Biodegradable Microparticles as Non-Live Viral Vectors for Respiratory Tract Vaccination.

End of Project ReportThe potential of a microparticulate vaccine delivery system in eliciting a specific humoral response in the upper respiratory tract of calves was evaluated. Microparticles composed of poly(lactideco- glycolide) containing ovalbumin, a model immunogen, were prepared by a solvent evaporation technique. The microparticles were under 10μm in diameter as determined by fluorescence activated cell sorter (FACS) analysis. Following immunisation, the microparticles induced production of specific secretory IgA (sIgA) in nasal samples.The sIgA was detected after only one week and persisted throughout the length of the study. Additionally, the effects of microencapsulated synthetic peptides (F peptide (0.5mg) and G peptide (0.5mg), representing known protective epitopes against bovine respiratory syncytial virus (BRSV), on the cellular and humoral immune responses of calves were investigated. ∗ No significant change in the cellular immune response was detected. * The secretory IgA response was significantly more prolonged following administration of the SF (F111-148) peptide when compared with the SG (G174-187) peptide. * It is concluded that microparticles incorporating antigens show potential in the quest for generating complete protection in the young bovine against respiratory tract pathogens. * Vaccination of calves with the SF (F111-148) and SG (G174-187) peptide resulted in a significant reduction in the requirement to treat with antibiotics for respiratory disease in the post-vaccination period.European Union Structural Funds (EAGGF