Влияние детоксифицированного липополисахаридаShigella sonnei на экспрессию клетками меланомы В16 опухоль-ассоциированного антигена gp100 и антигенов MHC I Федеральное государственное бюджетное учреждение «Государственный научный центр «Институт иммунологии» Федерального медико-

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.

Variants of genetic constructions are discussed which encode a receptor-binding domain (RBD) of coronavirus SARS-CoV-2 spike protein fused with a monomeric Fc-fragment of human immunoglobulins. A cell line producing RBD-Fc is established. High titers of anti-RBD antibodies and virus-neutralizing antibodies are obtained upon mice immunization with the purified RBD-Fc.

Effects of different classes of adjuvants (aluminum hydroxide, spherical protein particles, thermolabile В protein, low-endotoxic pyrogen-free lipopolysaccharide) have been studied in order to enhance the immunogenicity of inactivated vaccines against hemorrhagic fever with renal syndrome. The Puumala virus-based monovaccine and multivalent vaccine based on Puumala, Hantaan and Sochi viruses were analyzed, and BALB/c mice were used as an animal model. It was shown that low-endotoxic pyrogen-free lipopolysaccharide stimulated the production of virus-neutralizing antibodies and increased the vaccine stability during storage, which allows to reduce the antigenic load of the vaccine. Aluminum hydroxide slightly increased the production of T-cells immune response mediators and did not affect the neutralizing antibodies induction and vaccine stability. Despite the adjuvant effect, it was shown that spherical protein particles and thermolabile В protein were unacceptable for vaccines administered to humans due to the high protein load and toxic effects, respectively. hantavirases, hemorrhagic fever with renal syndrome, inactivated vaccines, adjuvants, immune response The authors are grateful to Dr. O.V. Karpova (Department of Virology, Moscow State University) for providing the preparation of spherical particles, and to Dr. A.N. Noskov (Gamaleya Research Institute of Epidemiology and Microbiology, Moscow) for providing the preparation of the thermolabile enterotoxin B-subunit.

Журнал для непрерывного медицинского образования врачей Эпидемиологические особенности и иммунопрофилактика брюшного тифа (материал для подготовки лекции)

The development of HIV vaccine remains an important goal in prophylaxis and therapy of HIV/ AIDS epidemics. There are various approaches for development of а candidate vaccine based on induction of neutralizing antibodies and cell-mediated immunity. Synthetic peptides are considered promising vaccine antigens since they are capable of activating both humoral and cellular immune response. HIV-1 envelope gp120 is the target for neutralizing antiviral antibodies. The V3 region of the HIV-1 gp120 is highly immunogenic and important for the virus-coreceptor interaction. In a RV144 vaccine trial, the levels of vaccine-induced IgG antibodies recognizing V1V2 regions from multiple HIV-1 subtypes show inverse correlations with a risk for HIV-1 infection. Meanwhile, HIV is characterized by high diversity. The consensus and mosaic immunogens are complete but artificial proteins, which are computationally designed to elicit immune responses with improved cross-reactive broadness. We have been studied immunogenic properties of synthetic peptides derived from V1, V2, V3 loop regions of the consensus M HIV1 (CON-S) sequence group of the gp 120 envelope protein and V3 loop derived from a Russian RUA022a2 isolate. These peptides specifically reacted to HIV-positive sera in ELISA, thus indicating their similarity to appropriate HIV proteins. The peptides proved to be weakly immunogenic. Therefore, Freund complete adjuvant was used to enhance peptide immunogenicity. To assess the immunogenicity, the mice were immunized with a peptide mixture. Antibodies have been developed to every peptide from the mixture, being, predominantly, of IgG isotype. The antibody titers depended on the length of peptide sequences. However, the sera from immunized mice did not have a HIV neutralizing activity. The serum neutralization was assessed by pseudovirus-based assay, using a molecular clone of virus isolates CAP 45.2.00.G3 and QH.209.14.M.EnvA2. The virus neutralization is a complex process and may be influenced by several factors, such as antibody titer, isotype, or antibody structure. Probably, to induce neutralizing antibodies by this peptide mixture, it is necessary to choose appropriate adjutants and immunization schedule. Moreover, it was shown that peptides could increase in vitro virus infectivity in pseudovirus-based model, using the CAP 45.2.00.G3, QH209.14M.ENV.A2, QD435.100M.ENV.E1 molecular clone. These viral isolates belong to different HIV-1 subtypes.

Целью данного исследования было изучение эффективности экспериментальной аллерген-специфической иммунотерапии (ЭАСИТ) комплексом мономерного аллергоида, полученного сукцинилированием овальбумина (сОА) и иммуномодулятора (ИМ) - экзополисахарида (эПС), полученного из Shigella sonnei (S. sonnei), на экспериментальной модели атопического дерматита (ЭМАтД). Мыши BALB/c с ЭМАтД получали ЭАСИТ немодифицированным ОА, мономерным аллергоидом (сОА) и комплексом сОА и эПС. В ходе ЭАСИТ и по её завершении отмечено преимущество АСИТ комплексом сОА и эПС по сравнению с ЭАСИТ немодифицированным ОА и сОА по динамике анти-ОА IgE, IgG1 IgG2a антител, по изменению интерлейкинового профиля (IL-4, IL-5, IL-17 и IFN-γ) с Th2-зависимого на Th1-зависимый, а также по улучшению гистологической картины аллергического воспаления в коже. По совокупности полученных данных можно сделать вывод о том, что АСИТ мономерным аллергоидом в комплексе с экзополисахаридом из S. sonnei может быть эффективным подходом при терапии атопического дерматита.

Lipopolysaccharide (LPS) Salmonella typhi is one of the most toxic & pyrogenic among LPS's of Enterobacteriacae. (Jsing combination of appropriate methods for separalion and purification we were successful in isolation of relatively low pyrogenic lipopolysaccharide (LPS) from S. typhi 0:901. Pyrogenicily of LPS was examined on rabbits according to standard WHO/EI.PL. protocol for polysaccharide vaccines. Maximal apyrogenic dose (dry weight of LPS per kilogram of rabbit weight) was 0.025 Wg. bw pyrogenicity of LPS was correlated with decreased Limulus gelating activity (I,AL assay) in vitro. Threshold concentrations which caused positive LAL test were estimated within a range 0.004 0.0008 1tg/ml. The similar thresholds evaluatecl for traditional highly-pyrogenic for rabbits Westphal type LPS were detected in significantLy low concentration zone below 0.000I6 Stg/ml. It was registered decreased endotoxicity for low-pyrogenic LPS samples. Injection of LPS in doses 100 and 150 mg/kg dirln't cause the death of (CBAx C57B\/6)FI mice. Mice were injected with doses of LPS t, 5, 10, 25 1t"g, which may be calculated as apyrogenic by use dilution cofficient 1: 2000 for iesting polysaccharide vaccines. Primary intmune response was induced after immunisation of mice with LPS. O:9 LPS,specffic antibodies have been detected in sera of immunized mice. The results obtainecl indicate that such ùnmunobiological activity as pyrogenicity of our LPS met WHO pyrogenicity control parameter 0.025 1tg/kg applied for purified polysaccharide vaccines (ryphoid, meningococcal). The approaches to possible application of low pyrogenic LPS as protective immunogen or adjuvant for vaccine construction is still under investigation. Suppl I 1998 Immunobiological characterization of low toxic & INTRODUCTION Lipopolysaccharides (LPS's) represent one of the most attractive type of biologically active molecules from the vaccine construction immunomodulation viewpoint. LPS's manifest excellent protective properties3 and may be used as a vaccine components but high toxicity and pyrogenicity interfere with such application. Poster Session 247

The article presents the results of the I phase of clinical trials of a vaccine preparationfor prevention of Flexner dysentery on the basis of modified Shigella flexneri lipopolysaccharide on the limited contingent of adult volunteers (26 persons). Studying general and local post-inoculative reactions showed good acceptability and low reactogenicity of candidate vaccine "FLEXVAC®" in the doses from 25 to 100 gg. In the majority ofvolunteers immunized by the candidate vaccine "FLEXVAC®" we registered 4 and more times seroconversion of IgG and IgA classes antibodies playing basic role in the formation of adaptive anti-shigella immune response.

From enterobacterien Shigella sonnei, phase 1, a new natural variant of zwitterionic polysaccharide exopolysaccharide (EPS), which includes the lipid component, representing the diacilglycerophosphate, and repeated the link are identical with those of The o-specific polysaccharide S.sonnei. The drug EPMs possessed a high degree of security: not called for pyrogenic reactions in rats and death of mice when administered in high doses (1 g/kg). When preventive immunization EPMs noted slowing down the development of the experimental peritonitis and the extension of the time of the survival rate of mice (CBA×C57B1/6)F1 in the development of septic process. In the preliminary introduction the drug also effectively ensured the survival rate of mice, and mastered the production of TNF-α with a load of bacterial endotoxine E.coli O:55 in the dose of 150 mg/kg.

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.

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.

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 further purified by triple reprecipitation with hexadecyltrimethylammonium bromide. The content of the LPS admixture in the resulting Vi-antigen samples was determined quantitatively 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.