Induction of antigen-specific Th1-type immune responses by gamma-irradiated recombinant Brucella abortus RB51
Induction of antigen-specific Th1-type immune responses by gamma-irradiated recombinant Brucella abortus RB51
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DOI：
10.1128/cdli.12.12.1429-1436.2005
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发表时间：
2005-12-01
期刊：
影响因子：
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通讯作者：
Vemulapalli, R
中科院分区：
文献类型：
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作者：
Sanakkayala, N;Sokolovska, A;Vemulapalli, R
牛种布氏杆菌RB 51株是美国等国家用作牛种布氏杆菌病活疫苗的减毒粗糙突变株。我们先前报道了菌株RB 51作为细菌疫苗载体用于诱导针对异源蛋白的Th 1型免疫应答的发展。由于安全性问题可能妨碍使用基于菌株RB 51的重组活疫苗，我们探索了γ辐照重组RB 51菌株在BALB/c小鼠中诱导异源抗原特异性免疫应答的能力。将表达大肠杆菌β-半乳糖苷酶的菌株RB 51 G/LacZ暴露于至少300千拉德的γ辐射导致复制能力的完全丧失。然而，这些细菌仍然保持代谢活性，并继续合成β-半乳糖苷酶。单次腹腔接种109 CFU当量的γ-辐射，但不热杀死，RB 51 G/LacZ诱导β-半乳糖苷酶特异性Th 1型免疫应答的小鼠。虽然对B的免疫应答没有明显差异。流产特异性抗原，用γ-辐射但不是热灭活的疫苗接种的小鼠，RB 51 G/LacZ对强毒B的攻击产生了显著的保护作用。流产体外实验表明，γ射线照射和热灭活RB 51 G/LacZ诱导树突状细胞的成熟，然而，与γ射线照射的细菌刺激导致更多的白细胞介素-12分泌。这些结果表明，暴露于适当的最小剂量的γ辐射的重组RB 51菌株不能复制，但保留了它们刺激针对异源抗原的Th 1免疫应答并赋予针对B的保护的能力。小鼠流产攻毒。
Brucella abortus strain RB51 is an attenuated rough mutant used as the live vaccine against bovine brucellosis in the United States and other countries. We previously reported the development of strain RB51 as a bacterial vaccine vector for inducing Th1-type immune responses against heterologous proteins. Because safety concerns may preclude the use of strain RB51-based recombinant live vaccines, we explored the ability of a gamma-irradiated recombinant RB51 strain to induce heterologous antigen-specific immune responses in BALB/c mice. Exposure of strain RB51G/LacZ expressing Escherichia coli beta-galactosidase to a minimum of 300 kilorads of gamma radiation resulted in complete loss of replicative ability. These bacteria, however, remained metabolically active and continued to synthesize beta-galactosidase. A single intraperitoneal inoculation of mice with 109 CFU equivalents of gamma-irradiated, but not heat-killed, RB51G/LacZ induced a beta-galactosidasespecific Th1-type immune response. Though no obvious differences were detected in immune responses to B. abortus-specific antigens, mice vaccinated with gamma-irradiated, but not heat-killed, RB51G/LacZ developed significant protection against challenge with virulent B. abortus. In vitro experiments indicated that gamma-irradiated and heat-killed RB51G/LacZ induced maturation of dendritic cells; however, stimulation with gamma-irradiated bacteria resulted in more interleukin-12 secretion. These results suggest that recombinant RB51 strains exposed to an appropriate minimum dose of gamma radiation are unable to replicate but retain their ability to stimulate Th1 immune responses against the heterologous antigens and confer protection against B. abortus challenge in mice.