Functional and Immunological Relevance of Anaplasma marginale Major Surface Protein 1a Sequence and Structural Analysis

Abstract

Bovine anaplasmosis is caused by cattle infection with the tick-borne bacterium, Anaplasma marginale. The major surface protein 1a (MSP1a) has been used as a genetic marker for identifying A. marginale strains based on N-terminal tandem repeats and a 5′-UTR microsatellite located in the msp1a gene. The MSP1a tandem repeats contain immune relevant elements and functional domains that bind to bovine erythrocytes and tick cells, thus providing information about the evolution of host-pathogen and vector-pathogen interactions. Here we propose one nomenclature for A. marginale strain classification based on MSP1a. All tandem repeats among A. marginale strains were classified and the amino acid variability/frequency in each position was determined. The sequence variation at immunodominant B cell epitopes was determined and the secondary (2D) structure of the tandem repeats was modeled. A total of 224 different strains of A. marginale were classified, showing 11 genotypes based on the 5′-UTR microsatellite and 193 different tandem repeats with high amino acid variability per position. Our results showed phylogenetic correlation between MSP1a sequence, secondary structure, B-cell epitope composition and tick transmissibility of A. marginale strains. The analysis of MSP1a sequences provides relevant information about the biology of A. marginale to design vaccines with a cross-protective capacity based on MSP1a B-cell epitopes.

Outbreak of anaplasmosis associated with the presence of different Anaplasma marginale strains in dairy cattle in the states of São Paulo and Goiás, Brazil

“…The global distribution and variation in pathogenicity of A. marginale are associated to the genetic diversity and variability of this bacterium (FUENTE et al, 2007). The genetic diversity of A. marginale strains is high in cattle in endemic regions worldwide FUENTE et al, 2007;CABEZAS-CRUZ et al, 2013;SILVA et al, 2015a).…”

Characterization of two strains of Anaplasma marginale isolated from cattle in Rio de Janeiro, Brazil, after propagation in tick cell culture

“…The genetic heterogeneity of A. marginale strains is high in cattle from endemic regions worldwide (de la Fuente et al, 2005(de la Fuente et al, , 2007Pohl et al, 2013;Cabezas-Cruz et al, 2013). Three out of six major surface proteins (MSPs), MSP5, MSP4 and MSP1␣ have been extensively used for the molecular characterization of A. marginale (Aubry and Geale, 2011).…”

Anaplasma marginale major surface protein 1a: A marker of strain diversity with implications for control of bovine anaplasmosis

“…Tandem repeat 13 was found to be highly represented in A. marginale strains from South Africa Mutshembele et al, 2014) and was also present in some strains from Argentina, Venezuela and Mexico. However, this tandem repeat was reported to be in low abundance in A. marginale strains from Brazil Cabezas-Cruz et al, 2013). In addition, this particular strain (UFMG2) clustered with only 3 other strains of A. marginale from Brazil, suggesting minimal relatedness with other strains circulating in this country .…”

“…marginale is an example of an intracellular tick-borne rickettsia that genetically is highly variable. Sequence analysis of the msp1a gene has been used extensively to define A. marginale strain variation and characterize the worldwide genetic diversity of these many strains de la Fuente et al, 2007;Pohl et al, 2013;Cabezas-Cruz et al, 2013;Mutshembele et al, 2014).…”