In order to prepare human-mouse chimeric cytomegalovirus-immunoglobulin M (CMV-IgM) in vitro and study the effects of different signal peptides on the secretion of CMV-IgM, genes were amplified from hybridoma cell line using RLM-RACE to construct the expression vector of chimeric CMV-IgM. Then, the signal peptide of SigF itself was replaced by five different secreted signal peptides (SigA-SigE) by PCR method, and the CHO cell was chosen as host cell for in vitro expression. SDS-PAGE, SEC-HPLC and ELISA experiments were carried out to evaluate the protein expression level and immunoreactivity of the purified CMV-IgM. A 910 kDa recombinant protein was successfully prepared and signal peptides (SigA-SigE) had an increased expressed CMV-IgM, which were 6.72, 5.19, 1.44, 1.85 and 1.98 times higher than that of the CMV 6# cell signal peptide SigF. In summary, this work provides a theoretical basis for the development of human-mouse chimeric CMV-IgM, and a novel route to increase the expression level of CMV-IgM.
Animals ; Antibodies, Viral ; genetics ; immunology ; Cricetinae ; Cytomegalovirus ; immunology ; Enzyme-Linked Immunosorbent Assay ; Gene Expression ; Humans ; Immunoglobulin M ; immunology ; Mice ; Protein Sorting Signals ; Recombinant Fusion Proteins ; immunology

OBJECTIVE: To prepare the recombinant peptide MVF-HER3 I composed of the 183-227aa peptide segment of human epidermal growth factor receptor 3 (HER3 I) and the measles virus protein 288-302 peptide segment (MVF), and prepare polyclonal antibodies (PcAb) against this recombinant peptide. METHODS: The MVF-HER3 I gene was synthesized chemically and subcloned into pET21b or pET32a plasmid containing Thioredoxin (Trx) tag gene. The recombinant plasmids were identified by endonuclease digestion. MVF-HER3 I was expressed in BL21(DE3) cells under an optimal bacterial expression condition. The fusion protein Trx-MVF-HER3 I was purified using nickel ion affinity chromatography, and the purified protein was digested by enterokinase to remove Trx tag. The digested mixture underwent further nickel ion affinity chromatography to obtain purified MVF-HER3 I. The purified MVF-HER3 I was used to immunize SD rats subcutaneously for preparing anti-MVF-HER3 I PcAb. The titer of PcAb was determined using ELISA. The bindings of anti-MVF-HER3 I PcAb to MVF-HER3 I, native HER3 and MCF7 cells were analyzed using immunoblotting, immunoprecipitation and laser confocal microscopy. The growth inhibition effect of the antibodies on MCF7 cells cultured in the absence or presence of NRG was assessed using sulforhodamine B. RESULTS: The recombinant peptide gene could not be expressed alone, but could be efficiently expressed after fusion with Trx gene under optimized conditions. The fusion peptide MVF-HER3 I was successfully prepared from Trx-MVF-HER3 I. The anti-MVF-HER3 I PcAb, with a titer reaching 1: 512 000, specifically bound to MVF-HER3 I, recognized native HER3 and bound to the membrane of MCF7 cells. The obtained PcAb could dose-dependently inhibit the growth of MCF7 cells irrespective of the presence or absence of NRG. CONCLUSIONS We successfully obtained the recombinant peptide MVF-HER3 I and prepared its PcAb, which can facilitate further functional analysis of HER3 signaling pathway.
Animals ; Antibodies ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; Humans ; Plasmids ; Rats ; Rats, Sprague-Dawley ; Receptor, ErbB-3 ; immunology ; Recombinant Fusion Proteins

OBJECTIVE: To evaluate the effect of intranasal immunization with CTA1-DD as mucosal adjuvant combined with H3N2 split vaccine. METHODS: Mice were immunized intranasally with PBS (negative control), or H3N2 split vaccine (3 μg/mouse) alone, or CTA1-DD (5 μg/mouse) alone, or H3N2 split vaccine (3 μg/mouse) plus CTA1-DD (5 μg/mouse). Positive control mice were immunized intramuscularly with H3N2 split vaccine (3 μg/mouse) and alum adjuvant. All the mice were immunized twice, two weeks apart. Then sera and mucosal lavages were collected. The specific HI titers, IgM, IgG, IgA, and IgG subtypes were examined by ELISA. IFN-γ and IL-4 were test by ELISpot. In addition, two weeks after the last immunization, surivival after H3N2 virus lethal challenge was measured. RESULTS: H3N2 split vaccine formulated with CTA1-DD could elicit higher IgM, IgG and hemagglutination inhibition titers in sera. Furthermore, using CTA1-DD as adjuvant significantly improved mucosal secretory IgA titers in bronchoalveolar lavages and vaginal lavages. Meanwhile this mucosal adjuvant could enhance Th-1-type responses and induce protective hemagglutination inhibition titers. Notably, the addition of CTA1-DD to split vaccine provided 100% protection against lethal infection by the H3N2 virus. CONCLUSION CTA1-DD could promote mucosal, humoral and cell-mediated immune responses, which supports the further development of CTA1-DD as a mucosal adjuvant for mucosal vaccines.
Adjuvants, Immunologic ; Administration, Intranasal ; Animals ; Cholera Toxin ; Female ; Immunity, Humoral ; Influenza A Virus, H3N2 Subtype ; immunology ; Influenza Vaccines ; Mice, Inbred BALB C ; Nasal Mucosa ; immunology ; Random Allocation ; Recombinant Fusion Proteins

OBJECTIVETo eliminate the side effects of aluminum adjuvant and His-tag, we constructed chimeric VLPs displaying the epitope of EV71 (SP70) without His-tagged. Then evaluating whether the VLPs could efficiently evoke not only humoral but also cellular immune responses against EV71 without adjuvant.

METHODSThe fusion protein was constructed by inserting SP70 into the MIR of truncated HBcAg sequence, expressed in E. Coli, and purified through ion exchange chromatography and density gradient centrifugation. Mice were immunized with the VLPs and sera were collected afterwards. The specific antibody titers, IgG subtypes and neutralizing efficacy were detected by ELISA, neutralization assay, and EV71 lethal challenge. IFN-γ and IL-4 secreted by splenocytes were tested by ELISPOT assay.

RESULTSHBc-SP70 proteins can self-assemble into empty VLPs. After immunization with HBc-SP70 VLPs, the detectable anti-EV71 antibodies were effective in neutralizing EV71 and protected newborn mice from EV71 lethal challenge. There was no significant difference for the immune efficacy whether the aluminum adjuvant was added or not. The specific IgG subtypes were mainly IgG1 and IgG2b and splenocytes from the mice immunized produced high levels of IFN-γ and IL-4.

CONCLUSIONThe fusion proteins without His-tagged was expressed and purified as soluble chimeric HBc-SP70 VLPs without renaturation. In the absence of adjuvant, they were efficient to elicit high levels of Th1/Th2 mixed immune response as well as assisted by aluminum adjuvant. Furthermore, the chimeric VLPs have potential to prevent HBV and EV71 infection simultaneously.

Adjuvants, Immunologic ; Animals ; Antibodies, Neutralizing ; Antibodies, Viral ; blood ; Enterovirus A, Human ; genetics ; Enterovirus Infections ; immunology ; virology ; Epitopes ; immunology ; metabolism ; Escherichia coli ; metabolism ; Female ; Immunity, Cellular ; Immunity, Humoral ; Mice ; Recombinant Fusion Proteins ; immunology

Acinetobacter baumannii (A. Baumannii) is an emerging opportunistic pathogen responsible for hospital-acquired infections, and which now constitutes a sufficiently serious threat to public health to necessitate the development of an effective vaccine. In this study, a recombinant fused protein named OmpK/Omp22 and two individual proteins OmpK and Omp22 were obtained using recombinant expression and Ni-affinity purification. Groups of BALB/c mice were immunized with these proteins and challenged with a clinically isolated strain of A. baumannii. The bacterial load in the blood, pathological changes in the lung tissue and survival rates after challenge were evaluated. Mice immunized with OmpK/Omp22 fused protein provided significantly greater protection against A. baumannii challenge than those immunized with either of the two proteins individually. The results provide novel clues for future design of vaccines against A. baumannii.
Acinetobacter Infections ; pathology ; prevention & control ; Acinetobacter baumannii ; genetics ; immunology ; Animals ; Antibodies, Bacterial ; blood ; Bacterial Load ; Bacterial Outer Membrane Proteins ; genetics ; immunology ; Bacterial Vaccines ; immunology ; Disease Models, Animal ; Female ; Mice, Inbred BALB C ; Pneumonia, Bacterial ; pathology ; prevention & control ; Recombinant Fusion Proteins ; genetics ; immunology

OBJECTIVETo observe the effects of recombinant fusion protein interleukin (IL)-18 on the expression of immune-inflammatory factors in the mice infected with Staphylococcus aureus (SA), and to investigate the mechanism of action of IL-18 in defense of SA infection in vivo.

METHODSA total of 40 specific pathogen-free female BLAB/c mice were randomly divided into four groups: control, SA infection, immunized, and intervention. A mouse model of SA infection was established by nasal inoculation with SA liquid. The immunized group and the intervention group were intranasally given IL-18 before SA modeling, and then the SA infection group and the intervention group received the nasal inoculation with SA liquid; the control group was treated with phosphate buffered saline instead. The levels of IL-4, interferon (IFN)-γ, tumor necrosis factor (TNF), granulocyte colony-stimulating factor (G-CSF), IgM in the serum and bronchoalveolar lavage fluid (BALF) of mice were measured by enzyme-linked immunosorbent assay. The expression of macrophage inflammatory protein (MIP)-1α mRNA and MIP-2β mRNA in the lung tissue of mice were determined by real-time fluorescent quantitative PCR.

RESULTSCompared with the control group, the SA infection group and the immunized group had significantly higher levels of IL-4, G-CSF, and IgM in the serum and BALF and expression of MIP-1α mRNA and MIP-2β mRNA in the lung tissue (P<0.05); the SA infection group had a significantly lower level of IFN-γ and a significantly higher level of TNF in the serum and BALF (P<0.05); the immunized group had a significantly higher level of IFN-γ in the serum and BALF (P<0.05). Compared with the SA infection group, the intervention group had significantly higher levels of IL-4, IFN-γ, G-CSF, and IgM in the serum and BALF and expression of MIP-1α mRNA in the lung tissue. In contrast, the intervention group showed a significantly lower level of TNF in the serum and BALF and expression of MIP-2β mRNA in the lung tissue (P<0.05). All the above indicators in the intervention group were significantly higher than those in the control group (P<0.05), except the serum level of IFN-γ.

CONCLUSIONSIn the mice infected with SA, the recombinant fusion protein IL-18 by mucosal immunity can affect inflammatory factors in the serum and BALF and the expression of MIP-1α mRNA and MIP-2β mRNA in the lung tissue to promote the anti-infective immune response and enhance the ability to clear pathogens.

Animals ; Chemokine CCL3 ; analysis ; Female ; Granulocyte Colony-Stimulating Factor ; blood ; Interferon-gamma ; blood ; Interleukin-18 ; therapeutic use ; Interleukin-4 ; blood ; Mice ; Mice, Inbred BALB C ; Recombinant Fusion Proteins ; pharmacology ; therapeutic use ; Staphylococcal Infections ; drug therapy ; immunology

Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells contribute to the body's immune defenses. Current chimeric antigen receptor (CAR)-modified T cell immunotherapy shows strong promise for treating various cancers and infectious diseases. Although CAR-modified NK cell immunotherapy is rapidly gaining attention, its clinical applications are mainly focused on preclinical investigations using the NK92 cell line. Despite recent advances in CAR-modified T cell immunotherapy, cost and severe toxicity have hindered its widespread use. To alleviate these disadvantages of CAR-modified T cell immunotherapy, additional cytotoxic cell-mediated immunotherapies are urgently needed. The unique biology of NK cells allows them to serve as a safe, effective, alternative immunotherapeutic strategy to CAR-modified T cells in the clinic. While the fundamental mechanisms underlying the cytotoxicity and side effects of CAR-modified T and NK cell immunotherapies remain poorly understood, the formation of the immunological synapse (IS) between CAR-modified T or NK cells and their susceptible target cells is known to be essential. The role of the IS in CAR T and NK cell immunotherapies will allow scientists to harness the power of CAR-modified T and NK cells to treat cancer and infectious diseases. In this review, we highlight the potential applications of CAR-modified NK cells to treat cancer and human immunodeficiency virus (HIV), and discuss the challenges and possible future directions of CAR-modified NK cell immunotherapy, as well as the importance of understanding the molecular mechanisms of CAR-modified T cell- or NK cell-mediated cytotoxicity and side effects, with a focus on the CAR-modified NK cell IS.
Animals ; HIV Infections ; immunology ; therapy ; HIV-1 ; immunology ; Humans ; Immunity, Cellular ; Immunological Synapses ; Immunotherapy ; Killer Cells, Natural ; transplantation ; Neoplasms ; immunology ; therapy ; Receptors, Antigen, T-Cell ; genetics ; immunology ; Recombinant Fusion Proteins ; genetics ; immunology ; T-Lymphocytes ; immunology ; transplantation

Chimeric antigen receptor (CAR) is a recombinant immunoreceptor combining an antibody-derived targeting fragment with signaling domains capable of activating cells, which endows T cells with the ability to recognize tumor-associated surface antigens independent of the expression of major histocompatibility complex (MHC) molecules. Recent early-phase clinical trials of CAR-modified T (CAR-T) cells for relapsed or refractory B cell malignancies have demonstrated promising results (that is, anti-CD19 CAR-T in B cell acute lymphoblastic leukemia (B-ALL)). Given this success, broadening the clinical experience of CAR-T cell therapy beyond hematological malignancies has been actively investigated. Here we discuss the basic design of CAR and review the clinical results from the studies of CAR-T cells in B cell leukemia and lymphoma, and several solid tumors. We additionally discuss the major challenges in the further development and strategies for increasing anti-tumor activity and safety, as well as for successful commercial translation.
Animals ; Humans ; Immunity, Cellular ; Immunotherapy ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ; immunology ; pathology ; therapy ; Receptors, Antigen, T-Cell ; immunology ; Recombinant Fusion Proteins ; immunology ; T-Lymphocytes ; immunology ; transplantation

Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.
Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; chemistry ; genetics ; metabolism ; Binding Sites ; Cell Line ; Crystallography, X-Ray ; Enterovirus A, Human ; drug effects ; genetics ; growth & development ; immunology ; Fibroblasts ; drug effects ; virology ; Gene Expression ; HEK293 Cells ; Humans ; Immunoglobulin Fab Fragments ; chemistry ; genetics ; metabolism ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; immunology ; Mice ; Models, Molecular ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Receptors, Scavenger ; chemistry ; genetics ; immunology ; Receptors, Virus ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Sequence Alignment ; Sequence Homology, Amino Acid ; Sf9 Cells ; Spodoptera ; Thermodynamics

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (CRISPR/Cas9) system, an RNA-guided DNA targeting technology, is triggering a revolution in the field of biology. CRISPR/Cas9 has demonstrated great potential for genetic manipulation. In this review, we discuss the current development of CRISPR/Cas9 technologies for therapeutic applications, especially chimeric antigen receptor (CAR) T cell-based adoptive immunotherapy. Different methods used to facilitate efficient CRISPR delivery and gene editing in T cells are compared. The potential of genetic manipulation using CRISPR/Cas9 system to generate universal CAR T cells and potent T cells that are resistant to exhaustion and inhibition is explored. We also address the safety concerns associated with the use of CRISPR/Cas9 gene editing and provide potential solutions and future directions of CRISPR application in the field of CAR T cell immunotherapy. As an integration-free gene insertion method, CRISPR/Cas9 holds great promise as an efficient gene knock-in platform. Given the tremendous progress that has been made in the past few years, we believe that the CRISPR/Cas9 technology holds immense promise for advancing immunotherapy.
Animals ; Clustered Regularly Interspaced Short Palindromic Repeats ; immunology ; Gene Editing ; methods ; Humans ; Immunotherapy ; methods ; Receptors, Antigen, T-Cell ; genetics ; immunology ; Recombinant Fusion Proteins ; genetics ; immunology