Possible interference of human beta-herpesviruses-6 and -7 in gastrointestinal cancer development

Aim: The high incidence of gastrointestinal cancer combined with high mortality from the disease if diagnosed at a late stage, signifies the need for better diagnostic, prognostic and predictive tools. Human beta-herpesviruses have been suggested as possible cofactors in the development of gastrointestinal cancer. Methods: Sixty five patients with gastrointestinal cancer before surgery and without any treatment were enrolled in this study and divided into two groups depending on lymphocytes’ count: I group (n = 35) — lymphocytes > 1400x10⁶ /L and II group (n = 30) — lymphocytes < 1400x10⁶ /L. Nested polymerase chain reaction was used to detect latent and active stage of persistent human herpesvirus-6 and -7 infection, laser flow cytometry with monoclonal antibodies — to determine immunological parameters. Results: Activation of herpesvirus-6 and -7 was more frequently observed in the patients’ group with lymphopenia (HHV-6 1/1 (100%), HHV-7 4/8 (50%) and HHV-6 + HHV-7 6/9 (66%); p < 0.05). Cellular immune parameters were analysed in immunocompromised II group’s patients dependently on beta-herpevirus infection. Although number of leukocytes was higher in patients with active HHV-6/-7 infection (p = 0.01), number of lymphocytes CD3⁺, CD4⁺, CD8⁺ and CD38⁺ in patients with active HHV-6/-7 infection tended to decrease (p < 0.0001, P = 0.0002, p = 0.0001 and p < 0.0001, respectively). However, number of CD19+ had tendency to increase (p = 0.03). Conclusion: Activation of herpesvirus-6 and -7 may lead to decrease of lymphocytes total count and develop immunosuppression in patients with gastrointestinal cancer. Key Words: beta-herpesvirus-6, beta-herpesvirus-7, gastrointestinal cancer

Lamellar-to-MLV transformation in SDS/octanol/brine examined by microfluidic-SANS and polarised microscopy

The lamellar-to-multilamellar vesicle (MLV) transformation in a model surfactant system, sodium dodecyl sulfate (SDS), octanol and brine, is investigated under continuous and oscillatory microfluidic contraction–expansion flows, employing polarised optical microscopy and small angle neutron scattering (SANS), with sample volume probed down to ≃20 nL. We determine the lamellar-to-MLV transition requirements at varying flow velocity, oscillation amplitude, frequency, and number of oscillatory cycles. The spatio-temporal evolution of the hierarchical fluid structure is elucidated: lamellar sheets initially align with flow direction upon entering a constriction and then perpendicularly upon exiting; the formation of MLVs at the nanoscale is first observed by SANS within a few (<5) oscillatory cycles, followed by the gradual appearance of a regular (albeit not crystalline) MLV arrangement, at the micronscale, by optical microscopy after tens of cycles, under the conditions investigated. Once MLVs form under flow, these remain metastable for several days

CROSSREACTIVE ANTIBODIES AND MEMORY T CELLS TO HUMAN AND ZOONOTIC INFLUENZA A VIRUSES IN VOLUNTEERS

There exists a real hazard of transferring zoonotic influenza A viruses, either swine, or avian, into human population. In such case, severity of such pandemics depends on the pathogen-specific immunity in the population. Virtual absence of such immunity in humans was declared in the literature. In this work, we assessed systemic, local, and T-cell immunity to potentially pandemic H3N2sw, H5N1, H5N2, H7N3, H7N9 and H2N2 influenza A viruses in a group of healthy adults of different age. Our results indicate that these subjects develop the following immune reactions: (i) local (i.e., nasal IgA) and cellular (CD4+ and CD8v memory T cells) heterosubtypic immunity, in absence of detectable virus-specific serum antibodies to avian influenza A viruses; (ii) Local immune responses (as nasal IgA) to human A (H2N2) virus which circulated in 1957-1968 were detected both in subjects who could be primed at that time, but also in subjects born after 1968; (iii) full-scale systemic and local immunity to potentially pandemic А (H3N2sw) swine virus was found in the group. Conclusion. In order of proper epidemiological forecasts and planning appropriate preventive measures for potentially pandemic Influenza A viruses, a regular monitoring of collective immunity should be performed using different adaptive markers. In this respect, any conclusion based on molecular analysis only could lead to considerable mistakes, and should be accomplished by the mentioned immunological studies

AVIDITY EVALUATION OF LOCAL IgA ANTIBODIES IN PERSONS IMMUNIZED WITH LIVE INFLUENZA VACCINE

Abstract. At present, immunogenicity evaluation of influenza vaccines is performed by quantitative assessment of increased serum antibodies. It was, however, shown that the degree of human defense against influenza is mostly related to their qualitative characteristics, i.e., avidity (functional activity). Leading role of local immunity is demonstrated in protection against influenza. Such immunity is mediated by IgA antibodies from mucosal airways. Meanwhile, the avidity issues for local antibodies still remain open.In present study, an attempt was undertaken to evaluate post-vaccination local immunological memory for influenza A virus, according to IgA antibodies from upper respiratory secretions. Two techniques were used to evaluate antibody avidity, that were previously applied for studying this phenomenon with serum imunoglobulins, i.e., a dynamic test (measurement of antigen-antibody reaction rates), and a test with urea, a chaotropic agent (avidity is determined as a strength of antigen-antibody complex). A total of 202 persons (18 to 20 years old) were enrolled into the study.With both tests, a broad range of individual avidity values was observed for the antibodies. A significant cohort (up to 30 per cent) of persons immunized with live influenza vaccine, showed sharply increased avidity of secretory IgA antibodies by both methods, along with accumulation of these immunoglobulins after vaccination. A reverse relationship is revealed between avidity levels of these antibodies before vaccination, and increase of this parameter post-immunization. The data present convincing arguments for specific renewal of local humoral immunological memory, as induced by live influenza vaccine. The study substantiates a necessity for application of the both tests in parallel, when determining avidity of secretory IgA antibodies. (Med. Immunol., vol. 10, N 4-5, pp 423-430)

APPLICATION OF METHOD BASED ON IN VITRO ANTIBODY QUANTIFICATION IN PBMC SUPERNATANT SAMPLES FOR IMMUNOGENICITY EVALUATION OF A (H5N1) AND A (H5N2) POTENTIALLY PANDEMIC INFLUENZA VACCINES IN CLINICAL TRIALS

There are many data worldwide which suggest that the methods for evaluation of influenza vaccines immunogenicity should be improved. The only method validated in Russia is a HAI (haemagglutination inhibition) assay with serum samples from vaccinated volunteers. This assay does not, however, completely reflect the vaccine-induced immunological changes. In this study, we evaluated antibody immune responses to A (H5N1) inactivated influenza vaccine boosting in healthy volunteers previously primed with A (H5N2) live attenuated influenza vaccine. We compared three methods of antibody detection: (i) HAI assay with serum samples; (ii) ELISA with serum samples; (iii) ELISA with PBMC (peripheral blood mononuclear cells) culture supernates, i.e., an alternative test based on quantification of antibodies secreted by PBMC in vitro. The latter test was shown to have an advantage over other techniques in IgA and IgG antibody detection at early timepoints (day 7) after vaccination. The first two methods allowed immunogenicity assessment at day 28 after vaccination.Thus, a test based on antibody quantification in PBMC supernatant samples can be used as an alternative method for evaluation of influenza vaccines immunogenicity. This method also exhibits a better strainspecificity

LOCAL ANTIBODY AND CELLULAR IMMUNE RESPONSES TO INFLUENZA INFECTION AND VACCINATION

Abstract. Local immune responses of mucous membranes of an organism are the first and most significant barriers preventing many virus infections, including influenza. The barrier against influenza infection is the mucosalassociated lymphoid tissue of the upper airways. It is considered, that nasopharyngeal-associated lymphoid tissue (NALT) in rodents is an equivalent of lymphoid tissue in human Waldeyer’s ring. Present work is the first attempt to analyze and compare the development of cellular and antibody immune responses in NALT in a mouse model of experimental influenza infection using a pathogenic influenza A (H1N1) virus and an attenuated reassorted (2/6 genetic formula) live influenza A (H1N1) vaccine.It was shown, that the vaccine strain inherits the ability to induce high-grade local antibody responses like as the virulent parental strain. However, the vaccine strain is inferior to virulent parental strain in capacity to stimulate production of circulating antibodies. Both parental and Р 2/6 strains are equally able to induce lymphoproliferative immune response in NALT lymphocytes. The attenuated reassortant virus is able to stimulate proliferation of Th (CD4+), B-cells (CD19+) and CTL (CD8+) in NALT. As shown by the cytokine activity testing (IFN-γ, IL-6), the attenuated reassortant virus activates both Th1- and Th2-lymphocytes in NALT.This data suggest that intranasal immunization with live attenuated reassortant viruses (genetic formula 2/6) results into active and balanced stimulation of both Th1-and Th2-immune responses at the primary site of infection (NALT)

INDUCTION OF LONG-TERM T AND B CELL MEMORY IMMUNITY TO INFLUENZA A VIRUS (H5N1) IN PERSONS VACCINATED WITH LIVE INFLUENZA A VACCINE (H5N2)

Over last years, a novel strategy for vaccination of people against potentially pandemic influenza A viruses is actively developed worldwide, i.e., a combined (prime-boost) vaccination. It provides  amplification (boosting) of immune response  for a vaccine  be means  of pre-vaccination (priming) with another vaccine.  We have first studied an issue of immunological consequences for people after priming  by live attenuated influenza H5N2 vaccine (LAIV), followed by a boost with inactivated influenza H5N1 vaccine (IIV) 1.5 years later. Unlike non-primed volunteers, the primed persons developed more rapid and high production of serum antibodies (of HAI-, MN-, ELISA-types) after a single vaccination with H5N1 IIV. That concerned induction of antibodies to the H5N1 vaccinal strain A, and other heterologous strains containing H5 haemagglutinin. In primed persons, the antibodies showed  higher  avidity as compared to non-primed individuals. Before inoculation with H5N1 IIV, the  IgG-antibody titers  to A virus (H5N1), and  the  levels of specific  CD4+  and  CD8+   memory T-cells proved  to be higher  in primed subjects  than  in non-primed persons.  The  boosting  effect  of H5N1 IIV did not correlate with HAI-and MN-based data on immunogenicity of priming  H5N2 live attenuated vaccine.  In general, the results obtained justify a new direction in applications of LAIVs for protection against potentially pandemic influenza virus A

SYSTEMIC ANTIBODY AND CELLULAR IMMUNE RESPONSES IN INFLUENZA INFECTION AND POSTSVACCINATION

Abstract. Post-infection immunity represents an immunogenicity standard for antiviral vaccines, including those against influenza. To estimate the immunogenic properties of vaccine preparations, it is necessary to compare the quantitative and qualitative parameters of immune responses to the vaccine strain and the virulent virus from which it is prepared. However, for ethical reasons, such human studies are difficult, because there is the possibility of pathogenic viral infection.The aim of this experimental work was to compare systemic immune responses to the pathogenic mouse influenza virus A (H1N1), and an attenuated reassortant virus, genetic formula 2/6 (R 2/6), an experimental analogue to the live influenza vaccine.It was shown, that R 2/6 lagged behind the pathogenic parental virus (PPV) in activated induction of circulating IgG-antibodies, secretion of a marker Th1-cytokine IFN-γ by splenocytes, and CTL (CD8+) production in the spleen. On the other hand, R 2/6 was highly competitive with PPV, with regard to quantitative proliferative parameters of pooled splenocytes, stimulation of Th (CD4+) cells, B-cells (CD19+), and Th2-cytokine IL-2. IL-6 production in the spleen was poorly induced by both viruses.Thus, attenuation of influenza A (H1N1) virus by the 2/6 genetic reassortment differentially influences the induction of systemic immunity constituents. i.e., some parameters of immune response may be reduced, while others are not altered. When preparing vaccine strains for live influenza vaccines, an attention should be given first of all to increased induction of circulating antibodies that comprise the major components of antiviral immunity