Submicron-sized superantigen biomimetic liposomes with highly efficient pulmonary accumulation to remodel local immune microenvironment for cancer chemoimmunotherapy

Metastatic lung cancer continues to cause a high number of deaths due to high malignancy and poor prognosis, and the efficacy of typical chemotherapy or immunotherapy is less than ideal due to the low pulmonary accumulation and targeting of therapeutics. Here, a submicron-sized biomimetic liposome was formulated for the lung-targeted co-delivery of bacterial superantigen and paclitaxel. Recombinant staphylococcal enterotoxin C2 (rSEC2), a bacterial superantigen, was expressed with the <i>Escherichia coli</i> system and showed potent immunostimulatory activities to mediate tumor cell death. The submicron-sized (∼800 nm) biomimetic liposomes, namely 4T1 cell membrane-hybrid rSEC2 paclitaxel liposomes (TSPLs), exhibited high lung-accumulation efficiency and tumor homologous effect due to the suitable particle size and membrane hybridization of cancer cell membranes with phospholipids. Intravenous TSPLs remarkably inhibited metastatic lung cancer with limited systemic immune responses. TSPLs reversed the immunosuppressive state and increased the proportion of local CD4⁺ and CD8⁺ T cells in the lung; moreover, paclitaxel increased tumor cell apoptosis and reduced tumor burden. In summary, the high lung cancer targeting was achieved by particle size control and cell membrane hybridization, and the highly efficient anticancer effect was achieved by the co-delivery of superantigens and chemotherapeutic drugs.