Fig 4.

L. pneumophila ΔsdhA causes rapid, transient hemocyte depletion. Hemocytes from larvae infected with WT, ΔdotA, ΔsdhA, or ΔsdhA plus p4HA-SdhA L. pneumophila were extracted at 2, 5, 10, 18, and 24 h p.i., and viable cells were counted. Infection with the ΔsdhA mutant, but not with WT or complemented strains, caused significant (P < 0.0001) hemocyte depletion at 5 h p.i. By 18 h p.i., the hemocyte levels had almost recovered to the 2-h p.i. levels in larvae infected with the ΔsdhA strain, while hemocyte depletion was seen in the larvae infected with WT or ΔsdhA plus p4HA-SdhA (P < 0.0001 compared to ΔsdhA strain). Results are means of at least 4 experiments ± standard deviations.