Veterinary Vaccine最新文献

Saccharomyces boulardii has emerged as a promising probiotic agent in bolstering the immune system. In vaccinology, its application can be explored to optimize vaccine efficacy by augmenting host immune response and consequently enhancing the immunogenicity of antigenic formulations. However, it is imperative to conduct further research to comprehend the effectiveness of this probiotic in novel vaccines targeting significant pathogens affecting animal health. Hence, this study investigated the effects of a short (3 - 5 days) or continuously (56 days) S. boulardii supplementation (3 × 10⁸ CFU/mL) on the adaptive immunity of sheep immunized with a recombinant antigen against Paeniclostridium sordellii (rAPS). Four immunized groups (G1-G4) were evaluated, varying the regimen of S. boulardii supplementation. Elevated levels of anti-rAPS IgG immunoglobulins were detected in all vaccinated animals. Daily supplementation with S. boulardii (G1) resulted in higher IgG levels, reaching antibody titers of up to 25,600, which were 16 times higher than those observed in not supplemented group (G4) and 4 times higher than in the group supplemented for 3 days (G3) or 5 days (G2) before each immunization. These findings demonstrate that S. boulardii can enhance vaccine-induced immune responses against P. sordellii, particularly IgG-mediated immune responses in sheep. The possibility of a short supplementation for 5–3 days is a very important finding for animal husbandry, considering the supplementation and supply management cost.

Porcine circovirus type 2 (PCV2) has been recognized as a critical pathogen associated with numerous porcine circovirus-related diseases. Immunization is commonly regarded as the most efficient method to combat PCV2 infection. The virus's main antigen is the Cap protein, which is encoded by the ORF2 gene. In this investigation, we cloned the PCV2 Cap gene into the pYA3681 plasmid and subsequently electrotransferred it into the delayed lysis Salmonella strain χ11802, ultimately generating the χ11802 (pYA3681-Cap) vaccine candidate strain. We assessed the levels of sIgA and IgG specific to the Cap protein in mice, revealing that their mucosal and humoral immunity had been activated by χ11802 (pYA3681-Cap). The result was a substantial elevation in antibody levels, and a notable reduction in viral load in the immunized group compared to the unvaccinated group. Furthermore, the study revealed a significant decrease in the viral load in the lungs, liver, and spleen of mice inoculated with χ11802 (pYA3681-Cap), in comparison to both the empty carrier group and the phosphate buffered saline control group. This study further investigated the lytic effect of the delayed lysis vaccine vector. The χ11802 (pYA3681-EGFP) strain was undetectable 10 days post-challenge, indicating that the vaccine strain can effectively release the carried exogenous antigen and prevent the residual vaccine strain from spreading and causing pollution in the environment. A successful construction of the χ11802 (pYA3681-Cap) strain expressing the PCV2 Cap protein was executed in this study. To summarize, our study suggests that PCV2-Cap, when expressed in the delayed lysis Salmonella strain χ11802, could serve as a safe and economically efficient candidate PCV2 vaccine.

Chicken coccidiosis caused by the Eimeria parasites, including E. acervuline, E. brunetti, E. maxima, E. mitis, E. necatrix, E. praecox and E. tenella, is one of the most economically important chicken diseases. The main measure to control chicken coccidiosis is chemoprophylaxis. However, the concerns of public about the over chemical residues in products and the strict legislation to limit the applications of drugs and the residues in products push chicken farmers to turn to the vaccination strategy to control coccidiosis. While the antigen diversity of Eimeria significantly decreased the traditional live vaccines. The cryptic strains of Eimeria, which have recently appeared and spread widely, can evade all commercial coccidiosis vaccines, thus becoming an emerging threat to global poultry production. For this reason, the development of universal subunit vaccines using the conserved proteins of Eimeria, effective against all species including the cryptic strains infecting chickens, is crucial for the sustainable development of global poultry industry. In this article, we reviewed the research progresses on the conserved proteins of Eimeria, including stage conserved proteins, species conserved proteins and both stage and species conserved proteins, with their possible applications in the development of universal subunit vaccines. Meanwhile, the cytokines and polymer-based nanomaterials used as adjuvants to enhance the protections of subunit vaccines were also summarized.

Since the introduction of the feline panleukopenia virus (FPV) vaccine in China in 2011, it has played a crucial role in safeguarding the health of numerous pet cats by preventing FPV infections. However, an observed rise in FPV infections among cats previously vaccinated has prompted our investigation. Our laboratory has identified a specific FPV isolate, FPV-251, which raises concerns about its potential to evade the immune response. To validate this hypothesis, we conducted a correlational study on FPV-251. Ten sera samples were collected from ten cats two months after receiving the vaccine three times. These samples were prepared in the laboratory to assess their ability to neutralize FPV-251. Results indicated that the neutralization titers of the 10 sera ranged from 1:313.7 to 1:1051.0, with an average titer of 1:627.4. Considering the diversity and complexity of clinical practice, we expanded our study to include 86 sera samples collected from cats at the clinic after three-time immunizations. Among these, 8 out of 43 sera collected after one year post three-time immunizations and 5 out of 43 sera collected within one year post three-time immunizations exhibited a neutralization index (NI) of less than 50 against FPV-251. Despite its potential immune evasion capabilities, immunization with inactivated FPV-251 demonstrated effectiveness in providing substantial protection for cats. This was evident from the high levels of sera antibodies against FPV-251 in cats with FPV-251 immunization, as well as their ability to survive and maintain good health after being challenged with FPV-251. Furthermore, sera antibodies from immunized cats displayed the ability to neutralize the other five FPV isolates, indicating a robust cross-protection capacity of the FPV-251 vaccine. Our research findings suggest that although FPV-251 may exhibit certain immune evasion capabilities, it holds significant potential for development into a vaccine to protect pet cats from FPV infection.

Feline infectious peritonitis (FIP) is a lethal disease caused by a pathogenic coronavirus, feline infectious peritonitis virus (FIPV), in cats. Effective vaccines have been unsuccessful due to the frequent mutation of FIPV and antibody-dependent enhancement (ADE) caused by vaccine-induced IgG antibodies (Abs). This study examined the induction of pan-coronavirus IgM Ab in mice and its ameliorating effects in feline FIP using CoV-mMAP8, an octavalent dendrimer composed of multiple antigenic peptides. The 11-amino acid peptide (SAIEDLLFNKV) was designed as the highly conserved region of the fusion peptide at the N-terminus of S2’ subunit of the spike protein found in human and animal coronaviruses and was then conjugated to an octavalent dendrimer to form CoV-mMAP8. After a total of three injections of CoV-mMAP8 into Balb/c mice with α-galactosylceramide (α-GC) co-administered in the second injection, serum titers of IgM Abs increased against the peptide, recombinant spike proteins of SARS-CoV-2 and MERS-CoV, and crude viral antigens of canine coronavirus, porcine endemic diarrhea virus, and FIPV. In contrast, serum titers of IgG Abs did not significantly increase against any antigens. When CoV-mMAP8 was injected into three cats experimentally infected with FIPV, hyperthermia was improved within seven days after the injection with ameliorating inflammatory markers such as the platelet-to-lymphocyte ratio and the systemic immune-inflammatory index. One cat that showed recurrent hyperthermia received an additional injection of CoV-mMAP8, and clinical improvement was observed again. Postmortem examinations confirmed chronic lesions of FIP in all the cats, providing evidence that FIPV had been successfully infected and treated with CoV-mMAP8 in all the cats. Based on the induction of pan-coronavirus IgM Abs in mice and ameliorating effects in FIP of cats, it is assumed that CoV-mMAP8 has the potential to overcome the challenges posed by variants and ADE in FIPV. The mutational compatibility of CoV-mMAP8 can make it a viable universal vaccine for various coronaviruses beyond FIPV.

Neonatal calf diarrhea (NCD) is an important cause of morbidity and mortality in calves. Four major pathogens, including Enterotoxigenic Escherichia coli (ETEC), bovine rotavirus (BRV), bovine coronavirus (BCV), and Cryptosporidium spp., are associated with NCD, with Cryptosporidium parvum (C. parvum) recognized as a major contributor. Despite various treatment options available, there is no effective vaccine for bovine cryptosporidiosis yet. In this study, recombinantly expressed C. parvum gp40 was evaluated as a candidate vaccine in pregnant animals. The vaccine was administered to pregnant cows during the last trimester of their pregnancy resulting in highly statistically significantly increased anti-gp40 antibody titers. The resulting anti-gp40 antibodies were transmitted to the calves via colostrum. Both suckling (n = 29; test:14, control:15) and non-suckling (n = 16; 8 per group) calves were challenged with live C. parvum oocysts. The calves that received the colostrum from gp40 vaccinated cows showed a highly statistically significant improvement in health (p < 0.0001), reduced incidence (p < 0.0001), and duration of severe diarrhea (p < 0.001) and increased weight gain in suckling calves (p < 0.0001). This study demonstrates that immune bovine colostrum, induced by immunization of late-gestation cows with C. parvum gp40, provided substantial protection to calves against cryptosporidiosis. These findings suggest that the gp40 vaccine has potential for preventing outbreaks of neonatal diarrhea associated with cryptosporidiosis in calves, thereby improving animal welfare and performance.

African swine fever virus (ASFV) has caused recent outbreaks of viral haemorrhagic fever in domestic pigs and wild boar in Africa, Asia, Europe, Oceania and North America. Control measures for African swine fever are limited in most countries to biosecurity at the farm gate followed by movement restrictions and selective or complete culling of pigs on affected premises. Modified live vaccines are being trialled in several countries, however development of safe and effective African swine fever subunit vaccines has been restricted by a poor understanding of the key antigens required for protection, particularly for the panzootic genotype II viruses. The cellular immune response is thought to be critical for protection against African swine fever and therefore to develop an effective subunit vaccine that stimulates an anti-ASFV T-cell response we screened lymphocytes from pigs which survived challenge with Georgia 2007/1. Using an overlapping peptide library corresponding to 168 annotated open reading frames and 24 potential minor open reading frames we identified seventeen proteins which strongly stimulated secretion of interferon gamma in an ELISpot assay. The phenotype of the T cells which were stimulated by these pools of peptides were then investigated by flow cytometry. Proteins stimulating predominantly CD8⁺ T cells were incorporated into bivalent replication deficient adenovirus vectors and tested as potential vaccine candidates in immunisation and challenge experiments in pigs.