乙型肝炎表面抗体的抗独特型研究

用 HBsAg/a 决定簇的7A_4单克隆抗体(McAb_1)复合物,免疫同系 BALB/C 小鼠,制备了高效价抗独特型(Ab_2)血清和两株抗独特型 McAb(McAb_2).Ab_2血清和 McAb_2都能识别7A_4McAb_1的互补位独特型.Ab_2血清中有与异种(豚鼠、驴、兔和羊)抗—HBs 结合的抗体,两株 McAb 不能与异种抗-HBs结合的抗体,两株 McAb 不能与异种抗-HBs 结合,属非内影像 Ab_2γ.研究表明,HBsAg/a 决定簇的 McAb_1有不同的互补位,McAb_2可作为一种生物探针,用于区别 McAb_1的互补位.     

针对单克隆抗体MGb1的重组抗独特型抗体的筛选与鉴定

目的 利用噬菌体呈现技术筛选针对抗胃癌单克隆抗体（简称单抗）MGb1的重组抗独特型抗体（抗-Id）,为研制胃癌重组抗-Id瘤苗提供候选分子。方法 以单克隆抗体MGb1免疫Balb／c小鼠,取脾分离mRNA。RT-PCR分别扩增抗体VL和VH cDNA,经linker DNA连接形成ScFv DNA。将scFv DNA与载体pCANTAB5E的连接产物转化于大肠杆菌TG1,经M13KO7感染后,获得重组噬菌体抗体ScFv文库。以单抗MGb1对文库进行4轮淘选后,随机挑取克隆经ELISA筛选呈现抗-Id scFv的噬菌体单克隆,进而经竞争ELISA对其所属抗-Id类型进行初步鉴定。结果 VL和VH cDNA分别约为320和340bp,ScFv DNA约为750bp。抗体ScFv文库经四轮淘选后,在随机筛检的50个克隆中得到18个呈现抗-Id ScFv的噬菌体单克隆。在18个克隆中,有4个呈现β或γ型抗-Id ScFv。结论 经重组噬菌体抗体技术成功地筛选到了针对单抗MGb1的噬菌体呈现型抗-Id ScFv,从而为进一步获得能诱导抗胃癌免疫的抗-Id ScFv奠定了基础。     

Lack of awareness of Hepatitis B screening and vaccination in high-risk groups

Background/aim Hepatitis B virus (HBV) vaccination rates are insufficient in high-risk patients worldwide. This study aimed to investigate the screening, immunization, and vaccination rates in three high-risk groups for HBV infection: allogeneic hematopoietic stem cell transplantation (AHSCT), renal transplantation (RT), and chronic hepatitis C (CHC) groups. Materials and methods The serological data of consecutive patients between 2014 and 2019 were reviewed using the hospital database. Results The HBV screening rates were 100.0%, 90.4%, and 82.4% in the AHSCT, CHC, and RT groups, respectively (p = 0.003). The immunization rates against HBV through either previous exposure or vaccination were 79.5%, 71.7%, and 46.5% in the AHSCT, RT, and CHC groups, respectively (p < 0.001). The HBV vaccination rate was significantly low in the CHC group (71.5%, 69.0%, 34.6% in the AHSCT, RT, and CHC groups, respectively, p < 0.001). If patients lost their immunity due to immunosuppressive therapy were accounted, the vaccination rates increased to 95.2% in the AHSCT group and 72.9% in the RT group. The rate of annual screening for HBV status was 97.9% in the AHSCT group, but it was only 23.9% in the RT group. Conclusion HBV screening and vaccination rates were significantly lower in the RT and CHC groups than in the AHSCT group.     

Mechanisms of dendritic cell-based vaccination against infection

Due to their unique capacity to initiate and regulate adaptive immune responses, dendritic cells (DC) represent the most potent antigen-presenting cells of the immune system. Immature DC reside in peripheral tissues, where they sample and process antigens and efficiently sense a large variety of signals from the surrounding environment. Toll-like receptors (TLR) expressed by DC play a critical role in the detection of invading pathogens as well as in triggering the subsequent immune responses. The differential expression of TLR by different DC subsets may correlate with the induction of different patterns of adaptive immune responses. The rapidly expanding and fundamental knowledge of DC biology furthers promising perspectives for the development of vaccination strategies in different fields. For example, the immunotherapeutic potential of antigen-pulsed DC for the treatment of cancer has been confirmed in a number of experimental tumour models. Furthermore, DC have been shown to serve as natural adjuvants in different models of infectious diseases, mediating protection against various types of pathogens. Using murine leishmaniasis as an example, we have demonstrated that DC, once properly conditioned ex vivo, mediate complete and durable protection against infection. Critical parameters determining the efficiency of DC-based vaccination against microbial pathogens include the origin of DC, the choice of antigen to be used for DC loading, the route of immunization and the state of DC maturation and activation. In the present review, we discuss the necessity to define the mechanisms responsible for the immunostimulatory capacity of DC in vivo, in order to exploit their full potential as vaccination tools.     

Preparation of anti-idiotypic antibody against avian influenza virus subtype H9

To generate monoclonal anti-idiotypic antibodies(mAb2)against avian influenza virus subtype H9(H9 AⅣ),BALB/c mice were immunized with purified chicken anti-H9-AⅣ IgG and the splenocytes of immunized mice werefused with myeloma cells NS-1.Hybridoma cells were screened by indirect enzyme-linked immunosorbent assayswith both chicken and rabbit anti-H9-AⅣ IgG as coating antigens.One hybridoma cell clone secreting monoclonalantibody against idiotypes shared by both chicken and rabbit anti-H9-AⅣ IgG was established.Experimentsdemonstrated the mAb2 was able to inhibit the binding of hemagglutinin to anti-H9-AⅣ IgG and to inducechickens to generate hemagglutination inhibition antibodies,indicating this anti-species-sharing-idiotypic antibodybore the internal image of hemagglutinin on avian influenza virus.Cellular & Molecular Immunology.2005;2(2):155-157.     

Isolation,production, and characterization of a new single chain anti-idiotypic antibody against benzo[a]pyrene

Polycyclic aromatic hydrocarbons are chemical carcinogens which could induce the development of human cancers. Anti-idiotypic antibodies against benzo[a]pyrene (BP) are perspective for human cancer immunoprophylaxis and tumor immunodiagnostic techniques. The purpose of this study was to isolate anti-idiotypic antibodies against BP from human lymphocytes naïve phage library. The anti-idiotypic antibody, named B5, was selected. Analysis of the nucleotide and amino acid sequences B5 showed no similarity to known protein databases antibodies. B5 bound idiotypic antibodies against BP in direct and competitive ELISA. It was suggested that the B5 carried an immunological image of BP and bound the idiotypic antibodies against BP.

Abbreviations: scFv: single-chain variable fragment; Ab1: idiotypic antibodies; Ab2: anti-idiotypic antibodies; CBD: cellulose binding domain; BSA: bovine serum albumin; PBS: phosphate buffer; BP-BSA: benzo[a]pyrene-BSA conjugate; Cr-BSA: chrysene-BSA conjugate; Py-BSA: pyrene-BSA conjugate; Ac-BSA: anthracene-BSA conjugate; Ba-BSA: benz[a]anthracene-BSA conjugate; PAH: polycyclic aromatic hydrocarbons; pSh: mouse idiotypic single-chain variable fragment against benzo[a]pyrene; T72: human idiotypic single-chain variable fragment against benzo[a]pyrene.     

A recombinant single chain antibody neutralizes coronavirus infectivity but only slightly delays lethal infection of mice

The variable region genes of a murine anti-coronavirus monoclonal antibody (mAb) were joined by assembly polymerase chain reaction and expressed in Escherichia coli in a single chain variable fragment (scFv) configuration. After induction of expression, the expected 32-kDa protein was identified by Western immunoblotting with specific rabbit anti-idiotype antibodies. The scFv fragments were purified from soluble cytoplasmic preparations by affinity chromatography on nickel agarose, which was possible with an N-terminal but not with a C-terminal histidine tag. Purified scFv fragments retained the antigen-binding properties of the parental antibody, could inhibit its binding to viral antigens with apparently higher efficiency than monovalent antigen-binding (Fab) fragments, but neutralized viral infectivity with lower efficiency (about sevenfold at a molar level). To evaluate the usefulness of these smaller and less immunogenic molecules in the treatment of viral diseases, mice were treated with purified recombinant scFv fragments and challenged with a lethal viral dose. A small delay in mortality was observed for the scFv-treated animals. Therefore, even though the scFv could neutralize viral infectivity in vitro, the same quantity of fragments that partially protected mice in the form of Fab only slightly delayed virus-induced lethality when injected as scFv fragments, probably because of a much faster in vivo clearance: the biologic half-life was estimated to be about 6 min. Since a scFv derived from a highly neutralizing and protective mAb is only marginally effective in the passive protection of mice from lethal viral infection, the use of such reagents for viral immunotherapy will require strategies to overcome stability limitations.     

Idiotypes and anti-idiotypic antibodies: a review

An idiotype (Id), defined as an epitope within the variable region of immunoglobulin, is used as a structural and functional marker of the region. Anti-idiotypic antibodies (anti-Ids or Ab2s) can be generated upon immunization with an antibody (Ab1) which contains a variety of Ids. One set of anti-Ids, referred to as internal-image Ab2s, recognizes an Id which is shared by antibodies with the same or similar specificities. This Id is designated a common Id. Anti-Ids that recognize a common Id and represent an internal image of the antigen have been generated in many systems. Many experimental studies have shown the potentials of anti-Ids as immune regulators to various pathogens. The antigenic mimicry of internal-image Ab2β makes them valuable not only as immunogens for eliciting specific immune response to infectious pathogens but also as probes for studying cell receptors, as well as for immune therapy for tumors.     

生长抑素抗独特型卵黄抗体对大鼠胰岛SST受体定位及功能调节的研究

目的:探究人SST抗独特型卵黄抗体对大鼠胰腺SST受体定位、荧光共定位及对胰腺内分泌功能的调节作用,探讨其能否用于糖尿病治疗.方法:DAB染色观察大鼠胰腺SST受体分布.免疫荧光共定位观察大鼠胰岛SST受体与内分泌激素共定位.大鼠腹腔注射SST抗独特型卵黄抗体,ELISA检测不同时间点大鼠血浆胰高血糖素、胰岛素和血糖水...     

Leishmania donovani infection initiates T cell-independent chemokine responses,which are subsequently amplified in a T cell-dependent manner

Control of Leishmania donovani infection in immunocompetent mice is associated with hepatic inflammation and granuloma formation, both of which are absent in severe combined immunodeficient ( scid ) mice. In both BALB/c and scid mice, L. donovani infection induced a rapid hepatic accumulation of mRNA encoding macrophage inflammatory protein-1α (MIP-1α), monocyte chemoattractant protein-1 (MCP-1) and interferon-γ inducible protein-10 (γIP-10). This response was not preceded by increased IL-4 production in either strain, unlike that reported in other infectious disease models. Interestingly, only γIP-10 mRNA was maintained at elevated levels throughout the first 7 days of infection, by mechanisms involving CD4⁺ and CD8⁺ T cells, and CD4⁻ CD8⁻ cells not activated in scid mice. By in vivo depletion and reconstitution of scid mice it was demonstrated that T cells regulate the expression of all three chemokines studied, while they themselves only produce γIP-10 in appreciable quantities.     

Modulation of pulmonary DC function by vaccine‐encoded GM‐CSF enhances protective immunity against Mycobacterium tuberculosis infection

The rational design of new vaccines engineered to target key components of the host immune response is crucial to aid control of important infectious diseases such as tuberculosis. In this report, we determined whether modifying the function of pulmonary APC could improve protection against infection with Mycobacterium tuberculosis. Targeted delivery to the lung of the cytokine GM‐CSF, expressed by the Mycobacterium bovis BCG vaccine strain, increased pulmonary DC numbers and secretion of the immunoregulatory cytokine IL‐12, compared with parental BCG immunization. This impact on APC number by BCG:GM‐CSF resulted in accelerated priming of antigen‐specific CD4⁺ T cells in the mediastinal lymph nodes and increased migration of activated CD4⁺ T cells into the lung. i.n. administration of BCG:GM‐CSF resulted in significantly increased protection against M. tuberculosis infection compared with mice vaccinated with BCG alone. BCG:GM‐CSF exhibited an improved safety profile, as immunodeficient RAG1^?/? mice vaccinated i.n. with BCG:GM‐CSF survived significantly longer than control BCG‐vaccinated mice. These data demonstrate that manipulating immune cells in the lung by BCG‐based delivery of GM‐CSF can assist the development of protective mucosal immunity against pulmonary bacterial infection.     

DNA vaccination of infants in the presence of maternal antibody: a measles model in the primate

To eradicate measles in developing nations a vaccine capable of being administered at birth may be necessary. We immunized newborn rhesus macaques with naked DNA encoding the measles virus hemagglutinin, fusion and nucleoprotein genes. Prior to vaccination we passively transferred measles immunoglobulin to mimic maternal antibody. In the presence or absence of measles immunoglobulin, 23 of 25 infant macaques had detectable cell mediated immunity and 16 had protective levels of neutralizing antibody. The co-administration of an IL-2/IgG plasmid augmented the vaccine, increasing cell mediated immunity in all infants and increasing the antibody response in infants vaccinated without immunoglobulin. We show for the first time that DNA vaccination can protect a newborn primate from the high-level viremia that correlates with severe measles, even in the presence of maternal antibody. Further, the addition of a molecular IL-2 adjuvant augments this DNA vaccine.     

The early cellular signatures of protective immunity induced by live viral vaccination

Here, we have used primary vaccination of healthy donors with attenuated live yellow fever virus 17D (YFV-17D) as a model to study the generation of protective immunity. In short intervals after vaccination, we analyzed the induction of YFV-17D specific T- and B-cell immunity, bystander activation, dendritic cell subsets, changes in serum cytokine levels, and YFV-17D-specific antibodies. We show activation of innate immunity and a concomitant decline of numbers of peripheral blood T and B cells. An early peak of antigen-specific T cells at day 2, followed by mobilization of innate immune cells, preceded the development of maximal adaptive immunity against YFV-17D at day 14 after vaccination. Interestingly, potent adaptive immunity as measured by high titers of neutralizing YFV-17D-specific antibodies, correlated with early activation and recruitment of YFV-17D-specific CD4(+) T cells and higher levels of sIL-6R. Thus our data might provide new insights into the interplay of innate and adaptive immunity for the induction of protective immunity.     

Human CD4 internal antigen anti-idiotypic monoclonal antibody. Immunochemical and sequence analysis

The mouse mAb2 16D7 recognizes the paratope of the syngeneic anti-human CD4 mAb HP2/6 (mAb1 of our idiotypic cascade) and mimics CD4 in xenogeneic settings in humans. Immunochemical and sequence analyses were performed to define the minimum structural requirement for this mimicry. Binding assay of mAb1 with isolated naive 16D7 H and L chains showed that only the second reacted with mAb1. Specificity was indicated by the lack of reactivity of mAb1 with the L chain of mAb2 14D6, which also recognizes mAb1-paratope. It is likely that the 16D7-L mAb1-specific epitope is “sequence-dependent”, since fully denatured 16D7-L still reacted with mAb1. Sequence analysis of 16D7 and mAb1 showed a high degree of homology of their VH, as both were coded by the same gene family (V/II), whereas CDR3 showed the greatest diversity. Alignment of 16D7-H CDR3 with CD4, however, produced no similarity. In contrast, analyses of the 16D7 VL sequence (XX/V) defined a CDR3 6-mer peptide with a 50% identity (83% of similarity) to the CD4 stretch 218–223. This peptide seems a suitable replacement for 16D7 in active immunotherapy as it did not match any protein fragment retrieved from the n-r database (NCBI) and both the peptide and the corresponding CD4 amino acid stretch are surface accessible. Based on their immunochemical profiles and similarity to CD4, four additional 16D7-derived peptides were designed for synthesis. The data indicate that CD4 mimicry by mAb2 can be obtained at the level of primary structure and provide useful information for the synthesis of peptide(s) with bioactive potential. Received: 17 October 2000 / Accepted: 23 May 2001     

抗戾饮对呼吸道冠状病毒感染雏鸡血清抗体生成的影响

目的:研究抗戾饮对呼吸道冠状病毒——传染性支气管炎病毒（IBV）感染雏鸡模型症状的改善情况，并评价抗戾饮对IBV抗体生成的影响。方法：7 d龄雏鸡接种IBV 并隔离在适度低温和高湿环境下饲养造模。从攻毒第1 d开始，分别灌胃给予模型组、空白对照组无菌生理盐水，治疗组给予抗戾饮水煎剂高中低剂量，阳性对照组给予更昔洛韦。实验时间为5 d。观察IBV感染模型临床症状。实验结束后，取肺与气管组织进行病理切片，并采用ELISA方法检测各组雏鸡血清中IBV抗体含量。结果：与模型组相比，抗戾饮组的血清IBV抗体的滴度升高明显（P<0.05），并能有效改善IBV模型的一般症状及肺与支气管组织的病理损伤。结论：抗戾饮可以有效提高模型血清中IBV抗体滴度，改善模型的症状，减轻组织病理损伤，增强IBV感染雏鸡的抗病毒能力。     

Vaccine-induced protection against gastrointestinal bacterial infections in the absence of secretory antibodies

Secretory IgA (SIgA) is widely held to be responsible for the defense of the mucosae against pathogenics and other potentially harmful agents. In this study, polymeric Ig receptor (pIgR) knockout mice, which lack secretory antibodies (SAb), were used to investigate the role of vaccine-elicited SAb in protection against gastrointestinal bacterial infections. An essential role for specific SAb in protection against Vibrio cholerae was evident from experiments showing that vaccinated pIgR(-/-) mice, but not vaccinated C57BL/6 mice, were susceptible to cholera toxin challenge. Vaccination of C57BL/6 mice with Salmonella typhimurium elicited strong antigen-specific, mucosal responses, which blocked in vitro invasion of epithelia. However, vaccinated C57BL/6 and pIgR(-/-) mice were equally resistant to challenge infection with virulent S. typhimurium. Finally, we investigated the importance of SIgA in protection against recurrent infections with Citrobacter rodentium. Although higher numbers of bacteria were detected early after challenge infection in feces of vaccinated pIgR(-/-) mice compared with vaccinated C57BL/6 mice, both mouse strains showed complete clearance after 9 days. These results suggested that, in immune animals, SIgA is crucial for the protection of gastrointestinal surfaces against secreted bacterial toxins, may inhibit early colonization by C. rodentium, but is not essential for protection against re-infection with S. typhimurium or C. rodentium.     

The woodchuck: A model for therapeutic vaccination against hepadnaviral infection

Interferon-α and nucleoside analogues are available for the treatment of chronic hepatitis B virus (HBV) infection but do not lead to a satisfactory result. New findings about the immunological control of HBV during acute infection suggest the pivotal role of T-cell mediated immune responses. Several preclinical and clinical trials were undertaken to explore the possibility of stimulating specific immune responses in chronically infected animals and patients by vaccination. However, vaccination with commercially available HBV vaccines in patients and immunization in woodchucks with core or surface proteins of woodchuck hepatitis virus (WHV) did not result in effective control of HBV and WHV infection, suggesting that new formulations of therapeutic vaccines are needed. Some new approaches combining antiviral treatments with nucleoside analogues, DNA vaccines and protein vaccines were tested in the woodchuck model. It could be shown that therapeutic vaccinations are able to stimulate specific B- and T-cell responses and to achieve transient suppression of viral replication. These results suggest the great potential of therapeutic vaccination in combination with antivirals to reach an effective and sustained control of HBV infection.     

Dendritic cell-based immunity and vaccination against hepatitis C virus infection

Hepatitis C virus (HCV) has chronically infected an estimated 170 million people worldwide. There are many impediments to the development of an effective vaccine for HCV infection. Dendritic cells (DC) remain the most important antigen-presenting cells for host immune responses, and are capable of either inducing productive immunity or maintaining the state of tolerance to self and non-self antigens. Researchers have recently explored the mechanisms by which DC function is regulated during HCV infection, leading to impaired antiviral T-cell responses and so to persistent viral infection. Recently, DC-based vaccines against HCV have been developed. This review summarizes the current understanding of DC function during HCV infection and explores the prospects of DC-based HCV vaccine. In particular, it describes the biology of DC, the phenotype of DC in HCV-infected patients, the effect of HCV on DC development and function, the studies on new DC-based vaccines against HCV infection, and strategies to improve the efficacy of DC-based vaccines.     

Threat of infection: microbes of high pathogenic potential--strategies for detection, control and eradication

Infectious diseases due to microbes of high pathogenic potential remain a constant and variable threat for human and animal health. The emergence of new diseases or the re-emergence of diseases that were previously under control complicates the situation to date. Infectious disease research, which has undergone a dramatic progress in understanding disease mechanisms such as host-pathogen interactions, is now focusing increasingly on new strategies for prevention and therapy. Significant progress has been achieved in the development of delivery systems for protective heterologous protein antigens and in veterinary vaccinology. A landmark of infectious diseases research is the chemical synthesis of genomes, a major new field of research referred to as "synthetic biology", that to date has resulted in the chemical synthesis of the poliovirus and of phage phiX174 genomes and their expression as infectious viruses. On the molecular level the evolution of pathogens and mechanisms of genome flexibility, which account for several pathogenic properties of infectious agents, have received increased attention. Bacterial toxins are an additional threat to human health and their interference with host cells and cellular functions is receiving more attention.     

Immunity against hepatitis E virus infection: Implications for therapy and vaccine development

Hepatitis E virus (HEV) is the leading cause of acute viral hepatitis worldwide and an emerging cause of chronic infection in immunocompromised patients. As with viral infections in general, immune responses are critical to determine the outcome of HEV infection. Accumulating studies in cell culture, animal models and patients have improved our understanding of HEV immunopathogenesis and informed the development of new antiviral therapies and effective vaccines. In this review, we discuss the recent progress on innate and adaptive immunity in HEV infection, and the implications for the devolopment of effective vaccines and immune‐based therapies.