This study investigated the specific immune response of BALB/c mice that was induced by a circular RNA (circRNA) vaccine expressing the herpes simplex virus type II (HSV-2) glycoprotein D (gD). The aim was to evaluate the immunological potential of this vaccine and lay a foundation for developing an mRNA vaccine against HSV-2. PCR and homologous recombination were employed to integrate the gD gene obtained from the pT7AMP-gD ectodomain plasmid into pUC57 to generate the recombinant plasmid pUC57-circ-gD, which was then sequenced and characterized. In vitro transcription and cyclization were performed on the template DNA to generate pUC57-circ-gD mRNA. To validate the formation of circular RNA, we cleaved the pUC57-circ-gD mRNA with RNase R and employed RT-PCR to validate the cyclization. The pUC57-circ-gD mRNA was then transfected into 293T cells. After 72 h, the cell supernatant was collected, and Western blotting was employed to measure the protein level of gD. Subsequently, the mRNA was encapsulated in lipid nanoparticles (LNPs) by microfluidic encapsulation. BALB/c mice were administrated with the encapsulated mRNA, and blood was collected from the fundus venous plexus after 21 and 35 days, and from the enucleated eyeballs after 49 days. Enzyme-linked immunosorbent assay was employed to measure the titers of antibodies, including virus-neutralizing antibodies. After 49 days, spleens were harvested and assessed for secretion of interferon-gamma (IFN-γ) by solid-phase enzyme-linked immunospot. The results showed successful construction and sequencing of the recombinant plasmid. RNase R digestion confirmed the presence of circular RNAs. Western blotting of the 293T cells transfected with the mRNA showed clear specific bands. The quality of the vaccine was tested by size exclusion chromatography-high performance liquid chromatography, which showed that the purity of the vaccine was about 90%. The mRNA-LNP showcased the particle size of 82.76 nm and an encapsulation rate of approximately 98%. Following three-dose vaccination, all immunized mice exhibited steady weight gain with 100% survival rate throughout the 28-day observation period, indicating no significant acute toxicity associated with the vaccine formulation. The immunized mice showed dose-dependent increases in serum IgG antibody titer and IFN-γ secretion by splenocytes and they were resistant to virus attacks. These findings indicate good immunogenicity and persistence of the pUC57-circ-gD mRNA vaccine, providing a reference for further studies on circRNA vaccines.
Animals ; Mice, Inbred BALB C ; RNA, Circular ; Mice ; Humans ; Herpesvirus 2, Human/genetics* ; Viral Envelope Proteins/genetics* ; Antibodies, Viral/blood* ; HEK293 Cells ; Female ; Nanoparticles ; Plasmids

This study aims to investigate the potential of oncolytic nanoparticles encapsulating Coxsackievirus A21 (CVA21) full-genome mRNA (CVA21@ONP) to resurrect CVA21 and induce apoptosis in host cells, as well as the antitumor immune effects of CVA21@ONP in immunocompetent tumor-bearing BALB/c mice. We used lipid nanoparticles (LNPs) to encapsulate CVA21 full-genome mRNA, thus preparing CVA21@ONP. The killing efficacy of CVA21@ONP was determined by the plaque assay and cell counting kit-8 (CCK-8), and the apoptosis in HT29 and CT26-iRFP cells was evaluated by flow cytometry. Mice were administrated with CVA21@ONP at high and low doses intratumorally, and the growth of tumors expressing infra-red fluorescent protein (iRFP) was monitored. Additionally, the types and changes of immune cells in the spleen were analyzed by flow cytometry. The results demonstrated that CVA21@ONP successfully resurrected CVA21 in both HT29 and U87MG cells. The plaque assay revealed robust killing effects of CVA21@ONP against both human and murine cell lines, and flow cytometry results showed increased early and late apoptotic cells. Notably, intratumoral detection revealed significantly down-regulated expression of iRFP in both high- and low-dose CVA21@ONP groups. Flow cytometry results further indicated that CVA21@ONP treatment effectively reduced the levels of immunosuppressive cells, including myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), in the spleen, while enhancing T cell-dependent antitumor immune responses. These findings suggest that CVA21@ONP can replicate and survive extensively both in vitro and in vivo, activating the immune system of mice administrated with CVA21@ONP to target cells at the tumor site, thereby remodeling the tumor immune microenvironment and accelerating the suppression or even complete regression of tumors. The oncolytic performance of CVA21@ONP has been verified through intratumoral injection administration in this study, aimed at further exploring its therapeutic potential and promoting the development of the field of tumor treatment.
Animals ; Nanoparticles/chemistry* ; Mice ; Mice, Inbred BALB C ; Humans ; Apoptosis ; Oncolytic Viruses/genetics* ; Oncolytic Virotherapy/methods* ; Cell Line, Tumor ; RNA, Messenger/genetics* ; HT29 Cells

The enterotoxigenic Escherichia coli (ETEC) infection is a major factor restricting the development of animal husbandry. However, the abuse of antibiotics will lead to the antibiotic residues and emergence of antibiotic-resistant bacteria. The existing vaccines face challenges in stimulating intestinal immunity, demonstrating limited prevention effects. Therefore, it is indispensable to develop a new vaccine that is safe and suitable as a feed additive to activate intestinal immunity. This study constructed yeast-cell microcapsules (YCM) carrying the DNA vaccine against ETEC by genetic engineering. Furthermore, animal experiments were carried out to explore the regulatory effects of feeding YCM on the intestinal immune system and intestinal microbiota. Saccharomyces cerevisiae was selected as the oral delivery vehicle (microcapsules) of the DNA vaccine. The codon-optimized nucleic acid sequence of K88, the main antigen of mammal-derived ETEC, was synthesized, and the yeast shuttle vector containing the corresponding DNA vaccine expression cassette was constructed by DNA recombination. The recombinant strain of YCM was prepared by transforming JMY1. Additionally, the characteristics of the YCM strain and its feasibility as an oral vaccine were comprehensively evaluated by the fluorescence reporter assay, gastrointestinal fluid tolerance assay, intestinal epithelial cell adhesion assay, intestinal retention assessment, antiserum detection, and intestinal microbiota detection. The experimental results showed that the DNA vaccine expression cassette was expressed in mammals, and the recombinant strain of YCM could tolerate up to 8 hours of gastrointestinal fluid digestion and had good adhesion to intestinal epithelial cells. The results of mouse feeding experiments indicated that the recombinant strain of YCM could stay in the intestinal tract for at least two weeks, and the DNA vaccine expression cassette carried by YCM entered the intestinal immune system and triggered an immune response to induce the production of specific antibodies. Moreover, feeding YCM recombinant bacteria also improved the abundance of gut microbiota in mice, demonstrating a positive effect in regulating intestinal flora. In summary, we prepared the recombinant strain of YCM carrying the DNA vaccine against ETEC and comprehensively evaluated its characteristics and feasibility as an oral vaccine. Feeding the recombinant YCM could induce specific immune responses and regulate intestinal microbiota. The findings provide a reference for the immunoprevention of ETEC-related animal diseases.
Animals ; Enterotoxigenic Escherichia coli/genetics* ; Saccharomyces cerevisiae/metabolism* ; Vaccines, DNA/genetics* ; Mice ; Escherichia coli Infections/immunology* ; Escherichia coli Vaccines/genetics* ; Capsules ; Mice, Inbred BALB C ; Female

Vaccination is a crucial strategy for the prevention and control of infectious diseases. Virus-like particles (VLPs), composed of structural proteins, have garnered significant attention as a novel type of vaccine due to their excellent safety and immunogenicity. However, similar to most vaccine antigens, VLPs exhibit insufficient thermal stability, which not only restricts the widespread application of vaccines but also increases the risk of vaccine inactivation. This study aims to enhance the stability and shelf life of VLPs derived from type A foot-and-mouth disease virus (FMDV) by employing vacuum freeze-drying technology. The optimal lyoprotectant formulation was determined through single-factor and combinatorial screening. Subsequently, the correlation between the immunogenicity of the freeze-dried vaccine and the content of FMDV VLPs was evaluated via a mouse model. The stability of FMDV VLPs before and after freeze-drying was further assessed by storing them at 4, 25, and 37 ℃ for varying time periods. Results indicated that the lyoprotectant formulation No.1, composed of 7.5% trehalose, 0.1% Tween 80, 50 mmol/L glycine, 1% sodium glutamate, and 3% polyvinylpyrrolidone (PVP), effectively preserved the content of FMDV VLPs during the vacuum freeze-drying process. The immunization trial in mice revealed that the levels of specific antibodies, immunoglobulin G1 (IgG1), interleukin-4 (IL-4), and neutralizing antibodies induced by freeze-dried FMDV VLPs were comparable to those induced by non-freeze-dried FMDV VLPs. The heat treatment results showed that the storage periods of freeze-dried FMDV VLPs at 4, 25, and 37 ℃ were significantly longer than those of non-freeze-dried FMDV VLPs. In conclusion, the selected lyoprotectant formulation effectively improved the stability of FMDV VLPs vaccines. This study provides valuable insights for enhancing the stability of novel subunit vaccines.
Freeze Drying/methods* ; Animals ; Foot-and-Mouth Disease Virus/immunology* ; Mice ; Vaccines, Virus-Like Particle/chemistry* ; Foot-and-Mouth Disease/immunology* ; Vacuum ; Drug Stability ; Mice, Inbred BALB C ; Viral Vaccines/immunology*

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*

Hemoglobin A1c (HbA1c) has a unique structure that makes monoclonal antibody (mAb) preparation challenging. This study aims to develop a method for preparing HbA1c mAbs and establish a fluorescent immunochromatographic assay (FICA) for rapid detection of HbA1c. Three glycosylated peptides were synthesized and used to prepare complete antigens, which were identified by dot enzyme-linked immunosorbent assay (Dot-ELISA) and ultraviolet absorption spectroscopy. The complete antigens and natural HbA1c were used for cross-immunization of mice, and the optimal complete antigen was selected. The mouse with the highest serum titer was chosen for mAb preparation. The purity and specificity of the mAbs were verified, and a FICA method was developed. The optimal complete antigen, with a titer of 1:512 000, was successfully prepared and selected. Fusion with splenocytes resulted in four specific HbA1c antibodies (purity > 90%). The best antibody exhibited a binding constant (Ka) of 1.67×10¹⁰ L/mol with the antigen. Based on this antibody, a FICA method was successfully established, capable of producing results within 15 min. The method demonstrated a good linear range (3%-13% HbA1c, y=0.071 3x+0.005 6, R²=0.993 7), recovery rates of 98%-102%, precision < 10.00%, and no nonspecific reactions. Clinical testing of 210 samples showed positive agreement of 96.36%, negative agreement of 97.00%, and overall agreement of 96.68%. The receiver operating characteristic (ROC) curve analysis yielded an area under curve (AUC) of 0.980 9 [95% confidence interval (CI): 0.961 0-1.000 0], with high consistency verified in multicenter studies. We successfully developed a key technique for preparing HbA1c monoclonal antibodies and established a FICA method for rapid detection of HbA1c. It will provide an efficient and convenient detection method for the early diagnosis and long-term management of diabetes and its complications.
Antibodies, Monoclonal/biosynthesis* ; Animals ; Mice ; Glycated Hemoglobin/immunology* ; Mice, Inbred BALB C ; Humans ; Antibody Specificity ; Chromatography, Affinity/methods* ; Enzyme-Linked Immunosorbent Assay/methods* ; Female

Human alphaherpesvirus 2 (HSV-2) is the main pathogen resulting human genital herpes, which poses a major threat to the socio-economic development, while there is no effective vaccine. In this study, we developed a novel lipopolyplex (LPP)-delivered mRNA vaccine expressing the HSV-2 envelope glycoprotein gD and evaluated its immunogenicity in mice. The mRNA vaccine was prepared from the genetically modified gD mRNA synthesized in vitro combined with the LPP delivery platform and it was named gD-ORI mRNA. The expression of gD antigen in the mRNA vaccine was validated in vitro by Western blotting and indirect immunofluorescence assay, then the immune responses induced by this mRNA vaccine in mice were evaluated. The immunization with gD mRNA alone induced strong humoral and cellular immune responses in mice. Robust and long-lasting gD-specific IgG antibodies were detected in the mouse serum after booster immunization with gD-ORI mRNA. The immunized mice exhibited a Th1/Th2 balanced IgG response and robust neutralizing antibodies against HSV-2, and a clear dose-response relationship was observed. The gD-specific IgG antibodies were maintained in mice for a long time, up to 18 weeks post-booster immunization. At the same time, multifunctional gD-specific CD4⁺ and CD8⁺ T cells in vaccinated mice were detected by intracellular cytokine staining (ICS). This novel gD-expressing mRNA vaccine delivered by LPP induces strong and long-lasting immune responses in mice post booster immunization and has a promising prospect for development and application. This study provides scientific evidence and reference for the development of a new mRNA vaccine for HSV-2.
Animals ; Herpesvirus 2, Human/genetics* ; Viral Envelope Proteins/genetics* ; Mice ; Herpes Genitalis/immunology* ; RNA, Messenger/immunology* ; Female ; Mice, Inbred BALB C ; Antibodies, Viral/blood* ; mRNA Vaccines/immunology* ; Antibodies, Neutralizing/blood* ; Humans

Objective To investigate the effect of the small molecule inhibitor C42 of kallikrein-related peptidase 7(KLK7)on ovarian cancer with elevated expression of KLK7 and evaluate the feasibility of C42 as a new therapeutic strategy for ovarian cancer.Methods The CCK-8 assay,flow cytometry,cell scratch assay,Transwell assay,and Western blotting were employed to assess the effects of C42 on the proliferation,migration,and invasion of the ovarian cancer cell line SKOV3,which was characterized by high KLK7 expression.Additionally,a subcutaneous xenograft model of ovarian cancer was established with SKOV3 cells in nude mice to evaluate the effects of C42 on the tumor growth and metastasis.The expression levels of proteins associated with tumor metastasis and invasion in the tumor tissue were examined by immunohistochemical techniques.Results The cellular experiment showed that C42 suppressed the proliferation,migration,and invasion(all P<0.001)of SKOV3 cells,compared with the control group.The animal experiment showed that compared with the control group,the 10.2 mg/kg C42 group exhibited a decreased tumor weight(P=0.009) and attenuated liver metastases.Immunohistochemical staining revealed that the 10.2 mg/kg C42 group demonstrated down-regulated expression of the tumor proliferation marker Ki-67(P=0.002)and the tumor metastasis and invasion-associated proteins such as matrix metalloproteinase-9(P=0.027)and Vimentin(P=0.039).Conclusion The small molecule inhibitor C42 of KLK7 effectively suppresses the proliferation,migration,and invasion of ovarian cancer SKOV3 cells.
Female ; Humans ; Ovarian Neoplasms/drug therapy* ; Kallikreins/antagonists & inhibitors* ; Animals ; Mice, Nude ; Cell Line, Tumor ; Cell Proliferation/drug effects* ; Mice ; Cell Movement/drug effects* ; Xenograft Model Antitumor Assays ; Mice, Inbred BALB C

OBJECTIVE: To investigate the effect of irradiation dose rate of ⁶⁰Co γ-ray on hematopoietic and immune cells in total body irradiation (TBI) mice. METHODS: After TBI with 8 Gy ⁶⁰Co γ-ray at three irradiation dose rates of 0.027, 0.256 and 0.597 Gy/min, the survival and change of body weight of C57BL/6J mice were observed within 30 days. The peripheral blood parameters were examined at each time point within 30 days post-irradiation. The hematopoietic stem/progenitor cell counts of mice were examined on the 10^th and 30^th day post-irradiation by flow cytometry, as well as the proportions of immune cells in peripheral blood, bone marrow and spleen of mice on the 30^th day post-irradiation. RESULTS: After TBI with 8 Gy ⁶⁰Co γ-ray, the 30-day survival rate of high dose-rate group was 0, which was significantly lower than 90% of medium dose-rate group and 100% of low dose-rate group (both P < 0.001). The peripheral blood parameters of all three groups showed a sharp decline → low value → gradually recovering trend. The count of white blood cell, neutrophil, lymphocyte, red blood cell, platelet and hemoglobin level in the high dose-rate and medium dose-rate groups were significantly lower than those in the low dose-rate group on day 7-18 post-irradiation (all P < 0.05), but there were no significant differences between the high dose-rate and medium dose-rate groups (P >0.05). On the 10^th day after irradiation, the proportion and number of bone marrow hematopoietic stem/progenitor cells (including LK, LSK, LT-HSC, ST-HSC, and MPP cells) in the low dose-rate and medium dose-rate groups were significantly decreased compared to those in the normal group (all P < 0.05), but there were no significant differences between the two groups (P >0.05). On the 30^th day after irradiation, LSK, LT-HSC, ST-HSC and MPP cells in the low dose-rate group recovered to normal levels, while those in the medium dose-rate group were still significantly lower than those in the low dose-rate group (all P < 0.001). The results of bone marrow and peripheral immune cell tests on the 30^th day after irradiation showed that the ratios of T and B lymphocytes in the low dose-rate and medium dose-rate groups were reduced compared to that in the normal group (both P < 0.05), while the ratio of neutrophils was increased (P < 0.01). The trend of changes in the spleen and peripheral blood was consistent. CONCLUSION The degree of hematopoietic and immune cell damage in mice after TBI with 8 Gy ⁶⁰Co γ-ray is related to the dose rate, and low dose-rate irradiation can reduce the damage in the animal model. Therefore, choosing the appropriate dose rate of irradiation is a key factor in establishing an objective and reliable experimental animal model of irradiation.
Animals ; Mice ; Whole-Body Irradiation ; Gamma Rays ; Mice, Inbred C57BL ; Hematopoietic Stem Cells/radiation effects* ; Cobalt Radioisotopes ; Dose-Response Relationship, Radiation ; Male

BACKGROUND: Motion sickness is a common transportation issue worldwide. Vestibular dysfunction has been reported to be a key etiology of motion sickness. However, there are limited technologies for alleviating motion sickness. METHODS: The most appropriate frequency (Hz) and level (dBZ) of pure tone for modulation of vestibular function were determined by an ex vivo study using murine utricle explants. The preventive effects of the selected pure tone on motion sickness were then confirmed by using a beam balance test in mice. The alleviating effects of pure tone on motion sickness induced by a swing, driving simulator or real car were objectively assessed by using posturography and electrocardiography (ECG) and were subjectively assessed by using the Motion Sickness Assessment Questionnaire (MSAQ) in humans. RESULTS: The effect of short-term (≤5 min) exposure to a pure tone of 80-85 dBZ (= 60.9-65.9 dBA) at 100 Hz on motion sickness was investigated in mice and humans. A mouse study showed a long-lasting (≥120 min) alleviative effect on shaking-mediated exacerbated beam test scores by 5-min exposure to a pure tone of 85 dBZ at 100 Hz, which was ex vivo determined as a sound activating vestibular function, before shaking. Human studies further showed that 1-min exposure to a pure tone of 80-85 dBZ (= 60.9-65.9 dBA) at 100 Hz before shaking improved the increased envelope areas in posturography caused by the shakings of a swing, a driving simulator and a vehicle. Driving simulator-mediated activation of sympathetic nerves assessed by the heart rate variable (HRV) and vehicle-mediated increased scores of the MSAQ were improved by pure tone exposure before the shaking. CONCLUSION: Since the exacerbated results of posturography and HRV reflect shaking-mediated imbalance and autonomic dysfunction, respectively, the results suggest that the imbalance and autonomic dysregulation in motion sickness could be improved by just 1-min exposure to a pure tone with daily exposable sound pressure levels. TRIAL REGISTRATION Registration number: UMIN000022413 (2016/05/23-2023/04/19) and UMIN000053735 (2024/02/29-present).
Motion Sickness/therapy* ; Animals ; Mice ; Humans ; Male ; Adult ; Female ; Sound ; Middle Aged ; Young Adult ; Mice, Inbred C57BL