Protection of human influenza vaccines against a reassortant swine influenza virus of pandemic H1N1 origin using a pig model

Interleukin 17 (IL-17) manipulates mouse bone marrow- derived neutrophils in response to acute lung inflammation

Interleukin 17 (IL-17) mediates neutrophil migration to the lungs during acute inflammation, potentially leading to lung tissue damage. In the present study, we evaluated whether IL-17 could facilitate certain neutrophil functions in a mouse model. Mice were divided into four groups and intranasally challenged with PBS (1 = Control), Influenza A (H1N1) and Klebsiella pneumoniae (2 = Mix), Influenza A alone (3 = Flu), or K. pneumoniae (4 = KP) alone. Bone marrow, BAL cells, and lung specimens were collected seven days post-challenge for analysis. Mice in the Flu group showed the highest mortality rate. Neutrophils were the prominent cell type in BAL from Mix and KP, whereas lymphocytes were most numerous in Flu. Lesions in the lungs revealed considerably damage in the Mix, Flu, and KP groups. Isolated bone marrow-derived neutrophils were in vitro primed with mouse recombinant IL-17A protein (rIL-17A) followed by various functional assays. The reactive oxygen species (ROS) levels in rIL-17A primed cells showed significant elevations in all groups. Phagocytosis and bacterial destruction showed no significant difference between (+) or (-) rIL-17A groups. The formation of neutrophil extracellular traps (NETs) in rIL-17A-primed neutrophils showed elevated NET production. We next monitored expressions of genes in neutrophils. IL-17A mRNA expression was significantly increased in Mix and Flu; IL-1β mRNA only significantly increased in Flu, and IL-17RA showed constitutive expressions in all groups. In summary, neutrophils may cause tissue damage during lung inflammation through specific functions influenced by IL-17.

Highly sensitive electrochemical biosensor based on redox - active monolayer for detection of anti-hemagglutinin antibodies against swine-origin influenza virus H1N1 in sera of vaccinated mice

Background

In this work, we report an electrochemical biosensor for the detection of anti-hemagglutinin antibodies against the swine virus H1N1 present in mice sera immunized with mixture of His₆-H1 HA in monomeric and oligomeric form. The oriented immobilization of the recombinant His-tagged hemagglutinin (His₆-H1 HA) consists of: (i) formation of a mixed layer of 4-mercaptobutanol (MBT) and the thiol derivative of dipyrromethene (DPM); (ii) complexation of Cu (II) by DPM; (iii) immobilization of His₆-H1 HA via coordination bonds between Cu (II) sites from DPM–Cu (II) complex and imidazole nitrogen atoms of a histidine tag; (iv) filling free spaces with bovine serum albumin. The interactions between recombinant His₆- H1 HA covalently attached to the electrode surface and the anti-hemagglutinin H1 antibodies present in mice sera were explored with Osteryoung square-wave voltammetry.

Results

This analytical device was able to detect the antibodies present in vaccinated mice sera diluted from 1 × 10⁹ to 1 × 10⁸ fold.

Conclusions

The unprecedented sensitivity of described biosensor is much better than widely use ELISA test and other analytical methods for determination of antibodies against the influenza A viruses. It has been proved that redox active DPM-Cu (II) monolayer is a universal platform suitable for stable and oriented immobilization of any His-tagged sensing elements. Thus, this universal layer could be a base of numerous analytical devices suitable for detection of antibodies against different viruses.

Modulation of Immunogenicity and Conformation of HA1 Subunit of Influenza A Virus H1/N1 Hemagglutinin in Tubular Immunostimulating Complexes

The HA1 subunit of the influenza virus hemagglutinin (HA) is a valuable antigen for the development of vaccines against flu due to the availability of most antigenic sites which are conformational. Therefore, a novel adjuvanted antigen delivery system, tubular immunostimulating complexes (TI-complexes) comprising monogalactosyldiacylglycerol (MGDG) from different marine macrophytes as a lipid matrix for an antigen, was applied to enhance the immunogenicity of recombinant HA1 of influenza A H1N1 and to study the relation between its immunogenicity and conformation. The content of anti-HA1 antibodies and cytokines was estimated by ELISA after the immunization of mice with HA1 alone, and HA1 was incorporated in TI-complexes based on different MGDGs isolated from green algae Ulva lactuca, brown algae Sargassum pallidum, and seagrass Zostera marina. Conformational changes of HA1 were estimated by differential scanning calorimetry and intrinsic fluorescence. It was shown that the adjuvant activity of TI-complexes depends on the microviscosity of MGDGs, which differently influence the conformation of HA1. The highest production of anti-HA1 antibodies (compared with the control) was induced by HA1 incorporated in a TI-complex based on MGDG from S. pallidum, which provided the relaxation of the spatial structure and, likely, the proper presentation of the antigen to immunocompetent cells.