM and IgG antibodies were produced in the brain itself. In patients who had previously suffered from TBE now with a different inaseptic meningitis, TBE antibodies could also be detected in CSF but only of the IgG class. Again the serum-to-CSF antibody ratio indicated that the antibodies were produced within the central nervous system. For routine diagnosis the micro-ELISA method was found to be useful; antigen-coated plates can be stored as long as three months at +4 degrees C.

[Serumconcentrations of non esterified fatty acids during operative stress and blockade of betaadrenergic receptors (author's transl)]

Every stress reaction leads to an increased, hormonelly induced mobilisation of fatty acids, the extent of which may be considered as a parameter of the aggression mechanism. In 15 patients with idiopathic trigeminal neuralgia, who were operated under neurolepthypalgesia, the problem of quantitative alterations of the concentration pattern of fatty acids was investigated during the operation. In contrast to some reports of the literature, the increase of the concentration of total fatty acids was due to corresponding increases of all individual fatty acids. By preoperative administration of the beta-adrenergic blocking agent Pindolol the increase of fatty acids was reduced without a qualitative shifting of individual fatty acids.

[Live influenza vaccination of military personnel (author's transl)]

A field study was performed on 118 members of army personnel with the intranasally-applied live influenza vaccine, RIT 4050. 91 subjects were revaccinated 7 days thereafter. The immune response was best in subjects with a low prevaccination titre and was better in subjects vaccinated twice than only once. An immune response was also detected in the nasal secretion measuring the secretory IgA antibodies. Live influenza vaccine can be regarded as a suitable alternative to other influenza vaccines, with the qualification that it lacks an influenza B component.

[A new influenza subunit vaccine: hemagglutinating antibodies one year after vaccination (author's transl)]

The antibody response to a new influenza subunit vaccine was compare d one year after vaccination with the responses induced by two other influenza vaccines. The subunit vaccine was given either in a high dose form containing 2100 IU, or in a low dose form containing 700 IU. As comparison a split vaccine was used containing 800 IU and AI(OH)3 as adjuvant and a whole virus vaccine containing 2100 IU. Of the 399 vaccinated subjects which had taken part in this study 151 were available for hemagglutination inhibiting (HAI) antibody determinations one year after vaccination. Protection rates assessed for the respective groups on the assumption that serum HAI titers of 1 : 32 or greater confer protection. With the high dose of subunit vaccine 85% of volunteers were considered still to have protective titers one year after vaccination, compared with 77% of those who received the whole virus vaccine. Although the high dose subunit vaccine and whole virus vaccine induced similarly high protective levels lasting at least one year, the reactions observed on vaccination were significantly less with the subunit preparation. The lower dose of subunit vaccine induced lower levels of protection (60%) after one year, and lower mean HAI titers than the high dose subunit vaccine. Nevertheless protection was superior to that of the split virus adjuvant vaccine. The addition of adjuvant thus does not seem materially to improve the immune response to influenza virus antigens. An increase of antigen content can however be seen as a practical alternative for achieving higher antibody levels. The subunit vaccine would appear to be particularly suitable in this respect as even with a higher dose there is no increase in reactogenicity.

Protection of mice against tick-borne encephalitis by different classes of immunoglobulins

The protective capacities of IgM and IgG immunoglobulins from fractionated human or mouse sera were investigated in tests with tick-borne encephalitis virus. Mice were resistant to challenge with tick-borne encephalitis virus if previously inoculated with specific immunoglobulins but not nonspecific immunoglobulins. The protective ability of IgM, whether derived from mouse or human sera, was only about 1/40 of that of IgG preparations adjusted to the same haemagglutination inhibition or neutralising titres.

[Solid-phase radioimmunoassay for class specific immunoglobulins against tick-borne encephalitis virus (author's transl)]

By adsorbing purified Tick-borne encephalitis (TBE) virus antigen onto beads of polystyrene, a solid-phase radioimmunoassay (RIA) for specific antibodies of the IgM- and IgG-class in untreated and nonfractionated human sera could be developed. The antibodies were measured by antihuman-gamma and antihuman-mu globulin labelled with 125 I. The RIA was about 20 times as sensitive as the hemagglutination-inhibition test. About 10% more cases of TBE could be diagnosed with the RIA than with the 2-mercaptoethanol test.

Characterization of tick-borne encephalitis virus and immunogenicity of its surface components in mice

Tick-borne encephalitis (TBE) virus grown in chick embryo cells and purified by rate-zonal centrifugation was shown to have a density of 1.195 g/cm3 in sucrose density gradients. Under the conditions used, CsCl centrifugation caused disruption of the virus and less than 5% of input infectivity could be recovered from the virus peak at 1.23 g/cm3. As in other fiaviviruses, three polypeptides (V1, V2, V3) were detected by polyacrylamide gel electrophoresis in radioactively labelled purified TBE virus. After disruption of TBE virus with Nonidet P-40, Tween-80/Tri-(n-butyl)-phosphate or sodium deoxycholate, a 120--130 S nucleoprotein could be separated by rate zonal centrifugation from more slowly sedimenting haemagglutinins. Immunization of mice with these haemagglutinins showed that they induced haemagglutination inhibiting, neutralizing and complement fixing antibodies. A pronounced increase in immunogenicity could be observed by the use of Al(OH3) as an adjuvant.

Concentration and purification of tick-borne encephalitis virus grown in suspensions of chick embryo cells

Tick-borne encephalitis (TBE) virus grown in suspensions of chick embryo cells was precipitated by various concentrations of polyethylene glycol (PEG) 6000. Quantitative recovery was obtained at PEG concentrations of 5% and higher. As precipitation of contaminating non-viral protein increases with increasing PEG concentrations, best results with respect to purity and recovery were obtained at 5% PEG 6000. Analysis of virus concentrates by rate zonal centrifugation revealed two peaks--rapidly sedimenting haemagglutinin (RHA) associated with infectivity and slowly sedimenting haemagglutinin (SHA)--characteristic of Flaviviruses. Purification factors after PEG precipitation followed by rate zonal centrifugation in sucrose density gradients ranged from 50 to 200 for HA activity and from 40 to 50 for infectivity.

Field study with a live influenza vaccine (RIT 4050) in children

In autumn of 1976 a study was performed with Gripovax (RIT 4050) in 126 schoolchildren in Vienna. Sixty-one of the children were 10 to 14 years old and 65 were 7 to 10 years old. The study was initiated in the older group (10-14 years old) by transnasal administration of a single dose of vaccine; 23 children received a second dose 7 days later. Symptoms were recorded daily up to the 7th postvaccinal day. 53 out of 61 vaccines did not report any symptoms during the 7 day postvaccinal period. 8 complained of mild and transient nasal stuffiness and only 1 child had a rise in temperature (37.8 degrees C). In a second group (7 to 10 years of age), 65 children received 2 doses of the vaccine at a 7 day interval. No symptoms were recorded in 57 subjects and only 8 reported mild and transient nasal stuffiness. Hemagglutination inhibition (HI) antibody titers were determined before and after vaccination. In the older age group (10-14 years), after one dose of vaccine (vaccinees with prevaccinal titers less than 1:20), seroconversion occurred in 20 out of 28 (71.4%) and after two doses, in 18 out of 21 (85.7%). Children aged 7 to 10 years received both doses of the vaccine. In subjects with prevaccinal titers less than 1:20, seroconversion occurred in 40 out of 43 (93%). Geometric mean of titers (GMT) before and after one dose was 24.3 and 97.4, respectively. The GMT of those children who received two doses (both age groups) was 30 preceding and 185 after vaccination.

[IgM diagnosis of Epstein-Barr virus (EBV) infections by means of the immunofluorescent method]

Sera were investigated of patients possibly suffering from an EBV infection, without showing clinical features characteristic of infectious mononucleosis. The method of investigation was the detection of antibodies of the IgM-type by means of the immunofluorescent method using a three-layer technique. Diagnosis of EBV infection was established in 10 out of 90 patients with facial palsy, one with myelitis, one with sudden deafness and one with polyneuritis. In addition, 4 out of 19 cases of hepatitis (Hbs-negative) proved to be due to infection with EBV. The specific IgM test proved to be superior to the heterophil agglutination test.

[Effect, hazards and risks of the new vaccination against tick-borne encephalitis (TBE) as calculated by special formulas (author's transl)]

The effect and risks of the vaccination against TBE virus was calculated by means of formulas for Q and D. Q considers the relation between total risk of unvaccinated and vaccinated persons and D the yearly difference in risks between unvaccinated and vaccinated members of a community. In recommendable vaccinations Q should exceed 1,0 and D should be greater than 0. Vaccination against TBE was performed by 2 injections at an interval of 4 weeks followed by a 3rd injection after 9 months. No major side effects were observed in vaccinations of about 50,000 persons. After one injection only, the conversion rate was 76% and Q 4,17, after 2 injections the conversion rate was 96% and Q 25 and after the total course of 3 injections the conversion rate was 98% and Q was calculated to be 50. With respect to morbidity DM was 7,18 X 10(-5) and regarding mortality DL was 1,1 X 10(-6). That means that proper vaccination of persons at risk in Austria could prevent 500-600 cases of encephalitis and approximately 8 deaths due to TBE per year. It was concluded that the new vaccination is effective and recommendable. Revaccinations will be necessary probably at intervals of 2-3 years, the exact time period still being under study.

[Field trial with a new type of influenza subunit vaccine (author's transl)]

In a field trial a new influenza subunit vaccine was tested in parallel with a vaccine prepared from the whole virus. The subunit vaccine essentially contained only the proteins of the viral envelope, haemagglutinin and neuraminidase, which had been selectively solubilized by treatment with cetyl trimethylammonium bromide. Both vaccines contained 700 IU of strain A/Port Chalmers/73 in 0.5 ml. They were given to volunteers by the subcutaneous route with and without the addition of Al (OH)3 as adjuvant. Blood samples were taken on days 0, 28 and 90. Development of antibodies was assayed in the haemagglutination-inhibition (HI) and neuraminidase-inhibition (NI) test. All vaccines exhibited a very good immunogenic effect as judged from the number of volunteers with at least a four-fold rise in antibodies in the HI-test and those reaching titres that are considered to be sufficiently high for protection against disease. The best results were obtained with the aqueous subunit vaccine. All four vaccines also stimulated the formation of neuraminidase-inhibiting antibodies. The vaccines were well tolerated by the volunteers. The incidence of minor local reactions such as redness, swelling and pain varied according to the vaccine used, as shown on statistical evaluation. The aqueous subunit vaccine clearly proved to be superior in this respect.

[A new influenza subunit vaccine: reactogenicity and antigenicity in comparison to split and whole virus vaccines (author's transl)]

The reactogenicity and immunogenicity of a new influenza subunit vaccine essentially containing only haemagglutinin and neuraminidase was studied in man. The vaccine was compared to commercially available vaccines, an adjuvant containing tween-ether split vaccine (800 IU per dose), and a fluid whole-virus vaccine (2100 IU per dose). Two dosages (700 and 2100 IU) of the fluid subunit vaccine were compared. All vaccines contained the virus strains recommended by the WHO for the 1975/76 season. In a double-blind study 399 volunteers were randomly selected to receive one of the four vaccines. The volunteers were examined for side-effects 24 and 48 hr after vaccination. Antibodies inhibiting haemagglutination were determined prior to and four weeks after vaccination. The sudunit vaccine at 700 IU per dose caused significantly fewer local side effects than the comparable split vaccine, and resulted in significantly higher antibody titers against both influenza A strains. A comparison of the subunit and whole virus vaccines containing high dosages (2100 IU) showed striking differences in reactogenicity. Subunit vaccine was very well tolerated. whereas whole virus vaccine caused systemic reactions, including fever and headache, in 15% of the volunteers. No significant reactogenicity was seen with a high dosage of subunit vaccine (2100 IU) although this is a three-fold increase on the currently used European dosage. Antibody titers were significantly enhanced however.

[Field studies with a new tick-borne encephalitis (TBE) vaccine]

The vaccine used contained formalin-inactivated TBE virus that was grown in chick embryo cells and adsorbed to Alhydrogel. In a first study, conducted in 1973, a total of 81 volunteers were given subcutaneously two doses of vaccine 4 weeks apart, and a third dose 7-9 months later. After each vaccination, the rates of seroconversion were assayed in the hemagglutination inhibition test. The values obtained were 76%, 96% and 98%, respectively. The geometric mean titers found were 1:26, 1:36 and 1:44. The vaccine was well tolerated locally and systematic reactions such as fever headache and fatigue were only recorded after the first dose of vaccine. In 1974 and 1975 a total of 30,000 persons were vaccinated in areas where the disease is endemic. Most of the vaccinees work in forests and are, therefore, at high risk of infection. Circumstantial evidence indicates that the vaccine is protective.

Rotating beam splitter for the extreme vacuum ultraviolet

We have built a rotating-mirror beam splitter at grazing incidence which was used to measure directly (with minor corrections) the transmissivity of thin films in the 20-280 eV photon energy region. The intensity fluctuations usually encountered when using electron accelerators as light sources were efficiently eliminated. The same instrument could be used to measure differential transmissivities DeltaT/T with a sensitivity of a few tenths of a percent. In another arrangement a deflecting mirror which is incorporated as the photocathode into an open electron multiplier served as a very efficient beam monitor against intensity fluctuations.