J Microbiol Biotechnol, 2014, 01, 1728─1735

Protective immunity of 56-kDa type-specific antigen of Orientia tsutsugamushi casuing scrub typhus

Sangho Choi ,HangJin Jeong, Y Ju, B Gill, Hwang, J Lee

Abstract

Scrub typhus, caused by infection with Orientia tsutsugamushi, is a mite-borne zoonotic disease endemic to the Asian-Pacific region. In Korea, the incidence of this disease has increased with climate changes, and over 10,000 cases of infection were reported in 2013. Although this infection is treatable with antibiotics such as doxycycline and azithromycin, an effective prophylactic vaccine against O. tsutsugamushi would be more desirable for preventing scrub typhus in endemic areas. In this study, we investigated the 56-kDa type-specific antigen (TSA56), which is a major outer membrane protein of O. tsutsugamushi, as a vaccine candidate. Intranasal immunization of recombinant TSA56 (rec56) induced a higher level of TSA56- specific IgG than that induced by intramuscular immunization of tsa56-expressing DNA (p56). Both types of immunization induced a cell-mediated immune response to TSA56, as demonstrated by the splenic cell proliferation assay. Mice immunized with p56, followed by rec56 plus heat-labile enterotoxin B subunit from E. coli, had a stronger protection from a homologous challenge with the O. tsutsugamushi Boryong strain than with other combinations. Our preliminary results suggest that an effective human vaccine for scrub typhus can include either recombinant TSA56 protein or tsa56-expressing DNA, and provide the basis for further studies to optimize vaccine performance using additional antigens or different adjuvants.

• ISBN or ISSN: 1017-7825

• 본 연구는 질병관리본부 연구개발과제(과제번호 2013-NG52001-00) 연구비를 지원받아 수행되었습니다.
• This research was supported by a fund(code 2013-NG52001-00) by Research of Korea Centers for Disease Control and Prevention.