Results of studying a live mumps vaccine from strain L-3 manufactured by the Moscow Research Institute of Viral Preparations. The reactogenic and antigenic properties of the vaccine]

The reactogenic and antigenic properties of live mumps vaccine from the L-3 strain were studied in 1507 children of 1 to 12 years of age. A single injection was given, one immunizing dose containing 10(4)HAdU50 of mumps virus. The live mumps vaccine from the L-3 strain irrespective of the lot of preparation, kind (live or lyophilized), method of application (jet-injector or needle/syringe), age of the vaccinees and the amount of virus in the immunizing dose received by a vaccinee, was demonstrated to be practically areactogenic and markedly antigenic. Serological examinations by neutralization tests of 346 paired serum specimens established variation in seroconversion between individual lots to be within 62.5--82.3% (average 69.9%) of cases. Comparative studies on the postvaccination and postinfection immunitiy in mumps showed the level of antibody in the vaccinees to vary within 4.2--5.1 log2 in different years, and in convalescents within 5.1--5.9 log2 in the same years. The results indicate a sufficiently high and intensive immunity for 5 years (the observation period).     

Study of the properties of a tissue smallpox vaccine manufactured by the Moscow Research Institute of Viral Preparations]

The tissue culture vaccine against smallpox has some important advantages over the dermal preparation: it is free from bacterial contamination, contains no serum proteins, and suitable for intradermal inoculation with jet injections. The virus for the tissue culture smallpox vaccine is grown in Japanese quail embryo cultures controlled for the absence of contaminating viruses. In trials of the tissue culture smallpox vaccine in 800 revaccinated volunteers no untoward reactions or complications were observed. The antigenic activity of the tissue culture smallpox vaccine was superior to that of dermal vaccine used in the same dose: the geometric mean neutralizing antibody titre after vaccination with the tissue and dermal preparations was 1 : 256 and 1 : 158, respectively, and the antibody rise was 4.5- and 2.5-fold.     

Testing for the safety, reactogenicity and antigenic properties of a live thermostable mumps vaccine made from the Leningrad-3 strain]

A live mumps vaccine (LMV) from strain Leningrad-3 with a new stabilizer LS-18 was tested for reactogenicity and antigenic potency. Examinations of vaccinated children for vaccination reactions showed its complete areactogenicity and safety. LMV induced synthesis of virus-neutralizing antibodies in 78-82% of the vaccinees. Determinations of the dynamics, intensity and duration of circulation of specific antihemagglutinating, antineuraminidase and virus-neutralizing antibodies demonstrated marked antigenic potency of the LMV and established production of earliest specific antineuraminidase antibodies in 75% of the vaccinees. EIA was found to be the most sensitive test.     

Physicochemical characteristics of a vaccinal strain of the Leningrad-3 mumps virus (L-3)

Purified virions of the vaccine strain Leningrad-3 of mumps virus propagated in Japanese quail embryo cell cultures had a buoyant density 1.18-1.19 g/ml in sucrose gradient, contained 50 S RNA and showed variable sizes in electron microscopy as manifested by heterogeneity of the virus zone in sedimentation analysis. Purified L-3 virus contained 5 major polypeptides with molecular weights of 74,000, 68,000, 58,000, 45,000, and 39,000 daltons. Each polypeptide had an individual oligopeptide composition.     

A live attenuated turkey rhinotracheitis virus vaccine. 2. The use of the attenuated strain as an experimental vaccine

An attenuated turkey rhinotracheitis (TRT) vaccine strain, when given either by eye drop or by aerosol, has been shown to be effective in protecting 1- to 11-day-old turkey poults against an experimental challenge with TRTV up to 14 weeks later. TRT antibody-free poults and poults hatched from TRT-immune dams were both equally well protected, although a high proportion of the latter did not respond serologically to the vaccine. As little as 1 CD50 of vaccine was found to be effective in protecting poults against challenge. Immunity developed within about 6 days of vaccination of 7-day-old TRT antibody-free poults and humoral antibody persisted for at least 14 weeks after a single vaccination at 4 weeks of age.     

Construction and characterization of a Vi-positive variant of the Salmonella typhi live oral vaccine strain Ty21a.

The viaB locus coding for the Vi antigen of Salmonella typhi Ty2 was cloned on a 40.6-kilobase fragment into the cosmid vector pHC79. The live, oral, attenuated Vi-negative S. typhi Ty21a vaccine strain was transformed with the recombinant cosmid encoding the viaB locus. Homologous recombination of the viaB locus into the chromosome of S. typhi Ty21a was induced by UV irradiation, and Vi-positive recombinants were selected in the presence of D-cycloserine. One such isolate, termed WR4103, contained no plasmids or the attendant antibiotic resistance markers and expressed the Vi antigen stably. Vi antigen extracted from WR4103 was immunologically indistinguishable from Vi antigen purified from S. typhi Ty2. The only detectable difference between Ty21a and WR4103 was in the production of Vi antigen. The mean lethal doses of Ty21a and WR4103 for mice were nearly identical. Immunization of mice with WR4103 engendered a Vi antibody response and afforded complete protection against fatal infection with virulent S. typhi Ty2. Thus, S. typhi WR4103 may serve as an improved oral vaccine for protection against typhoid fever.     

Several membrane polypeptides of the live vaccine strain Francisella tularensis LVS stimulate T cells from naturally infected individuals.

The currently used live vaccine strain Francisella tularensis LVS was derived several decades ago from a wild strain of the species. In the present report, several membrane polypeptides of LVS are shown to be recognized by T cells from individuals immunized by natural infection with F. tularensis. Bacterial membranes of a capsule-deficient mutant of LVS were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Thereafter, gels were divided into seven fractions, each fraction containing a different number of peptide bands. From other gels, four bands were excised, each containing one major polypeptide. Eluates of each fraction and of each polypeptide band induced a proliferative response and an interleukin-2 response in lymphocytes from most of the individuals. When the lymphocytes were separated after induction, most of the proliferative response was found to occur in CD4+ T cells. Lymphocytes from nonimmune individuals responded poorly to all membrane polypeptides. To study the possible heterogeneity of antigen determinants among the polypeptides, T-cell clones were raised towards F. tularensis and tested for proliferative response to the four major membrane polypeptides. Five clones, all CD4+ CD8-, responded to one or more of the polypeptides, each clone with a unique pattern of response. In conclusion, F. tularensis possesses a high number of T-cell-reactive membrane polypeptides. There seems to be a heterogeneity of T-cell determinants among these polypeptides. Determinants involved in immunization by natural infection are well conserved in LVS.     

The effect of a live vaccine on the horizontal transmission of Mycoplasma gallisepticum.

The effect of a live Mycoplasma gallisepticum vaccine on the horizontal transmission of this Mycoplasma species was quantified in an experimental animal transmission model in specific pathogen free White Layers. Two identical trials were performed, each consisting of two experimental groups and one control group. The experimental groups each consisted of 20 birds 21 weeks of age, which were housed following a pair-wise design. One group was vaccinated twice with a commercially available live attenuated M. gallisepticum vaccine, while the other group was not vaccinated. Each pair of the experimental group consisted of a challenged chicken (10(4) colony-forming units intratracheally) and a susceptible in-contact bird. The control group consisted of 10 twice-vaccinated birds housed in pairs and five individually housed non-vaccinated birds. The infection was monitored by serology, culture and quantitative polymerase chain reaction. The vaccine strain and the challenge strain were distinguished by a specific polymerase chain reaction and by random amplified polymorphic DNA analysis. In both experiments, all non-vaccinated challenged chickens and their in-contact 'partners' became infected with M. gallisepticum. In the vaccinated challenged and corresponding in-contact birds, a total of 19 and 13 chickens, respectively, became infected with M. gallisepticum. Analysis of the M. gallisepticum shedding patterns showed a significant effect of vaccination on the shedding levels of the vaccinated in-contact chickens. Moreover, the Cox Proportional Hazard analysis indicated that the rate of M. gallisepticum transmission from challenged to in-contact birds in the vaccinated group was 0.356 times that of the non-vaccinated group. In addition, the overall estimate of R (the average number of secondary cases infected by one typical infectious case) of the vaccinated group (R = 4.3, 95% confidence interval = 1.6 to 49.9) was significantly lower than that of the non-vaccinated group (R = infinity, 95% confidence interval = 9.9 to infinity). However, the overall estimate of R in the vaccinated group still exceeded 1, which indicates that the effect of the vaccination on the horizontal transmission M. gallisepticum is insufficient to stop its spread under these experimental conditions.     

Lymphocyte responses to rubella antigen and phytohemagglutinin after administration of the RA 27/3 strain of live attenuated rubella vaccine.

Lymphocyte phytohemagglutinin (PHA) responsiveness was found suppressed in both rubella sero-negative and sero-positive recipients of RA 27/3 strain of live attenuated rubella vaccine; the suppression was readily demonstrable only when a suboptimal dose of PHA was applied in the test. Lymphocytes from sero-negative vaccinees, which initially showed little or no in vitro response to concentrated rubella virus, became responsive after vaccination by day 21, when the highest sensitization to rubella antigen was seen. In the sero-positive vaccinees. lymphocytes responded to rubella antigen in vitro before vaccination, and in most cases vaccination did not result in significant changes in lymphocyte response. These results suggest that rubella vaccination leads to temporarily increased lymphocyte reactivity to rubella antigen, and the increased lymphocyte response to specific antigen may occur at the time of mild suppression of PHA response.     

Characteristics of epidemiological strains of influenza A virus (H3N2) isolate in 1997-1999. Virus A/Moscow/10/99--a candidate to become the vaccine strain

Antigenic properties of influenza A(H3N2) viruses isolated during two epidemic seasons 1997-98 and 1998-99 in Russia are analyzed. All strains are antigenic variants of the reference strain A/Sydney/5/97. Characteristics of epidemic strain A/Moscow/10/99, proposed by WHO expert committee as vaccine strain for 1999-2000 have been studied. This strain, isolated on chick embryos, is characterized by high reproductive activity in chicken embryos with an infectious titer of 10(6) EID50/0.2 ml, easily adapts to MDCK culture, and has a thermostable hemagglutinin.     

Protection of rabbits against experimental pasteurellosis by a streptomycin-dependent Pasteurella multocida serotype 3:A live mutant vaccine.

Pasteurella multocida (serotype 3:A) was isolated from a rabbit with clinical signs of suppurative rhinitis. This P. multocida strain was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine to obtain a genetically stable streptomycin-dependent mutant, from which a life vaccine was prepared. Pasteurella-free rabbits were inoculated intranasally three times at weekly intervals and challenged intranasally with a virulent serotype 3:A rabbit P. multocida isolate 2 weeks after the third vaccination. The rabbits were killed 2 to 3 weeks later. The vaccine did not cause clinical disease, death, or gross or microscopic lesions. Furthermore, the vaccine protected the challenge rabbits from developing clinical disease, death, and gross lesions. However, mild focal lung lesions were noted in several of the vaccinated-challenged animals. In contrast, nonvaccinated-challenged rabbits developed pyrexia and anorexia. Furthermore, three of four of these rabbits died with severe gross lesions including pyothorax, suppurative pericarditis, and fibrinopurulent pneumonia. Microscopically, the four nonvaccinated rabbits had moderate to severe suppurative pneumonia and mild to moderate suppurative rhinitis, and two had mild tympanitis. The mutant vaccine did not appear to colonize the nasal cavities. The vaccine prevented the colonization of the virulent challenge organism in lungs, liver, spleen, genital tracts, and blood, but not the nasal cavities.     

Cell-mediated and humoral immune responses induced by scarification vaccination of human volunteers with a new lot of the live vaccine strain of Francisella tularensis.

Tularemia is a disease caused by the facultative intracellular bacterium Francisella tularensis. We evaluated a new lot of live F. tularensis vaccine for its immunogenicity in human volunteers. Scarification vaccination induced humoral and cell-mediated immune responses. Indications of a positive immune response after vaccination included an increase in specific antibody levels, which were measured by enzyme-linked immunosorbent and immunoblot assays, and the ability of peripheral blood lymphocytes to respond to whole F. tularensis bacteria as recall antigens. Vaccination caused a significant rise (P less than 0.05) in immunoglobulin A (IgA), IgG, and IgM titers. Lymphocyte stimulation indices were significantly increased (P less than 0.01) in vaccinees 14 days after vaccination. These data verify that this new lot of live F. tularensis vaccine is immunogenic.     

Inhibition of airway eosinophilia and pulmonary pathology in a mouse model of allergic asthma by the live vaccine strain of Francisella tularensis

Background It has been suggested that exposure to certain microbes and their products, particularly during neonatal and early childhood periods, may shift the immune response towards a T-helper cell (Th) 1 phenotype and thereby prevent the development of and/or alleviate the clinical symptoms of allergic airway diseases.
Objective We evaluated the ability of the live vaccine strain (LVS) of Francisella tularensis to suppress airway eosinophilia and pulmonary pathology in a murine model of allergic airway disease.
Methods C57BL/6 mice were sensitized by intraperitoneal injection of ovalbumin (OVA) on days 1 and 14, and challenged intranasally (i.n.) with OVA on day 21 or thereafter. Some sensitized mice were i.n. treated with live LVS or its cell-free sonicate extract (CFSE) before i.n. OVA challenge. Bronchoalveolar lavage fluid, regional lymph node cells, lung tissues and serum samples were collected 3–7 days after the i.n. challenge.
Results Intranasal and, to a lesser degree, intradermal immunization of OVA-sensitized mice with LVS suppressed the development of airway eosinophilia and associated pulmonary pathology induced by i.n. OVA challenge. Moreover, CFSE prepared from LVS showed a similar inhibitory effect whereas neither LPS nor DNA purified from F. tularensis LVS had such an effect. The inhibition was associated with the reduction in mRNA expression and protein levels of Th2 cytokines IL-5 and IL-13 in the lungs and the enhanced production of OVA-induced IFN-γ by local draining lymph node cells, but not with the serum levels of OVA-specific IgG1 or IgE.
Conclusion F. tularensis LVS is capable of suppressing allergic airway inflammation probably through a Th1-mediated suppression of an ongoing Th2 response mechanism, and raises the possibility of exploring LVS and its components as potential therapeutic modalities for human allergic asthma.     

Identification and characterization of a new base substitution in the vaccine strain of Sabin 3 poliovirus.

The complete RNA sequence of Sabin 3 (LED3) used in vaccine in the United States has been determined. The LED3 Sabin 3 sequence contains the attenuating mutations at bases 472 and 2034 but differs from that published by Stanway et al. (Nucleic Acids Res., 11, 5629-5643, 1983) at two other base positions, 2493 and 6061. The change at base 6061 is silent and does not affect amino acid composition. The other base, a C at position 2493, is contained in the viral capsid protein VP1 and predicts a new Sabin 3 specific amino acid change of a threonine instead of an isoleucine at amino acid 6 of the protein [corrected]. Reversion of this base to that present in the pathogenic progenitor strain, Leon, is observed to occur after replication of vaccine virus in the gut of primary vaccines and in nervous tissue of neurovirulence test monkeys. Passage conditions have been identified that lead to the reversion of base 2493 as well as the reversion of the attenuated base to the parental base (Leon) at position 472 in the 5' noncoding region. The observation that these two bases delta position are found to revert during passage suggests that there is a selective advantage for virus containing the parental bases at these positions.