Figure 2.

Streptococcus equi mutants lacking sagA fail to elicit a mast cell response. (a–c) 1 × 10⁶ BMMCs/ml were cultured either alone (Untr.) or in the presence of WT S. equi (4047; WT) or knockout strains lacking seM, recA, pyrC, aroB, or sagA as indicated (multiplicity of infection = 10). After 4 hr, conditioned media were harvested and analysed for IL‐6, TNF, and MCP‐1 by ELISA. (d–f) Cells were recovered after 4‐hr incubation of mast cells with bacteria and were analysed by qPCR for expression of the IL6, TNF, and Nr4a3 genes. Expression relative to the housekeeping gene (HPRT) is presented. (g–i) Time course experiment showing the release of IL‐6, TNF, and MCP‐1, measured by ELISA. Data are given as mean values ± standard error of the mean, pooled from at least 4 biological replicates (1‐3 hr, n = 5; 4 hr, n = 6; 24 hr, n = 10). Two‐factor analysis of variance was performed with Tukey's post hoc test. ^*** p ≤ .001; n.s., not significant