DAO 94:117-124 (2011)  -  DOI: https://doi.org/10.3354/dao02318

ABSTRACT: Striped bass Morone saxatilis were studied in order to characterize their immune responses over the short term following challenge with Mycobacterium marinum. The expression of immunity-related genes (IL-1β, TNF-α, Nramp and TGF-β) quickly increased following infection with M. marinum, but these genes were subsequently down-regulated despite the fact that bacterial counts remained high. The number of monocytes and neutrophils also initially increased at 1 d post-infection. This confirms the importance of these types of cells in initial inflammation and mycobacterial infection in striped bass. The phagocytic index of splenic leukocytes over these same time frames did not change significantly following infection. The discrete window in which inflammatory mechanisms were stimulated in striped bass may be related to the intracellular nature of this pathogen.

KEY WORDS: Mycobacteriosis · Striped bass · Gene expression · Interleukin-1β · IL-1β · Tumor necrosis factor-α · TNF-α · Natural resistance-associated macrophage protein · Nramp · Transforming growth factor-β · TGF-β