Showing papers on "Anthrax vaccines published in 1999"

Expression of the protective antigen of Bacillus anthracis by Lactobacillus casei: towards the development of an oral vaccine against anthrax.

Abstract: Bacillus anthracis is the causative organism of the disease anthrax. The ability of the organism to form resistant spores and infect via the aerosol route has led to it being considered as a potential biological warfare agent. The current available human vaccines are far from ideal, they are expensive to produce, require repeated doses and may invoke transient side-effects in some individuals. There is also evidence to suggest that they may not give full protection against all strains of B. anthracis. A new generation of anthrax vaccine is therefore needed. The use of Lactobacillus as a vector for expression of heterologous proteins from pathogens supplies us with a safe system, which can be given orally. Lactobacilli are commensals of the gut, generally regarded as safe and have intrinsic adjuvanticity. Oral vaccines may stimulate the mucosol immune system to produce local IgA responses in addition to systemic responses. These vectors are delivered at the mucosal surface, the site where the infection actually occurs and where the first line of defence lies. The gene encoding the protective antigen (PA) of B. anthracis, an immunogenic non-toxic component of the two toxins produced, is being cloned into different homologous vectors and subsequently transformed to various Lactobacillus strains. High intracellular expression levels for the PA in Lact. casei were achieved. Mucosal antigen presentation and humoral and cellular immune responses following immunization with transformants expressing PA in various ways (intracellular, surface-anchored and extracellular) are being studied.

Vaccination against anthrax with attenuated recombinant strains of Bacillus anthracis that produce protective antigen.

Abstract: The protective efficacy of several live, recombinant anthrax vaccines given in a single-dose regimen was assessed with Hartley guinea pigs. These live vaccines were created by transforming ΔANR and ΔSterne, two nonencapsulated, nontoxinogenic strains of Bacillus anthracis, with four different recombinant plasmids that express the anthrax protective antigen (PA) protein to various degrees. This enabled us to assess the effect of the chromosomal background of the strain, as well as the amount of PA produced, on protective efficacy. There were no significant strain-related effects on PA production in vitro, plasmid stability in vivo, survival of the immunizing strain in the host, or protective efficacy of the immunizing infection. The protective efficacy of the live, recombinant anthrax vaccine strains correlated with the anti-PA antibody titers they elicited in vivo and the level of PA they produced in vitro.

Human immune responses to the UK human anthrax vaccine

Abstract: The IgG anti-protective antigen subclass antibody response of individuals who had been infected with anthrax was compared with that of healthy individuals immunized with the UK licensed anthrax vaccine. The predominant subclass in both groups was IgG1. In addition, IgG3 was seen in convalescent serum while vaccinees produced IgG2, IgG3 and IgG4 subclass. The significance of these results is discussed. Further work is required to determine the role of antibodies in mediating protective immunity in man.

Bacillus anthracis: medical issues of biologic warfare.

Abstract: Recent world events refocused attention on the possibility of nations engaging in biologic warfare, including an attack with Bacillus anthracis. The single available anthrax vaccine in the United States for human use, formerly known as MDPH-PA, has decreased ability to protect laboratory animals against virulent B. anthracis strains, especially compared with new vaccines being developed. Studies with these vaccines, however, have several shortcomings. The pathogenesis, diagnosis, treatment, and prophylaxis of anthrax are discussed, as well as the implications that an attack with B. anthracis would place on the health care system.

Vaccines: Past, Present and Future

Abstract: The earliest bacterial vaccines were live strains derived from virulent cultures isolated from cases of natural infection. These were attenuated by empirical methods based on sub-culture under adverse conditions. Sometimes this involved exposure to unusually high temperatures or culture on media that contained substances inhibitory to wild-type strains. Occasionally attempts were made to select strains by passage in unnatural host species, but generally this approach was less successful than for viral attenuation. Examples of vaccines produced by these processes include the fowl cholera (Pasteurella multocida) and anthrax vaccines developed by PASTEUR (1880, and PASTEUR et al. 1881) and the bacille Calmette-Guerin (BCG) tuberculosis vaccine developed by CALMETTE et al. (1928). The Pasteur anthrax vaccine strains were selected by growth at high temperature (42°C) and were notoriously unstable and difficult to administer consistently.

Aerosol vaccination against dangerous infectious diseases

Abstract: The paper summarizes the results of development of the aerosol method, one of the mass ways of human vaccination. Analysis of materials suggests that Russia has designed highly effective live plague, tularemia, and anthrax vaccines that can be used to immunize in different ways: by epicutaneous and subcutaneous, and inhalation routes. The advantages and disadvantages of aerosol vaccination are shown. The correct use of this method provides a substantial effect when the epidemic situation is complicated and when there is a need for vaccination of large cohorts at the earliest possible time.

Method of maintenance of anthrax vaccine strain sti-1

Abstract: FIELD: medicine, microbiology. SUBSTANCE: invention relates to the production of stable vaccine antianthrax preparations of the high quality. Microbic population is passaged through the body of susceptible animal, analyzed culture is sown on an agar medium containing an antianthrax globulin. Medium ensures to detect toxin-forming clones. Clones are detected under the full value control of the most immunologically important determinants pag, lef, cya by method of polymerase chain reaction. Invention ensures to obtain homogeneous and high-immunogenic cultures by indices of toxin formation determinants from heterogeneous cultures of the vaccine strain STI-1 of decreased immunogenicity and to prevent possible increase of dissociation of properties of cultures at frequent resowing under nonselective conditions. EFFECT: improved method of maintenance. 3 tbl, 4 ex