Bovine viral diarrhea virus (BVDV) is an important animal pathogen that affects cattle. Infections caused by the virus have resulted in substantial economic losses and outbreaks of BVDV are reported globally. Virus-like particles (VLPs) are promising vaccine technology largely due to their safety and strong ability to elicit robust immune responses. In this study, we developed a strategy to generate BVDV-VLPs using a baculovirus expression vector system (BEVS). We were able to assemble BVDV-VLPs composed of dimerized viral proteins E2 and E^rns, and the VLPs were spherical particles with the diameters of about 50 nm. Mice immunized with 15 μg of VLPs adjuvanted with ISA201 elicited higher levels of E2-specific IgG, IgG1, and IgG2a antibodies as well as higher BVDV-neutralizing activity in comparison with controls. Re-stimulation of the splenocytes collected from mice immunized with VLPs led to significantly increased levels of CD3⁺CD4⁺T cells and CD3⁺CD8⁺T cells. In addition, the splenocytes showed dramatically enhanced proliferation and the secretion of Th1-associated IFN-γ and Th2-associated IL-4 compared to that of the unstimulated control group. Taken together, our data indicate that BVDV-VLPs efficiently induced BVDV-specific humoral and cellular immune responses in mice, showing a promising potential of developing BVDV-VLP-based vaccines for the prevention of BVDV infections.

Egg quality and nutritional value are becoming increasingly important to consumers, offering a new direction for the development of high-quality eggs. In this study, we conducted a comprehensive analysis of egg quality and nutrient profiles in native breeds at different ages, integrating pedigree data. Our results reveal dynamic changes in egg qualities, stronger associations among eggshell-related traits, and the effect of onset production and body weight on egg qualities. The heritability of different traits was estimated, ranging from 0.05 to 0.62. Subsequently, we elucidated that the moisture and nutritional content in the egg yolk were not influenced by the percentage of yolk but were indeed subject to age regulation. There was a notable decrease in moisture, an elevation in crude fat, and an increase in the diversity of fatty acids of yolk with advancing age. In summary, investigating the trends and interrelationships in egg quality, nutrient content, and heritability across the whole laying cycle offers valuable insights for breeders to optimize feeding management strategies and aids consumers in meeting their expectations of egg quality.

The Madin–Darby bovine kidney (MDBK) cell line is currently used for the production of bovine alphaherpesvirus-1 (BoHV-1) vaccine. For the purpose of vaccine manufacturing, suspension cells are preferred over adherent ones due to simplified sub-cultivation and an easier scale-up process, both of which could significantly reduce production cost. This study aimed to establish a procedure for the culture of BoHV-1 in the suspended MDBK cell line in serum-free medium. We screened several commercially available serum-free media and chose ST503 for subsequent experiments. We successfully adapted the adherent MDBK cells to suspended growth in ST503 in the absence of serum. The maximum density of suspension-adapted MDBK cells could reach 2.5 × 10⁷ cells/mL in ST503 medium with optimal conditions. The average size of suspension-adapted cells increased to 18 ± 1 µm from 16 ± 1 µm. Moreover, we examined tumorigenicity of the suspended cells and found no sign of tumorigenicity post adaptation. Next, we developed a protocol for the culture of BoHV-1 in the cell line described above and found that ultrasonic treatment could facilitate virus release and enhance virus yield by 11-fold, with the virus titer reaching 8.0 ± 0.2 log₁₀TCID₅₀/mL. Most importantly, the prototype inactivated BoHV-1 vaccine we generated using the suspension cultures of MDBK cells induced neutralizing antibodies to a titer comparable to that of the commercial inactivated BoHV-1 vaccine. Overall, we established and optimized a protocol for the production of inactivated BoHV-1 vaccine in MDBK cells adapted for suspension culture, which provides insights for future large-scale manufacturing of BoHV-1 vaccine.

Background/Objectives: Bovine viral diarrhea (BVD) is a major infectious disease of cattle caused by bovine viral diarrhea virus genotypes 1 and 2 (BVDV-1 and BVDV-2). Current inactivated and live attenuated vaccines provide incomplete cross-genotype protection and may exhibit limitations related to durability of immunity or safety. This study evaluated whether co-expression of the BVDV envelope glycoproteins E1 and E2 in a Modified Vaccinia Ankara (MVA) vector could support antigen expression and induce immune responses in a proof-of-concept model. Methods: Recombinant Modified Vaccinia Ankara (MVA) viruses expressing BVDV-1 E1E2 or BVDV-2 E1E2 were generated by homologous recombination. Recombinant viruses were purified and characterized for antigen expression, genetic stability, and growth properties in vitro. Immunogenicity was evaluated in a BALB/c mouse model by measuring E2-specific antibody responses, virus-neutralizing antibodies, and antigen-responsive cellular immune responses. Results: Both recombinant MVA constructs showed detectable E2 expression when E1 and E2 were co-expressed, and exhibited growth characteristics comparable to parental MVA with stable maintenance after serial passage. In contrast, recombinant MVA expressing E2 alone did not yield detectable E2 protein under the same experimental conditions. Immunization induced detectable humoral and cellular immune responses, including E2-specific IgG antibodies, virus-neutralizing antibodies, and increased frequencies of antigen-responsive CD8⁺ T cells with a tendency toward a Th1-biased profile. Conclusions: These findings indicate that co-expression of BVDV E1 and E2 in an MVA vector can support detectable antigen expression and induce measurable immune responses in a mouse proof-of-concept model. Further studies in cattle, including challenge experiments, will be required to determine the protective efficacy and practical applicability of this platform for BVDV vaccine development.