Domain analysis of supervillin, an F-actin bundling plasma membrane protein with functional nuclear localization signals

A growing number of actin-associated membrane proteins have been implicated in motile processes, adhesive interactions, and signal transduction to the cell nucleus. We report here that supervillin, an F-actin binding protein originally isolated from bovine neutrophil plasma membranes, contains functional nuclear targeting signals and localizes at or near vinculin-containing focal adhesion plaques in COS7-2 and CV1 cells. Overexpression of full-length supervillin in these cells disrupts the integrity of focal adhesion plaques and results in increased levels of F-actin and vinculin. Localization studies of chimeric proteins containing supervillin sequences fused with the enhanced green fluorescent protein indicate that: (1) the amino terminus promotes F-actin binding, targeting to focal adhesions, and limited nuclear localization; (2) the dominant nuclear targeting signal is in the center of the protein; and (3) the carboxy-terminal villin/gelsolin homology domain of supervillin does not, by itself, bind tightly to the actin cytoskeleton in vivo. Overexpression of chimeras containing both the amino-terminal F-actin binding site(s) and the dominant nuclear targeting signal results in the formation of large nuclear bundles containing F-actin, supervillin, and lamin. These results suggest that supervillin may contribute to cytoarchitecture in the nucleus, as well as at the plasma membrane

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

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)

OMOLOGICAL AND HETEROLOGICAL ANTIBODY AND T CELL IMMUNE RESPONSES TO LIVE ATTENUATED INFLUENZA VACCINE A (H5N2) AND A (H7N3)

From the beginning of 21th century outbreaks of H5, H7 and H9 avian flu are registered from time to time. These viruses are considered as one of the possible causes of the next pandemia. The development of avian influenza vaccines is one of the WHO priorities. The aim of this work was to study antibody and cellular immune responses to avian A (H5N2) and A (H7N3) live attenuated influenza vaccines (LAIVs). We examined serum antibodies (HAI assay, microneutralization assay, ELISA), local antibodies (ELISA) and virus-specific CD4+ and CD8+ central memory and effector memory T cells. Two doses vaccination of healthy volunteers with A (H5N2) and A (H7N3) LAIVs induced homological antibody and cellular immune responses (i. e. serum and local antibody conversions, virus-specific memory T cell growth). These vaccines also stimulated heterological immunity (heterological serum and local antibodies and T cells). Heterological immune response intensity depended on antigenic structure of vaccine strain and heterological virus, particularly on HA type

An inherited variant in the gene coding for vitamin D-binding protein and survival from cutaneous melanoma: a BioGenoMEL study

Dermatology-oncolog