Objective: To investigate the genetic stability of virus seed H₂M₂₀K₇ (K7) of live attenuated Hepatitis A virus H2 strain (HAV, H2 strain) for production of hepatitis A (Live) vaccine, lyophilized after continuous passages. Methods: The virus seed K7 of H2 strain was proliferated and passaged in KMB₁₇ cells in cell factories. Viruses of different passages were harvested after continuous passages. Virus RNA was extracted and the complete genomes of different virus passages (K7, K10, K11, K13, K15, K18) were sequenced by using next-generation deep sequencing. The mutation rates of different passages were compared. The infectivity titers of different virus passages of H2 strain were tested by ELISA. Results: The mutation rates of complete genomes of different passages were low after continuous passages of master virus seed. The structure of gene was stable and non-synonymous mutation rate was lower than 0.57%. The mutation rate of 5 ’non-coding regions was lower than 0.1%. There was no significant mutation in VP1/2 A and 2C virulence site. The infectious titers of H2 strains of different passages were within 7.76-8.50 lgCCID₅₀/ml. No statistically significant difference was found in this study. Conclusions The gene structure of the master virus seed, working seed and different passages of H₂M₂₀K₇ after subculture was stable and the mutation rate was low. No significant mutation was found in 5’non-coding regions, and the critical virulence sites such as VP1/2 A, 2B and 2C showed attenuated characteristics with low mutation rate. Virulence of the virus did not changed. The H2 strain maintained stable viral infectivity and genetic stability and comply with the requirements as virus seed for vaccine manufacturing.

AIM:To examine the effects of borneol on inflammation and myocardial remodeling after myocar-dial infarction(MI)in mice,and to investigate the underlying mechanisms.METHODS:Eight-week-old wild-type(WT)C57BL/6 mice and transient receptor potential cation channel subfamily M member 8(TRPM8)gene knockout(TRPM8-/-)mice were randomly divided into sham and MI groups,and were subsequently treated with normal saline(control group)or borneol(borneol group)via gavage.Survival curves were plotted for WT and TRPM8-/-mice with MI treated with or with-out borneol.After 28 d,cardiac function of the mice was assessed through echocardiography,and haemodynamic indexes were evaluated using a multi-channel physiological instrument.Infarct size,myocardial hypertrophy and interstitial fibro-sis were assessed via pathological staining.In addition,inflammatory response in the peri-infarct region was detected.RE-SULTS:The TRPM8 expression was up-regulated in the peri-infarct region of the mice with MI(P＜0.05),and borneol had no effect on TRPM8 expression(P＞0.05).Borneol increased the survival rate,reduced the infarct size,inhibited car-diac remodeling and improved cardiac function in WT mice with MI(P＜0.05 or P＜0.01).However,it did not affect the survival rate,infarct size,myocardial hypertrophy,myocardial fibrosis or cardiac function in TRPM8-/-mice(P＞0.05).Furthermore,borneol reduced inflammatory cell infiltration and the expression of inflammatory cytokines,tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),IL-6 and monocyte chemotactic protein-1(MCP-1),in WT mice(P＜0.05 or P＜0.01)but not in TRPM8-/-mice(P＞0.05).CONCLUSION:Borneol attenuates inflammation,inhibits cardiac re-modeling and improves cardiac function in mice with MI via TRPM8.

Objective To determine the serum IgM and IgG antibody levels post-COVID-19 vaccination， and provide scientific evidence for COVID-19 antibody response after vaccination. Methods A total of 980 healthy persons were included in Kunming Third People’s Hospital from July through August， 2021， which had been vaccinated with COVID-19 vaccines and then tested for anti-SARS-CoV-2 IgM and IgG antibodies. Results After the COVID-19 vaccination， 469 persons （positive rate， 47.86%） were positive for anti-IgG antibody. Of them， 75 were males with （positive rate， 39.06%）， and the average IgG level was 0.618 （0.180， 2.526） AU·mL^-1［M（Q₁，Q₃）］； 394 were females （50.00%）， and the IgG level was 0.999 （0.305， 3.334） AU·mL^-1. In addition， 53 persons （5.41%） were anti-IgM antibody positive. Of them， 14 were males （positive rate， 7.29%）， and the average IgM level was 0.057 （0.026， 0.195） AU·mL^-1； 39 were females （4.95%）， and the IgM level was 0.047 （0.027， 0.110） AU·mL^-1. The positive rate of anti-IgG antibody was highest in those aged ≤30 years， which was 51.02% in male （n=25） and 55.88% in female （n=133）. The anti-IgG response differed significantly by gender （χ²=7.401， D=0.135 1， P<0.05）， whereas the anti-IgM response was not significantly different （χ²=1.656， P>0.05）. Among the age groups， anti-IgG antibody level was higher in those aged ≤30 and 51-70 years， with 158 （55.05%） and 122 （52.36%） persons， respectively； the average antibody level was 1.209 （0.426， 4.386） AU·mL^-1 and 1.074 （0.191， 7.670） AU·mL^-1， respectively. The differences in the positive rates of IgG and IgM antibodies and the levels of IgG antibodies among different age groups were statistically significant （P<0.05）. Using Kruskal-Wallis test and Spearman correlation analysis， it showed a high correlation between the IgG and IgM antibodies （r=0.836 4， H=64.82， 20.09， P<0.05）. Conclusion The Anti-SARS-CoV-2 IgG antibody remains high six months post-COVID-19 vaccination， while anti-IgM antibody is low. The IgM and IgG response are higher in the young and elderly. The response differs by gender and age， demonstrating a correlation.