Fig 3. Wild type (D39) but not PLY-deficient (PLN-A) pneumococci cause cardiomyocyte dysfunction and death in vitro.

(A) Viability of HL-1 cells was assessed at 8 h after incubation with increasing CFUs of D39 and PLN-A. Viability of untreated cells (UT) was set at 100%. Data are presented as Mean±SD (n = 4). (B) Time course of HL-1 cell viability after incubation with 5x10⁶ CFU/ml D39 or PLN-A in the presence or absence of antibiotics (AB). Data are presented as Mean±SD (n = 4). (C) and (D) Effects of D39 and PLN-A (5x10⁶ CFU/ml) on the total number of spontaneously contracting HL-1 cells over time using antibiotic-free (C) and antibiotic-containing media (D). Data are presented as Mean±SD (n = 4). (E) Effects of D39 and PLN-A (5x10⁶ CFU/ml) on the rhythm and rate of contraction of HL-1 cells over time. Typical traces of spontaneous contraction are presented. (F-J) Effects of D39 and PLN-A (5x10⁶ CFU/ml) on Peak Shortening (F), maximum velocity of shortening (+dL/dt) (G), Time to Peak (TTP) (H), Time to 90%-re-lengthening tR₉₀ (I) and maximum velocity of relaxation (-dL/dt) (J) of HL-1 cells after 4 h treatment are presented as Mean±SD (n = 9 from 3 independent experiments). *ANOVA test, p<0.05.