Phillips R W, Elzer P H, Robertson G T, Hagius S D, Walker J V, Fatemi M B, Enright F M, Roop R M
Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130, USA.
Res Vet Sci. 1997 Sep-Oct;63(2):165-7. doi: 10.1016/s0034-5288(97)90012-6.
It has been previously demonstrated that a Brucella melitensis high-temperature-requirement A (htrA) deletion mutant is more susceptible to oxidative killing in vitro than the parental strain and is attenuated in mice. To evaluate the contribution of the B melitensis HtrA protease to virulence in ruminants, the capacity of the B melitensis htrA mutant RWP5 to produce abortion in goats was compared to that of the virulent parental strain 16M. Experimental infection with strain 16M caused abortion in eight of 12 pregnant nannies, while none of the 12 nannies inoculated with RWP5 aborted. Furthermore, intramuscular injection of fetuses in utero with RWP5 led to colonisation of the fetus with subsequent colonisation of the nanny, but no abortion was observed. Nannies vaccinated with RWP5 showed complete protection against abortion when challenged with 16M during the third trimester of pregnancy. However, these animals were not protected from colonisation by 16M. The results presented here clearly indicate that the B melitensis htrA gene product contributes to pathogenesis in goats, but the utility of B melitensis htrA mutants as vaccines in this host appears to be limited.
先前已经证明，布鲁氏菌病羊种高温需求A（htrA）缺失突变体在体外比亲本菌株更容易受到氧化杀伤，并且在小鼠中减毒。为了评估羊种布鲁氏菌HtrA蛋白酶对反刍动物毒力的贡献，将羊种布鲁氏菌htrA突变体RWP5在山羊中产生流产的能力与强毒亲本菌株16M进行了比较。用菌株16M进行实验性感染导致12只怀孕母羊中的8只流产，而接种RWP5的12只母羊中没有一只流产。此外，在子宫内给胎儿肌肉注射RWP5导致胎儿定殖，随后母羊定殖，但未观察到流产。在妊娠晚期用16M攻击时，用RWP5疫苗接种的母羊表现出对流产的完全保护。然而，这些动物没有受到16M定殖的保护。此处给出的结果清楚地表明，羊种布鲁氏菌htrA基因产物有助于山羊发病，但羊种布鲁氏菌htrA突变体作为该宿主疫苗的效用似乎有限。
