Preclinical immunogenicity assessment of a cell-based inactivated whole-virion H5N1 influenza vaccine.

In influenza vaccine development, Madin-Darby canine kidney (MDCK) cells provide multiple advantages, including large-scale production and egg independence. Several cell-based influenza vaccines have been approved worldwide. We cultured H5N1 virus in a serum-free MDCK cell suspension. The harvested virus was manufactured into vaccines after inactivation and purification. The vaccine effectiveness was assessed in the Wuhan Institute of Biological Products BSL2 facility. The pre- and postvaccination mouse serum titers were determined using the microneutralization and hemagglutination inhibition tests. The immunological responses induced by vaccine were investigated using immunological cell classification, cytokine expression quantification, and immunoglobulin G (IgG) subtype classification. The protective effect of the vaccine in mice was evaluated using challenge test. Antibodies against H5N1 in rats lasted up to 8 months after the first dose. Compared with those of the placebo group, the serum titer of vaccinated mice increased significantly, Th1 and Th2 cells were activated, and CD8+ T cells were activated in two dose groups. Furthermore, the challenge test showed that vaccination reduced the clinical symptoms and virus titer in the lungs of mice after challenge, indicating a superior immunological response. Notably, early after vaccination, considerably increased interferon-inducible protein-10 (IP-10) levels were found, indicating improved vaccine-induced innate immunity. However, IP-10 is an adverse event marker, which is a cause for concern. Overall, in the case of an outbreak, the whole-virion H5N1 vaccine should provide protection.

Modifying the thermostability of inactivated influenza vaccines.

BACKGROUND: Respiratory infections caused by influenza viruses spread rapidly, resulting in significant annual morbidity and mortality worldwide. Currently, the most effective public health measure against infection is immunisation with an influenza vaccine matching the relevant circulating influenza strains. Although a number of developments in terms of influenza vaccine production, safety and immunogenicity have been reported, limitations in our understanding of vaccine stability still exist. In this report we seek to identify compounds that increase influenza vaccine thermostability. METHODS: We use plaque inhibition on confluent MDCK cells to identify compounds which inhibit the entry of various seed strain viruses. The effect of these compounds on vaccine thermal lability is evaluated through SRID analysis. The significance of these results is tested by a two-way analysis of variance (ANOVA) method. RESULTS: We identify two compounds which selectively inhibit entry of different group I or group II influenza strains through prevention of the neutral-pH to low-pH conformational change of hemagglutinin. Compounds which were able to inhibit virus entry were also able to limit thermally induced potency loss in matched influenza vaccines. Furthermore, we demonstrate that this effect is independent of product formulation or the presence of multiple HA types. CONCLUSIONS: This work provides further evidence for a link between HA conformational stability in the virus and thermostability of the corresponding vaccine preparation. It also suggests straightforward approaches to improve the stability and predictability of influenza vaccine preparations.

Dietary and lifestyle changes associated with high prevalence of hyperuricemia and gout in the Shandong coastal cities of Eastern China.

OBJECTIVE: To demonstrate the prevalence of hyperuricemia and gout associated with dietary and lifestyle changes and evaluate the implication of metabolic disorders to the development of hyperuricemia. METHODS: Data collected from 5,003 subjects randomly recruited from 5 coastal cities (Qingdao, Rizhao, Yantai, Weihai, and Dongying) of Shandong province in Eastern China were analyzed. RESULTS: Overall, the prevalence for hyperuricemia and gout in the studied populations was 13.19% and 1.14%, respectively. The prevalence was significantly higher in men as compared to women (18.32% vs 8.56% for hyperuricemia, 1.94% vs 0.42% for gout). Hyperuricemia was more common in men over age 30 and in women over age 50. A significant steady increase for the prevalence was noted as compared to the previous published data. Urban residents showed much higher prevalence of hyperuricemia as compared to rural residents (14.9% vs 10.1%, p = 0.004). Similarly, higher prevalence was noted in the developed city compared to the less developed city (18.02 vs 5.3%). These discrepancies were highly correlated with economic development as manifested by the increase of daily consumption of meat and seafood. Additionally, alcohol, overweight or obesity, hypertension, and abnormal triglycerides were highly associated with higher prevalence of hyperuricemia. Moreover, hyperuricemia is likely a risk factor for the development of diabetes mellitus. CONCLUSION: There was a remarkable increase for the prevalence of hyperuricemia and gout, which is highly correlated with the development of the economy as manifested by dietary and lifestyle changes.