Preclinical safety assessment and immunological evaluation of xenogeneic mammary cells of porcine origin, utilized as an intralesional immunotherapeutic agent

Xenogeneic cells isolated from safe animal tissues and expanded <i>ex vivo</i> hold potential as immunotherapeutic agents capable of stimulating the body's immune system to treat cancers. This study aimed to evaluate the <i>in vivo</i> safety and immunological effects of xenogeneic mammary cells of porcine origin (XMC), ensuring that their local administration is a safe medical intervention for breast cancer treatment. The safety of local XMC treatment was assessed by injecting varying doses of these cells into the abdominal mammary fat-pad tissues as prime and booster shots. Over a 28-day observation period, the tested dose range showed no significant changes in body weight or organ weight, and histopathological analysis revealed no pathological alterations in liver or kidney tissues. No abnormal findings were observed in hematology and serum biochemistry parameters. However, a dose-dependent periductal inflammation and lymphoid tissue infiltration were observed at the injection site. To further assess immune responses to xenogeneic cells, we evaluated their ability to stimulate immune cell proliferation and cytokine secretion in co-cultures with mouse splenocytes and human leukemia cell lines. Cell proliferation was measured by flow cytometry, and cytokine was analyzed using the ELISA method. Co-cultures of mouse splenocytes, KG-1, or Jurkat cells with XMCs elicited a proliferative response and increased secretion of cytokines, including interleukin-2 and interferon gamma, which are involved in immune rejection and antitumor activity. Physical interactions between immune cells and xenogeneic cells have also been demonstrated. The mouse safety study and cell-based bioassay results indicate that XMCs were safe within the tested dose range in this preclinical <i>in vivo</i> assessment, and their immune-stimulatory effects were clearly measurable.