ESX1 and infection: The upregulation of the ESX-1 secretion system at both the RNA and the protein level in M. bovis AF2122/97 with the observed upregulation of DNA-sensing pathways and the NLRP3/IL-1β pathway in M. bovis AF2122/97-infected macrophages shows how the expression level of virulence factors between MTBC species, rather than their presence or absence, can drive divergent host responses and influence infection outcome overall.