Epithelial cells of adenoid origin were grown in tissue culture to examine viral replication in cells that are the primary target of many human pathogens. These cells remained highly differentiated, with subpopulations of cells which retained active ciliary motility and others which demonstrated specialized secretory functions. The epithelial cells were permissive for growth of influenza A virus. Primary respiratory epithelial cells provide a model system for examining virulence, cell tropism, and receptors which replicate in the nasopharynx.