Purification of Cell Envelopes of <i>Rickettsia tsutsugamushi</i>

Takahashi, Kumiko; Urakami, Hiroshi; Tamura, Akira

doi:10.1111/j.1348-0421.1985.tb00848.x

Cited by 4 publications

(4 citation statements)

References 9 publications

(6 reference statements)

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“…A previous comparative DNA analysis of genes from six strains revealed that the Tsa has four regions of amino acid variability interspersed among five regions of amino acid conservation (25). Previous studies have shown that a type-specific B-cell determinant for the Karp strain is present in the VD I region (aa 105 to 133) (41); however, in this study, strainspecific MAb KI4 bound to the VD II region (aa 151 to 174), which partially overlaps with AD II. Moreover, we obtained similar results with group-specific MAb KI57.…”

Section: Discussioncontrasting

confidence: 77%

Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi

et al. 1997

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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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Section: Discussioncontrasting

confidence: 77%

Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi

et al. 1997

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“…Interestingly, the predicted T-cell epitopes are primarily located outside of the variable domains of TSA56 ( Supplementary Figure S2 ). 32 By contrast, antigenic determinants for antibody responses generally overlap with variable domains of TSA56, 42 , 43 and immunological pressure on the major outer membrane protein during vertebrate host infection might be a crucial driver of genetic diversification of O. tsutsugamushi . 1 Discovery of the preservation of T-cell epitopes in the major outer membrane protein among different genotypes represents a significant advancement toward generating universal and protective T-cell responses that encompass the diverse genotype strains of O. tsutsugamushi .…”

Section: Discussionmentioning

confidence: 99%

Longevity of antibody and T-cell responses against outer membrane antigens of Orientia tsutsugamushi in scrub typhus patients

Kim

Min

et al. 2017

Emerging Microbes & Infections

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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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“…Thus, the individual serum showed a great variety in the reactivity. Additionally, from the 1251 labeling experiments of intact rickettsiae and the analysis of components of the purified envelope of the rickettsiae, 54-56K, 35K, and 21-25K polypeptides were demonstrated to be constitutional proteins of the rickettsial SERA OF SCRUB TYPHUS surface, while the 60K polypeptide was estimated to be the rickettsial inner protein (7,10). It is not known, at present, why an individual patients would show such a variety in the immune response and why the 60K polypeptide is antigenic only in a few cases of human infections.…”

Section: Discussionmentioning

confidence: 99%

Immunoblotting Analysis of Anti‐Rickettsial Antibodies Produced in Patients of Tsutsugamushi Disease

Ohashi¹,

Tamura²,

Suto

1988

Microbiology and Immunology

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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 groupspecific, 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.Several antigenic variants of Rickettsia tsutsugamushi have been recognized in Japan. The prototype strains of Gilliam, Karp, and Kato are generally recognized, and other antigenic types such as Shimokoshi and Kawasaki strains have been isolated (9, 12). Our recent comparative immunoblotting analyses of these variants with guinea pig hyperimmune sera and strain-specific monoclonal antibodies demonstrated that the major polypeptide of 54 to 56 kilodalton (54-56K) on the rickettsial surface is antigenically strain-or type-specific, whereas the 70K and 46-47K polypeptides are group-specific (5, 10). Other workers reported also the several antigenic polypeptides of R. tsutsugamushi (2-4).The indirect immunoperoxidase (IP) or indirect immunofluorescence (IF) test is generally used for a serodiagnosis of Tsutsugamushi disease (scrub typhus) to detect antibodies against R. tsutsugamushi in the sera of patients. However, the reactivity of antibodies produced after infection has not been examined with the individual rickettsial polypeptides. In this study we analyzed the reactivity of rickettsial antigens with sera from patients of Tsutsugamushi disease by the immunoblotting technique.

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Purification of Cell Envelopes of Rickettsia tsutsugamushi

Cited by 4 publications

References 9 publications

Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi

Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi

Longevity of antibody and T-cell responses against outer membrane antigens of Orientia tsutsugamushi in scrub typhus patients

Immunoblotting Analysis of Anti‐Rickettsial Antibodies Produced in Patients of Tsutsugamushi Disease

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