Phosphorimages of cDNA expression array membranes for MH-S cells infected with or not infected with L. pneumophila. The total RNA was extracted from cells infected with either virulent (B) or avirulent (C) L. pneumophila and cells not infected with either strain (A) as the control at 5 h postinfection and subjected to cDNA expression array assay. Arrowheads, double arrowheads, and arrows indicate β-actin, MIP-1β, and MCP-3 cDNA, respectively.