scholarly journals Antigenic Classification of Rickettsia felis by Using Monoclonal and Polyclonal Antibodies

2003 ◽  
Vol 10 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Rong Fang ◽  
Didier Raoult
Keyword(s):  
Monoclonal Antibodies ◽  
Polyclonal Antibodies ◽  
Spotted Fever ◽  
Spotted Fever Group ◽  
Neighbor Joining ◽  
Rickettsia Felis ◽  
Polyclonal Antisera ◽  
Antigenic Profile ◽  
Sfg Rickettsia

ABSTRACT Rickettsia felis is a flea-transmitted rickettsia. There is a discrepancy between its reported phylogenic and phenotypic identifications. Following the first report of R. felis, it was considered by tests with serologic reagents to be closely related to another recognized flea-transmitted rickettia, R. typhi. Subsequently, it appeared to be more closely related to spotted fever group (SFG) rickettsiae by genetic analysis. In the present work, R. felis was studied by microimmunofluorescence (MIF) serologic typing and with monoclonal antibodies (MAbs). Mouse polyclonal antisera to R. felis cross-reacted only with SFG rickettsiae. A neighbor-joining analysis based on MIF indicated that R. felis is actually related to SFG rickettsiae antigenically, clustering with R. australis, R. akari, and R. montanensis. A panel of 21 MAbs was raised against a 120-kDa protein antigen or a 17-kDa polypeptide of R. felis. They cross-reacted with most members of the SFG rickettsiae but not with R. prowazekii, R. typhi, or R. canadensis of the typhus group (TG) rickettsiae. Sixty-four MAbs previously generated to seven other ricketttsial species were tested with R. felis. Three MAbs reacted with the 120-kDa antigen and were generated by R. africae, R. conorii, and R. akari, respectively. They exhibited cross-reactivities with R. felis. All our data show that R. felis harbors the antigenic profile of an SFG rickettsia.

scholarly journals Genetic Classification of “Rickettsia heilongjiangii” and “Rickettsia hulinii,” Two Chinese Spotted Fever Group Rickettsiae

2000 ◽  
Vol 38 (9) ◽  
pp. 3498-3501 ◽  
Author(s):  
J. Z. Zhang ◽  
M. Y. Fan ◽  
Y. M. Wu ◽  
P. E. Fournier ◽  
V. Roux ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Phylogenetic Position ◽  
Spotted Fever Group ◽  
Neighbor Joining ◽  
Likelihood Methods ◽  
Genetic Classification ◽  
Repeat Units ◽  
Statistical Bootstrap ◽  
Maximum Likelihood Methods

To determine the phylogenetic position of two new rickettsial strains isolated from ticks in China, 16S ribosomal DNA,gltA, and ompA (apart from the tandem repeat units) genes were amplified by PCR and sequenced. The phylogenetic relationships between these strains and other rickettsiae were inferred from the comparison of sequences of the three genes by the parsimony, neighbor-joining, and maximum-likelihood methods. The results demonstrated that the 054 strain, a rickettsia pathogenic in humans, and the HL-93 strain were related and clustered together withRickettsia japonica. Significant statistical bootstrap values (100 and 92%) supported the nodes in this cluster. Based on previous genotypic and antigenic data and the phylogenetic analysis presented here, the 054 and HL-93 strains should be considered as new species, and we formally propose that they be named “Rickettsia heilongjiangii” and “Rickettsia hulinii,” respectively.

Application of the Numerical Characteristic of Formal Order Analysis of the Prokaryotic Genomes for Reclassification within the Genus Rickettsia

2016 ◽  
Vol 11 (2) ◽  
pp. 336-350 ◽  
Author(s):  
С.Н. Шпынов ◽  
S.N. Shpynov
Keyword(s):  
Spotted Fever ◽  
Numerical Characteristic ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
New Approach ◽  
Order Analysis ◽  
Ancestral Group ◽  
Prokaryotic Genomes ◽  
Information Chain

Genomes representing Rickettsiaceae family were analyzed using formal order analysis (FOA) of information chain in order to develop a new approach for the classification of prokaryotes. Average remoteness – the numerical characteristic of order was used to compare the genomes. FOA allows one to directly take into account arrangement of nucleotides in each sequence. The obtained results clarified the previously known classification. In addition Rickettsia felis group was discovered between the ancestral group and spotted fever group (SFG) and R. akari group located between the SFG and genus Orientia. Software used for the analysis of nucleotide sequences with FOA is freely available at http://foarlab.org.

Use of monoclonal and polyclonal antibodies to detect prostatic acid phosphatase by immunoblotting.

1986 ◽  
Vol 32 (10) ◽  
pp. 1832-1835 ◽  
Author(s):  
P C Patel ◽  
L Aubin ◽  
J Côte
Keyword(s):  
Monoclonal Antibodies ◽  
Acid Phosphatase ◽  
Western Blot ◽  
Polyclonal Antibodies ◽  
Prostatic Acid Phosphatase ◽  
The Other ◽  
Dot Blot ◽  
Western Blots ◽  
Dot Blot Assay ◽  
Polyclonal Antisera

Abstract We investigated two techniques of immunoblotting--the Western blot and the dot blot--for use in detecting prostatic acid phosphatase (PAP, EC 3.1.3.2). We used polyclonal antisera to human PAP, produced in rabbits by hyperimmunization with purified PAP, and PAP-specific monoclonal antibodies in the immunoenzymatic protocols. We conclude that PAP can be readily detected by Western blots with use of polyclonal antisera, but not with monoclonal antibodies. On the other hand, using a dot blot assay, we could easily detect PAP with both polyclonal and monoclonal antibodies.

scholarly journals Taxonomic Relationships among Spotted Fever Group Rickettsiae as Revealed by Antigenic Analysis with Monoclonal Antibodies

1998 ◽  
Vol 36 (4) ◽  
pp. 887-896 ◽  
Author(s):  
Wenbin Xu ◽  
Didier Raoult
Keyword(s):  
Monoclonal Antibodies ◽  
Phylogenetic Analyses ◽  
Spotted Fever ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Antigenic Analysis ◽  
Taxonomic Relationships ◽  
Rickettsia Africae ◽  
Rickettsia Slovaca ◽  
Rickettsia Sibirica

The spotted fever group (SFG) is made up of more than 20 different rickettsial species and strains. Study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. In this study, we determined taxonomic relationships among the SFG rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. A total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodominant proteins or on the lipopolysaccharide-like antigens of strains of Rickettsia africae, Rickettsia conorii, Rickettsia massiliae, Rickettsia akari, Rickettsia sibirica, and Rickettsia slovaca, were used in the study. The distribution and expression of the epitopes among 29 SFG rickettsiae and Rickettsia bellii were assessed by determination of reaction titers in a microimmunofluorescence assay. The results were scored as numerical taxonomic data, and cluster analysis was used to construct a dendrogram. The architecture of this dendrogram was consistent with previous taxonomic studies, and the implications of this and other findings are discussed.

scholarly journals Seasonal and Gender Differences in Presence of Rickettsia felis and Blood meals Provide Additional Evidence of a Vector Role for Mosquitoes

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Jilei Zhang ◽  
Guangwu Lu ◽  
Patrick John Kelly ◽  
Chengming Wang
Keyword(s):  
Gender Differences ◽  
Blood Meal ◽  
Mosquito Species ◽  
Spotted Fever ◽  
Infection Model ◽  
Spotted Fever Group ◽  
Egg Hatching ◽  
Rickettsia Felis ◽  
And Gender

Rickettsia felis belongs to spotted fever group Rickettsia and is an emerging human pathogen most commonly transmitted by a range of fleas and ticks. While recent evidence has suggested mosquitoes are infected with R. felis, there is little information about the role of mosquitoes in the organism’s transmission. In this study, around 100 mosquitoes were collected monthly between 2013 and 2014 from the same residential dwelling at Yangzhou, China. The collected mosquitoes were identified for their species and gender, followed by gltA-based PCR and hydroxymethylbilane synthase-based PCR to determine the prevalence of Rickettsia and blood meal. Three mosquito species (Culex pipiens: 76%, 996/1,304; C. tritaeniorhynchus: 17%, 216/1,304; Aedes albopictus: 7%, 92/1,304) were identified. For 1,088 female mosquitoes, 31% of them n=336 were positive for blood meal and 7% n=77 carried R. felis DNA. In a strong contrast, none of the 216 male mosquitoes were positive for blood meal but two males were positive for Rickettsia. Interestingly, 63% of R. felis-positive mosquitoes (50/79) were negative for blood meal, being significantly higher than 37% of mosquitoes and being positive for both R. felis and blood meal P=0.008. Furthermore, we compared the prevalence of Rickettsia and blood meal in the mosquitoes collected in the months with temperature below and above 23°C, the minimum temperature required for mosquito egg hatching. Mosquitoes captured in the months below 23°C showed significant higher positivity of R. felis(71/936, 7.6% vs. 8/368, 2.2%; P=0.002) and blood meal (294/936, 31.4% vs. 36/368, 9.8%; P<10−4) than in the months above 23°C. Collectively, the seasonal and gender differences of R. felis and blood meal in mosquitoes add to the existing evidence, supporting a potential vector role of mosquitoes in the transmission of R. felis. Studies with a R. felis infection model covering the full life cycle of mosquitoes is necessary to unambiguously prove the transstadial and transovarial transmission of R. felis in mosquitoes.

scholarly journals Development of a Multiplex Loop-Mediated Isothermal Amplification (LAMP) Method for Simultaneous Detection of Spotted Fever Group Rickettsiae and Malaria Parasites by Dipstick DNA Chromatography

Diagnostics ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 897
Author(s):  
Lavel Chinyama Moonga ◽  
Kyoko Hayashida ◽  
Naoko Kawai ◽  
Ryo Nakao ◽  
Chihiro Sugimoto ◽  
...  
Keyword(s):  
Detection System ◽  
Spotted Fever ◽  
Simultaneous Detection ◽  
Febrile Illness ◽  
Isothermal Amplification ◽  
Lamp Method ◽  
Spotted Fever Group ◽  
Loop Mediated Isothermal Amplification ◽  
Rickettsia Monacensis ◽  
Sfg Rickettsia

Spotted fever group (SFG) rickettsiae causes febrile illness in humans worldwide. Since SFG rickettsiosis’s clinical presentation is nonspecific, it is frequently misdiagnosed as other febrile diseases, especially malaria, and complicates proper treatment. Aiming at rapid, simple, and simultaneous detection of SFG Rickettsia spp. and Plasmodium spp., we developed a novel multiple pathogen detection system by combining a loop-mediated isothermal amplification (LAMP) method and dipstick DNA chromatography technology. Two primer sets detecting SFG Rickettsia spp. and Plasmodium spp. were mixed, and amplified products were visualized by hybridizing to dipstick DNA chromatography. The multiplex LAMP with dipstick DNA chromatography distinguished amplified Rickettsia and Plasmodium targeted genes simultaneously. The determined sensitivity using synthetic nucleotides was 1000 copies per reaction for mixed Rickettsia and Plasmodium genes. When genomic DNA from in vitro cultured organisms was used, the sensitivity was 100 and 10 genome equivalents per reaction for Rickettsia monacensis and Plasmodium falciparum, respectively. Although further improvement will be required for more sensitive detection, our developed simultaneous diagnosis technique will contribute to the differential diagnosis of undifferentiated febrile illness caused by either SFG Rickettsia spp. or Plasmodium spp. in resource-limited endemic areas. Importantly, this scheme is potentially versatile for the simultaneous detection of diverse infectious diseases.

scholarly journals Rickettsia hoogstraalii sp. nov., isolated from hard- and soft-bodied ticks

2010 ◽  
Vol 60 (4) ◽  
pp. 977-984 ◽  
Author(s):  
Darja Duh ◽  
Volga Punda-Polic ◽  
Tatjana Avsic-Zupanc ◽  
Donald Bouyer ◽  
David H. Walker ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Novel Species ◽  
Spotted Fever ◽  
Vero Cells ◽  
Embryonic Cell ◽  
Spotted Fever Group ◽  
The Novel ◽  
Rickettsia Felis ◽  
Separate Species ◽  
Genotypic Characteristics

A novel spotted fever group Rickettsia was found in Haemaphysalis sulcata ticks collected from sheep and goats in Croatia in 2006. At the same time, a genetically identical organism was co-isolated with the embryonic cell line CCE3 obtained from the soft tick Carios capensis in Georgia, USA. In this study, further phenotypic and genotypic characteristics of the novel rickettsial strain present in H. sulcata ticks were investigated. Based on the cultivation of bacteria in mosquito and Vero cell cultures, the presence of rickettsiae in tick tissues and cell cultures [confirmed by transmission electron microscopy (TEM)] and the amplification and sequencing of five rickettsial genes, it was demonstrated that the novel Rickettsia strain fulfils the criteria to be classified as a novel species. The name Rickettsia hoogstraalii sp. nov. is proposed for the new strain. Rickettsia hoogstraalii sp. nov., an obligately intracellular bacterium, was grown in Vero cells and arthropod CCE3, ISE6 and C6/36 cell lines. The morphology of the cells of the novel species was typical of SFG rickettsiae. The small coccobacillary appearance of the bacteria was apparent with light microscopy. A Gram-negative bacterial cell wall and a cytoplasmic membrane separated by a narrow periplasmic space were visible by TEM. To date, Rickettsia hoogstraalii sp. nov. has been isolated from two species of ticks, H. sulcata and C. capensis. The novel species appears to be geographically widely distributed, having been detected in Croatia, Spain and Georgia, USA. Although no information is available regarding the possible pathogenicity of the novel species for vertebrate hosts, R. hoogstraalii sp. nov. has a cytopathic effect in Vero, CCE3 and ISE6 cells. Sequence analyses of the 16S rRNA, 17 kDa, gltA, ompA and ompB genes indicated that even though R. hoogstraalii sp. nov. was closely related to Rickettsia felis, it represents a separate species within the spotted fever group. The type strain of R. hoogstraalii sp. nov. is strain CroaticaT (=DSM 22243T=UTMB 00003T).

scholarly journals The Rickettsia conorii Autotransporter Protein Sca1 Promotes Adherence to Nonphagocytic Mammalian Cells

2010 ◽  
Vol 78 (5) ◽  
pp. 1895-1904 ◽  
Author(s):  
Sean P. Riley ◽  
Kenneth C. Goh ◽  
Timothy M. Hermanas ◽  
Marissa M. Cardwell ◽  
Yvonne G. Y. Chan ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Spotted Fever ◽  
Expression System ◽  
Host Cells ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Gram Negative Bacteria ◽  
Heterologous Expression System ◽  
Cell Association ◽  
Sfg Rickettsia

ABSTRACT The pathogenesis of spotted fever group (SFG) Rickettsia species, including R. conorii and R. rickettsii, is acutely dependent on adherence to and invasion of host cells, including cells of the mammalian endothelial system. Bioinformatic analyses of several rickettsia genomes revealed the presence of a cohort of genes designated sca genes that are predicted to encode proteins with homology to autotransporter proteins of Gram-negative bacteria. Previous work demonstrated that three members of this family, rOmpA (Sca0), Sca2, and rOmpB (Sca5) are involved in the interaction with mammalian cells; however, very little was known about the function of other conserved rickettsial Sca proteins. Here we demonstrate that sca1, a gene present in nearly all SFG rickettsia genomes, is actively transcribed and expressed in R. conorii cells. Alignment of Sca1 sequences from geographically diverse SFG Rickettsia species showed that there are high degrees of sequence identity and conservation of these sequences, suggesting that Sca1 may have a conserved function. Using a heterologous expression system, we demonstrated that production of R. conorii Sca1 in the Escherichia coli outer membrane is sufficient to mediate attachment to but not invasion of a panel of cultured mammalian epithelial and endothelial cells. Furthermore, preincubation of a recombinant Sca1 peptide with host cells blocked R. conorii cell association. Together, these results demonstrate that attachment to mammalian cells can be uncoupled from the entry process and that Sca1 is involved in the adherence of R. conorii to host cells.

scholarly journals One Health Approach to Rickettsiosis: A Five-Year Study on Spotted Fever Group Rickettsiae in Ticks Collected from Humans, Animals and Environment

2021 ◽  
Vol 10 (1) ◽  
pp. 35
Author(s):  
Ilaria Pascucci ◽  
Elisa Antognini ◽  
Cristina Canonico ◽  
Marco Giuseppe Montalbano ◽  
Alessandro Necci ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Rhipicephalus Sanguineus ◽  
Geographic Area ◽  
Molecular Diagnostic ◽  
Spotted Fever Group ◽  
Rickettsia Species ◽  
Glta Gene ◽  
Starting Point ◽  
Pcr Products ◽  
Sfg Rickettsia

The spotted fever group of Rickettsiae is a heterogeneous group of Rickettsiae transmitted by ticks, causing similar diseases in humans (spotted fever). Until recently, it was supposed that a single pathogenic tick-borne SFG Rickettsia circulated in each different geographic area and that R. conorii subsp. conorii was the SFG Rickettsiae circulating in Italy, but in the last decade, thanks to molecular diagnostic, several different Rickettsia species, previously not considered pathogenic for decades, have been isolated from ticks and definitively associated to human disease, also in Italy. The present survey was carried out with the aim of investigating the presence of different SFG Rickettsia species in a geographic area where no information was available. Ticks collected from animals submitted to necropsy, removed from humans in local hospitals and collected from the environment were identified and tested by PCR for Rickettsia spp. based on the gltA gene, and positive PCR products were sequenced. A total of 3286 ticks were collected. Fifteen tick species were recognized, the most represented (79.52%) species in the collection was Ixodes ricinus, followed by Rhipicephalus sanguineus (9.13%). The overall prevalence of Rickettsia infection was 7.58%. Eight species of Rickettsia were identified, the most frequent was R. monacensis (56%), followed by R. helvetica (25.50%). Noteworthy, is the detection in the present study of Rrhipicephali, detected only twice in Italy. These are the first data available on SFG Rickettsiae circulation in the study area and they can be considered as starting point to assess the possible risk for humans.

scholarly journals Propagation of Arthropod-Borne Rickettsia spp. in Two Mosquito Cell Lines

2007 ◽  
Vol 73 (20) ◽  
pp. 6637-6643 ◽  
Author(s):  
Joyce M. Sakamoto ◽  
Abdu F. Azad
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Spotted Fever ◽  
Culture Conditions ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
Transitional Group ◽  
Mosquito Cell Lines

ABSTRACT Rickettsiae are obligate intracellular alphaproteobacteria that include pathogenic species in the spotted fever, typhus, and transitional groups. The development of a standardized cell line in which diverse rickettsiae can be grown and compared would be highly advantageous to investigate the differences among and between pathogenic and nonpathogenic species of rickettsiae. Although several rickettsial species have been grown in tick cells, tick cells are more difficult to maintain and they grow more slowly than insect cells. Rickettsia-permissive arthropod cell lines that can be passaged rapidly are highly desirable for studies on arthropod-Rickettsia interactions. We used two cell lines (Aedes albopictus cell line Aa23 and Anopheles gambiae cell line Sua5B) that have not been used previously for the purpose of rickettsial propagation. We optimized the culture conditions to propagate one transitional-group rickettsial species (Rickettsia felis) and two spotted-fever-group rickettsial species (R. montanensis and R. peacockii) in each cell line. Both cell lines allowed the stable propagation of rickettsiae by weekly passaging regimens. Stable infections were confirmed by PCR, restriction digestion of rompA, sequencing, and the direct observation of bacteria by fluorescence in situ hybridization. These cell lines not only supported rickettsial growth but were also permissive toward the most fastidious species of the three, R. peacockii. The permissive nature of these cell lines suggests that they may potentially be used to isolate novel rickettsiae or other intracellular bacteria. Our results have important implications for the in vitro maintenance of uncultured rickettsiae, as well as providing insights into Rickettsia-arthropod interactions.

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