Transcriptional response of bovine macrophages after infection with two Argentinean Mycobacterium bovis isolates

Infection of cattle with Mycobacterium bovis causes severe financial hardship in many countries, in addition to presenting a health risk for humans. As an intracellular pathogen, M. bovis, adapted to survive and thrive within the intramacrophage environment. However, little is known about expression patterns in the macrophage, particularly in the bovine host. In this study, DNA microarray analysis was used to detect genes expressed in Holstein bovine macrophages derived from peripheral blood mononuclear cells infected during four hours with two Argentinean strains of M. bovis, a virulent strain, 04-303 and an attenuated strain, 534. Genes encoding antrax toxin receptor, cell division and apoptosis regulator, ankyrin proteins that are found within the membrane associated cytoskeleton, protein of cell differentiation and regulators of endocytic traffic of membrane were more strongly expressed in infected macrophages. Blood from healthy Holstein bovines was taken in sterile conditions and peripheral blood mononuclear cells (PBMC) were separated from heparinized blood. PBMCs were used to prepare ten independent cultures which were incubated at 37C for one week in RPMI 1640 complete medium supplemented with 10% of autologous plasma. Four cultures were infected with viable cells of M. bovis virulent strain 04-303, four with avirulent strain 534 and two were left as uninfected controls. Four hours post infection, the cells were scraped, lysed. RNA was extracted, labeled and hybridized to ten Affymetrix Bovine Genome arrays.