Objective To establish a sandwich enzyme-linked immunosorbent assay (ELISA) method for the quantitative detection of Chromogranin A (CHGA) in saliva, and to explore its preliminary application in the testing of saliva samples. Methods Recombinant human CHGA protein was used to immunize BALB/c mice, and monoclonal antibodies (mAbs) were prepared and screened using conventional hybridoma technology. A double-antibody sandwich ELISA detection method was constructed, and the matrix effect of saliva samples was optimized. This method was then applied to detect the concentration of CHGA in the saliva of stressed individuals. Results Twenty-one stable hybridoma cell lines secreting high affinity anti-human CHGA antibodies were obtained. A pair of detection antibodies with the best effect was selected, and the optimal coating concentration was determined to be 10 μg/mL, with the optimal dilution of detection antibodies being 1:32 000. The accuracy and reproducibility of this method were verified, with both intra-batch and inter-batch variation coefficients less than 15×, and the recovery rate between 80× and 120×. The matrix effect was further optimized to make it suitable for saliva sample detection. Saliva samples from individuals in different stress states were collected, and the CHGA levels were detected using the method established in this study, indicating its potential to reflect the intensity of stress. Conclusion A reliable saliva CHGA ELISA detection method has been successfully established, and its potential as a biomarker in stress-related research has been preliminarily explored.
Saliva/metabolism* ; Enzyme-Linked Immunosorbent Assay/methods* ; Humans ; Animals ; Mice, Inbred BALB C ; Mice ; Chromogranin A/immunology* ; Antibodies, Monoclonal/immunology* ; Female ; Male ; Reproducibility of Results ; Adult

Objective To investigate the effects of LBL-007, a novel fully human lymphocyte activation gene 3 (LAG-3) monoclonal antibody, in combination with programmed cell death protein 1 (PD-1) antibody, on the invasion, migration and proliferation of tumor cells, and to elucidate the underlying mechanisms. Methods Human lymphocyte cells Jurkat were co-cultured with A549 and MGC803 tumor cell lines and treated with the isotype control antibody human IgG, LBL-007, anti-PD-1 antibody BE0188, or tumor necrosis factor-alpha (TNF-α, the NF-κB signaling pathway agonist). Tumor cell proliferation was assessed using a colony formation assay; invasion was measured by Transwell^TM assay; migration was evaluated using a wound healing assay. Western blotting was employed to determine the expression levels of NF-κB pathway-related proteins: IκB inhibitor kinase alpha (Ikkα), phosphorylated Ikkα (p-IKKα), NF-κB subunit p65, phosphorylated p65 (p-p65), NF-κB Inhibitor Alpha (IκBα), phosphorylated IκBα (p-IκBα), matrix metalloproteinase 9 (MMP9), and MMP2. Results Compared with the control and IgG isotype groups, LBL-007 and BE0188 significantly reduced tumor cell proliferation, invasion, and migration. They also decreased the phosphorylation of p-IKKα, p-p65 and p-IκBα, and the expression of MMP9 and MMP2 of tumor cells in the co-culture system. The combined treatment of LBL-007 and BE0188 enhanced inhibitory effects. Treatment with the NF-κB signaling pathway agonist TNF-α reversed the suppressive effects of LBL-007 and BE0188 on tumor cell proliferation, invasion, migration, and NF-κB signaling. Conclusion LBL-007 and anti-PD-1 antibody synergistically inhibit the invasion, migration, and proliferation of A549 and MGC803 tumor cells by blocking the NF-κB signaling pathway.
Humans ; Cell Proliferation/drug effects* ; Cell Movement/drug effects* ; Signal Transduction/drug effects* ; NF-kappa B/metabolism* ; Neoplasm Invasiveness ; Antibodies, Monoclonal/pharmacology* ; Programmed Cell Death 1 Receptor/antagonists & inhibitors* ; Cell Line, Tumor ; Antigens, CD/immunology* ; Lymphocyte Activation Gene 3 Protein ; A549 Cells ; I-kappa B Kinase/metabolism* ; Jurkat Cells ; Matrix Metalloproteinase 9/metabolism*

Objective To investigate prokaryotic expression of the antigen sequence (amino acids 59-145) of mouse leukemia-related protein 16 (LRP16) protein and preparation of rabbit anti-mouse LRP16 polyclonal antibody. Methods The prokaryotic expression plasmid pLS962-LRP16 was constructed by the molecular cloning method and transferred into E.coli Rosetta to express LRP16 protein induced by IPTG. The recombinant protein was purified using Ni-NTA affinity columns followed by gel filtration chromatography. New Zealand white rabbits were immunized with the purified antigen to generate polyclonal antiserum, with antibody titer quantified by ELISA. Antigen-specific IgG was affinity-purified using Sepharose-coupled LRP16 and validated through Western blot and immunofluorescence assays. Results SDS-PAGE analysis confirmed insoluble expression of the LRP16 fusion protein as inclusion bodies. ELISA demonstrated exceptional antiserum titer (1:256 000). Western blot and immunofluorescence verified that the polyclonal antibody could specifically recognize endogenous LRP16 in murine tissues. Conclusion The prokaryotic expression of the LRP16 gene is successfully achieved, and the rabbit anti-mouse LRP16 polyclonal antibody exhibiting high specificity is prepared. This lays the foundation for further studies on the function of the LRP16 gene.
Animals ; Rabbits ; Mice ; Antibodies/immunology* ; Escherichia coli/metabolism* ; Enzyme-Linked Immunosorbent Assay ; Blotting, Western ; Antibody Specificity

Objective The study aims to investigate the immunological functions of the nucleocapsid (N) protein of the novel coronavirus Omicron (BA.1, BA.2) and evaluate the differences among different N proteins of mutant strains in immunogenicity. Methods By aligning sequences, the mutation sites of the Omicron (BA.1, BA.2) N protein relative to prototype strain of the novel coronavirus (Wuhan-Hu-1) were determined. The pET-28a-N-Wuhan-Hu-1 plasmid was used as template to construct pET-28a-BA.1/BA.2-N through single point mutation or homologous recombination. The three kinds of N protein were expressed in prokaryotic system, purified through Ni-NTA affinity chromatography, and then immunized into mice. The titer and reactivity of the polyclonal antibody, as well as the expression level of IL-1β and IFN-γ in mouse spleen cells, were detected using indirect ELISA and Western blot assay. Results The constructed prokaryotic expression plasmids were successfully used to express the Wuhan-Hu-1 N, BA.1 N, and BA.2 N proteins in E.coli BL21(DE3) at 37 DegreesCelsius for 4 hours. The indirect ELISA test showed that the titers of polyclonal antibody prepared by three N proteins were all 1:51 200. All three N proteins can increase the expression of IFN-γ and IL-1β cytokines, but the effect of Omicron N protein in activing two cytokines was more obvious than that of Wuhan-Hu-1 N protein. Conclusion The study obtained three new coronavirus N proteins and polyclonal antibodies, and confirmed that mutations in the amino acid sites of the N protein can affect its immunogenicity. This provides a basis for developing rapid diagnostic methods targeting N protein of different novel coronavirus variants.
Animals ; Mice ; SARS-CoV-2/genetics* ; Coronavirus Nucleocapsid Proteins/immunology* ; Nucleocapsid Proteins/isolation & purification* ; COVID-19/immunology* ; Antibodies, Viral/immunology* ; Mice, Inbred BALB C ; Interferon-gamma/metabolism* ; Interleukin-1beta/metabolism* ; Female ; Escherichia coli/metabolism* ; Mutation ; Humans

OBJECTIVES: To explore the role of C1q, the promoter of the classical pathway of the complement system, in regulating postpartum depressive-like behaviors in mice and the therapeutic mechanism of C1q-neutralizing antibodies. METHODS: Female C57BL/6 mouse models of postpartum depression established by hormone-simulated pregnancy (HSP) were evaluated for depression-like behaviors, and peripheral blood levels and hippocampal expressions of C1q were detected using ELISA and Western blotting. Immunofluorescence staining was used for detecting co-labeling of C1q and microglia, and the differentially expressed mRNAs in the hippocampus of HSP mice were analyzed using RNA sequencing. The Edinburgh Postnatal Depression Scale was used to screen patients with postpartum depression, from whom peripheral blood mononuclear cells were extracted for detecting C1q expression levels with Western blotting. The HSP mice were subjected to stereotactic injection of C1q-neutralizing antibody or a control IgG in the hippocampus, and the changes in depressive-like behaviors and hippocampal expression of C3 were examined. RESULTS: The HSP mice exhibited obvious depressive behaviors, demonstrated by significantly decreased preference for sugar water and increased forced swimming and tail suspension time. The mouse models showed significantly increased peripheral blood C1q level and hippocampal expression level of C1q, accompanied by an increase in Iba1 and C1q co-labeling in the hippocampus. The expression level of C1q in peripheral monocytes was also significantly increased in patients with postpartum depression. In HSP mice, stereotactic injection of C1q-neutralizing antibody, but not the control IgG, obviously alleviated depressive-like behaviors, shown by significantly increased preference for sugar water and decreased forced swimming and tail suspension time, resulting also in decreased expression of C3 in the hippocampus and lowered serum levels of IL-6 and TNF-α. CONCLUSIONS C1q-neutralizing antibodies improve postpartum depressive-like behaviors in mice possibly by regulating the C1q/C3 signaling pathway.
Animals ; Female ; Depression, Postpartum ; Complement C1q/metabolism* ; Antibodies, Neutralizing/pharmacology* ; Mice, Inbred C57BL ; Mice ; Hippocampus/metabolism* ; Pregnancy ; Disease Models, Animal

Neutralizing antibodies have been designed to specifically target and bind to the receptor binding domain (RBD) of spike (S) protein to block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus from attaching to angiotensin converting enzyme 2 (ACE2). This study reports a distinctive nanobody, designated as VHH21, that directly catalyzes the S-trimer into an irreversible transition state through postfusion conformational changes. Derived from camels immunized with multiple antigens, a set of nanobodies with high affinity for the S1 protein displays abilities to neutralize pseudovirion infections with a broad resistance to variants of concern of SARS-CoV-2, including SARS-CoV and BatRaTG13. Importantly, a super-resolution screening and analysis platform based on visual fluorescence probes was designed and applied to monitor single proteins and protein subunits. A spontaneously occurring dimeric form of VHH21 was obtained to rapidly destroy the S-trimer. Structural analysis via cryogenic electron microscopy revealed that VHH21 targets specific conserved epitopes on the S protein, distinct from the ACE2 binding site on the RBD, which destabilizes the fusion process. This research highlights the potential of VHH21 as an abzyme-like nanobody (nanoabzyme) possessing broad-spectrum binding capabilities and highly effective anti-viral properties and offers a promising strategy for combating coronavirus outbreaks.
Single-Domain Antibodies/immunology* ; Spike Glycoprotein, Coronavirus/metabolism* ; SARS-CoV-2/immunology* ; Animals ; Humans ; Antibodies, Neutralizing/immunology* ; Camelus ; COVID-19/immunology* ; Antibodies, Viral/immunology* ; Angiotensin-Converting Enzyme 2

To prepare antibodies that specifically recognize the conserved domain in the large extracellular loop of the CD63 protein, we expressed anti-CD63 single-chain variable fragment (scFv) antibody in Pichia pastoris in a secreted form. The purified expression product was found to bind specifically with CD63 protein and recognize CD63 on the surface of SK-MEL-28 cells. The variable region of the anti-CD63 monoclonal antibody in an anti-CD63-positive cell line was sequenced. The anti-CD63 scFv consisted of a variable heavy chain and a variable light chain linked by a flexible peptide was then designed. After codon optimization, the gene was synthesized and cloned into the expression plasmid pPICZα-A. The SacI-linearized plasmid was electroporated into P. pastoris X33, and 1% methanol were used to induce the expression of scFv. The fermentation supernatant was purified by Ni column. Anti-CD63 scFv was identified by SDS-PAGE and Western blotting, and its biological activities were analyzed by immunoblotting, immunofluorescence, cell-based ELISA, and flow cytometry. A P. pastoris strain capable of expressing and secreting anti-CD63 scFv was successfully obtained. The antibody had a molecular weight of approximately 30 kDa and specifically recognized CD63 protein. The expression of anti-CD63 scFv in P. pastoris paves the way for the production of anti-CD63 antibodies on a large-scale, which is undoubtedly an economical and effective way of antibody acquisition.
Single-Chain Antibodies/immunology* ; Humans ; Tetraspanin 30/immunology* ; Recombinant Proteins/immunology* ; Pichia/genetics* ; Saccharomycetales/metabolism*

Pseudorabies (PR) is an infectious disease caused by the pseudorabies virus (PRV), affecting various domesticated and wild animals. Since pigs are the only natural hosts of PRV, PR poses a serious threat to the pig farming industry. Currently, PR is primarily prevented through vaccination with inactivated vaccines or genetically modified attenuated live vaccines. Developing safe and effective genetically engineered vaccines would facilitate the eradication and control of PR. In this study, the PRV vaccine strain Bartha-K61 was used as the reference strain. The gB protein was expressed via the baculovirus-insect cell expression system. Non-denaturing gel electrophoresis confirmed that the gB protein could form a trimeric structure. The purified gB protein was used to immunize mice, and the immune effect was evaluated by a challenge test. The results showed that the gB antigen induced a strong immune response in mice, with the serum-neutralizing antibody titer above 1:70. The lymphocyte stimulation index reached more than 1.29, and the level of (interferon gamma, IFN-γ) release was higher than 100 pg/mL. After immunization, mice were challenged with the virus at a dose of 10⁴ TCID₅₀/mL, 200 μL per mouse, and the clinical protection rate was 100%. Immunohistochemistry, histopathological section, and tissue viral load results showed that the pathological damage and viral load in the gB-immunized group were significantly lower than those in the PBS group. In summary, the gB protein obtained in this study induced strong humoral and cellular immune responses in mice, laying a foundation for developing a recombinant gB protein subunit vaccine.
Animals ; Mice ; Baculoviridae/metabolism* ; Viral Envelope Proteins/biosynthesis* ; Herpesvirus 1, Suid/genetics* ; Pseudorabies/immunology* ; Swine ; Pseudorabies Vaccines/genetics* ; Antibodies, Viral/blood* ; Insecta/cytology* ; Mice, Inbred BALB C ; Female ; Viral Vaccines/immunology*

OBJECTIVE: To stratify systemic lupus erythematosus (SLE) patients clinically, to analyze the clinical characteristics of patients with and without disease activity, and to explore the application va-lue of key clinical indicators in assessing disease activity, as well as to construct an evaluation model. METHODS: A retrospective analysis was conducted on clinical data of the SLE patients diagnosed at Peking University People' s Hospital from May 1995 to April 2014. Demographic information, clinical manifestations, laboratory tests, and antibody detection results were collected. The patients were divided into active and inactive groups based on systemic lupus erythematosus disease activity index 2000(SLEDAI-2000)scores. t-tests, Mann-Whitney U tests, and χ² tests were used to compare the differences between the groups. Spearman correlation analysis was used to evaluate the relevant clinical indicators associated with SLE activity in the active disease group. Based on the results of statistical analysis, a Logistic regression model was constructed, and the performance of the model was evaluated. RESULTS: No significant differences were found in demographic characteristics between the two groups. In the active disease group, positive rates of antinuclear antibodies (ANA) and anti-double-stranded DNA antibodies (anti-dsDNA) were increased; white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HGB), lymphocytes (LY), total protein (TP), albumin (ALB), and complement 3(C3) levels were significantly decreased; while immunoglobulin A and G levels were markedly elevated. The correlation analysis results showed that hemoglobin, albumin, C3, and complement 4(C4) had higher correlation indices compared with other clinical indicators. Among these, C3 exhibited a certain negative correlation with disease activity. The Logistic regression model based on 12 significantly different indicators (P < 0.05) achieved an accuracy of 91.4%, sensitivity of 94.4%, specificity of 81.0%, and the area under curve (AUC) of the receiver operating characteristic (ROC) was 0.944. CONCLUSION This study comprehensively evaluated a range of clinical indicators related to SLE disease activity, providing a thorough understanding of both laboratory and clinical markers. The Logistic regression model, which was primarily constructed using laboratory test indicators, such as inflammatory markers, immune response parameters, and organ involvement metrics, demonstrated a high degree of accuracy in assessing the disease activity in SLE patients. Consequently, this model might provide a new basis for the diagnosis and treatment of SLE patients, offering significant clinical diagnostic value.
Humans ; Lupus Erythematosus, Systemic/diagnosis* ; Retrospective Studies ; Antibodies, Antinuclear/blood* ; Complement C3/metabolism* ; Complement C4/metabolism* ; Logistic Models ; Severity of Illness Index ; Leukocyte Count ; Female ; Male ; Serum Albumin/analysis*

This study developed ferritin-based nanoparticles carrying the African swine fever virus (ASFV) p30 protein and evaluated their immunogenicity, aiming to provide an experimental basis for the research on nanoparticle vaccines against ASFV. Initially, the gene sequences encoding the p30 protein and SpyTag were fused and inserted into the pCold-I vector to create the pCold-p30 plasmid. The gene sequences encoding SpyCatcher and ferritin were fused and then inserted into the pET-28a(+) vector to produce the pET-F-np plasmid. Both plasmids were expressed in Escherichia coli upon induction. Subsequently, the affinity chromatography-purified p30 protein was conjugated with ferritin in vitro, and the p30-ferritin (F-p30) nanoparticles were purified by size-exclusion chromatography. The morphology and structural integrity of F-p30 nanoparticles were examined by a particle size analyzer and transmission electron microscopy. Mice were immunized with F-p30 nanoparticles, and the humoral and cellular immune responses were assessed. The results showed that F-p30 nanoparticles were successfully prepared, with the particle size of approximately 20 nm. F-p30 nanoparticles were efficiently internalized by bone marrow-derived dendritic cells (BMDCs) cells in vitro. Compared with the p30 protein alone, F-p30 nanoparticles induced elevated levels of specific antibodies and cytokines in mice and stimulated the proliferation of follicular helper T cell (T_FH) and germinal center B cell (GCB) in lymph nodes as well as CD4⁺ and CD8⁺ T cells in the spleen. In conclusion, we successfully prepared F-p30 nanoparticles which significantly enhanced the immunogenicity of p30 protein, giving insights into the development of vaccines against ASFV.
Animals ; Nanoparticles/chemistry* ; Mice ; African Swine Fever Virus/genetics* ; Ferritins/chemistry* ; Swine ; Viral Vaccines/genetics* ; African Swine Fever/immunology* ; Mice, Inbred BALB C ; Viral Proteins/genetics* ; Escherichia coli/metabolism* ; Dendritic Cells/immunology* ; Immunogenicity, Vaccine ; Antibodies, Viral/blood* ; Female ; Capsid Proteins/genetics*