Dairy cow mastitis is a serious disease that is mainly caused by intramammary infection with Staphylococcus aureus and Streptococcus agalactiae [group B streptococcus (GBS)]. FnBP and ClfA are the virulence factors of S. aureus, while GapC is the respective factor for S. agalactiae. Sip is a highly immunogenic protein, and it is conserved in all GBS serotypes. In this study, we analyzed the abovementioned four genes prepared a FnBP+ClfA chimeric protein (FC), a GapC+Sip chimeric protein (GS), and a FnBP+ClfA+GapC+Sip chimeric protein (FCGS) based on the antigenic sites to evaluate their use in vaccine development. After expression and purification of the recombinant proteins in Escherichia coli, BALB/c mice were immunized with them to examine resistance effects. The total lethal and half lethal doses of S. aureus and S. agalactiae were then measured, and the immunoprotective effects of the fusion proteins were evaluated. The FC and FCGS chimeric proteins could induce mice to produce high levels of antibodies, and bacterial loads were significantly reduced in the spleens and livers after challenge. After immunization with FCGS, the recipients resisted the attacks of both S. aureus and S. agalactiae, indicating the potential of the fusion protein as a mastitis vaccine.

OBJECTIVES:The capsid protein (VP1) of the foot-and-mouth (FMD) AKT-III strain was expressed on the surface of the T7 phage capsid (AKT-T7 strain) and the potential of AKT-T7 strain as an FMD vaccine was evaluated.RESULTS:The AKT-T7 strain was successfully constructed and was not cytotoxic to BHK-21, MDBK, or sheep kidney cells. The AKT-T7 strain was well phagocytosed by mouse macrophages. Immunization of BALB/c mice revealed that animals were quickly induced and produced high levels of FMDV antibodies. Monitoring data indicated that FMDV antibody levels could be maintained at higher levels for longer periods of time. The AKT-T7 strain induced high levels of IFN-γ levels in mice with little effect on IL-4.CONCLUSIONS:The AKT-T7 induced the mice to produce FMDV antibodies, which has the advantage of phage and FMDV, and is a potential candidate for an FMD vaccine.

AbstractThe FMDV VP1 protein has different structures which could decrease or increase the immune response. We undertook a meta-analysis to evaluate the protective effect of VP1 on the FMDV. A systematic search of the PubMed, Embase, CNKI and Wan fang DATA was conducted up to April 2020. Experimental studies involving the VP1 protection effect on FMDV were included. Extracted data were analyzed using Rev-Man 5.3 software. Chi-square tests were used to analyze the heterogeneity among the documents. The fixed-effect model was used for meta-analysis to find the combined effect value and 95% confidence interval. Sensitivity analysis was performed on the differences in the combined values of model effects, and the inverted funnel chart method was used to assess the publication bias of the included literature. A total of 12 articles were included for meta-analysis. The results of showed that VP1 had a protective effect on FMDV [MH= -0.66, 95%CI= (−0.75, -0.56),P< 0.00001]. Sensitivity analysis showed that the results were robust. The funnel graph method showed that the published literature had a small publication bias and met the requirements of this study. It is necessary to study the epitopes of VP1 to produce new vaccines. VP1 could protect animals from FMDV attacks. It is necessary to study the VP1 protein and its epitopes and use it as a new vaccine and diagnostic product.

Background: Foot-and-mouth disease (FMD) is a highly transmissible disease that leads to vast economic losses in many countries. Prevention using inactivated vaccines is one effective measure used to control FMD. Unfortunately, inactivated FMD vaccines provide only short-term protection and require a cold-chain system. In recent years, many studies have shown that layered double metal hydroxides (LDHs) carrying antigens can be used to strongly induce immune responses. In this study, LDH nanoparticles (NPs) were prepared by hydrothermal synthesis. LDH particle size, electric potential, and morphology were measured and observed. The adsorption capacity of LDH NPs to FMDV was tested. The effects of LDH as an adjuvant on inactivated FMDV vaccines were further evaluated and compared with commercial FMDV ISA-206 in BALB/C female mice and Yorkshire pigs.Results: LDH NPs were successfully prepared with a uniform particle size of ~87.21 nm, regular edges, a loose hexagonal shape and positive zeta charge of 32 mV. The maximum absorption concentration was 0.16-0.31 µg FMDV/µg LDH. In the mouse experiment, antibody of immunized with LDH + FMDV were induced significantly higher from days 42-98 compared to saline + FMDV (P<0.01) and significantly higher compared to ISA-206+FMDV on day 56 post-immunization (P<0.05). After day14 post-immunization, IFN-γ content was significantly increased (P<0.05). In the pig experiment, antibody levels in both the ISA-206 + FMDV and LDH + FMDV were positive and were significantly higher compared with the PBS group on day 7 (P<0.005). Antibody levels in 90% pigs were positive on day 56 in the LDH group. The neutralizing antibody levels in the LDH and ISA-206 groups were significantly higher from days 7-28 compared to the PBS control group (P<0.05). Thus, LDH NPs were effective at inducing an immune response against FMDV.Conclusions: LDHs with a loose hexagonal shape and a positive charge were prepared. LDHs can effectively induce humoral- and cell-mediated immune responses in mice and pigs. In addition, the LDHs had a slow-release effect and produced antibodies continuously. LDHs may act as an excellent FMDV adjuvant.

Background Foot-and-mouth disease (FMD) is a highly transmissible disease that leads to vast economic losses in many countries. Prevention using inactivated vaccines is one effective measure used to control FMD. Unfortunately, inactivated FMD vaccines provide only short-term protection and require a cold-chain system. In recent years, many studies have shown that layered double metal hydroxides (LDHs) carrying antigens can be used to strongly induce immune responses. In this study, LDH nanoparticles (NPs) were prepared by hydrothermal synthesis. LDH particle size, electric potential, and morphology were measured and observed. The adsorption capacity of LDH NPs to FMDV was tested. The effects of LDH as an adjuvant on inactivated FMDV vaccines were further evaluated and compared with commercial FMDV Montanide ISA-206 in BALB/C female mice and Yorkshire pigs. Results LDH NPs were successfully prepared with a uniform particle size of ~ 87.21 nm, regular edges, a loose hexagonal shape and positive zeta charge of 32 mV. The maximum absorption concentration was 0.16–0.31 μg FMDV/μg LDH. In the mouse experiment, antibody levels in group LDH + FMDV were significantly higher compared to group saline + FMDV ( P < 0.01) from days 42–98 and were significantly higher to group ISA-206 + FMDV on day 56 post-immunization ( P < 0.05). After day 14 post-immunization, IFN-γ content was significantly increased ( P < 0.05). In the pig experiment, antibody levels in both the ISA-206 + FMDV and LDH + FMDV were positive and were significantly higher compared with the PBS group on day 7 ( P < 0.005). Antibody levels in 90% pigs were positive on day 56 in the LDH group. The neutralizing antibody levels in the LDH and ISA-206 groups were significantly higher from days 7–28 compared to the PBS control group ( P < 0.05). Thus, LDH NPs were effective at inducing an immune response against FMDV. Conclusions LDHs with a loose hexagonal shape and a positive charge were prepared and evaluated as adjuvant for FMD vaccine. It was demonstrated that LDHs can induce immune responses in mice and pigs. In addition, the LDHs produced antibodies continuously which may indicate a slow-release effect. The study shows that LDHs may act as a potentially useful FMDV adjuvant.

为了研究石河子地区某牛场乳房炎临床发病牛中病原菌感染情况及耐药性,试验采用鉴别培养基对乳样进行了致病菌的分离与鉴定、生化试验与16S rRNA PCR试验及药敏试验.结果 表明:共分离鉴定出疑似链球菌12株.用生化试验结合基因测序鉴定,结果显示其中1株为无乳链球菌,其16S rRNA序列与NCBI公布的9个序列(登录号分别为CP044091.1、CP033822.1、CP021870.1、CP007632.1、DQ232512.1、AL766845.1、AL766844.1、AL766843.1、AF015927.1)基因相似性为100％.分离菌株对万古霉素、环丙沙星、替考拉宁、哌拉西林、诺氟沙星、新霉素、头孢噻肟高度敏感,而对青霉素、苯唑西林、阿莫西林、链霉素、红霉素、四环素耐药.说明该牛场临床型奶牛乳房炎致病菌中存在无乳链球菌,且链球菌存在耐药性.

为了研究淋巴细胞活化基因-3蛋白的生物学特性,试验采用PCR方法扩增淋巴细胞活化基因-3胞外区序列,构建重组质粒,将重组质粒转染至HEK293感受态细胞中表达目的蛋白,并对目的蛋白进行SDS-PAGE及Western-blot检测,通过ProtParam软件分析淋巴细胞活化基因-3蛋白性质,通过SWISS-MODEL软件预测蛋白质结构.结果 表明:PCR法成功扩增出目的条带,大小约为1 430 bp,1.0％琼脂糖凝胶电泳显示酶切成功;经10％ SDS-PAGE凝胶电泳分析,在68 ku处出现目的条带,目的蛋白成功表达;纯化后的蛋白质经Western-blot检测证明具有特异性;目的蛋白具有22种可能的折叠形态,理论等电点pI值为9.08,蛋白质结构不稳定,亲水性较差.说明试验成功表达了淋巴细胞活化基因-3蛋白.