Bos indicus cattle resistant to digital dermatitis exhibit a balanced proinflammatory cytokine response upon exposure to Treponema phagedenis in contrast to Bos taurus cattle

Abstract Bovine digital dermatitis (BDD) is a globally distributed infectious hoof disease that negatively impacts the wellbeing and productivity of the affected animal. Treponema species and in particular Treponema phagedenis are the microbes strongly associated with the disease. Recently, it has been reported that Bos indicus cattle are more resistant to BDD and to the colonization by Treponema phagedenis in contrast to many Bos taurus breeds. This study investigated whether Bos indicus mount a different immune response to Treponema phagedenis compared with Bos taurus cattle, to better understand the different disease outcome in the two subspecies. Therefore, we exposed freshly isolated primary bovine blood cells to Treponema phagedenis and dissected subsequent bovine immune responses. The comparison between the two subspecies revealed significant different immune responses to Treponema phagedenis . We observed a stronger Th1/proinflammatory cytokine induction in Bos taurus animals mainly driven by CD4 + T and CD21 low B cells in secreting IFN-γ. We assume that these distinct initial immune responses are linked to the control of Treponema phagedenis and the outcome of BDD. Additionally, we observed significant higher levels in the expression of the matrix metalloproteinase-9 by peripheral blood mononuclear cells in Bos indicus cattle, which likely benefits the host response to Treponema phagedenis .