An engineered Lactococcus lactis strain exerts significant immune responses through efficient expression and delivery of Helicobacter pylori Lpp20 antigen.

OBJECTIVES: To produce and deliver Helicobacter pylori lipoprotein Lpp20 via using Lactococcus lactis with aim of developing an efficient way to use this protective antigen in vaccine formulation.

RESULTS: An engineered L. lactis strain carrying the lpp20 gene from H. pylori was constructed. The inducible expression of Lpp20 in L. lactis was detected as a 20 kDa intracellular protein by SDS-PAGE. Lpp20 constituted 10 % of the L. lactis cellular proteins. The expression product was highly immunoreactive, as demonstrated by western blot assays using mouse anti-H. pylori sera. Animal experimentation showed that oral vaccination with the engineered strain excited significantly elevated levels of serum Lpp20-specific IgG antibodies in BALB/c mice (P < 0.05).

CONCLUSIONS: This report presents the first efficient expression and delivery of whole Lpp20 protein to the immunization sites by using L. lactis, demonstrating an efficient utilization mode of Lpp20 in anti-H. pylori vaccination.