Figure 1.

Intracellular degradation of C. acnes by human macrophages. A CFU assay was performed using PMA-differentiated THP-1 cells. (A) THP-1 cells were either infected with C. acnes strain NCTC737 or L.m. for indicated timepoints. Graphs show the standard deviation and mean of five independent experiments. (B) Differentiated THP-1 cells were infected with one strain of each C. acnes phylotype: NCTC737 (phylotype IA₁), P. acn31 (phylotype IA₂), KPA171202 (phylotype IB), PV66 (phylotype IC), ATCC11828 (phylotype II), and Asn12 (phylotype III) for indicated timepoints. Graphs show the standard deviation and mean of three independent experiments. (A, B) Unpaired t-test of log transformed values compared to the 2-h timepoint was calculated for each timepoint. P-values (*P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P ≤ 0.0001; ns, not significant).