Vol 5, No 3 (2015)

Plague is a zoonosis caused by gram-negative bacteria Yersinia pestis, which, as a rule, is transmitted to humans from septicemic rodents by the bites of infected fleas. This microbe killed more people than all of the wars in the human history. Y. pestis circulation in the natural plague foci is ensured by the whole number of pathogenicity factors with differing functional orientation. This review is devoted to one of them, Y. pestis capsular antigen (F1 or Caf1). The history of its discovery and studying of its genetic control, biosynthesis, isolation and purification, and physicochemical properties are reviewed. Its roles in plague pathogenesis and its application as a main component of plague vaccines are also discussed. Y. pestis capsule under light microscopy is visually amorphous, while high-resolution electron microscopy displays the structure formed from separate fimbria-like cords up to 200 nm long, diverging from the bacterial surface in different directions. At 37°C Y. pestis produce 800–1000 times more capsular antigen than at 28°C. Genes coding for 17.6-kD Caf1 protein, which contains 170 amino acids, are located in caf1 operon of pFra plasmid. Analysis of caf1 operon nucleotide sequence testified its close phylogenetic relationship with the gene clusters coding for pilus adhesins that were secreted with the help of chaperone/usher systems in enterobacteria including six additional adhesins in Y. pestis. Y. pestis multiplication within macrophages is the obligatory stage of plague pathogenesis, and the plague pathogen virulence correlates not with resistance to phagocyte ingesting but with bacterial ability to survive and multiply within phagolysosomes of phagocytes due to neutralization of antibacterial functions of eukaryotic cells. The capsule formed out of the Caf1 aggregates protects Y. pestis from ingestion by naïve host’s phagocytes and prevents from initiation of the alternative pathway of the complement system. Molecular usher Caf1A responsible for capsular antigen anchoring on the surface of bacterial cell has a high affinity to human interleukin 1β. Caf1 can compete with interleukins 1α, 1β, and 1ra in binding to receptors on lymphoid cells preventing development of adequate immune response. Immunodiagnosis of plague is based on detection of Caf1 or anti-Caf1 antibodies since this Y. pestis antigen is species specific. Covering bacterial surfaces capsular antigen is also the paramount component of all modern plague vaccines. Its leading role in induction of intense immunity in mice, rats, monkeys, and men was shown clearly. However, non-capsulated (Caf1–) variants of Y. pestis keeping their virulence at the level of the wild-type strains might be selected and accumulated in immune animals. This indicates inadmissibility of application of monoantigen plague vaccines and necessity for design of immunoprophylactic preparations aimed at two or three molecular targets. 

The purpose of the research was to assess the endogenous intoxication degree and reactivity condition of an organism by calculation the blood leukocyte indexes and their influence assessment for the outcome of first time diagnosed infiltrative lung tuberculosis for the revealed socially safe patients. Case-records of 260 patients were analysed retrospectively. Inclusion criteria were: first time diagnosed and confirmed diagnosis of infiltrative lungs tuberculosis; age at least 18 years; socially adopted patients (the patients taking official or informal work place), the constant income in a family, a residence, a registration. Exception criteria were: extra pulmonary or other forms of lung tuberculosis at the patient; existence of a serious somatic illness; HIV infection; existence of malignant new growths; mental diseases; the social disadaptation (homeless persons who aren’t working, released from jails or being under examination, abusing alcohol in the form of hard drinkings and accepting drugs). All patients included in research were divided into two groups: first (main) — patients with a failure in quantity the 66, second (group of comparison) — patients with a favourable outcome of infiltrative tuberculosis of lungs, in number of 194. Failure criterion was the existence (preservation) of a disintegration lung cavity confirmed by the last X-ray picture. According patients blood test results the intoxication leukocyte index (ILI, with Kalf-Kalif formula), an blood leukocytes shift index (BLSI), an organism resistance index (ORI), a Dashtayants nuclear index was carried out. Followly the Spirmen correlation analysis with Statistica 6.0 software package was estimated. As a result of research the following data were obtained. The Dashtayants nuclear index high level at primary blood test has the strongest impact on development of infiltrative lungs tuberculosis failure in patients; the ILI and BLSI high levels at the time of the beginning of therapy have moderate negative impact. The ORI low level at the time of an treatment initiation had weak positive impact on development of a failure of tuberculosis, and weak negative — rendered the LII high level after the first month of treatment and high BLSI in 2 months of intensive treatment in a hospital. The complex assessment of integrated indexes of blood allows judging objectively weight of a condition of the patient, need and duration of desintoxication therapy that influences an outcome of the main disease. 

In this paper the nephritogenic activity of Streptococcus pyogenes genotype emm1 and emm12 clinical isolates from scarlet fever patients and healthy children was considered. As earlier established, strains of these types differ in Fc-binding profile, interacting with native IgG and immune complexes (IC), respectively. As expected, all the type emm1 strains bound native IgG; besides, ICs interacted only with strains from patients but not with those from carriers. In contrast, all type emm12 strains appeared to be negative for native IgG, whereas ICs were bound by strains from patients exclusively. None of the tested strains bound IgG3. By immunization of rabbits, binding of native IgG as well as ICs was associated with increasing of anti-IgG antibodies titer, formation of ICs, «crescent» deposition of IgG and C3-complement, local production of the proinflammatory cytokine TNFα, аnd also with accumulation of lymphocytes in kidney tissue. These signs indicated immune inflammation, leading to experimental membrane-proliferative glomerulonephritis (PSGN). It is known that PSGN development depends on IC-binding by tissue FcγR, on complement activation as well as on tissue infiltration by macrophages/monocytes. According to the data of morphometric evaluation the nephritogenic activity of the type emm12 strains exceeded those of type emm1. On testing of three IC-binding emm12 strains in six rabbits, typical PSGN developed in 5 of them and an abortive process in 1 animal. In case of five IgG-binding type emm1 strains, out of ten rabbits full-blown PSGN was observed only in 3 of them, but abortive changes in 5 and negative result in 2 animals. No pathologic changes were elicited by the «carrier» strains of either genotype; the inability of these to bind ICs, according to literature data, could be explained by mutation in the Mga-regulator gene thereby impeding M-proteins synthesis. We conclude that isolation of type emm12 IC-binding strains at acute streptococcal infection should be considered a high risk-factor for postinfectious sequelae development. The rabbit model of PSGN used in this research thus allowed to reveal some main stages and features of its pathogenesis. 

Introduction.HIV-infection is associated with significant pathological changes of the host metabolic processes, such as energy dysfunction, dyslipidemia, protein catabolic effects and amino acid imbalance, which ultimately form the polymorphism of clinical symptoms of the disease. The significant disturbances of protein and lipid metabolism are widely described in asymptomatic and advanced stage HIV-infected patients, but infection-related amino acid abnormalities is not fully explored. The further research of HIV impact on the host metabolic processes in particular, the plasma amino acid profile, are essential for understanding the pathophysiology of HIV-infection. Our aim was to determine the association between CD4 lymphocytes, viral load and plasma L-lysine levels in clinical stages HIV-infected patients. Material and methods.A total of 750 HIV-1-infected males before highly active antiretroviral therapy (HAART) monitored in our center. The patients were classified into four stages of the disease 3, 4a, 4b and 4c, according to the classification system for HIV-infection in Russian Federation (2006). Quantitative HIV-1 RNA assay was performed using (RT-PCR) reverse-transcriptase polymerase chain reaction. The plasma L-lysine levels were assessed by thin layer chromatography (TLC). Results. We observed that plasma L-lysine concentrations markedly decreased with the clinical stages of HIV-infection. Low levels of essential amino acid were found in 57% of HIV-infected subjects in the asymptomatic stage (3), 67% and 68% in the advanced stages (4a and 4b, 4c, respectively). Our data revealed that plasma amino acid concentrations were positively correlated with CD4 count lymphocytes (P < 0.01) and inversely with HIV viral load (P < 0.05) in the total cohort. The mean L-lysine acid levels were significantly lower in advanced stage (4a and 4b, 4c) HIV-infected patients than in controls and asymptomatic stage (3) patients (P < 0.01 and P < 0.001, respectively). Conclusion. There was evidence of the association between plasma L-lysine and HIV-1 RNA level, immunological markers and clinical stages of HIV-infection among the entire cohort. The results show that advanced stages of HIV-infection are characterized by significant changes in plasma L-lysine concentrations with the disease stages of HIV-infection. Levels of this basic amino acid negatively correlating with viral load and inversely with CD4 count lymphocytes. These findings are important for understanding the pathophysiology of HIV-infection and the development of new approaches in the treatment. Although the mechanism is at present conjectural, the influence of plasma L-lysine on the HIV-1 RNA levels must be considered and remains to be proved. 

Introduction. It is known that interferon is a cytokine and is a substantial part of the immune system necessary for antigenic challenge immune response full expression. Also it is considered that every antigen is an interferon inducer. Interferon induces antivirus response via binding to specific receptors, this receptors can be revealed straight on cell membranes of immune cells. Research objective. To evaluate the interferon inducer ability of some Influenza A virus strains upon indications of receptors functional activity (capacity) to alpha and gamma interferons on peripheral mononuclear blood cells (PBMC) induced in vitro by different Influenza A virus strains. Material and methods. The method is based on lymphocytes separation from the venous heparinized blood, with followed by in vitro lymphocytes inducing at temperature 36.5°С in the presence of 5% CO2. Blood samples were taken in different time intervals, labelled by mouse anti-idiotipyc FITCconjugated antibodies, structurally simulated human alpha and gamma interferon, samples were fixed with paraformaldehyde. Interferon receptors expression were performed by flow cytometer. Results. The in vitro experiments have determined the interferon-inducing ability of three influenza virus strains: A/PR8/34 (H1N1), A/Krasnodar/101/59 (H2N2) and A/ Ryazan/6103/87 (H3N2). MPBC blood sample (blood group was 0, Rh factor – positive) was induced by irradiated noninfectious allantoic fluid with hemagglutinating activity. Expression of alpha and gamma interferon receptors (alpha and gamma IFNR) on MPBC was determined by IFNR markers labelled with FITC and it (expression) was estimated by flow cytometer. In parallel we compared expression of alpha and gamma IFNR on MPBC in primed and non primed cells by low doses of human alpha interferon. It was found that expression of alpha and gamma IFNR on MPBC, induced influenza A/ PR8/34 (H1N1) antigen, with high hemagglutinating activity was higher in primed MPBC in comparison with non primed and higher then expression was induced by influenza virus A/Krasnodar/101/59 (H2N2) and A/Ryazan/6103/87 (H3N2) with lower hemagglutinating activity. It should be noted that IFN alpha receptor (IFNAR) expression on induced by influenza virus strain A/PR8/34 (H1N1) and primed by low doses of alpha interferon, repose on high level from induction point (1 hour) and protract during high level during 5 hours. Evaluation of gamma IFNR (IFNGR) expression level on MPBC induced by different influenza virus strains testify that firstly up-regulation IFNGR expression on MPBC primed by low doses of alpha interferon is absent and secondly up-regulation IFNGR on MPBC bear no relation with hemagglutinating activity of Influenza virus antigen. Conclusion. Experiment results clearly suggest that all influenza strains used carry the interferon induced ability which is possible to see by expression of IFNAR and IFNGR on MPBC induced by described above virus antigens. Rate of interferon induce ability in different influenza virus A connected on one side with virus hemagglutinating activity level in estimating IFNAR and on the other side with virus strains in estimating IFNGR.