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Strain diversity in major surface protein 2 expression during tick transmission of Anaplasma marginale.

ABSTRACT: Specific major surface protein 2 (MSP2) variants are expressed by Anaplasma marginale within the tick salivary gland and, following transmission, are expressed during acute rickettsemia. In previous work, we have shown that a restricted pattern of MSP2 variants is expressed in the salivary glands of Dermacentor andersoni ticks infected with the South Idaho strain of A. marginale. Now we demonstrate that the identical restriction does not apply to two other strains of A. marginale, and that different variants are also expressed when the same strain is transmitted by different Dermacentor spp. This indicates that antigenic diversity among strains is maintained in tick transmission and may be a significant constraint to MSP2 vaccine development.

SUBMITTER: Rurangirwa FR

PROVIDER: S-EPMC97523 | biostudies-literature | 2000 May

REPOSITORIES: biostudies-literature

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Strain diversity in major surface protein 2 expression during tick transmission of Anaplasma marginale.

Rurangirwa F R FR Stiller D D Palmer G H GH

Infection and immunity 20000501 5

Specific major surface protein 2 (MSP2) variants are expressed by Anaplasma marginale within the tick salivary gland and, following transmission, are expressed during acute rickettsemia. In previous work, we have shown that a restricted pattern of MSP2 variants is expressed in the salivary glands of Dermacentor andersoni ticks infected with the South Idaho strain of A. marginale. Now we demonstrate that the identical restriction does not apply to two other strains of A. marginale, and that diffe ...[more]

PMID: 10769008

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Restriction of major surface protein 2 (MSP2) variants during tick transmission of the ehrlichia Anaplasma marginale.

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| S-EPMC2712686 | biostudies-literature

Global transcriptional analysis reveals surface remodeling of Anaplasma marginale in the tick vector.

Project description:BackgroundPathogens dependent upon vectors for transmission to new hosts undergo environment specific changes in gene transcription dependent on whether they are replicating in the vector or the mammalian host. Differential gene transcription, especially of potential vaccine candidates, is of interest in Anaplasma marginale, the tick-borne causative agent of bovine anaplasmosis.MethodsRNA-seq technology allowed a comprehensive analysis of the transcriptional status of A. marginale genes in two conditions: bovine host blood and tick derived cell culture, a model for the tick vector. Quantitative PCR was used to assess transcription of a set of genes in A. marginale infected tick midguts and salivary glands at two time points during the transmission cycle.ResultsGenes belonging to fourteen pathways or component groups were found to be differentially transcribed in A. marginale in the bovine host versus the tick vector. One of the most significantly altered groups was composed of surface proteins. Of the 56 genes included in the surface protein group, eight were up regulated and 26 were down regulated. The down regulated surface protein encoding genes include several that are well studied due to their immunogenicity and function. Quantitative PCR of a set of genes demonstrated that transcription in tick cell culture most closely approximates transcription in salivary glands of recently infected ticks.ConclusionsThe ISE6 tick cell culture line is an acceptable model for early infection in tick salivary glands, and reveals disproportionate down regulation of surface protein genes in the tick. Transcriptional profiling in other cell lines may help us simulate additional microenvironments. Understanding vector-specific alteration of gene transcription, especially of surface protein encoding genes, may aid in the development of vaccines or transmission blocking therapies.

| S-EPMC4022386 | biostudies-literature

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Project description:Transmission of tick-borne pathogens requires transition between distinct host environments with infection and replication in host-specific cell types. Anaplasma marginale illustrates this transition: in the mammalian host, the bacterium infects and replicates in mature (nonnucleated) erythrocytes, while in the tick vector, replication occurs in nucleated epithelial cells. We hypothesized that proteins containing ankyrin motifs would be expressed by A. marginale only in tick cells and would traffic to the infected host cell nucleus. A. marginale encodes three proteins containing ankyrin motifs, an AnkA orthologue (the AM705 protein), AnkB (the AM926 protein), and AnkC (the AM638 protein). All three A. marginale Anks were confirmed to be expressed during intracellular infection: AnkA is expressed at significantly higher levels in erythrocytes, AnkB is expressed equally by both infected erythrocytes and tick cells, and AnkC is expressed exclusively in tick cells. There was no evidence of any of the Ank proteins trafficking to the nucleus. Thus, the hypothesis that ankyrin-containing motifs were predictive of cell type expression and nuclear localization was rejected. In contrast, AnkA orthologues in the closely related A. phagocytophilum and Ehrlichia chaffeensis have been shown to localize to the host cell nucleus. This difference, together with the lack of a nuclear localization signal in any of the AnkA orthologues, suggests that trafficking may be mediated by a separate transporter rather than by endogenous signals. Selection for divergence in Ank function among Anaplasma and Ehrlichia spp. is supported by both locus and allelic analyses of genes encoding orthologous proteins and their ankyrin motif compositions.

| S-EPMC3191954 | biostudies-literature

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