Group B Streptococcus Induces a Robust IFN-γ Response by CD4⁺ T Cells in an In Vitro and In Vivo Model

Figure 2

Ex vivo cytokine and chemokine production profile by total splenocytes. C57BL/6 mice were injected intraperitoneally with a dose of 10⁷ CFU of wild-type GBS serotype III strain COH-1 ( per group × 3 individual experimental infections). Spleens were harvested 6 h after infection and total splenocytes plated at 5 × 10⁶ cells/well. After 4 h of incubation, the bacteriostatic agent chloramphenicol (12 μg/mL) was added to the culture to prevent cell toxicity. Cells were then incubated for 48 h and 72 h and supernatants were collected for cytokine analysis by ELISA. Nonstimulated cells from mock-infected animals served as negative (−) control for basal expression. Cells stimulated with Concanavalin A (0.1 μg/mL) were used as positive (+) control. Data are expressed as means ± SEM (in pg/mL) from 3 different experimental infections. indicates statistically significant difference compared to (−) control cells.