Complete genome sequencing of Anaplasma marginale reveals that the surface is skewed to two superfamilies of outer membrane proteins

ABSTRACT Bacterial pathogens in the genera Anaplasma and Ehrlichia encode a protein superfamily, pfam01617, which includes the predominant outer membrane proteins (OMPs) of each species, major surface protein 2 (MSP2) and MSP3 of Anaplasma marginale and Anaplasma ovis, Anaplasma phagocytophilum MSP2 (p44), Ehrlichia chaffeensis p28-OMP, Ehrlichia canis p30, and Ehrlichia ruminantium MAP1, and has been shown to be involved in both antigenic variation within the mammalian host and differential expression between the mammalian and arthropod hosts. Recently, complete sequencing of the A. marginale genome has identified an expanded set of genes, designated omp1-14, encoding new members of this superfamily. Transcriptional analysis indicated that, with the exception of the three smallest open reading frames, omp2, omp3, and omp6, these superfamily genes are transcribed in A. marginale-infected erythrocytes, tick midgut and salivary glands, and the IDE8 tick cell line. OMPs 1, 4, 7 to 9, and 11 were confirmed to be expressed as proteins by A. marginale within infected erythrocytes, with expression being either markedly lower (OMPs 1, 4, and 7 to 9) or absent (OMP11) in infected tick cells, which reflected regulation at the transcript level. Although the pfam01617 superfamily includes the antigenically variable MSP2 and MSP3 surface proteins, analysis of the omp1-14 sequences throughout a cycle of acute and persistent infection in the mammalian host and tick transmission reveals a high degree of conservation, an observation supported by sequence comparisons between the St. Maries strain and Florida strain genomes.

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Identification of Novel Antigenic Proteins in a Complex Anaplasma marginale Outer Membrane Immunogen by Mass Spectrometry and Genomic Mapping

Infection and Immunity ◽

10.1128/iai.73.12.8109-8118.2005 ◽

2005 ◽

Vol 73 (12) ◽

pp. 8109-8118 ◽

Cited By ~ 79

Author(s):

Job E. Lopez ◽

William F. Siems ◽

Guy H. Palmer ◽

Kelly A. Brayton ◽

Travis C. McGuire ◽

...

Keyword(s):

Mass Spectrometry ◽

Membrane Proteins ◽

Outer Membrane ◽

Vaccine Development ◽

Outer Membrane Proteins ◽

Serum Antibody ◽

Elongation Factor ◽

Anaplasma Marginale ◽

Antigenic Proteins ◽

Associated Proteins

ABSTRACT Immunization with purified Anaplasma marginale outer membranes induces complete protection against infection that is associated with CD4+ T-lymphocyte-mediated gamma interferon secretion and immunoglobulin G2 (IgG2) antibody titers. However, knowledge of the composition of the outer membrane immunogen is limited. Recent sequencing and annotation of the A. marginale genome predicts at least 62 outer membrane proteins (OMP), enabling a proteomic and genomic approach for identification of novel OMP by use of IgG serum antibody from outer membrane vaccinates. Outer membrane proteins were separated by two-dimensional electrophoresis, and proteins recognized by total IgG and IgG2 in immune sera of outer membrane-vaccinated cattle were detected by immunoblotting. Immunoreactive protein spots were excised and subjected to liquid chromatography-tandem mass spectrometry. A database search of the A. marginale genome identified 24 antigenic proteins that were predicted to be outer membrane, inner membrane, or membrane-associated proteins. These included the previously characterized surface-exposed outer membrane proteins MSP2, operon associated gene 2 (OpAG2), MSP3, and MSP5 as well as recently identified appendage-associated proteins. Among the 21 newly described antigenic proteins, 14 are annotated in the A. marginale genome and include type IV secretion system proteins, elongation factor Tu, and members of the MSP2 superfamily. The identification of these novel antigenic proteins markedly expands current understanding of the composition of the protective immunogen and provides new candidates for vaccine development.

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Linkage between Anaplasma marginale Outer Membrane Proteins Enhances Immunogenicity but Is Not Required for Protection from Challenge

Clinical and Vaccine Immunology ◽

10.1128/cvi.00600-12 ◽

2013 ◽

Vol 20 (5) ◽

pp. 651-656 ◽

Cited By ~ 11

Author(s):

Susan M. Noh ◽

Joshua E. Turse ◽

Wendy C. Brown ◽

Junzo Norimine ◽

Guy H. Palmer

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Protective Immunity ◽

Bacterial Infections ◽

Vaccine Development ◽

Outer Membrane Proteins ◽

Anaplasma Marginale ◽

Anamnestic Response ◽

Covalent Bonds ◽

Content Type

ABSTRACTThe prevention of bacterial infections via immunization presents particular challenges. While outer membrane extracts are often protective, they are difficult and expensive to isolate and standardize and thus are often impractical for development and implementation in vaccination programs. In contrast, individual proteins, which are easily adapted for use in subunit vaccines, tend to be poorly protective. Consequently, identification of the specific characteristics of outer membrane-based immunogens, in terms of the antigen contents and contexts that are required for protective immunity, represents a major gap in the knowledge needed for bacterial vaccine development. Using as a modelAnaplasma marginale, a persistent tick-borne bacterial pathogen of cattle, we tested two sets of immunogens to determine whether membrane context affected immunogenicity and the capacity to induce protection. The first immunogen was composed of a complex of outer membrane proteins linked by covalent bonds and known to be protective. The second immunogen was derived directly from the first one, but the proteins were individualized rather than linked. The antibody response induced by the linked immunogen was much greater than that induced by the unlinked immunogen. However, both immunogens induced protective immunity and an anamnestic response. These findings suggest that individual proteins or combinations of proteins can be successfully tested for the ability to induce protective immunity with less regard for overall membrane context. Once protective antigens are identified, immunogenicity could be enhanced by cross-linking to allow a reduced immunogen dose or fewer booster vaccinations.

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Immune response of calves immunized with cocktail of DNA vaccine encoding complexed outer membrane proteins from Anaplasma marginale

Semina Ciências Agrárias ◽

10.5433/1679-0359.2013v34n6supl2p3877 ◽

2013 ◽

Vol 34 (6Supl2) ◽

pp. 3877 ◽

Cited By ~ 1

Author(s):

Adriana Letícia Mendes Coelho ◽

Rafael Felipe Da Costa Vieira ◽

Marcela Ribeiro Gasparini ◽

João Luis Garcia ◽

Odilon Vidotto ◽

...

Keyword(s):

Immune Response ◽

Membrane Proteins ◽

Outer Membrane ◽

Dna Vaccine ◽

Outer Membrane Proteins ◽

Anaplasma Marginale

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Immunogenicity of Outer Membrane Proteins VirB9-1 and VirB9-2, a Novel Nanovaccine against Anaplasma marginale

PLoS ONE ◽

10.1371/journal.pone.0154295 ◽

2016 ◽

Vol 11 (4) ◽

pp. e0154295 ◽

Cited By ~ 8

Author(s):

Liang Zhao ◽

Donna Mahony ◽

Antonino S. Cavallaro ◽

Bing Zhang ◽

Jun Zhang ◽

...

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Anaplasma Marginale

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Simultaneous Variation of the Immunodominant Outer Membrane Proteins, MSP2 and MSP3, during Anaplasma marginale Persistence In Vivo

Infection and Immunity ◽

10.1128/iai.71.11.6627-6632.2003 ◽

2003 ◽

Vol 71 (11) ◽

pp. 6627-6632 ◽

Cited By ~ 32

Author(s):

Kelly A. Brayton ◽

Patrick F. M. Meeus ◽

Anthony F. Barbet ◽

Guy H. Palmer

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Bacterial Pathogen ◽

Anaplasma Marginale ◽

Surface Proteins ◽

Mammalian Host ◽

Surface Coat ◽

Vector Borne

ABSTRACT Vector-borne bacterial pathogens persist in the mammalian host by varying surface antigens to evade the existing immune response. To test whether the model of surface coat switching and immune evasion can be extended to a vector-borne bacterial pathogen with multiple immunodominant surface proteins, we examined Anaplasma marginale, a rickettsia with two highly immunogenic outer membrane proteins, major surface protein 2 (MSP2) and MSP3. The simultaneous clearance of variants of the two most immunodominant surface proteins of A. marginale followed by emergence of unique variants indicates that the switch rates and immune selection for MSP2 and MSP3 are sufficiently similar to explain the cyclic bacteremia observed during infection in the immunocompetent host.

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