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Ha NY, Kim Y, Min CK, Kim HI, Yen NTH, Choi MS, Kang JS, Kim YS, Cho NH. Longevity of antibody and T-cell responses against outer membrane antigens of Orientia tsutsugamushi in scrub typhus patients. Emerg Microbes Infect 2017; 6:e116. [PMID: 29259327 PMCID: PMC5750460 DOI: 10.1038/emi.2017.106] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/01/2017] [Accepted: 11/07/2017] [Indexed: 01/30/2023]
Abstract
Scrub typhus, caused by Orientia tsutsugamushi infection, has been a serious public health issue in the Asia-Pacific region, with rising incidence and sporadic outbreaks. However, human protective immunity against specific antigens has been poorly characterized for this bacterium. In addition, immunity produced in early vaccine trials or even after natural infections, did not last long and had poor cross-reactivity among various genotypes. Here, we systematically investigated the kinetics and magnitude of specific adaptive immunity against two membrane antigens, 56 kDa type-specific antigen (TSA56) and surface cell antigen A (ScaA), that are involved in bacterial adhesion and invasion of the host in 64 recovered scrub typhus patients. Antibody responses to the bacterial antigens in patients were generally short-lived and waned to baseline levels 2 years after recovery. The anti-TSA56 IgG responses were predominantly composed of the IgG1 and IgG3 subclasses and persisted for up to 1 year after recovery, whereas IgG specific to ScaA primarily consisted of more transient IgG1, with limited responses by other subclasses. Cellular immunity, including CD4 and CD8 T-cells specific to membrane antigens, also rapidly declined from 1 year after infection, as measured by enzyme-linked immunospot (ELISPOT) assays and flow cytometry. The short longevity of antigen-specific adaptive immunity might be attributable to limited memory responses, as observed in earlier vaccine studies using whole bacterial antigens. Finally, we identified HLA-A*0201-restricted and highly conserved CD8 T-cell epitopes in the TSA56 antigen, which may be valuable tools for assessing cellular immunity against O. tsutsugamushi and developing an effective scrub typhus vaccine.
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Affiliation(s)
- Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Yuri Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Chan-Ki Min
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hong-Il Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Nguyen Thi Hai Yen
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Jae-Seung Kang
- Department of Microbiology, Inha University School of Medicine, Incheon 22212, Republic of Korea
| | - Yeon-Sook Kim
- Division of Infectious Diseases, Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon 35015, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.,Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Seoul 03080, Republic of Korea
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Kim YJ, Yeo SJ, Park SJ, Woo YJ, Kim MW, Kim SH, Chang IA, Jeon SH, Park BJ, Song GJ, Lee MG, Kim IS, Kim YW. Improvement of the diagnostic sensitivity of scrub typhus using a mixture of recombinant antigens derived from Orientia tsutsugamushi serotypes. J Korean Med Sci 2013; 28:672-9. [PMID: 23678257 PMCID: PMC3653078 DOI: 10.3346/jkms.2013.28.5.672] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 04/03/2013] [Indexed: 11/22/2022] Open
Abstract
Diagnosis of scrub typhus is difficult because its symptoms are very similar to other acute febrile illnesses, such as leptospirosis, murine typhus, and other viral hemorrhagic fevers. To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We have developed a chimeric recombinant antigen cr56 and two other recombinant antigens, r21 and kr56, from various serotypes of Orientia tsutsugamushi. They were tested for the detection of antibodies against O. tsutsugamushi in the patient's serum samples using enzyme-linked immunosorbent assay (ELISA) and dot-blot analyses. As of conventional immunofluorescence assay (IFA), when the mixture of these three recombinant antigens was used, both sensitivity and specificity of the recombinant antigens were increased up to 98% in IgM and IgG at ELISA and dot blotting. Additionally, both sensitivity and specificity by detection of IgM and IgG antibodies at rapid diagnostic test (RDT), using the mixture of three antigens and gold conjugated antibodies, were 99%. Our results suggest the use of mixture of these recombinant antigen proteins in ELISA or RDT is suitable as a diagnostic test for scrub typhus.
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Affiliation(s)
| | - Seon-Ju Yeo
- Immunemed, Chuncheon, Korea
- Medical Science Institute, Hallym University, Chuncheon, Korea
| | | | | | - Min-Woo Kim
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Korea
| | | | | | - Sung-Ho Jeon
- Department of Life Science, Hallym University, Chuncheon, Korea
| | - Byung-Jae Park
- Department of Life Science, Hallym University, Chuncheon, Korea
| | - Gi-Jun Song
- Department of Microbiology, College of Medicine, Korea University, Seoul, Korea
| | - Myoung-Gu Lee
- Division of Pulmonology, Department of Internal Medicine, Medical Center, Hallym University, Chuncheon, Korea
| | - Ik-Sang Kim
- Department of Microbiology, College of Medicine, Seoul National University, Seoul, Korea
| | - Yoon-Won Kim
- Immunemed, Chuncheon, Korea
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Korea
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Seong SY, Park SG, Huh MS, Jang WJ, Kim HR, Han TH, Choi MS, Chang WH, Kim IS. Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi. Infect Immun 1997; 65:5250-6. [PMID: 9393823 PMCID: PMC175756 DOI: 10.1128/iai.65.12.5250-5256.1997] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The 56-kDa protein (Bor56) of Orientia tsutsugamushi is an immunoprotective antigen and is the target molecule of neutralizing antibodies. This antigen is recognized by almost all of the serum antibodies produced by patients in the convalescence phase of scrub typhus. We expressed the Bor56 open reading frame in Escherichia coli and generated from it a series of deletion constructs as MalE fusion proteins. Antibody-binding domains were characterized by using patient sera, mouse monoclonal antibodies (MAbs), and Bor56-immunized-mouse sera. None of the antibodies bound to a fusion protein containing the carboxy-terminal 140 amino acids (aa) of the Bor56 protein, suggesting that the carboxy-terminal domain of Bor56 is not exposed on the surface of the molecule. Human immunoglobulin M (IgM) antibodies predominantly bound to antigenic domain I (AD I; amino acids [aa] 19 to 113) and AD III (aa 243 to 328). Human IgG antibodies also showed preferential binding to AD I. The epitope recognized by strain-specific MAb (KI4) or group-specific MAb (KI57) was mapped to AD II (aa 142 to 203). Mouse serum antibodies, elicited by immunization with deletion mutants, consistently bound to AD III. Moreover, the carboxy-terminal 140 aa of the Bor56 protein did not elicit an antibody response in C3H/HeDub mice. A model of the antigenic structure of Bor56 is presented and discussed. These results suggest that antigenic fragments from AD I and AD III are useful in the induction of humoral immunity against O. tsutsugamushi. These antigenic analyses provide an important foundation for further analyses of the neutralizing-antibody responses generated during rickettsial infections. They also provide potential peptide substrates for diagnostic assays and vaccine strategies.
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Affiliation(s)
- S Y Seong
- Biomedical Research Center, Korea Institute of Science and Technology, Seoul
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Ohashi N, Tamura A, Suto T. Immunoblotting analysis of anti-rickettsial antibodies produced in patients of Tsutsugamushi disease. Microbiol Immunol 1988; 32:1085-92. [PMID: 3146683 DOI: 10.1111/j.1348-0421.1988.tb01473.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The reactivity of sera from patients of Tsutsugamushi disease (scrub typhus) with the antigenic polypeptides of Rickettsia tsutsugamushi was analyzed by the immunoblotting method. The reactivity varied greatly among the sera of individual patients tested. IgG and IgM antibodies of most patients reacted with the 54-56 kilodalton (54-56K) polypeptide located on the rickettsial surface, suggesting that this polypeptide is a predominant antigen in the infection. Other polypeptides of 60K, 50-52K, 46-47K, 35K, and 21-25K were reactive with some but not all sera. From the reactivity of these polypeptides, it was suggested that the 54-56K polypeptide is both strain-specific and group-specific, the 60K polypeptide is group-specific, and the 35K and 21-25K polypeptides are subgroup-specific. IgG antibodies seem to be more cross-reactive with polypeptides of multiple strains than IgM antibodies and have a tendency of increased cross-reactivity that was observed in the sera obtained at the later stage of illness.
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Affiliation(s)
- N Ohashi
- Department of Microbiology, Niigata College of Pharmacy
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