Preclinical Safety Evaluation of Engineered Lactococcus lactis NZ3900 Biotherapeutics Using a 13-Week Repeated Dose Oral Toxicity Study in Rabbits

ABSTRACT Lactococcus lactis is one of the most important and safe microorganisms used in the dairy industry. Previously, we orally fed cholesterol-fed rabbits with recombinant Ling Zhi 8 (LZ8) protein from L. lactis NZ3900/pNZ8149 and showed anti-inflammatory effects during the development of fatty liver and atheroma. In order to generate a clinically effective oral immunotherapy for the treatment of allergy, L. lactis clones for Der p 2, Per a 2, and Cla c 14 were introduced into L. lactis NZ3900/pNZ8149 to obtain recombinant allergen-based vaccines. In this study, we developed a triple-antigen vaccine formulation, Lactis- IL-1Ra, Lactis-LZ8, Lactis-Triple, and evaluated their preclinical safety in rabbits by oral administration with repeated doses for 90 days. All of the rabbits survived the challenge without any adverse clinical signs or abnormal changes. A notable advantage of this vaccine is that it can be given orally, and thus self-administration at home would be feasible.