VaxArray assessment of influenza split vaccine potency and stability.

Vaccine manufacturers require more rapid and accurate tools to characterize the potency and stability of their products. Currently, the gold standard for influenza vaccine potency is the single radial immunodiffusion (SRD) assay, which has inherent disadvantages. The primary objective of this study was to investigate the ability of the VaxArray Influenza (VXI) seasonal hemagglutinin (sHA) potency assay to accurately quantify potency and stability in finished vaccines as well as to quantify hemagglutinin protein (HA) within crude in-process samples. Monobulk intermediates and mono- and multivalent vaccines were tested using VXI. Quantification of HA in crude samples was evaluated by spiking known concentrations of HA into allantoic fluid. VXI generated SRD equivalent potency measurements with high accuracy (within ±10%) and precision (CV 10±4%) for antigen components of monobulk intermediates and multivalent split vaccines. For these vaccines and vaccine intermediates, the VXI linear dynamic range was ∼0.01-0.6µg/mL, which is 12× greater than the linear range of SRD. The measured sample limit of detection (LOD) for VXI varied from 0.005 to 0.01µg/mL for the different subtypes, which in general is ≥600× lower than the LOD for SRD. VXI was able to quantify HA in crude samples where HA only accounts for 0.02% of the total protein content. Stability indication was investigated by tracking measured potency as a function of time at elevated temperature by both SRD and VXI. After 20 h at 56°C, the ratio of VXI to SRD measured potency in a quadrivalent vaccine was 76%, 125%, 60%, and 98% for H1/California, H3/Switzerland, B/Phuket and B/Brisbane, respectively. Based on the study results, it is concluded that VXI is a rapid, multiplexed immunoassay that can be used to accurately determine flu vaccine potency and stability in finished product and in crude samples from upstream processes.

Benefit of phosphodiesterase 4 inhibitors as supplemental therapy after lung transplantation concerning their antiproliferative effects: an experimental study using a heterotopic rodent model.

BACKGROUND: Recent advances in the understanding of immunomodulatory properties of phosphodiesterase 4 (PDE4) inhibitors recommend these drugs for immunosuppressive therapy after lung transplantation. The potency of three PDE4 inhibitors was tested using an established model of heterotopic tracheal transplantation in rats. METHODS: Five allogenic groups were investigated and treated with the PDE4 inhibitors: rolipram, cilomilast (Ariflo, SB-207499, SmithKline Beecham, Munich, Germany), roflumilast (Altana Pharmacia, Bad Homburg, Germany) or cyclosporine A (CsA), or left without immunosuppression. The grafts were quantitatively analyzed for epithelial integrity, monocyte/macrophage content, cell proliferation, and tracheal obliteration by histology/immunohistochemistry (days 1, 5, 7, 21, 28; n=4-7). RESULTS: In animals treated with the PDE4 inhibitors, the epithelium was completely lost until day 21. The epithelium was partially preserved in the rats receiving CsA until day 28. In the acute phase (days 5 and 7) the infiltration of monocytes and macrophages was significantly inhibited similarly (cilomilast) or less effective (rolipram, roflumilast) as in CsA-treated rats. In the chronic phase (day 28) the significant increase of monocytes and macrophages after CsA-treatment was not found in PDE4 inhibitor-treated rats. The PDE4 inhibitors showed lower (rolipram) or higher (cilomilast, roflumilast) potency as CsA to inhibit the cell proliferation. Only treatment with PDE4 inhibitor (Ariflo) significantly inhibited the obliteration, but to a lesser degree as CsA. CONCLUSION: The PDE4 inhibitors tested in our study are not suitable on their own for immunosuppressive therapy after lung transplantation because of the limited protection against the epithelial disturbance, infiltration of immune cells, and luminal obliteration. The strong anti-proliferative effect of the second-generation PDE4 inhibitors, cilomilast and roflumilast, suggest a benefit for the effective inhibition of immune cell and fibroblast proliferation contributing to the development of obliterative bronchiolitis.