Title |
Omp16, a conserved peptidoglycan-associated lipoprotein, is involved in Brucella virulence in vitro |
Author |
Feijie Zhi1, Dong Zhou1,2, Junmei Li1, Lulu Tian1, Guangdong Zhang1, Yaping Jin1,2*, and Aihua Wang1,2* |
Address |
1College of Veterinary Medicine, Northwest A&F University, Yangling, P. R. China, 2Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, P. R. China |
Bibliography |
Journal of Microbiology, 58(9),793–804, 2020,
|
DOI |
10.1007/s12275-020-0144-y
|
Key Words |
B. suis S2, Omp16, conditional expression, tetracycline,
attenuation |
Abstract |
Brucella, the bacterial agent of common zoonotic brucellosis,
primarily infects specific animal species. The Brucella outer
membrane proteins (Omps) are particularly attractive for developing
vaccine and improving diagnostic tests and are associated
with the virulence of smooth Brucella strains. Omp16
is a homologue to peptidoglycan-associated lipoproteins (Pals),
and an omp16 mutant has not been generated in any Brucella
strain until now. Very little is known about the functions and
pathogenic mechanisms of Omp16 in Brucella. Here, we confirmed
that Omp16 has a conserved Pal domain and is highly
conserved in Brucella. We attempted to delete omp16 in Brucella
suis vaccine strain 2 (B. suis S2) without success, which
shows that Omp16 is vital for Brucella survival. We acquired
a B. suis S2 Omp16 mutant via conditional complementation.
Omp16 deficiency impaired Brucella outer membrane integrity
and activity in vitro. Moreover, inactivation of Omp16
decreased bacterial intracellular survival in macrophage
RAW 264.7 cells. B. suis S2 and its derivatives induced marked
expression of IL-1β, IL-6, and TNF-α mRNA in Raw 264.7
cells. Whereas inactivation of Omp16 in Brucella enhanced
IL-1β and IL-6 expression in Raw 264.7 cells. Altogether, these
findings show that the Brucella Omp16 mutant was obtained
via conditional complementation and confirmed that Omp16
can maintain outer membrane integrity and be involved in
bacterial virulence in Brucella in vitro and in vivo. These results
will be important in uncovering the pathogenic mechanisms
of Brucella. |