Immunoproteomic profiling of Rickettsia parkeri and Rickettsia amblyommii

Pornwiroon, Walairat; Bourchookarn, Apichai; Paddock, Christopher D.; Macaluso, Kevin R.

doi:10.1016/j.ttbdis.2015.07.012

Cited by 7 publications

(10 citation statements)

References 59 publications

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“…typhi reisolates from BALB/c CB17 SCID mice. Thus, it seems that the absence of pressure through the adaptive immune system in BALB/c CB17 SCID mice influences the expression of a series of proteins including several immunoreactive ones such as FtsZ, PrsA, Sca4, 17 kDa surface antigen [ 43 – 47 ] and GroEL that is recognized by the BNI52 antibody.…”

Section: Resultsmentioning

confidence: 99%

GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi

et al. 2021

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Rickettsioses are neglected and emerging potentially fatal febrile diseases that are caused by obligate intracellular bacteria, rickettsiae. Rickettsia (R.) typhi and R. prowazekii constitute the typhus group (TG) of rickettsiae and are the causative agents of endemic and epidemic typhus, respectively. We recently generated a monoclonal antibody (BNI52) against R. typhi. Characterization of BNI52 revealed that it specifically recognizes TG rickettsiae but not the members of the spotted fever group (SFG) rickettsiae. We further show that BNI52 binds to protein fragments of ±30 kDa that are exposed on the bacterial surface and also present in the periplasmic space. These protein fragments apparently derive from the cytosolic GroEL protein of R. typhi and are also recognized by antibodies in the sera from patients and infected mice. Furthermore, BNI52 opsonizes the bacteria for the uptake by antigen presenting cells (APC), indicating a contribution of GroEL-specific antibodies to protective immunity. Finally, it is interesting that the GroEL protein belongs to 32 proteins that are differentially downregulated by R. typhi after passage through immunodeficient BALB/c CB17 SCID mice. This could be a hint that the rickettsia GroEL protein may have immunomodulatory properties as shown for the homologous protein from several other bacteria, too. Overall, the results of this study provide evidence that GroEL represents an immunodominant antigen of TG rickettsiae that is recognized by the humoral immune response against these pathogens and that may be interesting as a vaccine candidate. Apart from that, the BNI52 antibody represents a new tool for specific detection of TG rickettsiae in various diagnostic and experimental setups.

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Section: Resultsmentioning

confidence: 99%

GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi

et al. 2021

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“…The RNAi assay coupled with the catalase inhibitor assay showed reduced R. parkeri survival in tick tissues and reduced transovarial transmissions (Figs 1, 2). The rickettsial antioxidant and stress response genes were not studied but are determining factors in pathogen strategies for evading the tick's innate immune response and host manipulations (Mansueto et al, 2012;Pornwiroon et al, 2015). Tick antioxidants, in combination with pathogen stress response genes, when silenced together may help to eliminate R. parkeri from Am.…”

Section: Resultsmentioning

confidence: 99%

Catalase is a determinant of the colonization and transovarial transmission of Rickettsia parkeri in the Gulf Coast tick Amblyomma maculatum

Budachetri

Kumar

Karim

2017

Insect Molecular Biology

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The Gulf Coast tick (Amblyomma maculatum) has evolved as the competent vector of the spotted-fever group rickettsia, Rickettsia parkeri. In this study, the functional role of catalase, an enzyme responsible for the degradation of toxic hydrogen peroxide, in the colonization of the tick vector by R. parkeri and transovarial transmission of this pathogen to the next tick generation, was investigated. Catalase gene (CAT) expression in midgut, salivary glands, and ovarian tissues exhibited a 2–11-fold increase in transcription level upon R. parkeri infection. Depletion of CAT transcripts using an RNA-interference approach significantly reduced R. parkeri infection levels in midgut and salivary gland tissues by 53%–63%. The role of CAT in transovarial transmission of R. parkeri was confirmed by simultaneously blocking the transcript and the enzyme by injecting dsRNA-CAT and a catalase inhibitor (3-amino-1,2,4-triazole) into gravid females. Simultaneous inhibition of the CAT transcript and the enzyme significantly reduced the egg conversion ratio with a 44% reduction of R. parkeri transovarial transmission. These data suggest that catalase is required for rickettsial colonization of the tick vector and transovarial transmission to the next generation.

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“…Similar is true for GroEL from Rickettsia heilongjiangensis , Rickettsia helvetica , and R . parkeri that is recognized by antibodies in the sera from patients as well as mice infected with these pathogens [ 94 – 97 ]. GroEL acts as a chaperone that assists in the folding of proteins in the cytosol of prokaryotice cells and is up-regulated under circumstances of stress.…”

Section: Adaptive Immunity Against Rickettsiaementioning

confidence: 99%

The neglected challenge: Vaccination against rickettsiae

Osterloh

2020

PLoS Negl Trop Dis

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Over the last decades, rickettsioses are emerging worldwide. These diseases are caused by intracellular bacteria. Although rickettsioses can be treated with antibiotics, a vaccine against rickettsiae is highly desired for several reasons. Rickettsioses are highly prevalent, especially in poor countries, and there are indications of the development of antibiotic resistance. In addition, some rickettsiae can persist and cause recurrent disease. The development of a vaccine requires the understanding of the immune mechanisms that are involved in protection as well as in immunopathology. Knowledge about these immune responses is accumulating, and efforts have been undertaken to identify antigenic components of rickettsiae that may be useful as a vaccine. This review provides an overview on current knowledge of adaptive immunity against rickettsiae, which is essential for defense, rickettsial antigens that have been identified so far, and on vaccination strategies that have been used in animal models of rickettsial infections.

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Immunoproteomic profiling of Rickettsia parkeri and Rickettsia amblyommii

Cited by 7 publications

References 59 publications

GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi

GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi

Catalase is a determinant of the colonization and transovarial transmission of Rickettsia parkeri in the Gulf Coast tick Amblyomma maculatum

The neglected challenge: Vaccination against rickettsiae

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