Survival and density of colonizing bacteria in the intestine of C. elegans mutants with altered immune function. Panel A: Survival of N2 C. elegans and four mutants with altered intestinal immune function when grown on lawns of E. coli OP50. Panel B: Intestinal load of E. coli OP50 (dark bars) or S. typhimurium SL1344 (grey bars) within N2 C. elegans and the four mutants with altered intestinal immune function on day 2 (L4 stage + 2 days) of their lifespan. Data represent Mean ± SD from experiments involving 30 worms/group. Significant differences (p < 0.05) compared to N2 worms exposed to E. coli OP50 or S. typhimurium SL1344, indicated by * or **, respectively. Panel C: Survival of daf-2 and dbl-1 single mutants, and the daf-2;dbl-1 double mutant when grown on lawns of E. coli OP50. Panel D: Intestinal density of viable E. coli OP50 in the intestine of the single and daf-2;dbl-1 double mutants. The dbl-1 mutation suppresses both the daf-2 intestinal bacterial proliferation and lifespan phenotypes.