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In order to clarify the applicability of Inonotus obliquus fermentation product (IOFP) as the adjuvants of avain vaccines, commercial avian influenza inactivated vaccine and duck Tembusu virus attenuated live vaccine were selected to immunize SPF chicken and ducks, respectively. SPF chicken in the experimental group were fed with the commercial diet containing 0. 8% IOFP, SPF chicken in the control group were fed with the the commercial diet. The peripheral blood from the chicken and ducks was collected at different time points after immunization and the serum was separated to determine the specific hemagglutinin inhibition (HI) antibodies of avian influenza virus (AIV), specific antibodies of duck Tembusu virus (DTMUV), and their neutralizing antibody titer. The effects of IOFP on the humoral immune response were evaluated by using the statistical methods. After 28 days post immunization, the ducks were challenged with virulent DTMUV, and the cloacal detoxification volume was detected, so as to confirm the effects of IOFP on the detoxification volume of DTMUV. The results showed that IOFP as oral adjuvant could significantly improve the titers of specific and neutralizing antibodies against AIV and DTMUV, and especially the improvement effect on the antibodies at the early stage. In addition, adding IOFP could reduce the detoxification volume of DTMUV, and shorten the shedding time. Therefore, IOFP was a common oral adjuvant for avian viral vaccines, which had a great improvement effect on shortening the immune “gap period” and improving the protective effect of vaccines. [ABSTRACT FROM AUTHOR]

In the earliest days, the idea that surviving a single infection often resulted in lifelong immunity to the infecting pathogen was recorded and then led to the discovery of vaccination. We have now confirmed that such protection is primarily based on the generation of immunological memory in antibody response. With the wide implementation of more and more vaccines around the world, it is well documented that different vaccines have different potential regarding to the duration of antibody response. In clinical observations, live-attenuated vaccines often elicit long-term immunity but are also accompanied with risks in safety that are hard to avoid. In order to develop novel vaccines with both excellent potential in eliciting antibody memory and low safety risk, it is critical to further investigate the mechanism of antibody memory in the perspective of immunology. Antibody memory is mediated by certain longlived B cells: long-lived plasma cell can secret antibody to maintain serum antibody titer while memory B cell contributes to the rapid immune response during the secondary encounter of pathogens. Cellular and molecular processes that drive the production of long-lived plasma cells and memory B cells are subjects of intensive research and have important implications for global health. Several factors in the vaccine would indeed affect and regulate these processes, including the antigen valency, vaccine kinetics and the signal integration of both antigen and danger molecules. Many studies have focused on strategies to manipulate these factors to improve or develop new vaccines. Here, we will summarize our current knowledge on how the component in vaccines will affect their potential in generating and sustaining antibody memory, and also point out the challenges we face in the route of developing a "perfect" vaccine. [ABSTRACT FROM AUTHOR]

Objective：To construct a Bandavirus davieense virus (DBV) vaccine based on the strategy of mRNA vaccine, immunize BALB/c mice, and evaluate its immunologic characteristics. Methods：The coding sequence of DBV glycoprotein Gn was optimized and synthesized, then inserted into the pGEM -3Zf (+) plasmid. The linearization plasmids were enzyme digested by BamH Ⅰ, cap and polyA tailing were added with polymerase to complete in vitro transcription. Western blotting verified the protein expression by transient transfection of the mRNA into eukaryotic 293FT cells. The mRNA was delivered by lipid nanoparticles, and immunized BALB/c mice by intramuscular injection of low (2 μg/mouse), medium (5 μg/mouse) and high (20 μg/mouse) dose once every two weeks. The antibody titer in mice serum was detected by ELISA, and the ability of antibody to neutralize DBV in vitro was detected at the cellular level by virus neutralization assay. Results：The prepared DBV mRNA vaccine could be transcribed and expressed in vitro. All three immunization doses induced high levels of specific antibodies in mice, with the high-dose immunization group inducing stable antibody expression for over 10 weeks. The virus neutralization assay showed that immune sera could bind to the virus and block virus infection of cells. Conclusion：A DBV mRNA vaccine capable of inducing specific neutralizing antibodies in mice is obtained, laying the foundation for research on the prevention of DBV infection. [ABSTRACT FROM AUTHOR]

Objective: A SARS-CoV-2 pseudovirus （PsV） system was established for neutralizing antibody evaluation and virus entry inhibitor screening. Methods: Lentiviral vector plasmids psPAX2, pCDH-Luc and SARS-CoV-2 Spike （S） protein expression plasmids were co-transfected, and harvested pseudoviral supernatant was used to infect ACE2-293T cells. Protein content of p24 was determined to reflect titer of PsV, and expression of S protein in PsV was detected by Western blot. Neutralization capacity of an S protein monoclonal antibody was evaluated using original strain, D614G, Gamma, Delta, Omicron PsV. Two reported virus entry inhibitors, chloroquine and carrageenin, were used to detect effect on entry of Omicron PsV. Results: Lentiviral vector successfully incorporated S protein. Western blot results showed that S protein mutated at 665Y showed a different cleavage form（ 90 kD） than wildtype full-length S protein（ 180 kD）. Titer of PsV packaged by three plasmids system was higher. Ratio of S protein expression plasmid, transfer plasmid and packaging plasmid at 1∶3∶3 was optimum condition for viral packaging. Titer of PsV packaged under this condition was over 20 ng/ml. PsV could effectively infect ACE2-293T cells, and double reporter gene GFP and firefly luciferase were expressed obviously, whose chemiluminescence values reached 106. Monoclonal antibodies of S protein effectively neutralized four types of PsVs, but neutralization of original strain was 10~30 times greater than that of variant PsV. Virus entry inhibitors, chloroquine and ι-carrageenan significantly inhibited entry of Omicron PsV. Conclusion: SARS-CoV-2 PsV infection system we conducted can simulate entry of SARS-CoV-2 successfully. Effective pharmacodynamic evaluation of neutralizing antibodies and virus entry inhibitors can be performed efficiently by the system, which can provide a technical platform for evaluation of neutralizing antibody of SARS-CoV-2 and screening of virus entry inhibitors, and would benefit R&D of anti-SARS-CoV-2 drugs. [ABSTRACT FROM AUTHOR]

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Objective ·To screen the human-mouse chimeric antibodies that neutralize the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and analyse the key amino acid site changes in their light chain. Methods ·Antibody heavy chain gene-humanized mice were immunized with the spike protein of SARS-CoV-2. Enzyme-linked immunosorbent assay (ELISA) and pseudovirus neutralization assay were performed to analyse the antibody titer in serum level. Flow cytometry was used to sort plasma cells and germinal center (GC) B cells from the mouse spleen and lymph nodes, and the proportions of different B cells were analysed. RNA was extracted to construct a mouse-origin antibody light chain gene library, which was paired with the knocked-in human-origin antibody heavy chain gene for antibody expression. ELISA was employed to screen for high-affinity chimeric antibodies. Amino acid changes in the light chain of high-affinity chimeric antibodies were analysed by comparing them with mouse-origin germline antibody light chain genes. Chimeric antibodies with single amino acid changes in the light chain were constructed and expressed, and their affinity and neutralization abilities were tested through ELISA and pseudovirus neutralization experiments. By comparing the affinity and neutralization abilities of the chimeric antibodies with or without single amino acid changes in the light chain, the key single amino acid change was analysed. Results ·Compared to unimmunized mice, the immunized mice showed an increased titer of specific antibodies against SARS-CoV-2 on the serum level, along with an elevated proportion of plasma cells and GC B cells in the spleen and lymph nodes. ELISA showed that a high-affinity chimeric antibody was screened from GC B cells in the mouse spleen. The light chain of the antibody had a 76th serine-to-isoleucine substitution and a 98th phenylalanine deletion. Another ELISA showed that the chimeric antibody exhibited high affinity, the antibody without amino acid change on the light chain and the antibody with only the 98th phenylalanine deletion showed low affinity, and the antibody with only the 76th serine-to-isoleucine substitution demonstrated intermediate affinity between the chimeric antibody and the antibody without amino acid change on the light chain. Pseudovirus neutralization experiments revealed that the chimeric antibody had a half-maximal inhibitory concentration (IC50) of 0.995 ng/μL; the antibody with only the 76th serine-to-isoleucine substitution had an IC50 of 1.724 ng/μL, indicating a slight decrease in neutralization ability; the antibody with only the 98th phenylalanine deletion had an IC50 of 71.05 ng/μL; the antibody without amino acid change on the light chain had an IC50 of 42.06 ng/μL, suggesting weak neutralization ability. Conclusion ·For the screened human-mouse chimeric antibodies that neutralize SARS-CoV-2 in this study, the key amino acid change determining the neutralization ability of the chimeric antibody is the 76th serine-to-isoleucine substitution. [ABSTRACT FROM AUTHOR]

Copyright of China Tropical Medicine is the property of China Tropical Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ongoing global development of the COVID-19 epidemic has led to in-depth research on the disease, including therapeutic agents. As a promising specific antiviral agents, the neutralizing antibodies have been successfully applied on some viral infectious diseases. Currently, the development of neutralizing antibodies against SARS-CoV-2 is progressing rapidly internationally, several antibodies have been authorized for emergency use. This paper reviews the effect targets of neutralizing antibodies against SARS-CoV-2, the research progress of drugs, and the problems and shortcomings that need attention. [ABSTRACT FROM AUTHOR]

Copyright of China Tropical Medicine is the property of China Tropical Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Tropical Medicine is the property of China Tropical Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To construct a competitive ELISA method to test neutralizing antibody against poliovirus (type III) in the crowd)which is more convenient)fast and accurate compared with traditional poliovirus neutralization test. Method Based on the double-antibody sandwich method previously established in our laboratory, the purified Sabin poliovirus (type III) D antigen was used as the coating antigen)and rabbit anti-poliovirus polyclonal antibody as a competitive antibody against human serum after the immunization. Incubating both together can form a competitive binding. The coating conditions of various antibodies and antigens were determined by square matrix titration and the experimental conditions were further optimized .The consistency of the results with the traditional poliovirus neutralization test was evaluated. Results The experimental conditions of the competitive ELISA method were determined by repeated experiments: the antigen coating concentration was 99.6 DU/mL)and the working concentration of tested serum was 1:16. The coincidence rate of this method and the traditional poliovirus neutralization test was 100%)which effectively reduced the interference of false negative results, did not react with the poliovirus C antigen, and had the good specificity between types, which could meet the detection requirements. The study also established the good quality control standards beneficial to the study of clinical samples. Conclusion The competitive ELISA method established in this study can be used for the rapid and accurate detection of the neutralizing antibody against poliovirus (type III) in the crowd, and also can avoid the use of live viruses. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

目的观察新型冠状病毒疫苗 (后简称新冠疫苗) 接种者血清抗体表达水平变化, 分析中和抗体水平 与外周血淋巴细胞亚群的相关性。方法选择 56 例完成第二剂新冠灭活疫苗接种者纳入疫苗组, 同时纳入未 接种疫苗的志愿者 20 例作为对照组。疫苗组于接种第 2 剂疫苗后 3d6-8 d、13-15 d 28 - 35 d 对照组于人 组后检测血清新型冠状病毒抗体 IgM､IgG、中和抗体､ 总抗体接种疫苗 13-15 d 后通过流式细胞术测算两组外 周血淋巴细胞亚群比例及绝对计数分析疫苗组中和抗体水平与外周血淋巴细胞的相关性。结果疫苗组血清 IgM､IgG､中和抗体水平高于对照组 (P均<001)。疫苗组接种后 3d6 ~ 8 d､13 ~ 15 d､28~35 d 中和抗体阳性 率分别为 20.0%、100%、100%、857%。疫苗组接种后 6-8d13-15 d 血清 IgM 水平高于接种后 3d 接种后 6 - 8 d､13-15 d､28 - 35 d 血清 IgG､中和抗体､总抗体水平均高于接种后 3d (P均<0.05)。疫苗组 CD3+T 细胞 比例低于对照组, CD3+ C4+ T、CD3+ CD8+T、CD3- CD19+ B 细胞比例高于对照组 (P均<005)。疫苗组中和抗 体水平与 CD3+T 细胞、CD3+ CD8+T细胞比例呈正相关 (7分别为 0.307、0.333, P均<0.05), 与CD3+ CD4+T 细胞比例､CD4/CD8 比值呈负相关, 分别为 0.224、0331P 均<0.05)。结论 新冠疫苗接种后能够促进 IgM 抗体表达提高 IgG､中和抗体､ 总抗体水平, 中和抗体水平与 CD3+ T 细胞､CD3+ CD8+T 细胞比例及 CD3+ CD4+T细胞比例､CD4/CD8 比值有一定相关性。 [ABSTRACT FROM AUTHOR]

An effective strategy to prevent porcine epidemic diarrhea(PED)is to transfer immunity to newborn piglets by milk after oral immunization of sows. The secretory IgA(SIgA)and cytokines of milk play an important roles in the lactogenic immunity of sows.[Objectives] In this study,sows were taken orally recombinant Bacillus subtilis expressing S protein to evaluate the lactogenic immunity,so as to provide corresponding protection for piglets.[Methods] Sows were taken orally 2 mL recombinant Bacillus subtilis(1×109 CFU·mL-1)and injected intramuscularly 2 mL inactivated porcine epidemic diarrhea virus(PEDV)vaccine(1×107 TCID50·mL-1). Corresponding samples were collected at one day after delivery. Collecting milk and cells in it were used to test specific secretory IgA(SIgA),and then the levels of specific SIgA and cytokines(INF-γ and TGF-α)in oral and nasal secretions were detected;finally,the titer of neutralizing antibody in milk was evaluated.[Results] The levels of specific SIgA and IgA antibodys and the INF-γ and TGF-α in the milk and cells significantly increased(P<0.05,P<0.01). There was also a significant increase in the nasal and oral secretions(P<0.05,P<0.01). The titer of neutralizing antibody in the milk of sows with oral administration of recombinant Bacillus subtilis was 1:128,while sows with intramuscular injection was 1:64.[Conclusions] Recombinant Bacillus subtilis that expresses PEDV S protein orally can improve the humoral and cellular immune levels in sows’ milk,providing adequate lactogenic immunity for the prevention of PED in newborn pigs. [ABSTRACT FROM AUTHOR]

Objective: To produce human papillomavirus type 58(HPV58) virus-like particles(VLP) vaccine with Escherichia coli expression system. Methods: A synthesized HPV58 L1 gene optimized with bias condons of Escherichia coli was inserted into prokaryotic expression vector mpET22b, and expressed in BL21(DE3). Cells were sonicated and the supernatent was purified with ammonium sulfate precipitation plus cation-exchange chromatography. The purified HPV58 L1 protein was analyzed by dynamic light scatter(DLS), and then immunized mice twice with two week interval. Sera were analyzed with pseudovirion-based neutralization assays. Results: The HPV58 L1 protein was expressed largely in cell lysate and was easy to purify. Dynamic light scattering analysis showed that the mean hydrodynamic diameter of the purified protein was 74 nm, which was similar to that of HPV58 L1 VLP control, indicating the protein was self-assembled into HPV58 L1 VLP. The mean titer of HPV58 neutralizing antibody was as high as 10,000 in sera collected at week 4,and retained 5,000 at week 22. Conclusions: The HPV58 Ll VLP produced in prokaryotic system can induce high titer of long-lerm specific neutralizing antibody, which is a cost-effective candidate of HPV58 prophylatic vaccine. [ABSTRACT FROM AUTHOR]

Objective: To investigate specific immune response and protective effect of BALB/c mice induced by DV inactivated CVB3. Methods: Wild CVB3 m strain was inactivated by UV, and male BALB/c mice were immunized with 0.1 LD50 (10~4PFU) of UV inactivated CVB3, named CVB3-UV, PBS treated mice were set as compared group. On the 3, 5, 7 days post immunization mice were sacrificed, serum were collected and cytokines were detected by CBA method, T cell subset were analyzed by flow cytometry method in the splenocytes on the 3, 5, 7, 14 days post immunization, neutralizing antibody in the sera of immunized mice 1 month later were detected, further, mice survival rate were also evaluated after challenge with lethal dose of wild type CVB3. Results: Compared with PBS treated group, CVB3-UV could induce high levels of IL-1α, TNF-α and IL-6 (P<0.05), while IL-4 production was comparable between both groups. CD3+CD4+T cell development were found affected on the 14 days post immunization by CVB3-UV (P<0.05), and higher titer neutralizing antibody were induced in the CVB3-UV treated mice.In portantly, higher survival rate of mice were found in the CVB3-UV group after re-infection by lethal CVB3. Conclusion: UV-inactivated CVB3 could induce specific immune response and support obvious protective effect in BALB/c mice. [ABSTRACT FROM AUTHOR]