Enhanced protection against Rickettsia rickettsii infection in C3H/HeN mice by immunization with a combination of a recombinant adhesin rAdr2 and a protein fragment rOmpB-4 derived from outer membrane protein B

Vaccine ◽  
2015 ◽  
Vol 33 (8) ◽  
pp. 985-992 ◽  
Author(s):  
Wenping Gong ◽  
Pengcheng Wang ◽  
Xiaolu Xiong ◽  
Jun Jiao ◽  
Xiaomei Yang ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein Fragment ◽  
Rickettsia Rickettsii ◽  
Protein B

scholarly journals Yersinia outer-membrane protein B (YopB): a tool for identification of Yersinia pestis isolates

2006 ◽  
Vol 55 (4) ◽  
pp. 467-469 ◽  
Author(s):  
Rekha Khushiramani ◽  
Jyoti Shukla ◽  
Urmil Tuteja ◽  
Harsh Vardhan Batra
Keyword(s):  
Membrane Protein ◽  
Yersinia Pestis ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein B

scholarly journals Serological Reactivity and Biochemical Characterization of Methylated and Unmethylated Forms of a Recombinant Protein Fragment Derived from Outer Membrane Protein B of Rickettsia typhi

2008 ◽  
Vol 15 (4) ◽  
pp. 684-690 ◽  
Author(s):  
Chien-Chung Chao ◽  
Zhiwen Zhang ◽  
Hui Wang ◽  
Abdulnaser Alkhalil ◽  
Wei-Mei Ching
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Mass Spectrometry Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Composition Analysis ◽  
Rickettsia Typhi ◽  
Serological Reactivity ◽  
Lysine Residues ◽  
Protein B

ABSTRACT Rickettsia typhi, an obligate intracellular bacterium that causes murine typhus, possesses a heavily methylated outer membrane protein B (OmpB) antigen. This immunodominant antigen is responsible for serological reactions and is capable of eliciting protective immune responses with a guinea pig model. Western blot analysis of partially digested OmpB with patient sera revealed that most of the reactive fragments are larger than 20 kDa. One of these fragments, which is located at the N terminus (amino acids 33 to 273), fragment A (At), has been expressed in Escherichia coli. The expressed protein (rAt) was purified by chromatography and properly refolded by sequential dialysis. The refolded rAt protein was recognized by at least 87% of the typhus group patient sera as determined by enzyme-linked immunosorbent assay (ELISA). However, the titers were lower than those obtained with OmpB of R. typhi. Since native OmpB is hypermethylated at lysine residues, we chemically methylated the lysine residues in rAt. The methylation was confirmed by amino acid composition analysis, and the methylation pattern of the methylated rAt (mrAt) protein was similar to that of native At from OmpB, as revealed by liquid chromatography-mass spectrometry analysis. Both rAt and mrAt were evaluated in an ELISA for their serological reactivity with patient sera. Among patient sera tested, 83% exhibited higher titers with mrAt than with rAt. These results suggest that rAt, with or without methylation, can potentially replace rickettsia-derived OmpB or whole-cell antigen for the diagnosis of R. typhi infection.

scholarly journals Rickettsial outer-membrane protein B (rOmpB) mediates bacterial invasion through Ku70 in an actin, c-Cbl, clathrin and caveolin 2-dependent manner

2009 ◽  
Vol 11 (4) ◽  
pp. 629-644 ◽  
Author(s):  
Yvonne G. Y. Chan ◽  
Marissa M. Cardwell ◽  
Timothy M. Hermanas ◽  
Tsuneo Uchiyama ◽  
Juan J. Martinez
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Bacterial Invasion ◽  
Dependent Manner ◽  
Protein B

scholarly journals Molecular Basis of Immunity to Rickettsial Infection Conferred through Outer Membrane Protein B

2011 ◽  
Vol 79 (6) ◽  
pp. 2303-2313 ◽  
Author(s):  
Yvonne Gar-Yun Chan ◽  
Sean Phillip Riley ◽  
Emily Chen ◽  
Juan José Martinez
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Molecular Basis ◽  
Spotted Fever ◽  
Host Cells ◽  
Bacterial Invasion ◽  
Passenger Domain ◽  
Rickettsial Infection ◽  
Protein B

ABSTRACTPathogenic rickettsiae are the causative agents of Rocky Mountain spotted fever, typhus, and other human diseases with high mortality and an important impact on society. Although survivors of rickettsial infections are considered immune to disease, the molecular basis of this immunity or the identification of protective antigens that enable vaccine development was hitherto not known. By exploring the molecular pathogenesis ofRickettsia conorii, the agent of Mediterranean spotted fever, we report here that the autotransporter protein, rickettsial outer membrane protein B (rOmpB), constitutes a protective antigen for this group of pathogens. A recombinant, purified rOmpB passenger domain fragment comprised of amino acids 36 to 1334 is sufficient to elicit humoral immune responses that protect animals against lethal disease. Protective immunity requires folded antigen and production of antibodies that recognize conformational epitopes on the rickettsial surface. Monoclonal antibodies (MAbs) 5C7.27 and 5C7.31, which specifically recognize a conformation present in the folded, intact rOmpB passenger domain, are sufficient to confer immunityin vivo. Analysesin vitroindicate this protection involves a mechanism of complement-mediated killing in mammalian blood, a means of rickettsial clearance that has not been previously described. Considering the evolutionary conservation of rOmpB and its crucial contribution to bacterial invasion of host cells, we propose that rOmpB antibody-mediated killing confers immunity to rickettsial infection.

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