FOLactis

FOLactis is a bifunctional engineered strain of Lactococcus lactis developed for cancer immunotherapy. It expresses a fusion protein combining fms-like tyrosine kinase 3 ligand (Flt3L) and OX40 ligand (OX40L). This engineered probiotic is designed to be used as an in situ vaccination (ISV) approach, particularly for immunotherapy-resistant "cold tumors". The therapeutic strategy involves intratumoral injection of FOLactis combined with stereotactic body radiation therapy (SBRT) and PD-1 blockade to enhance anti-tumor immunity. This approach aims to convert immunologically "cold tumors" into "hot tumors" that will respond to cancer immunotherapy. In terms of immunological activity, FOLactis activates dendritic cells and CD8+ T cells. The engineered probiotic serves as an effective delivery carrier that helps pro-inflammatory proteins remain at the tumor site longer to achieve therapeutic effectiveness.