TLR2 and infection: To detect whether the attenuated virulence of SCVs in zebrafish were produced by lipoproteins through increasing proinflamatory response by TLR2, we evaluated the virulence of the three ΔsurA/SCV1, Δslp/SCV1, and ΔlpoB/SCV1 mutants in zebrafish and investigated the expression levels of TLR2, TNF-α, IL-1β, and IL-6 in response to infection with the mutants in RAW264.7 macrophages.