Evaluation of the vaccinal process in skin-scarification and oral immunization of rabbits with live smallpox vaccines

On the basis of comparative experimental evaluation of specific features in the course of the vaccinal process after the immunization of laboratory animals with live smallpox vaccines, intended for oral use (in tablets) and for skin scarification was proposed. In experiments on rabbits, made with the use of virological and immunological methods, the counteraction of the elements constituting the vaccinal process was analyzed, the integral evaluation of its course was given, the greater safety of the oral preparation in comparison with the traditional vaccine for immunization by skin-scarification method were established. The conclusion was made that oral immunization was the safest immunization method under modern conditions and promising one for using live vaccines with population immunity being at a low level or absent.     

Immunological responses of hamsters in the acquired immune state to Mycoplasma pneumoniae infection

Protective effects of vaccination of hamsters against Mycoplasma pneumoniae infection, evaluated according to the recovery of mycoplasmas and histopathological changes in the respiratory tract after challenge infection, persisted for at least 6 months after the final vaccination. Serum antibody levels reached a maximum in the second week after the last vaccination and decreased markedly between the first and the third months, but increased again in sera obtained from animals given booster injections. Metabolism-inhibiting antibodies were detected in bronchial washings of animals showing high resistance obtained by vaccinal or passive immunization. Antiserum transfer was also effective for protection but cell-mediated immune responses were not demonstrated in any animals up to 6 months after the vaccination. Even after 10 months, suppression of both mycoplasmal proliferation and lung lesions was apparent, and a single dose of the vaccine induced a significant booster effect. These findings suggest that (1) humoral immunity is more important than cell-mediated immunity in resistance of hamsters to M. pneumoniae pneumonia, and (2) the antibody secreted in the respiratory tract may be involved in the local defense mechanisms.     

The effect of the synergistic action of enterotoxin on the specific protective complex of Shigella sonnei]

The study has first established that enterotoxin enhances the protective potency of S. sonnei specific protective complex. This effect has been revealed both in experiments of the oral immunization of mice and in experiments of the conjunctival immunization of guinea pigs and depends on the dose of enterotoxin used in the experiment. The increase of protection has a specific character. These observations open prospects for further enhancement for the protective properties of S. sonnei specific protective complex, which should be taken into consideration in developing the vaccinal preparation.     

Evaluation of the toxicity of a chemical by adsorbed typhoid vaccine by a pharmacological test (hexenal sleep) and by a change in thymus weight in white mice

With the wide spread of immunoprophylaxis, investigations aimed at introducing new methods for the control of vaccines are gaining in importance. As indicated by the results of investigations, the reactogenicity of vaccinal preparations for humans may be evaluated, to a certain extent, by the degree of the stress action produced by these preparations and the duration of hexenal narcosis in laboratory animals.     

The mechanism of group differences in the character of the vaccinal process in immunization against natural smallpox

The effect of antigenic polymorphism of the ABO-system blood groups on the character of the vaccinal process after immunization against natural smallpox was investigated. The increased susceptibility of persons possessing A antigen to the harmful effect of smallpox vaccine virus is due to hereditary rather than to acquired factors. The leukocytes of peripheral blood of these persons showed a poorer binding capacity with respect to the smallpoxvaccine virus; they also exhibited a high rate of chromosomal aberration after vaccination, resulting to some extent from increased proliferative ability of the cells.     

Experience with the development of vaccinal prophylaxis in Perm Province

The results of the introduction of the system of epidemiological surveillance on vaccinal prophylaxis on the territory of Perm Province are presented. This system has permitted the realization of the principles of the regional tactics of immunization, while following the unified strategy acting on the territory of the Russian Federation. The optimization of the organizational foundations of vaccinal prophylaxis has made it possible to maintain the morbidity rates if infections, controlled by means of specific prophylaxis, on the levels below the average figures for the Federation and to preserve more stable tendencies to their decrease.     

Immunogenicity of the recombinant Bacillus strains with cloned gene of biosynthesis of protective antigen against Bacillus anthracis

Microbe Russian Anti-Plague Research Institute, Saratov A hybrid plasmid pUB110PA-1 demonstrating stable functioning in the cells of Bacillus strains and containing the gene of biosynthesis of Bacillus anthracis protective antigen was constructed. The recombinant strains surpassing the anthrax vaccinal cultures in the secreted synthesis of the protective antigen were obtained and their immunological efficacy was assessed. A single inoculation of Guinea pigs with the dose of 5 x 107 spores of the recombinant strains imparted efficient protection against B. anthracis challenge. Immune responses were characterized by high indices of immunity and titers of antibodies to the protective antigen. In contrast to the anthrax vaccinal preparations, the gene-engineering strains imposed no residual virulence for BALB/n mice and Guinea pigs.     

Prevention of mumps in preschool institutions using a live mumps vaccine made from strain L-3

The effectiveness of the emergency vaccinal prophylaxis of epidemic parotitis was studied in 19 children's day-care centers. As revealed in this study, the immunological effectiveness of vaccination did not depend on the age of vaccinees, but sharply decreased if live parotitis vaccine contained less than 10,000 HADU50 per immunization dose. After a single administration of the vaccine 91.1 +/- 0.98% of children were found to produce mumps antibodies. The immunization of children with live parotitis vaccine prepared from strain l-3 immediately after the first case of parotitis had been registered proved to be a highly effective measure. The coefficient of epidemiological effectiveness was 96.4%.     

An analysis of methods for controlling and regulating the concentration of vaccinal preparations during aerosol immunization

In this work the methods for the passive control and automatic regulation of the concentration of vaccinal aerosols in static chambers are analyzed. For such analysis, a method for the calculation of the parameters of vaccinal aerosols, taking account of the law of the distribution of particles by their sizes and of the processes of sedimentation and inactivation of microbial aerosols, has been developed. To make empirically established coefficients more precise, the necessary experimental studies have been carried out. High effectiveness of the method providing for the regulation of aerosol mass concentration has been demonstrated, and conditions necessary for effective aerosol immunization have been established.     

Reliability of the serological method of examination as a basis for diagnosis of associated respiratory virus infections.

The reliability of the results of serological examination in diagnostics of associated infections was studied on a model of artificially provoked vaccinal infections in humans and in laboratory animals. The effect of administered monopreparations on changes in the level of both homologous and heterologous antibodies was tested. The character of immunological changes following simultaneous administration of two or more respiratory viruses was analysed and the effect of these viruses in diseases of divers etiology was studied. According to the results of experiments on laboratory animals, repeated administration of any of the earlier used respiratory viruses stimulated the accumulation of only homologous antibodies while heterologous antibodies did not increase at all. The results revealed the possibility of simultaneous immunological reorganization of a child's organism in response to the influence of several different antigens from the group of respiratory viruses acting synchronously or in succession. Results of the analysis demonstrated the reliability of the employed serological methods of diagnosis of respiratory virus infections.     

Reactogenic properties of a DTP vaccine with a reduced antigen dosage

The reactogenic properties of batches of adsorbed DPT vaccine with the normal content of antigens and with the content of diphtheria and tetanus toxoids reduced, respectively, to 10 Lf and 5 BU per immunization dose have been studied under the conditions of a controlled epidemiological trial. The reduced antigenic content of adsorbed DPT vaccine decreased the number of vaccinal reactions 1.8 times, as well as the intensity of their manifestations.     

Effectiveness of enteric immunization in the development of secretory immunoglobulin A response and the outcome of infection with respiratory syncytial virus.

Cotton rats were immunized via intranasal, intradermal, or enteric routes with respiratory syncytial virus (RSV) or a live recombinant vaccinia virus expressing the RSV F glycoprotein (vaccinia F). The animals were tested for the appearance of RSV-specific antibody responses in the serum, bronchoalveolar lavage, and nasal wash after immunization and for virus replication 4 days after intranasal challenge with RSV. RSV antibody response in the serum and respiratory tract was demonstrated in all immunization groups and was significantly increased after intranasal challenge with RSV. Immunoglobulin A (IgA) antibody response in bronchoalveolar lavage fluid after intranasal or enteric immunization was two- to threefold higher than that after intradermal immunization. Nasal-wash IgA antibody response was not significantly different among three immunization groups, although mean antibody titer was the highest in intranasal immunization group. Complete resistance to replication of RSV challenge was observed in the lungs of cotton rats immunized by the intranasal or enteric routes, whereas a low level of replication was detected in the lungs of rats immunized intradermally. Enteric or intradermal immunization conferred partial protection to the upper respiratory tract, but complete protection of the upper respiratory tract was observed in the intranasal immunization group. These observations suggest that while enteric immunization is quite effective in inducing antibody responses in the respiratory tract, the magnitude of antiviral immunity induced in the respiratory tract after intranasal immunization may be superior to that observed after enteric immunization.     

Latex bread technique for detection of the plaque-forming cell response to teratocarcinoma tumor antigens

Summary A latex bead technique modified for measuring the plaque-forming cell (PFC) response to teratocarcinoma tumor antigens in syngeneic animals is described.With this method one can detect both the primary (IgM) and the secondary (IgG) immune response to tumor antigens. Optimal detection of the PFC response depends on the proper ratio of sheep red blood cells to latex beads and the dose of tumor cell antigen used for immunization. The presence of fetal calf serum interfered with immunization of animals and the coating of the latex beads with the tumor cell antigens. The plaques obtained in response to immunization with teratocarcinoma cell antigens varied in size, probably reflecting the complex immune response to more than one class of antigens on tumor cells.     

Latex bread technique for detection of the plaque-forming cell response to teratocarcinoma tumor antigens

A latex bead technique modified for measuring the plaque-forming cell (PFC) response to teratocarcinoma tumor antigens in syngeneic animals is described. With this method one can detect both the primary (IgM) and the secondary (IgG) immune response to tumor antigens. Optimal detection of the PFC response depends on the proper ratio of sheep red blood cells to latex beads and the dose of tumor cell antigen used for immunization. The presence of fetal calf serum interfered with immunization of animals and the coating of the latex beads with the tumor cell antigens. The plaques obtained in response to immunization with teratocarcinoma cell antigens varied in size, probably reflecting the complex immune response to more than one class of antigens on tumor cells.     

New immunofluorescent method for the rapid determination of microbial antibiotic sensitivity

A new procedure for rapid determination of the levels of antibiotic sensitivity in pathogenic microorganisms with the use of fluorescent antibodies is described. The procedure was developed with the use of a model of the vaccinal strains of Bacillus anthracis. It is based on determination of the microbial antibiotic resistance with the method of serial dilutions on solid media. Still, the medium with an antibiotic is inoculated instead of the pathogen with the native material subject to the analysis. The antibiotic effect on the microorganism is estimated with the method of fluorescent antibodies. The replica preparations obtained as a result of the pathogen growth in a mixed culture on nutrient media containing definite concentrations of the antibiotic are examined with the method of luminescence microscopy. The modification of the immunofluorescent procedure for rapid determination of the microbial sensitivity to antibiotics does not require obligatory isolation of the pathogen as a pure culture. This makes the procedure more economic with respect to the time necessary for the analysis. The following conditions for performing rapid analysis with respect to Bacillus anthracis are required: the minimal concentration of the pathogen in the specimen (2.10(5) spores/ml), preliminary thermal treatment of the specimen for destroying the spore microflora, additional cultivation for 6-8 hours at 37 degrees C. The presence of the accompanying sporulating microflora, i.e. common microorganisms present in the atmosphere, soil and open water bodies does not prevent the performance of the analysis.     

Analysis of the results of serum studies of children and adults for antibodies to the poliomyelitis virus in a multiyear effort at vaccinal prevention of this infection

The results of testing the blood sera of children and adults for the presence of antibodies to poliomyelitis have shown the low level of immunity to this infection. The authors believe that the main reasons of the tendency towards the decrease in immunity to poliomyelitis, observed in recent years, are the drawbacks of the vaccinal prevention of this infection and the absence of a differentiated approach to the choice of immunization methods under concrete conditions. Mass immunization against poliomyelitis is recommended, especially in the southern and south-eastern regions of the U.S.S.R.     

Tularemia study in Khmel'nitski Province

The differentiated approach to carrying out the vaccinal prophylaxis of tularemia is necessary in view of the determination of the types of the natural foci of this infection and their epizootic manifestation, as well as taking into account concrete local conditions and social factors. At the same time, the level of zooparasitological investigations must be maintained for the timely determination of the activity and spread of the natural foci of tularemia.     

Construction of an expression plasmid vector for accomplishing in vivo delivery of recombinant biologically active proteins. 2. Synthesis of HBcAG in a vaccine strain of Salmonella choleraesuis

The capacity of a previously described plasmid vector pAZ to deliver bioactive proteins to targets in vivo has been studied. This vector molecule has a strong constitutive promoter, is extremely stable in cells of vaccinal S. choleraesuis strain, and encodes the synthesis of marker protein beta-galactosidase which helps monitor the vector's fate in the host. The gene encoding hepatitis B virus core antigen (HBcAg) has been inserted into pAZ under its constitutive promoter. The resultant recombinant plasmid p19-24 has been used to transform Enterobacteriaceae (E. coli and S. choleraesuis) cells. Transformed cells produce immunologically active HBcAg. p19-24 was stable in S. choleraesuis cells during their culturing and during this strain persistence in mice. Triple oral immunization of rabbits in a dose of 1 x 10(9) S. choleraesuis cells TC177 induced the production of virus-specific antibodies. Successful transformation of cells of another vaccinal strain S. abortus ovis by this plasmid extends the potentialities of the vector. The results demonstrate good prospects of using pAZ vector for the construction of live oral vaccines.     

Nucleic acid molecular hybridization as a method for the laboratory diagnosis of influenza: its potentials and prospects

Experiments carried out by the present moment in a number of laboratories indicate that the method of molecular hybridization (MH) has great diagnostic potential. Sufficient methodological mastery of the reaction of radioactively labeled DNA probes with RNA samples applied into a polymer membrane and good supply of commercially available materials make it possible to recommend this method for use in reference laboratories at specialized diagnostic centers. Hybridization should be used in combination with traditional virological and serological tests; the combined use of MH and the enzyme immunoassay for the determination of viral antigens permits the documentation of 90-98% of all cases of influenza A with sufficient rapidity. In the near future DNA probes for the diagnosis of influenza B and C are likely to appear. MH has rather good prospects for the analysis of experimental infection in laboratory animals, as well as for the study of the replication of influenza virus in all cultures. The prospects of the study of the processes of expression of individual genes seem to be particularly attractive. MH may play an important role as a tool for documenting vaccinal reaction, as well as for the study of the action of different chemical preparations in volunteers. And finally, the greatest expectations are linked with the use of MH for the search of inapparent (persistent, latent, etc.) forms of influenza virus infection both in experimental systems and in humans. Optimistic prospects of the studies in this field are based on high sensitivity of this method combined with its equally high specificity. An additional reserve for enhancing sensitivity is also present here due to the amplification of target molecules.     

The characteristics of the antibody response of animals immunized with components of the surface structures of Francisella tularensis

Antibody formation in animals immunized with one of the components of F. tularensis surface structures was studied. The time course of antibody formation in 20 hamadryas baboons was studied in the passive hemagglutination (PHA) test, microagglutination (MA) test, and indirect enzyme immunoassay, used for the determination of IgG, IgA and IgM antibodies. The character of antibody response in the animals immunized with components of F. tularensis surface structures (S-complex) and with live tularemia vaccine was compared. The study revealed that immunization with the S-complex induced the formation of antibodies detected by all three methods. Antibody formation to the S-complex was found to be dose-dependent. With the increase of the injected dose of the S-complex, antibody titers determined in the PHA test decreased and those determined in the MA test increased, which was seemingly due to the induction of antibodies differing in their isotypes. After immunization with the S-complex the levels of IgG antibodies were lower and the levels of IgM antibodies by day 28 after immunization higher than after the injection of live tularemia vaccine.