The human surfactant protein C promoter drives the expression of the mouse mature Il18 cDNA fused with the signal peptide from the v-J2-C region of the mouse Igmu-chain in alveolar and bronchiolar epithelial cells. Western blot analysis confirmed expression in the lungs but not other tissues. Four founders were established: A, B, C, and D. Line A is a representative line as lines A, B, and C exhibit similar phenotypes.