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Strain diversity in major surface protein 2 expression during tick transmission of Anaplasma marginale
F R Rurangirwa1, D Stiller, G H Palmer
1Program in Vector-Borne Diseases, Washington State University, Pullman, Washington 99164-7040, USA.
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.
Insights
Anaplasma marginale expresses specific major surface protein 2 (MSP2) variants. Antigenic diversity is maintained during tick transmission, posing challenges for MSP2 vaccine development.
Area of Science:
- Veterinary Entomology
- Molecular Biology
- Immunology
Background:
- Anaplasma marginale expresses specific major surface protein 2 (MSP2) variants in tick salivary glands and during host rickettsemia.
- Previous studies identified a restricted pattern of MSP2 variant expression in Dermacentor andersoni ticks infected with the South Idaho strain.
Purpose of the Study:
- To investigate if MSP2 variant expression patterns are conserved across different A. marginale strains and tick species.
- To assess the impact of tick transmission on antigenic diversity of A. marginale.
Main Methods:
- Comparative analysis of MSP2 gene expression in different A. marginale strains.
- Examination of MSP2 variant expression in ticks of different Dermacentor species transmitting the same A. marginale strain.
Main Results:
- The restricted pattern of MSP2 variant expression observed in the South Idaho strain was not found in two other A. marginale strains.
- Different MSP2 variants were expressed when the same A. marginale strain was transmitted by different Dermacentor tick species.
Conclusions:
- Tick transmission plays a role in maintaining antigenic diversity among A. marginale strains.
- The variability in MSP2 expression presents a significant hurdle for developing effective MSP2-based vaccines against anaplasmosis.