Figure 7. Serum Resistance of non-Sg1 L. pneumophila.

(A) Percentage survival of Sg1 str. Philadelphia vs Sg6 str. Thunder Bay in the presence of no Serum (NS), serum with Sg1 antibodies (S1), S1 heated for 30 min at 56°C (S1ΔH), serum with Sg6 antibodies (S6) and S6 heated for 30 min at 56°C (S6ΔH). (B) Percentage survival of L. pneumophila serogroups after incubation in 90% non-immune human serum for 1 hour at 37°C. Both panels A and B are an average of three independent experiments. (C) Relative prevalence of non-SG1 in the clinical isolates database maintained at Public Health Ontario Laboratories. (D) Immunodetection of complement proteins C₃ and (E) C₉ at the surface of NHS treated Sg1 str. Philadelphia vs Sg6 str. Thunder Bay. Panels on the left are fluorescent captures of the differential interference contrast images on the right. The bacteria are seen as individual rods in these images. Images were acquired using Quorum Optigrid microscope with a 63× oil immersion objective (Leica DMI6000B stand with a Hamamatsu EM-1K, EMCCD camera). Image acquisition and post-acquisition processing was performed using Volocity 4.3 software (Improvision).