Efficacy of Raphamin against Pneumococcal Infection: a Preclinical Study.

The aim of the study was to evaluate the activity of Raphamin in a model of non-lethal pneumococcal infection caused by Streptococcus pneumoniae 3 in BALB/c mice. The drug or placebo was administered intragastrically 3 days prior to infection, 2 h before and 2 h post infection, and then for 3 full days, alone or in combination with antibiotic (amoxicil-lin/clavulanic acid). Raphamin monotherapy significantly decreased bacterial load in the lungs in comparison with placebo (p<0.05) which was comparable to the effect in antibiotic alone or combined with Raphamin. Raphamin prevented reproduction of Streptococcus pneumoniae in the lower respiratory tract and its combination with the antibiotic was safe and did not reduce the efficacy of amoxicillin/clavulanic acid.

[Study of cross-activity of Streptococcus pneumoniae antigen preparations].

AIM: Study cross-activity of S. pneumoniae antigen preparations. MATERIALS AND METHODS: Antigen preparations were obtained by ultrasound disintegration (from bacteria in R-form), extraction with water (from serotype 3 bacteria), cetavlon and trichloroacetic acid (from serotype 6A bacteria). Chemical composition and immunochemic properties of preparations were studied by contemporary methods as well as in experiments with direct and cross-protection of mice from infection. RESULTS: 3 of 4 preparations (except ultrasound disintegrate) had approximately 30% of protein. In immunodiffusion reaction they interacted with hyper immune rabbit sera obtained against 12 various pneumococcus serotypes--1, 3, 4, 6A, 6B, 9V, 9N, 14, 18C, 19A, 19F and 23F. In animal experiments 30 - 70% of mice were protected from subsequent infection with knowingly high dose of homologous and 3 heterologous pneumococcus strains. In immunoblotting the highest number of components serologically active with heterologous sera was formed by cetavlon extract (12 - 23). Addition of capsule polysaccharides to the preparation increased its cross-protective activity. CONCLUSION: By data set and the highest yield, water extract is reasonable for isolation of cross-reactive proteins of pneumococcus. Development of another method of extraction from cultural fluid is necessary for obtaining extracellular protein antigens. Generation of vaccines containing cross-reactive proteins of pneumococcus and capsule polysaccharides is a promising direction.

[Structure of the oligosaccharide region (core) of the lipopolysaccharides of Shigella flexneri types 2a and 5b].

The full structure of the lipopolysaccharide core of bacteria Shigella flexneri types 2a and 5b, the causative agents of bacillary dysentery (shigellosis), was established by chemical methods, high-resolution electrospray ionization mass spectrometry, and two-dimensional NMR spectroscopy. The structure of the O-antigen repeating unit and the configuration and position of the linkage between the O-antigen and the core were determined in the lipopolysaccharide of S. flexneri type 2a.

[Isolation of a highly purified capsular polysaccharide from Salmonella enterica serovar Typhi (Salmonella typhi)--Vi-antigen and its use in serological diagnosis of typhoid fever]. / Kapsul'nyi polisakharid Salmonella enterica serovara Typhi (Salmonella typhi)--Vi-antigen vysokoi stepeni ochistki dlia serologicheskoi diagnostiki briushnogo tifa.

For use in differential diagnostics of typhoid fever, samples of the capsular polysaccharide from Salmonella enterica serovar Typhi (usually named Vi-antigen) were isolated and characterized by physicochemical and serological methods. It was shown that only the sample of Vi-antigen with the minimal (0.57%) admixture of the corresponding lipopolysaccharide (LPS) from S. typhi retained a high serological activity in the tests with monoreceptor anti-Vi sera. However, it exhibited a substantially weaker reaction with sera from normal donors and patients with acute nontyphoid salmonelloses, than Vi-antigen preparations with a higher (0.8-1.2%) LPS content. The chromatographically pure Vi-antigen was purified by triple reprecipitation with hexadecyltrimethylammonium bromide. The content of the LPS admixture in the resulting Vi-antigen samples was quantitatively determined by GC. A high purification level of the Vi-antigen from the LPS admixture allows us to hope that this preparation could serve as a basic component of the test system for the diagnostics of typhoid fever. The English version of the paper.

Considerations regarding mass vaccination against typhoid fever as an adjunct to sanitation and public health measures: potential use in an epidemic in Tajikistan.

We report on the ongoing epidemic of typhoid fever in Tajikistan that started in 1996. It has involved more than 24,000 cases to date, and is characterized by multiple point sources, overflow of sewage, contaminated municipal water, and person-to-person spread. Of the Salmonella typhi isolates available for testing in western laboratories, more than 90% are multidrug-resistant (MDR). Most recently, 28 (82%) of 34 isolates are resistant to ciprofloxacin, representing the first reported epidemic of quinolone-resistant typhoid fever. In the past, mass immunization during typhoid fever epidemics has been discouraged. A review of this policy is recommended in light of the alarming emergence of quinolone-resistant strains of S. typhi, the availability of improved vaccines, and the ongoing epidemic in Tajikistan. Mass immunization may be a useful measure for the control of prolonged MDR typhoid fever epidemics, as an adjunct to correction of municipal infrastructure and public health intervention.

[Enhancement of infection resistance of mice infected with Salmonella typhi by factors of immune lymph nodes]. / Povyshenie protivoinfektsionnoi rezistentnosti myshei, zarazhennykh Salmonella typhi, faktorami immunnykh limfaticheskikh uzlov.

Mediators, secreted by lymph node cells shortly after immunization and draining the site of the injection of the antigen, produced a nonspecific activating effect on cells of the macrophagal series. The preventive injection of immune lymph node factors induced an increase in nonspecific resistance to S. typhi TU2 [correction of Ty2] No. [correction of N]4446.

[Secondary immune response to flagellin conjugates with polyacrylic acid]. / Vtorichnyi immunnyi otvet na kon''iugaty flagellina s poliakrilovoi kislotoi.

The conditions of the activation of immunological memory by means of flagellin and its conjugate with polyacrylic acid (PAA) have been studied. The flagellin-PAA conjugate has proved to be capable of inducing the appearance of memory cells when introduced in doses, considerably lower (0.01 and 0.001 micrograms) than those of native protein (0.1, 1 and 10 micrograms). At the same time no manifest differences in the reactivation of flagellin-induced and conjugate-induced memory cells by the antigen have been established. Immunization with protein, as well as with its conjugate, has been found to induce the formation of mainly anti-Hi : 1,2 IgG in secondary immune response.