SFTPC and immune system toxicity: In our subchronic (28-day) and chronic (56-day) exposure mouse models of MWCNT immunotoxicity, alveolar epithelial type II cells (AECII cells) showed inflammatory and proliferation (hyperplasia) response [14]; the analyses had shown induction of IL-1β, pro-surfactant protein-C (Pro-SP-C), and cell proliferation (Ki-67 expression) in AECII cells and granuloma formation in lung parenchyma [14].