IL10 and infection: Collectively, these findings provide new insights into the direct cellular effects of PQSE, encompassing: (1) lower expression of virulence protein factors from the T4-BSS (dotB) and the chaperone HSP60 (chaPs); (2) the promotion of a proinflammatory transcriptional program (more IL-12 than IL-10) invested in an active infection by the bacteria; and (3) a significant reduction in the intracellular multiplication of P. salmonis due the enhancement of the phagosome–lysosome fusion in the host’s head kidney macrophages (SHK-1).