Bio-mineralization has emerged as a promising strategy to enhance vaccine immunogenicity. This study optimized the calcium phosphate (CaP) mineralization process of foot-and-mouth disease virus-like particles (FMD VLPs) to achieve high mineralization efficiency and scalability. Key parameters, including concentrations of Ca²⁺, HPO₄^2-, NaCl, and VLPs, as well as stirring speed, were systematically optimized. Stability of the scaled-up reaction system and immunogenicity of the mineralized vaccine were evaluated. Optimal conditions [25.50 mmol/L Ca(NO₃)₂, 15 mmol/L Na₂HPO₄, 300 mmol/L NaCl, 0.75 mg/mL VLPs, and 1 500 r/min] yielded CaP-mineralized VLPs (VLPs-CaP) with high mineralization efficiency, uniform morphology, and a favorable particle size. Scaling up the reaction by 25 folds maintained consistent mineralization efficiency and particle characteristics. Immunization in mice demonstrated that VLPs-CaP induced higher titers of specific antibodies and neutralizing antibodies than unmineralized VLPs (P < 0.05). Higher IgG2a/IgG1 ratio and enhanced IFN-γ secretion (P < 0.05) further indicated robust cellular immune responses. We establish a stable and scalable protocol for VLPs-CaP, providing a theoretical and technical foundation for developing high-efficacy VLPs-CaP vaccines.
Vaccines, Virus-Like Particle/immunology* ; Immunogenicity, Vaccine ; Calcium Phosphates/chemistry* ; Foot-and-Mouth Disease Virus ; Biomineralization ; Particle Size ; Animals ; Mice ; Antibodies, Neutralizing/blood* ; Antibodies, Viral/blood* ; Immunity, Cellular

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*

To further enhance the immune effect of the foot-and-mouth disease (FMD) virus-like particles (VLPs) vaccine, this study prepared FMDV VLPs-zeolitic imidazolate (framework-8, ZIF-8) complexes with different particle sizes. We used a biomimetic mineralization method with Zn²⁺ and 2-methylimidazole in different concentration ratios to investigate the effect of size on the immunization effect. The results showed that FMDV VLPs-ZIF-8 with three different sizes were successfully prepared, with an approximate size of 70 nm, 100 nm, and 1 000 nm, respectively. Cytotoxicity and animal toxicity tests showed that all three complexes exhibited excellent biological safety. Immunization tests in mice showed that all three complexes enhanced the titers of neutralizing and specific antibodies, and their immune effects improved as the size of the complexes decreased. This study showed that ZIF-8 encapsulation of FMDV VLPs significantly enhanced their immunogenic effect in a size-dependent manner.
Animals ; Mice ; Foot-and-Mouth Disease/prevention & control* ; Foot-and-Mouth Disease Virus ; Antibodies, Neutralizing ; Immunity, Humoral ; Immunization ; Vaccines, Virus-Like Particle ; Antibodies, Viral ; Viral Vaccines

OBJECTIVE: To evaluate the application of surgical strategies for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) involving the C ₂ segment. METHODS: The literature about the surgery for cervical OPLL involving C ₂ segment was reviewed, and the indications, advantages, and disadvantages of surgery were summarized. RESULTS: For cervical OPLL involving the C ₂ segments, laminectomy is suitable for patients with OPLL involving multiple segments, often combined with screw fixation, and has the advantages of adequate decompression and restoration of cervical curvature, with the disadvantages of loss of cervical fixed segmental mobility. Canal-expansive laminoplasty is suitable for patients with positive K-line and has the advantages of simple operation and preservation of cervical segmental mobility, and the disadvantages include progression of ossification, axial symptoms, and fracture of the portal axis. Dome-like laminoplasty is suitable for patients without kyphosis/cervical instability and with negative R-line, and can reduce the occurrence of axial symptoms, with the disadvantage of limited decompression. The Shelter technique is suitable for patients with single/double segments and canal encroachment >50% and allows for direct decompression, but is technically demanding and involves risk of dural tear and nerve injury. Double-dome laminoplasty is suitable for patients without kyphosis/cervical instability. Its advantages are the reduction of damage to the cervical semispinal muscles and attachment points and maintenance of cervical curvature, but there is progress in postoperative ossification. CONCLUSION OPLL involving the C ₂ segment is a complex subtype of cervical OPLL, which is mainly treated through posterior surgery. However, the degree of spinal cord floatation is limited, and with the progress of ossification, the long-term effectiveness is poor. More research is needed to address the etiology of OPLL and to establish a systematic treatment strategy for cervical OPLL involving the C ₂ segment.
Humans ; Longitudinal Ligaments/surgery* ; Ossification of Posterior Longitudinal Ligament/surgery* ; Treatment Outcome ; Osteogenesis ; Decompression, Surgical/methods* ; Cervical Vertebrae/surgery* ; Laminoplasty/methods* ; Kyphosis/surgery* ; Retrospective Studies