Evasion of host defense by Brucella

Brucella, an adept intracellular pathogen, causes brucellosis, a zoonotic disease leading to significant global impacts on animal welfare and the economy. Regrettably, there is currently no approved and effective vaccine for human use. The ability of Brucella to evade host defenses is essential for establishing chronic infection and ensuring stable intracellular growth. Brucella employs various mechanisms to evade and undermine the innate and adaptive immune responses of the host through modulating the activation of pattern recognition receptors (PRRs), inflammatory responses, or the activation of immune cells like dendritic cells (DCs) to inhibit antigen presentation. Moreover, it regulates multiple cellular processes such as apoptosis, pyroptosis, and autophagy to establish persistent infection within host cells. This review summarizes the recently discovered mechanisms employed by Brucella to subvert host immune responses and research progress on vaccines, with the aim of advancing our understanding of brucellosis and facilitating the development of more effective vaccines and therapeutic approaches against Brucella.