Objective·To construct an mRNA vaccine encoding hemagglutinin(HA)of influenza A H1N1 virus,and explore the protective effects of different booster vaccination strategies.Methods·Firefly luciferase(Fluc)was used as the reporter gene to construct Fluc mRNA vaccine enveloped in lipid nanoparticles(LNP).The in vivo expression of Fluc mRNA-LNP after intramuscular injection was determined by live imaging assay in mice.Furthermore,M15-HA mRNA-LNP derived from H1N1 subtype(A/Michigan/45/2015)was constructed.Mice were immunized with 20,10,5,or 1 μg doses of M15-HA mRNA-LNP twice(with an interval of 3 weeks)through intramuscular injection.Serum antibody titers were measured by enzyme-linked immunosorbent assay(ELISA)at 2 weeks and 4 weeks after the second immunization,and functional antibody levels were detected by hemagglutination inhibition test.The third booster vaccination was performed 40 d after the second immunization in 1 μg dose group with 1 μg M15-HA mRNA-LNP or 10 μg HA subunit vaccine.The levels of specific antibody and functional antibody were detected by ELISA and hemagglutination inhibition test,respectively 2 weeks and 4 weeks later.Results·Live imaging assay showed that luciferase activity could be detected in mice 1 d after injection of Fluc mRNA-LNP.At 2 weeks and 4 weeks after the second immunization of M1 5-HA mRNA-LNP,HA-specific antibodies were significantly higher than those before the immunization in all vaccination groups at different doses(P=0.000).The hemagglutination inhibition test showed that the levels of functional antibodies in the 20 μg dose and 10 μg dose groups were significantly higher than those in the PBS control group(P＜0.05).After 1 μg dose group mice were immunized with HA protein or M15-HA mRNA-LNP,higher levels of HA-specific antibody and functional antibody were induced and maintained for a long time.There was no significant difference between the two different booster immunization strategies.Conclusion·M15-HA mRNA-LNP vaccine is constructed with immunogenicity and antibody neutralization activity.Low-dose mRNA priming vaccination followed by both homologous mRNA vaccine and heterologous protein subunit vaccine booster vaccination can induce stronger immune recall responses.

Objective To analyze and explore the analgesic effect of Angelica dahurica in neuropathic pain and its regulatory effect on the Mas-related G-protein coupled receptor member D(MrgprD)-transient receptor potential ankyrin 1(TRPA1)signaling pathway,using a mouse model of sciatic nerve chronic constriction injury(CCI).Methods A CCI mouse model was prepared by sterile surgical ligation and wrapping of the sciatic nerve in 30 mice.Pain-related behavioral changes induced by mechanical stimulation were detected by the VonFrey method,and the thermal hyperalgesic effects of Angelica dahurica were evaluated by thermal radiation experiments.The effects of Angelica dahurica on the protein expression levels MrgprD and TRPA1,the number of dorsal root ganglion(DRG)positive neurons,and mRNA levels of MrgprD and TRPA1 in mice were detected by Western Blot,immunofluorescence,and reverse transcription-polymerase chain reaction,respectively.Differences in fluorescence signal intensity in HEK293 cells after single transfection and co-transfection with MrgprD and TRPA1 plasmids,respectively,were analyzed by calcium imaging experiments.Results A total of 25 CCI mouse models were successfully prepared,with a modeling rate of 83.33％(25/30).The mechanical threshold and foot retraction latency were significantly higher in CCI mice treated with Angelica dahurica compared with the control group(P＜0.05).Expression levels of MrgprD and TRPA1 proteins were significantly lower in CCI mice treated with Angelica dahurica than in the control group(P＜0.05).The number of MrgprD-and TRPA1-positive neurons in the DRG was significantly lower group(P＜0.05)and the mRNA levels of MrgprD and TRPA1 were also significantly lower in CCI mice treated with Angelica dahurica than in the control group(P＜0.05).The fluorescence intensity was significantly higher in HEK293 cells co-transfected with MrgprD and TRPA1 plasmids than in single-transfected and blank control cells(P＜0.05).Conclusions This study demonstrated that the MrgprD-TRPA1 pathway is an important target for neuropathic pain,and indicated that Angelica dahurica can inhibit neuropathic pain by regulating this signal transduction pathway.These result provide a foundation for further research on the development of new clinical analgesic drugs and analgesic mechanisms.

The genetic background such as copy number, integration site and chromosome karyotype of exogenous genes of transgenic animals obtained by random integration is still unclear. There may be some problems such as silent integration, invalid integration, toxic integration and unpredictable expression level of exogenous genes. In this study, six primary (F0) and their corresponding offspring (F1) of human lactoferrin (hLF) transgenic goats were selected as the research objects, and blood samples were collected from jugular vein and DNA were extracted. The genetic background and expression level of exogenous genes were studied by chromosome karyotype analysis, real-time quantitative PCR (qPCR), ELISA and Western blotting. The chromosomes of six F0 transgenic goats had no obvious morphological variation, number change and other abnormalities. The relative copy number was different (2-16) and could be steadily inherited to the next generation. The copy number of F0 and F1 hLF gene was the same. The highest expression level of hLF was 1.12 g/L in F1 transgenic goats (L3-1, 8 copies). The results proved that the integrated exogenous genes could steadily inherit the next generation, and did not cause obstacles to the growth and development of transgenic goat individuals. Moreover, there was no obvious correlation between the number of copies and the expression level of hLF. This laid a foundation for the new varieties cultivation of transgenic goats and other transgenic animals, and analysis of genetic background.