Production of monoclonal antibodies against 53-kDa protein of Porphyromonas gingivalis in transgenic rice cell suspension culture

Periodontitis is a bacterial infection-induced inflammatory disease that affects the tissues surrounding the teeth and is the main cause of tooth loss in adults. Porphyromonas gingivalis, a black-pigmented gram-negative anaerobe, is a major causative agent of periodontitis. A 53-kDa protein of the bacterium has been demonstrated to be highly immunogenic and recognized by sera from most periodontitis patients, and it is now considered as a potential target of protective immunity. In this study, complementary DNA encoding monoclonal antibodies to 53-kDa protein of P. gingivalis A7A1-28 was cloned from hybridoma cell lines expressing the antibodies. The heavy and light chain genes were constructed into plant expression vectors under the control of the rice α-amylase 3D (RAmy3D) promoter. The recombinant plant expression vectors were introduced into rice cells (Oryza sativa L. cv. Dongjin) using particle bombardment transformation method. Transgenic rice calli were selected by genomic DNA PCR and used to establish cell suspension cultures. The expression of the heavy and light chain genes of the monoclonal antibodies in the rice cell suspension cultures was detected by western blot analysis. The plant-produced monoclonal antibodies showed specific reactivity with 53-kDa proteins of P. gingivalis. These results suggest that 53-kDa protein-specific monoclonal antibodies produced in the rice cell suspension cultures are biologically active against the bacterial protein and can be used for passive immunization to prevent P. gingivalis-induced periodontal disease.