A Novel Recombinant MAGE-B10-HSP110 Fusion Protein Enhances Innate and Adaptive Immune Responses in Mice: A Potential Vaccine Candidate for Canine Mammary Tumors.

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.