Non-GMO surface display of VP28 on Pediococcus pentosaceus for oral protection against white spot syndrome virus in shrimp

VP28, a major envelope protein of White Spot Syndrome Virus (WSSV), plays a critical role in viral entry and infection, making it an important target for developing novel control measures against this globally devastating shrimp pathogen. This study developed a non-GMO oral shrimp vaccine by externally immobilizing the WSSV VP28 protein on the surface of food-grade Pediococcus pentosaceus BT520 (Pp). VP28 was fused to the C-terminal domain of Lactococcus lactis N-acetylmuramidase AcmA (cA), a well-characterized cell wall binding module, and the resulting fusion protein was expressed, purified, and immobilized onto Pp cells. Surface display was confirmed by Western blot, flow cytometry and immunofluorescence microscopy. Its specific interaction with the shrimp Rab7 protein was also confirmed, and approximately 10 5 cA domains were estimated per bacterial cell. The VP28-displaying cells (Pp-VP28) remained stable in 25 ppt artificial seawater for up to 24 h. Oral administration of Pp-VP28 at 10 8 CFU g −1 feed to Penaeus vannamei (Pacific whiteleg shrimp) for 7 days yielded a relative percent survival (RPS) of 76.25 ± 3.75%, demonstrating marked protection against WSSV. These results highlight the potential of this non-GMO display platform for practical, scalable oral vaccination in sustainable shrimp aquaculture.