The Toll family of receptors are a group of conserved pattern recognition receptors (PRRs) essentially controlling the initiation of innate immune responses. The white spot syndrome virus (WSSV) and Vibrio parahaemolyticus are major pathogens of aquaculture shrimp. Previous study has suggested that expression of the Toll2 receptor in Pacific white shrimp Penaeus vannamei was up-regulated by white spot syndrome virus (WSSV) infection but did not significantly changed upon infection with the bacterial pathogen Vibrio parahaemolyticus. The current study intends to investigate the role of P. vannamei Toll2 in antibacterial and antiviral immunity. We demonstrated that compared with the control, the Toll2-silenced shrimp was more susceptible to V. parahaemolyticus infection, suggesting that Toll2 may play a positive role in antibacterial immunity. However, silencing of Toll2 significantly enhanced survivorship of shrimp infected with WSSV and reduced the viral load in shrimp tissues. The expression of WSSV structural protein VP28 was also inhibited in Toll2-silenced shrimp. Histologic pathology analysis further showed that the WSSV infection was attenuated in stomach tissues from Toll2-silenced shrimp. These suggested that Toll2 could promote WSSV infection in shrimp. In Toll2-silenced shrimp, expression of antimicrobial peptides ALFs and PENs was significantly changed, which may contribute to the role of Toll2 in antibacterial immunity and WSSV infection.

Toll 受体家族是一组保守的模式识别受体 (PRR)，主要控制先天免疫反应的启动。白斑综合征病毒（WSSV）和副溶血性弧菌是水产养殖虾的主要病原体。先前的研究表明，太平洋白虾南美白对虾Toll2 受体的表达被白斑综合征病毒 (WSSV) 感染上调，但在感染细菌病原体副溶血性弧菌后没有显着变化。目前的研究旨在调查南美白对虾的作用Toll2 在抗菌和抗病毒免疫方面。我们证明，与对照相比，Toll2 沉默的虾对V更敏感。副溶血性感染，提示 Toll2 可能在抗菌免疫中发挥积极作用。然而，Toll2 的沉默显着提高了感染 WSSV 的虾的存活率并降低了虾组织中的病毒载量。WSSV 结构蛋白 VP28 的表达在 Toll2 沉默的虾中也受到抑制。组织病理学分析进一步表明，WSSV 感染在 Toll2 沉默虾的胃组织中减弱。这些表明 Toll2 可以促进虾的 WSSV 感染。在 Toll2 沉默的虾中，抗菌肽 ALFs 和 PENs 的表达发生了显着变化，这可能有助于 Toll2 在抗菌免疫和 WSSV 感染中的作用。