Deng Shu-Xuan, Cheng An-Chun, Wang Ming-Shu, Yan Bin, Yin Nian-Chun, Cao Shen-Yan, Zhang Zheng-Hua, Cao Ping
Avian Diseases Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Yaan, Sichuan 625014, China.
Avian Dis. 2008 Sep;52(3):507-12. doi: 10.1637/8203-123107-ResNote.1.
The objective of this study was to understand the distribution patterns and levels of Salmonella Enteritidis (SE) in the immune organs of ducklings after oral challenge. We conducted serovar-specific real-time polymerase chain reaction (PCR) for SE to detect the genomic DNA of SE in the blood and immune organs, including the bursa of Fabricius, thymus, spleen, and Harderian gland, from ducklings after oral challenge at different time points. The results showed that SE was consistently detected in all the samples. The Harderian gland and spleen tested positive at 8 hr postinoculation (PI). The organism was detected in the blood, bursa of Fabricius, and thymus at 10 hr PI. The copy number of SE DNA in each tissue reached a peak at 24-36 hr PI. The spleen, blood, and Harderian gland contained high concentrations of SE, whereas the thymus and bursa of Fabricius had low concentrations. SE populations began to decrease and were not detectable at 2 days PI, but they were still present up to 9 days PI in the spleen, without producing any apparent symptoms. To validate these results, the indirect immunofluorescent antibody (IFA) technique was used, and the IFA results were similar to those of the fluorescent quantitative-PCR. In conclusion, the results provided insight into the SE life cycle in the immune organs; furthermore, the Harderian gland and spleen were determined to be the primary sites of invasion among the immune organs of normal ducklings after oral SE challenge. This study will help in understanding the pathogenesis of SE infection in vivo and may help in the development of a live Salmonella vaccine in the future.
本研究的目的是了解口服攻毒后雏鸭免疫器官中肠炎沙门氏菌（SE）的分布模式和水平。我们对SE进行了血清型特异性实时聚合酶链反应（PCR），以检测口服攻毒后不同时间点雏鸭血液和免疫器官（包括法氏囊、胸腺、脾脏和哈德氏腺）中SE的基因组DNA。结果显示，所有样本中均持续检测到SE。接种后8小时（PI），哈德氏腺和脾脏检测呈阳性。接种后10小时在血液、法氏囊和胸腺中检测到该菌。各组织中SE DNA的拷贝数在接种后24 - 36小时达到峰值。脾脏、血液和哈德氏腺中SE浓度较高，而胸腺和法氏囊中浓度较低。SE数量在接种后2天开始减少，接种后2天无法检测到，但在脾脏中直至接种后9天仍存在，且未产生任何明显症状。为验证这些结果，使用了间接免疫荧光抗体（IFA）技术，IFA结果与荧光定量PCR结果相似。总之，这些结果为SE在免疫器官中的生命周期提供了见解；此外，确定哈德氏腺和脾脏是正常雏鸭口服SE攻毒后免疫器官中的主要入侵部位。本研究将有助于了解SE体内感染的发病机制，并可能有助于未来开发活沙门氏菌疫苗。
