To detect more subtle effects of sma-6, sek-1 and daf-2 mutations on transcriptional responses to PA14 we compared the average differential expression of the immune and stress response genes under normal (OP50-1 exposure) and infection (PA14) conditions between mutant (Xmutant) and wildtype (Xwildtype) worms using a paired t-test (see Materials and Methods). This evidence concerns the gene MAP2K4 and infection.