Construction of engineered probiotic that adhere and display nanobody to neutralize porcine reproductive and respiratory syndrome virus

Pathogenic blue ear disease caused by porcine reproductive and respiratory syndrome virus (PRRSV) bring severe loss to breeding industry due to high infectivity and mortality. L. plantarum serves as the probiotic host strain, known for its beneficial properties in the gut microbiota. E. coli is used as a cloning host for the initial genetic engineering steps, facilitating the construction and amplification of the desired genetic constructs. In this study, using synthetic biology technology, we constructed engineered probiotics which could adhere and display nanobody on the surface to neutralize virus. Firstly, we screen an optimal nanobody to effectively bind with PRRSV by building library, expression and purification. Then, the integration of adhesion protein and nanobody into the genome of probiotics significantly improved its adhesion to IPEC-J2 cells. In addition, this engineered probiotic is almost non-toxic to cells with good safety, which can be used as a daily probiotics to prevent virus fecal transmission. Our study proposed this novel construction strategy of engineering probiotics with both adhesion and neutralization effects, which provided a new therapeutic view for intestinal virus clearance. Graphical Abstract