Volume 5, Issue 1

  • 2020, February

    original research

    Recombinant Protein D from Haemophilus influenzae Induces Mouse Bactericidal Antibodies Against Typeable and Non-Typeable Haemophilus influenzae, which Partially Protect Infant Rats Against Serotype b BacteraemiaOpen Access

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    Abstract [+]

    Aim

    To evaluate the immunogenicity of a recombinant protein D from Haemophilus Influenzae (Hi) and the functional activities of the induced protein D antibodies in a mouse model.

    Methods

    Female Balb/c mice were immunised subcutaneously with recombinant protein D in the presence or absence of adjuvants and the serum immunoglobulin G (IgG) response to protein D was assessed by ELISA. The functional activity of the immune sera was evaluated in vitro using bactericidal assay against typeable Hi serotype b (Hib) and non-typeable Hi (NTHi) clinical isolates and in vivo using an infant rat bacteraemia model and a Hib clinical isolate.

    Results

    A dose-dependent IgG response was induced in mice immunised with the recombinant protein D and this response was further increased by the adjuvants used [CPG, AlPO4 and Al(OH)3], with the latter showing the greatest effect on the antibody response. Immune sera were very effective in bactericidal assay against several Hib and NTHi clinical isolates, with a higher serum bactericidal titre against the NTHi than against the Hib isolates. This is possibly due to the lower expression of protein D on the Hib isolates used in our study, compared to the NTHi isolates. In addition, anti-protein D antibodies were partially protective in vivo infant rat bacteraemia model against a challenge with Hib Eagan strain.

    Conclusion

    Our results suggest that recombinant protein D is a good vaccine candidate against Hi and should be given in combination with other vaccine candidates to ensure complete protection against Hib and NTHi.

    Keywords

    Haemophilus influenzae (Hi); Haemophilus influenzae serotype b bacteraemia; Rats.


  • 2020, August

    original research

    Model Liposomal Delivery System for Drugs and VaccinesOpen Access

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    Abstract [+]

    Background

    Liposomes have been used for drug delivery since their discovery 60-years-ago. The advantages they provide as carriers have been recognised and exploited to improve the delivery of numerous drugs and eliminate harmful side-effects. Liposomal delivery has been tested for anticancer drugs, anti-tuberculosis drugs, variety of vaccines, just to list a few.

    Methods

    We developed a series of liposomal formulations with the addition of cholesterol and polyethylene glycol. The uptake of these formulations by human epithelial prostate cancer (PC-3) cells and mouse macrophages was examined and analysed by flow cytometry and confocal microscopy.

    Results

    Among the liposomes tested, small anionic liposome vesicles (≤200 nm) prepared with egg phosphatidylglycerol as the main lipid were most effectively taken up by PC-3 cells and macrophages.

    Conclusion

    We produced a liposome formulation that can be used as a model system for the delivery of drugs and vaccines.

    Keywords

    Liposomes; Drug delivery; Vaccines delivery; Egg phosphatidylglycerol; Polyethylene glycol.