Veterinary immunology and immunopathology最新文献

Canine parvovirus type 2 (CPV-2) infection remains a major cause of morbidity and mortality in dogs, particularly in unvaccinated puppies. Despite its clinical significance, the immunological mechanisms driving disease progression remain poorly understood. In this study, we analysed hematologic parameters, molecular viral typing, and the plasma cytokine profiles of 41 dogs naturally infected with CPV-2c, compared to 15 healthy controls. Lymphopenia and elevated IL-6, MCP-1, IL-8, IL-10, and KC-like levels were strongly associated with mortality. Conversely, lower IFN-γ levels correlated with recovery. Dead dogs exhibited strong correlations between IL-6 and KC-like, IL-6 and MCP-1, and IL-8 and MCP-1. All infected dogs harboured the CPV-2c variant, as confirmed by RFLP and sequencing. Although these results are based on single time-point measurements at admission, they highlight that cytokine profiling, particularly of IL-6, MCP-1 and IFN-γ, alongside lymphocyte counts, may serve as useful biomarkers for disease severity and prognosis in CPV-2c-infected dogs.

This study investigated the relationship between innate and adaptive immunity in B. henselae-positive cats by assessing the B. henselae-specific immune markers and bacteremia levels. Five cats were infested with Bartonella-carrying fleas to mimic natural infection, while three healthy cats served as uninfected controls. Blood samples were collected over 12 weeks to evaluate bacterial load from whole blood, TLR-4, TLR-9, IL-10, and TNF-α expression in PBMCs using qPCR, as well as IgM and IgG titers and CD4/CD8 profiles via immunofluorescence and flow cytometry. All experimentally infected cats became bacteremic by Week 1 post-infection (p.i) and remained positive throughout the study, demonstrating successful flea-mediated transmission and persistent infection. Bacterial loads exhibited an undulant pattern with inter-individual variability accompanied by dynamic changes in immune response throughout the study. TNF-α expression was significantly higher in infected cats (p = 0.036) compared to control cats from Week 4 to Week 12 p.i, indicating a delayed pro-inflammatory response. In contrast, no statistically significant differences were observed for TLR-4, TLR-9, or IL-10 expression, although temporal variation was noted. TNF-α and IL-10 expression showed a strong positive correlation, suggesting coordinated regulation of inflammatory and regulatory cytokine responses over time. All infected cats seroconverted by Week 2 p.i, with sustained IgG titers, while altered CD4:CD8 ratios were observed in three of five animals, highlighting heterogeneity in adaptive immune responses. Overall, these findings indicate that B. henselae establishes persistent infection in cats characterized by sustained bacteremia and dynamic, temporally regulated immune responses. This study provides novel insight into the kinetics of innate and adaptive immunity during feline B. henselae infection.

Currently, the prevention and control of zoonotic diseases such as brucellosis in some developing countries still primarily rely on "vaccination + quarantine and culling." However, the inability to differentiate between natural infection and vaccine-induced antibodies in immunized livestock has become a new challenge in veterinary clinical diagnosis. To address the issue of distinguishing between wild-type Brucella strains and attenuated vaccine strains in vaccinated animals, this study developed singleplex and multiplex PCR assays targeting six differential loci (NC7250, GL2189, wbkF-wbkD, WP788.1, eryC, and BP26). The primer concentrations and reaction conditions were optimized, ultimately determining the optimal primer concentration ratio as 2:1:1:4:2:4 and the optimal annealing temperature as 60 °C. The results demonstrated that the singleplex PCR exhibited excellent specificity, accurately distinguishing between different Brucella species as well as the A19 and S19 vaccine strains. The hexaplex PCR yielded negative results for non-target bacteria such as Streptococcus and Salmonella. The detection sensitivities were as follows: 1.99 × 10⁻¹ ng/μL for S2 strain DNA, 2 × 10⁻¹ ng/μL for Rev.1 strain DNA, and 2 × 10⁰ ng/μL for S19 strain DNA. The singleplex and hexaplex PCR methods targeting six genes established in this study enable the simultaneous differentiation of wild-type Brucella strains from commonly used vaccine strains, effectively addressing the clinical gap in diagnostic techniques for strain discrimination. This provides a scientific basis for veterinary quarantine, disease eradication, and vaccine selection strategies.