Immune Potential of a Novel Multiple-epitope Vaccine to FMDV Type Asia 1 in Guinea Pigs and Sheep

To develop a safe and efficient recombinant subunit vaccine to foot-and-mouth disease virus (FMDV) type Asia 1 in sheep, a tandem repeated multiple-epitope gene consisting of residues 137-160 and 197-211 of the VP1 gene of FMDV was designed and artificially synthesized. The biologically functional molecule, the ovine IgG heavy constant region (oIgG) as a protein carrier was introduced for design of the multiple-epitope recombinant vaccine and recombinant expression plasmids pET-30a-RE and pET-30a-RE-oIgG were successfully constructed. The recombinant proteins, RE and RE-oIgG, were expressed as a formation of inclusion bodies in E. coli. The immune potential of this vaccine regime in guinea pigs and sheep was evaluated. The results showed that IgG could significantly enhance the immune potential of antigenic epitopes. The recombinant protein RE-oIgG could not only elicit the high levels of neutralizing antibodies and lymphocytes proliferation responses in the vaccinated guinea pigs, but confer complete protection in guinea pigs against virus challenge. Although the recombinant protein RE could not confer protection in the vaccinated animals, it could delay the appearance of the clinical signs and reduce the severity of disease. Inspiringly, the titers of anti-FMDV neutralizing antibodies elicited in sheep vaccinated with RE-oIgG was significantly higher than that for the RE vaccination. Therefore, we speculated that this vaccine formulation may be a promising strategy for designing a novel vaccine against FMDV in the future.

Visco-elastoplastic damage constitutive model for compressed asphalt mastic

In order to describe the three-stage creep behavior of compressed asphalt mastic, a visco-elastoplastic damage constitutive model is proposed in this work. The model parameters are treated as quadratic polynomial functions with respect to stress and temperature. A series of uniaxial compressive creep experiments are performed at various stress and temperature conditions in order to determine these parameter functions, and then the proposed model is validated by comparison between the predictions and experiments at the other loading conditions. It is shown that very small permanent deformation at low stress and temperature increases rapidly with elevated stress or temperature and the damage may initiate in the stationary stage but mainly develops in the accelerated stage. Compared with the visco-elastoplastic models without damage, the predictions from the proposed model is in better agreement with the experiments, and can better capture the rate-dependency in creep responses of asphalt mastic especially below its softening point of 47 ℃