Association of S. suis with primary mouse glial cells. Various glial cell culture systems: (A) astrocyte mono-culture, (B) microglial cell mono-culture, (C) astrocyte mono-culture pre-incubated with supernatants (SN) of uninfected microglial cell cultures, (D) microglial cell mono-culture pre-incubated with SN of uninfected astrocyte cultures, (E) astrocyte-microglial cell co-culture (low amount of microglial cells), and (F) astrocyte-microglial cell co-culture (high amount of microglial cells), respectively, were infected with CFSE-labeled S. suis strain 10, 10cpsΔEF, or 10Δsly at a MOI of 10:1. Percentage of CFSE-positive cells were measured by flow cytometry. Results are expressed as means with standard deviation (SD) of three independent experiments, and statistically significant differences when compared to uninfected control cells are indicated by ** (p-value < 0.01), and *** (p-value < 0.001), one-way analysis of variance (ANOVA) followed by a Dunnett post-hoc test.