The melanoma-associated antigen gene (MAGE) is a key target in cancer immunotherapy. Given the potential of MAGE-B genes in veterinary immunotherapy for canine mammary tumors (CMTs), this study investigated the mRNA expression of MAGE-B1, -B4, -B5, and -B10 in CMT tissues and cells from dogs. Quantitative real-time PCR was used to analyze 28 CMT tissue samples, including 4 benign and 24 malignant tumors (13 simple carcinomas, 6 complex carcinomas, 3 carcinosarcomas, and 2 fibrosarcomas). Benign mixed tumor and complex carcinoma-type CMT cells were cultured and treated with a DNA methylase inhibitor (5-aza-2′-deoxycytidine; 5-aza-CdR) and a histone deacetylase inhibitor (Trichostatin A; TSA) under the following four conditions: (1) 5-aza-CdR for 72 h; (2) TSA for 24 h; (3) 5-aza-CdR for 48 h followed by TSA for 24 h; and (4) control. MAGE-B1 and -B4 showed the highest expression in the CMT samples (100% and 89.29%, respectively), followed by MAGE-B10 (82.14%). Carcinosarcomas and simple anaplastic carcinomas had significantly higher MAGE-B expression levels than simple tubulopapillary carcinomas (p < 0.05). 5-aza-CdR treatment increased MAGE-B expression, whereas TSA had a mild effect. Further research involving larger cohorts is needed to confirm these findings.

The prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) that causes pyoderma has been gradually shifting, according to many surveillance studies, with annual changes. The empirical co-trimoxazole regimen remains interesting, but research on co-trimoxazole susceptibility to MRSP is limited. The objective of this study was to evaluate the susceptibility of co-trimoxazole to canine pyoderma MRSP isolates. Sixty isolates of S. pseudintermedius were identified as 16 MRSP and 44 methicillin-susceptible S. pseudintermedius (MSSP) using an oxacillin disk diffusion test and VITEK 2 system with VITEK GP card. Using the VITEK 2 system with a VITEK AST-GP81 card, the susceptibility rates of MRSP (15.00%) and MSSP (35.00%) to co-trimoxazole was observed. The median MIC of co-trimoxazole on MSSP (median, ≤10; IQR, 10–320) was lower than that of MRSP (median, ≥320; IQR, 10–320) (p = 0.5889, Mann-Whitney test). Percent attainment of PK/PD targets in MRSP (q 12 h, 43.75; q 8 h, 43.75) were lower than that of MSSP (q 12 h, 52.27; q 8 h, 52.27) (p = 0.7710). These findings show the moderately phenotypic co-trimoxazole susceptibilities of both MRSP and MSSP. Further study is required to develop clinical trials examining the use of co-trimoxazole in dogs with pyoderma.

Melanoma-associated antigen (MAGE) is a promising immunotherapeutic target for cancer vaccines. Heat shock protein 110 (HSP110), expressed in various tumors, including canine mammary tumors, serves as a molecular marker. This study aimed to develop a recombinant fusion protein by linking HSP110 with MAGE-B10 to target MAGE-B10-expressed tumors and assess immune response efficacy. The recombinant MAGE-B10-HSP110 (rMAGE-B10-HSP110) fusion protein was constructed, and separate recombinant MAGE-B10 (rMAGE-B10) and recombinant HSP110 (rHSP110) proteins were also prepared for comparison. Our study on mice is distributed across five treatment groups: the rMAGE-B10-HSP110 fusion protein, rMAGE-B10, rHSP110, a protein mixture, and a PBS control. Antibody responses specific to canine MAGE-B10 were measured using ELISA, while splenocyte activation, proliferation, and cytokine production were analyzed using flow cytometry. The results showed significantly higher antibody responses in mice immunized with the rMAGE-B10-HSP110 fusion protein compared to those receiving PBS or rHSP110 on days 7, 14, and 21. The proportion of CD3+ and CD4+ lymphocytes were significantly higher in these mice (p < 0.05). rMAGE-B10-HSP110 fusion protein immunization also resulted in increased CD69+ lymphocytes and higher IFN-γ levels in stimulated lymphocytes (p < 0.05). In conclusion, the rMAGE-B10-HSP110 fusion protein effectively stimulates both innate and adaptive immune responses. Further in vivo investigation is recommended.

Porcine adenoviruses (PAdVs) are promising but still underdeveloped viral-vector platforms for swine vaccine development. Compared with human adenovirus-based vectors, PAdV vectors may offer potential advantages in host association, veterinary relevance, and mucosal delivery while avoiding direct reliance on common human adenovirus backbones. This review summarizes current knowledge on PAdV biology, vector engineering, vaccine applications, immune responses, translational challenges, and future priorities. Early studies showed that recombinant PAdV vectors can express heterologous antigens from important swine pathogens, including classical swine fever virus, pseudorabies virus, and transmissible gastroenteritis virus. The strongest direct proof-of-concept evidence comes from recombinant PAdV expressing classical swine fever virus E2/gp55, which induced neutralizing antibodies and protection in pigs. Comparative adenovirus-vectored swine vaccine studies support the broader feasibility of adenoviral antigen delivery for porcine reproductive and respiratory syndrome, porcine epidemic diarrhea, swine influenza, and African swine fever, but these data should not be interpreted as direct validation of PAdV for these diseases. Major gaps remain in anti-PAdV immunity, genetic stability, biosafety, shedding, target-animal safety, DIVA compatibility, manufacturing, and regulatory readiness. Recent advances in PAdV-5 reverse genetics provide new opportunities for modern vector design.

Canine monocytotropic ehrlichiosis (CME), caused by the intracellular bacterium Ehrlichia canis, is a significant tick-borne disease in dogs that requires effective vaccination strategies. This study aimed to evaluate recombinant TRP19 (rTRP19), a highly conserved immunodominant antigen, as a promising vaccine candidate against experimental E. canis infection in dogs, following its success in a mouse model. Fifteen E. canis-negative beagles were immunized intramuscularly with either 50-µg or 100-µg of rTRP19 in alum adjuvant or a PBS control, on days 0, 30, and 60. All dogs were then exposed intravenously to E. canis on day 90 and monitored for 120 days for clinical signs, hematological changes (platelet count, hematocrit, and body temperature), and antibody titers. The rTRP19 vaccine prototypes induced strong antigen-specific humoral responses. They caused a significant reduction in rickettsial load, with complete elimination observed in the 100-µg group by day 7 and in both vaccinated groups by day 14 of exposure. Furthermore, the mean body temperature in the 100-µg rTRP19 group was significantly lower than that of the control group, suggesting that the higher-dose vaccine mitigated febrile response. Collectively, these results suggest that rTRP19 vaccine prototypes hold promise in overcoming the clinical signs and hematological abnormalities of E. canis infection by inducing a strong antigen-specific antibody response.

Bovine adenovirus (BAdV)-based vectors, particularly those derived from bovine adenovirus 3 (BAdV-3), are emerging non-human adenoviral platforms for veterinary vaccine development. Adenoviral vectors are attractive for vaccination because they mediate efficient transgene expression, remain largely episomal, and induce robust innate and adaptive immune responses. However, widely used human adenoviral vectors, especially human adenovirus 5 (HAdV-5), may be compromised by pre-existing anti-vector immunity, supporting the development of rare human serotypes and non-human adenoviral alternatives. BAdV-3 is the best-characterized BAdV for recombinant vector engineering and has been used to express heterologous antigens from bovine herpesvirus-1, bovine respiratory syncytial virus, influenza virus, and Mycobacterium tuberculosis. Available evidence indicates that BAdV-based vectors can induce humoral, cellular, and mucosal immune responses and support intranasal antigen delivery. Protective efficacy has been demonstrated in selected experimental models, including mice and ferrets for influenza and tuberculosis vaccine candidates, whereas cattle challenge evidence remains more limited and is primarily represented by BHV-1 gD-expressing BAdV-3 vectors. These features make BAdV vectors relevant to bovine respiratory disease control, livestock vaccination, and One Health-oriented vaccine preparedness. Nevertheless, the platform remains at an early developmental stage. Key gaps include limited target-species efficacy data, pre-existing BAdV immunity in cattle, vector shedding, recombination risk, genetic stability, producer cell optimization, manufacturing scalability, and regulatory feasibility.