Immunogenicity Research Articles

Physicochemical and immunological characterization of two forms of recombinant norovirus GII.4 virus-like particles assembled in Hansenula polymorpha

Objective To investigate the physicochemical properties and immunogenicity of virus like particles(VLPs) in two different conformations assembled from the essential capsid protein VP1 of GⅡ.4 norovirus (NoV) in Hansenula polymorpha. Methods NoV GⅡ.4 VLPs in two different conformations were prepared from high-density fermentation of recombinant engineered strains and VLPs purification. Physicochemical properties of the two forms of VLPs were identified by Western blot, size-exclusion high performance liquid chromatography (SEC-HPLC), dynamic light scattering(DLS) and transmission electron microscopy. Serum VLPs binding activities and blocking activities against VLPs binding to histo-blood group antigen(HBGA-VLPs) were evaluated after immunization of BALB/c mice with the two forms of VLPs. Results VLPs of two different diameters with high homogeneity were obtained after purification. DLS results showed that particle sizes of two VLPs were 53.98 nm and 45.18 nm, respectively. The two VLPs were similar in binding abilities to HBGA receptors. Serum VLPs binding activities and blocking activities against HBGA-VLPs were found higher in NoV-VLP-L than NoV-VLP-S, but the difference was not statistically significant (P>0.05). Conclusion VLPs in two different conformations were obtained by expressing NoV GⅡ.4 VP1 proteins in Hansenula polymorpha. Though they were similar in physicochemical properties and immunogenicity, the NoV-VLP-L might be potential antigen candidates for the development of recombinant human norovirus vaccine. Key words: Norovirus; Virus-like particles; Histo-blood group antigen; Receptor binding assay

Novel Vaccines against Streptococcus p neumoniae Based on the Immunoprotective B-cell Epitope Region of Pneumococcal Choline Binding Protein D and Salmonella Enteritidis Flagellin

Pneumococcal conjugate vaccines (PCVs) were constructed through chemical conjugation of pneumococcal capsules to immunogenic carrier proteins. The PCVs implementation in developing countries was prevented by their high manufacturing costs. This issue can be overcome by development of protein based vaccines against pneumococci. Antibody responses are necessary for protection against S. pneumoniae. Choline binding protein D (CBPD) was already identified as a pneumococcal surface protein able to elicit protection against S. pneumoniae and its most protective B-cell epitope region (MIBR) was determined. MIBR was highly conserved in common pneumococcal serotypes. Whole antigens are not as potent as epitope based vaccines and B-cell epitope based vaccines are more effective than whole antigen based vaccines in the prevention of infections. Bacterial flagellins are effective adjuvants that signal via Toll like receptor 5 (TLR5). The TLR5 binding site of flagellin located in the D1 domain and its proper conformation is critical for TLR5 recognition of flagellin. In the present study, therefore, we aim to design effective chimeric vaccines against pneumococci based on MIBR and flagellin of Salmonella Enteritidis (FliC) using bioinformatics tools. FliC was joined to MIBR at N-terminus (CFH), C-terminus (FCH) and the D3 domain (D3Gly202, D3Thr275). All of the constructs were immunoprotective regarding the VaxiJen score (0.8). The codon optimization for constructs was done using OPTIMIZER. Analysis of the mRNA secondary structures using Mfold tool revealed no stable hairpins at 5' ends of constructs and thus the antigens can be expressed appropriately. SCRATCH results indicated that the antigens can be expressed in the soluble form in Escherichia coli at more than 80% probability. The 3D models of antigens resulted from I-TASSER indicated the presence of alpha helix, beta sheet, turn, coil, and 310 helix as the protein structural elements. Superimposing 3D models of D1 domains of antigens with the D1 domain of FliC using FATCAT indicated no change in the D1 conformation. Therefore, FliC can exert its adjuvant effects in these constructs through TLR5 signaling. Inserting MIBR in Gly202 of FliC enhanced the protein beta sheet content remarkably, which can result in appropriate thermostability of the antigen. Our results, therefore, demonstrated that D3Gly202 is a suitable vaccine candidate, which can elicit protection against common S. pneumoniae serotypes causing invasive pneumococcal disease in children less than 5 years of age.

Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP): a novel vaccine adjuvant

Aluminum salts are the most popular adjuvants applied in human vaccines currently. However, they can′t achieve satisfying results in the development of novel vaccines because of the cellular immune responses induced by them are weak and their adjuvant activities for some novel vaccines are poor, especially in vaccination against peptide antigens with small molecular weight. cGAMP (cyclic guanosine monophosphate-adenosine monophosphate) has recently been known as a mammalian second messenger, which plays an important role in the innate immune signaling pathway and is capable of boosting the immunogenicity of vaccines, activating antigen-presenting cells and enhancing specific T cell responses. cGAMP is expected to become a new generation of vaccine adjuvants against infectious diseases and cancer. In this review, we summarize the application and current situation of vaccine adjuvants, describe the discovery of cGAMP and its mechanism as a vaccine adjuvant, and focus on the advances in using cGAMP in the fields of vaccination against infectious diseases, intradermal immunization and tumor immunotherapy. Finally, it is also pointed out that cGAMP, as a novel vaccine adjuvant, will have a broad prospect of application in areas such as anti-tumor, anti-virus, anti-inflammatory and vaccines. Key words: cGAMP; Vaccine; Adjuvant

Bone marrow stromal cells as a therapeutic treatment for cerebral ischemic

Bone marrow stromal cells (BMSCs) are a kind of stem cells with multiple differentiation potential in bone marrow. BMSCs have been widely used in tissue engineering, cell transplantation, gene therapy and organ transplantation, due to their characteristics of wide range of sources, weak immunogenicity weak, easily transfected by exogenous gene, long survival time in the host, multi-directional differentiation, etc. Cerebral ischemia is caused by neurological impairment, which is the most common cause of death and quality-of-life impairments. The clinical manifestations of the patients with cerebral ischemia are motor function failure, sensory dysfunction and abnormal mental consciousness. A large number of studies have reported that BMSCs transplantation has the therapeutic effects of body sensory and motor function recovery, and can treat ischemic stroke. BMSCs transplantation has brought new hope for the clinical treatment of ischemic cerebrovascular disease. In this paper, the recent progress in the study of BMSCs transplantation for ischemic stroke was reviewed. The mechanism, pathways, influencing factors and clinical application of BMSCs transplantation were summarized. Key words: Bone marrow stromal cell; Transplantation; Cerebral ischemia

A Randomized, Double-Blind, Multicenter Study to Compare the Efficacy, Safety, and Immunogenicity of a Proposed Adalimumab Biosimilar (GP2017) with Originator Adalimumab in Patients with Moderate-to-Severe Chronic Plaque Psoriasis

Abstract Not Available

The efficacy of immune checkpoint inhibitor for bladder cancer and the management of immune-related adverse events

Bladder cancer remains a highly immunogenic and refractory malignant tumor today. Cancer immunotherapy is coming of age; it has prompted a paradigm shift in oncology treatment, in which therapeutic agents are used to target immune cells rather than cancer cells. Immunotherapy blocking immune checkpoints have been recently been applied to many aggressive cancers and changed interventions of urological cancers including advanced bladder cancer. The inhibition of PD-1/PD-L1 interactions can restore antitumor T-cell activity and enhance the cellular immune attack on antigens. The overall goals of this review are to introduce current cancer immunotherapy and immune checkpoint inhibitors, and to determine whether bladder cancer patients could benefit from this new cancer therapy through analyzing data in clinical trials. Furthermore, this review will also discuss the diagnosis and management of immune-related adverse events (irAEs), which deserve particular attention due to impact on the outcome of patients receiving these therapies. Key words: Bladder cancer; Immune checkpoint inhibitor; Immunotherapy; Programmed cell death 1(PD-1)/ programmed cell death ligation 1(PD-L1) inhibitor

Construction of weak immunogenicity virus vector with super antigen staphylococcal enterotoxin A gene

Objective To construct a weak immunogenicity lentiviral vector expressing the staphylococcal enterotoxin A (SEA) gene in order to exert a potent antitumor effect on activated T cells. Methods The human telomerase reverse transcriptase (hTERT)-CMV promoter sequence of 851 bp and the SEA gene of 774 bp were obtained by polymerase chain reaction (PCR). The target genes were constructed into lentiviral vector plasmids. After sequencing, they were transferred into DH5α competent cells and amplified. Viral supernatants were collected by co-transfection of 293FT cells with shuttle plasmids and packaging plasmids, and virus titer was determined by fluorescence titer. Different concentrations of virus supernatant were transfected into BIU-87 cell line. The target gene was sequenced and the expression of SEA gene was detected by Western blotting. Results The size of the vector was 10 458 bp, and the gene sequence was correct. No obvious mutation was found. The titer of the virus titer was (4.30±2.00)×109 TU/ml. PCR product sequencing of the target gene confirmed that the target gene was correct, the total RNA were 742、803、726 mg/L respectively by spectrophotometric assay. Western blotting revealed that SEA gene was successfully expressed. Conclusion The weak immunogenicity virus carrying the superantigen SEA gene was successfully constructed. Key words: Lentivirus; Staphylococcal enterotoxin A; Tumor; Super antigen

Expression, purification, characterization and immunogenicity of human immunodeficiency virus-1 glycoprotein gp120 derived from insect cells

Objective To establish an efficient baculovirus-insect cell expression system for the production of human immunodeficiency virus-1 (HIV-1) envelope glycoprotein gp120 and to evaluate the physiochemical properties, antigenicity and immunogenicity of the recombinant protein. Methods The gene encoding HIV-1 NL4-3 gp120 was cloned into the downstream of pH promoter of the baculovirus transfer vector pAcgp67B to construct the recombinant transfer vector pAc-gp120. Expression of the protein of interest was induced in baculovirus-infected High Five™ insect cells. ELISA, analytical ultracentrifugation and size-exclusion chromatography were carried out to characterize physicochemical properties of the expressed gp120 protein. Immunogenicity of the recombinant gp120 protein was analyzed by HIV neutralization assay after immunizing BALB/c mice with it. Results The recombinant HIV-1 gp120 protein was successfully obtained from the established insect cell expression system with a purity of more than 90% and a mean yield of 13 mg/L in four batches. That recombinant HIV-1 gp120 protein was characterized by homogeneity in solution and possessed a good immunoreactivity to neutralizing antibodies and antisera against HIV. Immunogenicity analysis in BALB/c mice demonstrated that the recombinant gp120 protein could induce effective immune responses against HIV-1 NL4-3. Conclusion A simple and scalable approach to obtain homogeneous and immunogenic HIV-1 gp120 antigen is successfully established, which will promote further investigation of HIV vaccine candidates. Key words: Human immunodeficiency virus-1; Insect cell expression system; Glycoprotein; gp120; Immune response

The Effect of Various Stabilizers on Preserving Immunogenicity of Lyophilized Mumps Vaccines.

Chemical stabilizers are added to live attenuated vaccines for enhancing the virus stability. The aim of this study was to evaluate the effect of various stabilizers on preserving immunogenicity of lyophilized mumps vaccines. An experimental study. Three mumps vaccines with different formulations were inoculated to three groups of Guinea pigs. Sterile water was injected to eight Guinea pigs as a control group. Blood samples were collected before inoculation and on 14, 28 and 42 d after vaccine injection. Mumps antibodies in the sera were measured using hemagglutination inhibition assay (HAI). All three formulated mumps vaccines induced antibody in Guinea pigs after two weeks. Formulation 1 containing trehalose dihydrate and formulation 2 comprised human serum albumin stimulated antibodies in the higher level than Razi routine formulation. Various stabilizers have different preservation potencies that differently affect immune response against virus. More stable and more immunogenic vaccines can be produced using stabilizers containing trehalose dihydrate.

Research progress on nanoparticles as delivery systems for cancer immunotherapy

In recent years, cancer immunotherapy has developed rapidly due to its significant advantages compared with the traditional cancer treatment methods. Tumor immunotherapy aims at mobilizing or stimulating the body's own immune function, thereby inhibiting and killing cancer cells. With the development of nanotechnology, biological nano-carrier materials provide a new insight into the vaccine development. Nano-vaccines are therapeutic or prophylactic vaccines based on nanotechnology including exogenous antigens for inducing immune responses, vectors delivering antigens, and adjuvants for enhancing immunogenicity and accelerating and prolonging the availability of cancer vaccines. Nano-delivery vectors have good biocompatibility as well as unique physical and chemical properties. They can effectively deliver the antigens, and further activated the immune response of antigen-specific cellulars based on the activation of the body's humoral immunity by regulating the presentation pathways in the antigen-presenting cells. In this paper, the applications of nano-delivery systems in cancer vaccine research were summarized. Key words: Cancer; Immunotherapy; Vaccine; Nanoparticles delivery system

Research progress of the cell microencapsulation

Cell microencapsulation aims to wrap the living target cells by one or several materials with good biological compatibility and semipermeable membrane properties. Cell microencapsulation not only can achieve immune isolation and prevent the attacks by macromolecular immunes and immune cells, but also can allow the free access of metabolites, small molecule nutrients and bioactive substances to the microcapsule. With the continuous progress of interdisciplinary technologies, cell microencapsulation shows increasing application prospects of making up a variety of limitations of organ transplantation. Moreover, with the development and maturation of cell microencapsulation, it has shown a strong advantage in regenerative medicine, which will certainly promote the rapid development of artificial cells and artificial organs. In this paper, the preparation of cell microcapsules, the effects of the outer membrane of microcapsules on immunological macromolecules and cytokines, the immunogenicity of the outer membrane, and the representative applications of cell microencapsulation were summarized. Key words: Cell microencapsulation; Immune isolation; Cytokines; Organ transplantation

On the feasibility of mining CD8+ T cell receptor patterns underlying immunogenic peptide recognition.

Current T cell epitope prediction tools are a valuable resource in designing targeted immunogenicity experiments. They typically focus on, and are able to, accurately predict peptide binding and presentation by major histocompatibility complex (MHC) molecules on the surface of antigen-presenting cells. However, recognition of the peptide-MHC complex by a T cell receptor (TCR) is often not included in these tools. We developed a classification approach based on random forest classifiers to predict recognition of a peptide by a T cell receptor and discover patterns that contribute to recognition. We considered two approaches to solve this problem: (1) distinguishing between two sets of TCRs that each bind to a known peptide and (2) retrieving TCRs that bind to a given peptide from a large pool of TCRs. Evaluation of the models on two HIV-1, B*08-restricted epitopes reveals good performance and hints towards structural CDR3 features that can determine peptide immunogenicity. These results are of particular importance as they show that prediction of T cell epitope and T cell epitope recognition based on sequence data is a feasible approach. In addition, the validity of our models not only serves as a proof of concept for the prediction of immunogenic T cell epitopes but also paves the way for more general and high-performing models.

A review of Brucellosis in Iran: Epidemiology, Risk Factors, Diagnosis, Control, and Prevention

Brucellosis caused by species of Brucella is among the most prevalent zoonoses with the annual incidence of half a million cases globally. Most parts of Iran are endemic for brucellosis, and the annual incidence of the human and animal brucellosis is still high. At present, there is no safe and protective human vaccine against brucellosis, and the only preventive strategy is animal vaccination, which harbors significant disadvantages. Considering the identification of many immunogenic proteins in Brucella, several studies have recently been performed to evaluate the vaccine potency of such antigens as a new subunit vaccine candidate. This review represents an overview of brucellosis in Iran, including epidemiology, transmission routs, diagnosis, and treatment. Moreover, it mainly highlights the history of brucellosis control and prevention in Iran, including eradication programs, vast livestock vaccination programs, and subunit vaccine studies. It also discusses major problems that the country encounters with disease control. In recent years, Persian scientists have focused on evaluating the efficacy of best Brucella immunogens in vivo to introduce a new subunit vaccine. The results of some studies could demonstrate the vaccine potential of some immunogens.

Human umbilical cord mesenchymal stem cell′s transplantation for the treatment of neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic-ischemic encephalopathy(HIE)is a common disease in neonatal nervous system injury, which often treated by the traditional measures such as three support′s and three symptomatic treatments.Moreover, there is no specific treatment nowadays.The human umbilical cord mesenchymal stem cells(HUC-MSC)are mixture of multifunctional stem cells from neonatal umbilical cord tissues, which has strong abilities of self-renewal and multilineage differentiation potential.HUC-MSC are easy to harvest and have more sources, low immunogenicity and without ethical problems.It can differentiate into neural cells under certain conditions, secrete neurotrophic factors, repair the damaged brain and promote the recovery of cerebral function.Transplantation of HUC-MSC provides a new way for the treatment of HIE. Key words: Human umbilical cord mesenchymal stem cell; Newborn; Hypoxic-ischemic encephalopathy; Transplantation

Recombinant Expression of Antigen Epitope Genes of Human Cytomegalovirus and Immunogenicity Detection of the Fusion Protein

Recombinant Expression of Antigen Epitope Genes of Human Cytomegalovirus and Immunogenicity Detection of the Fusion Protein

Advances of human papillomavirus therapeutic vaccine

Human papillomavirus continuous (HPV) infection is an essential factor to induce cervical intraepithelial neoplasia and cervical cancer. Treating HPV infection is considered as a starting point to develop an effective therapeutic vaccine, which is a new strategy for prevention and treatment of cervical cancer. In recent years, development and trials of therapeutic HPV vaccine have made great progress. Selection of vectors, utilization of adjuvants, synthesis of fusion proteins and chimeric proteins have been widely applied to research to enhance vaccine immunogenicity, to increase vaccination safety, to reduce the side effect and so on. The clinical trial results are encouraging: various types of vaccines can induce a specific immune response with good tolerance. However, numerous studies are still required to obtain further success. In addition, HPV exists in various forms, thus it is also the focus of study to expand the range of action and reduce immune escape. Key words: Papillomavirus vaccine; Uterine cervical neoplasms

The role of the tumor microenvironment in bladder cancer development and progression

Urothelial cell carcinoma (UCC) of the bladder comprises a mixture of heterogeneous tumor cell populations, the surrounding stroma (which is populated by different types of mesenchymal cells), and the extracellular matrix (ECM). Bladder cancer (BC) has certain characteristics that distinguish it from other cancers. First, BCs are categorized into two groups: non-muscle invasive BC (NMIBC) and muscle invasive BC (MIBC). The overall survival rate of patients with NMIBC is excellent compared with that of patients with other malignancies; however, some patients have a high risk of recurrence and a variable risk of progression despite administration of local therapies. The oft-cited “50% overall survival at 5 years” for MIBC has remained relatively unchanged over the last 20 years. Second, BC is a highly immunogenic cancer that shows a high rate of mutation due to the fact that more mutations are associated with a higher chance of tumor antigens triggering an appropriate immune response. The host immune response to tumor cells is based on the interactions that take place within the tumor microenvironment (TME). Intravesical bacillus Calmette-Guerin (BCG) therapy is the first U.S. Food and Drug Administration (FDA)-approved immunotherapy for BC and is the most successful immunotherapy for any established human neoplasm. Recently, the FDA approved the use of atezolizumab (Tecentriq ® ) and nivolumab (Opdivo ® ), which mimic programmed cell death ligand-1 inhibitor, to treat patients with locally advanced or metastatic UCC. Combination therapies involving cytotoxic chemotherapy, antiangiogenic agents, alternative immune checkpoint inhibitors, immunostimulatory cytokines, and cancer vaccines are currently under clinical investigation. This review summarizes recent studies of tumor-stromal crosstalk during pathogenesis of UCC of the bladder, and discusses the emerging roles of functionally important cellular components that interact within the cancer cell-TME. In addition, TME-targeted anticancer strategies such as chemotherapy, chemo-immunotherapy, and immunotherapy are briefly reviewed.

Establishment of rabbit model for immunogenicity evaluation of pneumococcal conjugate vaccine

Objective To establish an animal model for evaluating immunogenicity of pneumococcal conjugate vaccine. Methods New Zealand rabbits were intramuscularly administrated with three doses of 13-valent pneumococcal conjugate vaccine (PCV13) with two weeks interval between each injection. Serum samples were collected at different time points before and after vaccination. Quantitative enzyme-linked immunosorbent assay (ELISA) and opsonophagocytosis assay (OPA) that were in conformity with the World Health Organization (WHO) standards were used to detect the concentrations of serotype-specific antibodies and their bactericidal activities. Results The concentrations (Geometric mean concentration, GMC) of serotype-specific antibodies in rabbit serum samples were well correlated with their bactericidal activities (Geometric mean titer, GMT) following vaccination. Moreover, the dynamic changes of GMC and GMT of the same serotype-specific antibody remained consistent as time went by. Conclusion Rabbit model can be used to analyze the immunogenicity of PCV13 vaccine with quantitative ELISA and OPA, which indicates that it is a suitable animal model for evaluating immunogenicity of pneumococcal conjugate vaccine. Key words: Rabbit model; Enzyme-linked immunosorbent assay (ELISA); Opsonophagocytosis assay (OPA); Immunogenicity; 13-valent pneumococcal conjugate vaccine (PCV13)

Chemotherapy and tumor immunogenic cell death

Chemotherapy resist is the problem for clinic, and some researches find that chemotherapy with anthracycline and oxaliplatin not only induces the tumor cell apoptosis, but also the cell immunogenic cell death (ICD) by inducing the tumor cell apoptosis and releasing three kinds of signals: exposure of calreticulin on the cell surface to stimulate the dendritic cell (DC) to engulf, and the secretion of adenosine triphosphate to recruit DC to enter into tumor bed, and the release of the high mobility group B1 to promote DC to steadily bind with dying tumor cell to induce specific T cell antitumor immune response. It is with great meaning to promote the chemotherapy protocol by studying the ICD induced by chemotherapy. Key words: Drug therapy; T-cell antigen receptor specificity; Dendritic cells; Calreticulin; Immunogenic cell death

Research progress in vaccine adjuvant CpG ODN

CpG ODN, a synthetic oligodeoxynucleotide containing CpG motifs, is a TLR9 agonist as it could be recognized by Toll-like receptor 9 (TLR9) expressed on the membranes of B cells, dendritic cells, monocytes and macrophages. CpG ODN is the kind of vaccine adjuvant that promotes Th1 immune responses and enhances the immunogenicity of vaccines with high safety, showing promising prospects in the prevention and treatment of infections, tumors and allergic diseases. This review mainly focuses on the introduction, classification and structure features, immune mechanism, safety and clinical application of CpG ODN as vaccine adjuvant in order to provide references for further researches and application of CpG ODN as immune adjuvant. Key words: Immune adjuvant; CpG ODN; Vaccine; Immune response