Avian mycobacteriosis is a chronic disease of poultry caused by members of the M. avium-intracellulare complex (MAI) which includes Mycobacterium avium subspecies avium.
Data on infection processes of M. avium subsp. avium with host cells is limited so we investigated the invasion processes of M. avium isolates from avian and bovine sources using human and avian cell infection models. The aim of this work was to identify isolate specific differences in invasion processes and how these related to other mycobacterial species.
We used avian HD11 macrophage-like cells and compared them to control infections of human THP-1 macrophage cells.
Invasion levels were equivalent between individual isolates in both avian and human cells but there was a variation in post-invasion survival and growth dynamics between infections in avian and human cells.
Serum factors were host specific, with both calf and poultry serum providing an increase in invasion of avian cells not seen with human cells and with human serum providing an increase in invasion of human cells not seen with avian cells.
The role of the specific mannose, scavenger and complement receptors were investigated using blocking agents indicating similar roles for MR, SR reports in both human and avian cells but isolate specific effects for CR3. Studies with blocking agents for actin and tubulin also indicated strain to strain differences in invasion mechanism.
The differences observed between bacterial isolates and host cells being infected suggest subtle differences in initial invasion processes between different isolates and in different hosts some of which are strain dependent and some are host cell dependent.
The project is funded by the Ministry of Higher Education and Scientific Research in Kurdistan and the University of Nottingham.