Zhejiang Entry-Exit Inspection and Quarantine Bureau, 2 Wen San Road, Hangzhou 310012, People's Republic of China.
Dev Comp Immunol. 2010 Nov;34(11):1191-8. doi: 10.1016/j.dci.2010.06.013. Epub 2010 Jun 30.
Although Bombyx mori systematic immunity is extensively studied, little is known about the silkworm's intestine-specific responses to bacterial infection. Antimicrobial peptides (AMPs) gene expression analysis of B. mori intestinal tissue to oral infection with the Gram-positive (Staphylococcus aureus) and -negative (Escherichia coli) bacteria revealed that there is specificity in the interaction between host immune responses and parasite types. Neither Att1 nor Leb could be stimulated by S. aureus and E. coli. However, CecA1, Glo1, Glo2, Glo3, Glo4 and Lys, could only be trigged by S. aureus. On the contrary, E. coli stimulation caused the decrease in the expression of CecA1, Glo3 and Glo4 in some time points. Interestingly, there is regional specificity in the silkworm local gut immunity. During the immune response, the increase in Def, Hem and LLP3 was only detected in the foregut and midgut. For CecB1, CecD, LLP2 and Mor, after orally administered with E. coli, the up-regulation was only limited in the midgut and hindgut. CecE was the only AMP that positively responses to the both bacteria in all the testing situations. With development, the expression levels of the AMPs were also changed dramatically. That is, at spinning and prepupa stages, a large increase in the expression of CecA1, CecB1, CecD, CecE, Glo1, Glo2, Glo3, Glo4, Leb, Def, Hem, Mor and Lys was detected in the gut. Unexpectedly, in addition to the IMD pathway genes, the Toll and JAK/STAT pathway genes in the silkworm gut can also be activated by microbial oral infection. But in the developmental course, corresponding to the increase in expression of AMPs at spinning and prepupa stages, only the Toll pathway genes in the gut exhibit the similar increasing trend. Our results imply that the immune responses in the silkworm gut are synergistically regulated by the Toll, JAK/STAT and IMD pathways. However, as the time for approaching pupation, the Toll pathway may play a role in the AMPs expression.
尽管家蚕的系统性免疫已得到广泛研究，但对于家蚕肠道对细菌感染的特异性反应知之甚少。通过对家蚕肠道组织进行基因表达分析，发现革兰氏阳性（金黄色葡萄球菌）和革兰氏阴性（大肠杆菌）细菌的口服感染，宿主免疫反应与寄生虫类型之间存在特异性。Att1 和 Leb 均不能被金黄色葡萄球菌和大肠杆菌所刺激。然而，CecA1、Glo1、Glo2、Glo3、Glo4 和 Lys 只能被金黄色葡萄球菌所触发。相反，在某些时间点，大肠杆菌的刺激会导致 CecA1、Glo3 和 Glo4 的表达减少。有趣的是，家蚕局部肠道免疫具有区域特异性。在免疫反应过程中，仅在前肠和中肠中检测到 Def、Hem 和 LLP3 的增加。对于 CecB1、CecD、LLP2 和 Mor，在口服给予大肠杆菌后，上调仅局限于中肠和后肠。CecE 是唯一一种在所有检测情况下均对两种细菌均呈阳性反应的 AMP。随着发育的进行，AMP 的表达水平也发生了显著变化。即在吐丝和预蛹阶段，家蚕肠道中 CecA1、CecB1、CecD、CecE、Glo1、Glo2、Glo3、Glo4、Leb、Def、Hem、Mor 和 Lys 的表达水平大幅增加。出乎意料的是，除了 IMD 途径基因外，家蚕肠道中的 Toll 和 JAK/STAT 途径基因也能被微生物的口服感染所激活。但在发育过程中，与吐丝和预蛹阶段 AMP 表达增加相对应，只有肠道中的 Toll 途径基因表现出类似的增加趋势。我们的研究结果表明，家蚕肠道中的免疫反应是由 Toll、JAK/STAT 和 IMD 途径协同调控的。然而，随着化蛹时间的临近，Toll 途径可能在家蚕肠道中的 AMP 表达中发挥作用。
