Suilysin (SLY) is involved in the maturation of S. suis-induced IL-1β by bone marrow-derived dendritic cells (bmDCs). A bmDCs were infected with the S. suis wild-type strains P1/7 and SC84 or their SLY-deficient mutants (∆sly) for 16 h and IL-1β release was measured by ELISA; B bmDCs were infected with the different wild-type and mutant strains for 6 h and IL-1β mRNA expression was measured by RT-qPCR. Data are presented as “fold” increase in mRNA expression relative to non-infected cells. C bmDCs were stimulated with the different strains of S. suis in the presence or absence of cholesterol (CHOL) for 16 h and IL-1β production was measured by ELISA; D bmDCs were infected with the different strains of S. suis alone, in combination with 5 μg/mL of rSLY or with 5 μg/mL of rSLY and CHOL. Data are expressed as mean ± SEM (n = 3). #(p < 0.05) indicates a significant difference between SC84 and SC84Δsly and *(p < 0.05) with bacteria alone.