Novel polysaccharide antigen of Orientia tsutsugamushi revealed by a monoclonal antibody.
Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium that replicates in the cytosol of host cells. Although several protein antigens have been characterized and cloned, little information exists regarding the polysaccharide antigen of this bacterium. In this study, we identified and characterized a novel antigen defined by a monoclonal antibody (MAb), NT19, against O. tsutsugamushi. Immunofluorescence microscopic studies showed that the NT19 antigen is released from the bacteria in the cytosol of host cells forming aggregates with bacteria. Immunoblot analysis showed that MAb NT19 recognized a strong band with a molecular mass of 20 kDa that was resistant to proteinase K digestion and sensitive to periodate oxidation, suggesting that the NT19 antigen is a polysaccharide. The function of this polysaccharide is not known, but considering its distribution within a bacterial microcolony, it is suspected to be involved in forming a biofilm-like structure within host cells.
Lee
Sun-Myoung
SM
Department of Microbiology and Center for Advanced Medical Education by BK21 Project, Inha University School of Medicine, Incheon, Korea.
Kim
Mee-Kyung
MK
Kim
Mi-Jeong
MJ
Kang
Jae-Seung
JS
D000911:Antibodies, Monoclonal / Q000032:analysis* / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis / Q000276:immunology*; D012285:Orientia tsutsugamushi / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000032:analysis / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial