Objective:To prepare a recombinant hemagglutinin trimer (HA-Tri) vaccine against influenza viruses and to study its immunogenicity in a mouse model.Methods:A stable CHO cell line that could express HA-Tri was constructed. Western blot, single radial immunodiffusion, protein particle size detection and N-glycosylation site analysis were performed for qualitative and quantitative analysis of the recombinant protein. According to the different treatment conditions such as dosage and adjuvant, BALB/c mice were divided into 11 groups and subjected to consistent immunization procedures. Serum neutralizing antibody titers were measured on 56 d after the first immunization to evaluate the immunogenicity of HA-Tri.Results:The constructed CHO cells could secret and express HA-Tri proteins. The HA-Tri proteins were biologically active and capable of forming precipitation rings in the single radial immunodiffusion. The particle size of HA-Tri was approximately 18.79 nm and 10 N-glycosylation sites were detected, including high mannose, complex glycoforms and heterozygous glycoforms. After prime-boost immunization, there was no statistically significant difference in the titers of neutralizing antibodies induced in mice by 3.75 μg of HA-Tri in combination with RFH01 adjuvant and 15 μg of monovalent vaccine stock solution ( P=0.431 2, U=36). Serum antibody titers in the HA-Tri+ RFH01 groups were higher than those in the corresponding HA-Tri groups without RFH01 adjuvant, and the highest titer was induced in the 15 μg HA-Tri+ RFH01 group, which was 1 280. Conclusions:The recombinant HA-Tri protein was successfully prepared. HA-Tri in combination with RFH01 adjuvant could induce humoral immune responses against influenza viruses in BALB/c mice, which would provide reference for the development of influenza virus recombinant subunit vaccines.

Based on aliphatic alcohol, alcohol amine and amine, a new mixed expander (NB) for polyurethane prepolymer was prepared. This expander is very useful for rapid solidification medical polyurethane materials without carcinogenic ingredient. Taking a commercially available expander(MB), which is mainly composed of 4,4'\|methylene\|bis(2\|chloroaniline)(MOCA), as a reference, the reactions of the both expanders and polyether\|based polyurethane prepolymer were traced by IR and GPC. Both systems showed similar solidification time, but the material based on NB, or N\|PU, have a better initial fluidity, which is convenient for clinical operation. The reactive degree of isocyanate groups is higher in N\|PU than in M\|PU(material based on MB). The average molecular weight of N\|PU is much higher than that of M\|PU. The stress\|strain curves of the material of N\|PU and M\|PU behaved like “C” and reverse “S” type respectively. N\|PU does not show obvious creeping phenomenon and is less rigid. Environmental adaptability of both materials is the same. Therefore, NB is suggested to be a substitute for MB.