FIG 5.

L4 is an opsonic target in T. pallidum. (A) Percentages of rabbit peritoneal macrophages containing internalized treponemes following a 4-h incubation period with the indicated sera. (B) Representative micrographs. Each image is a composite of bright-field nuclei stained with DAPI and Alexa Fluor 488-labeled T. pallidum. Arrowheads indicate degraded T. pallidum in phagolysosomes. Scale bars, 10 μm. (C) Percentages of treponemes in supernatants recovered at the conclusion of the 4-h incubation period. The results shown in panels A and C are means ± SEMs for three independent experiments; P values of <0.05 were considered to be significant.