Mycobacteriosis is a chronic infection of poultry caused by members of the Mycobacterium avium-intracellulare complex (MAI). This work investigated the immunological interactions of M. avium subspecies avium isolated from avian, bovine and human sources on avian and human macrophage-like cells.
We infected THP-1 (human monocyte-derived macrophages) and HD11 (chicken macrophage-like cells) with eight clinical isolates of M. avium at an M.O.I. of 10:1 and observed the relative levels of invasion and cytokine stimulation at 2, 6 and 24 h post infection. Stimulation of pro-inflammatory cytokines and nitric oxide in response to infection was assessed in THP-1 cells by ELISA and in HD11 cells by qRT-PCR.
The data showed equivalent invasion proficiencies between mycobacterial isolates but differences were observed in the induced levels cytokine level between strains. These differences did not correlate with the source of the bacterial strains.
Analysis of MAPK signaling indicated the pathways involved were similar between isolates but signaling was different between human and avian host cells.
Overall the results suggest that some strain dependent signaling occurs and that signaling events have significant differences between avian and human cells. The results will be discussed in relation to host specificity.
The project is funded by the Ministry of Higher Education and Scientific Research in Kurdistan and the University of Nottingham.