Anaplasma marginale major surface protein 3 is encoded by a polymorphic, multigene family

Alleman, A. Rick; Palmer, Guy H.; McGuire, Travis C.; McElwain, Terry F.; Perryman, Lance E.; Barbet, Anthony F.

doi:10.1128/iai.65.1.156-163.1997

Cited by 60 publications

(33 citation statements)

References 19 publications

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“…Unlike other outer membrane proteins (Omps) in A. marginale , Msp2 and Msp3 each have a single expression site but multiple alleles distributed throughout the chromosome (Eid et al ., ; Alleman et al ., ; Barbet et al ., ; Brayton et al ., 2001; 2005). The alleles themselves are in ‘silent’ loci, lacking promoter and other regulatory elements, and encode only the central domains of Msp2 and Msp3 flanked by 5′ and 3′ sequences that are identical with but truncated relative to the sequences in the single expression sites (Brayton et al ., 2001; 2005).…”

Section: Antigenic Variation and Persistence In The Individual Hostmentioning

confidence: 98%

Antigenic variation and transmission fitness as drivers of bacterial strain structure

Palmer

Brayton

2013

Cell Microbiol

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Summary Shifts in microbial strain structure underlie both emergence of new pathogens and shifts in patterns of infection and disease of known agents. Understanding the selective pressures at a population level as well as the mechanisms at the molecular level represent significant gaps in our knowledge regarding microbial epidemiology. Highly antigenically variant pathogens, which are broadly represented among microbial taxons, are most commonly viewed through the mechanistic lens of how they evade immune clearance within the host. However, equally important are mechanisms that allow pathogens to evade immunity at the population level. The selective pressure of immunity at both the level of the individual host and the population is a driver of diversification within a pathogen strain. Using Anaplasma marginale as a model highly antigenically variable bacterial pathogen, we review how immunity selects for genetic diversification in alleles encoding outer membrane proteins both within and among strains. Importantly, genomic comparisons among strains isolated from diverse epidemiologic settings elucidates the counterbalancing pressures for diversification and conservation, driven by immune escape and transmission fitness, respectively, and how these shape pathogen strain structure.

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Section: Antigenic Variation and Persistence In The Individual Hostmentioning

confidence: 98%

Antigenic variation and transmission fitness as drivers of bacterial strain structure

Palmer

Brayton

2013

Cell Microbiol

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“…Polymorphic multigene families encoding the major OMPs have been identified in E. chaffeensis, the HGE agent, and A. marginale, which are closely related to E. canis based on 16S rRNA gene sequences. Six copies of the E. chaffeensis p28 gene (omp-1 gene family) are tandemly arranged with intergenic spaces (22), while copies of the HGE agent p44 gene and the A. marginale msp-2 and msp-3 genes are distributed widely throughout the genomes (1,23,34). In this study, the 30-kDa proteins of E. canis were also shown to be encoded by a polymorphic multigene family.…”

Section: Discussionmentioning

confidence: 75%

Cloning and Characterization of Multigenes Encoding the Immunodominant 30-Kilodalton Major Outer Membrane Proteins of Ehrlichia canis and Application of the Recombinant Protein for Serodiagnosis

et al. 1998

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A 30-kDa major outer membrane protein of Ehrlichia canis, the agent of canine ehrlichiosis, is the major antigen recognized by both naturally and experimentally infected dog sera. The protein cross-reacts with a serum against a recombinant 28-kDa protein (rP28), one of the outer membrane proteins of a gene (omp-1) family of Ehrlichia chaffeensis. Two DNA fragments of E. canis were amplified by PCR with two primer pairs based on the sequences of E. chaffeensis omp-1 genes, cloned, and sequenced. Each fragment contained a partial 30-kDa protein gene of E. canis. Genomic Southern blot analysis with the partial gene probes revealed the presence of multiple copies of these genes in the E. canis genome. Three copies of the entire gene (p30,p30-1, and p30a) were cloned and sequenced from the E. canis genomic DNA. The open reading frames of the two copies (p30 and p30-1) were tandemly arranged with an intergenic space. The three copies were similar but not identical and contained a semivariable region and three hypervariable regions in the protein molecules. The following genes homologous to three E. canis 30-kDa protein genes and the E. chaffeensis omp-1 family were identified in the closely related rickettsiae: wsp from Wolbachiasp., p44 from the agent of human granulocytic ehrlichiosis,msp-2 and msp-4 from Anaplasma marginale, and map-1 from Cowdria ruminantium. Phylogenetic analysis among the three E. canis 30-kDa proteins and the major surface proteins of the rickettsiae revealed that these proteins are divided into four clusters and the two E. canis 30-kDa proteins are closely related but that the third 30-kDa protein is not. The p30gene was expressed as a fusion protein, and the antibody to the recombinant protein (rP30) was raised in a mouse. The antibody reacted with rP30 and a 30-kDa protein of purified E. canis. Twenty-nine indirect fluorescent antibody (IFA)-positive dog plasma specimens strongly recognized the rP30 of E. canis. To evaluate whether the rP30 is a suitable antigen for serodiagnosis of canine ehrlichiosis, the immunoreactions between rP30 and the whole purified E. canis antigen were compared in the dot immunoblot assay. Dot reactions of both antigens with IFA-positive dog plasma specimens were clearly distinguishable by the naked eye from those with IFA-negative plasma specimens. By densitometry with a total of 42 IFA-positive and -negative plasma specimens, both antigens produced results similar in sensitivity and specificity. These findings suggest that the rP30 antigen provides a simple, consistent, and rapid serodiagnosis for canine ehrlichiosis. Cloning of multigenes encoding the 30-kDa major outer membrane proteins of E. caniswill greatly facilitate understanding pathogenesis and immunologic study of canine ehrlichosis and provide a useful tool for phylogenetic analysis.

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“…MSP 1 through 5 have been identified and information on the gene sequences, recombinant protein analogs, monospecific and monoclonal antibodies, isolate variability, and potential value in diagnostic assays and vaccines are available. [28][29][30][31][32][33]19,[34][35][36][37][38][39][40][41][42] MSP1 has been shown to confer partial protection in immunized cattle against A. marginale challenge, and to contain an epitope recognized by monoclonal antibodies capable of in vitro neutralization of isolated rickettsia. 38 MSP1a varies in size among different geographic isolates, but the neutralization-sensitive epitope is conserved.…”

Section: Development Of a Recombinant Or Synthetic Vaccinementioning

confidence: 99%

Anaplasmosis Control: Past, Present, and Future

Kocan

Blouin

Barbet

2000

Annals of the New York Academy of Sciences

110

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Control methods for anaplasmosis have not changed markedly during the past 50 years and include arthropod control, chemoprophylaxsis, vaccination, and maintenance of an Anaplasma‐free herd. Control measures implemented vary with geographic location, and depend on availability, cost, and the feasibility of application. Vaccination has been an effective means of preventing outbreaks of anaplasmosis, but these vaccines, both live and inactivated, are dependent on bovine blood as the source of infection or antigen. Blood‐derived vaccines are difficult to standardize and bear the risk of transmitting other bovine pathogens inapparent at the time of blood collection. Extensive purification is required to remove bovine cell membranes, which may cause side effects. Most importantly, geographic isolates of A. marginale are often not cross‐protective. Development of a tick cell culture system for A. marginale shows promise as a source of antigen for development of an improved inactivated vaccine in the near future that is free from bovine pathogens. Development of an antigenically defined molecular vaccine appears to be a realistic goal, although further research is required to determine epitopes involved in both humoral and cellular immunity, to define antigenic variation during cyclic rickettsemia, and to develop effective delivery systems for optimization of the immune response.

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Anaplasma marginale major surface protein 3 is encoded by a polymorphic, multigene family

Cited by 60 publications

References 19 publications

Antigenic variation and transmission fitness as drivers of bacterial strain structure

Antigenic variation and transmission fitness as drivers of bacterial strain structure

Cloning and Characterization of Multigenes Encoding the Immunodominant 30-Kilodalton Major Outer Membrane Proteins of Ehrlichia canis and Application of the Recombinant Protein for Serodiagnosis

Anaplasmosis Control: Past, Present, and Future

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