Development of a Hemagglutination Inhibition Assay for Duck Tembusu Virus

Synthesis of pterodontic acid derivatives and the study of their anti-influenza A virus (H1N1) activity

Laggera pterodonta (DC.) Benth, a folk herb widely distributes in southwest China, especially in Yunnan Province, demonstrates anti-pathogenic microorganisms, anti-inflammatory, inhibition of Helicobacter pylori activities in vitro et al. Interestingly, previous studies have shown that pterodontic acid (1), a eudesmane-type sesquiterpene isolated from L. pterodonta (DC.), displays excellent selective antiviral activity to H1N1 subtype of influenza A virus. At the same time, our group also discovered that the antiviral activity of 1 was relatively close to that activity of post-marketed ribavirin. Therefore, we consider that the synthesis of pterodontic acid (1) derivatives and evaluation of their anti-influenza A virus (H1N1) activities is of potential clinical significance. In this manuscript, a series of pterodontic acid derivatives were prepared and demonstrated significantly improved anti-influenza A virus (H1N1) activities, providing more opportunities for the treatment of respiratory viral diseases.

Immunogenicity and protective efficacy of an EB66® cell culture-derived duck Tembusu virus vaccine

The avian EB66^® cell line, derived from duck embryonic stem cells, has been widely used for producing human and animal therapeutic proteins and vaccines. In current study we evaluated the potential use of EB66^® cell line in a cell culture-derived duck Tembusu virus (DTMUV) vaccine development. After optimizing the growth conditions of DTMUV HB strain in EB66^® cells, we successfully generated three batches of viruses with ELD₅₀ titres of 10^5.9/0.1 ml, 10^5.3/0.1 ml and 10^5.5/0.1 ml, respectively, for using in the preparation of inactivated vaccines. The immunogenicity and protective efficacy of these EB66^® cells-derived inactivated vaccines were examined in ducks. Results indicated that all three batches of vaccines induced haemagglutination-inhibition (HI) antibody response in immunized birds at 2 weeks after a single immunization. Immunized ducks and ducklings were protected against a virulent challenge at 4 weeks after a booster immunization. The duration of immunity was for 3-4 months after a booster immunization. These results demonstrated the feasibility of using EB66^® cell line to grow up DTMUV for vaccine preparation. RESEARCH HIGHLIGHTS Duck Tembusu virus can be propagated in EB66^® cells. EB66^® cell-derived inactivated DTMUV vaccines are immunogenic and can provide protection against a virulent challenge. A long-lasting immunity is induced after a booster immunization.