@entity16451 , an ehrlichial pathogen of @entity291 and wild ruminants, is transmitted biologically by ticks. A developmental cycle of A. marginale occurs in a tick that begins in gut cells followed by infection of salivary glands, which are the site of transmission to @entity291 . Geographic isolates of A. marginale vary in their ability to be transmitted by ticks. In these experiments we studied transmission of two recent field isolates of A. marginale, an Oklahoma isolate from Wetumka, OK, and a Florida isolate from Okeechobee, FL, by two populations of Dermacentor variabilis males obtained from the same regions. The Florida and Oklahoma tick populations transmitted the Oklahoma isolate, while both tick populations failed to transmit the Florida isolate. Gut and salivary gland infections of A. marginale, as determined by quantitative PCR and microscopy, were detected in ticks exposed to the Oklahoma isolate, while these tissues were not infected in ticks exposed to the Florida isolate. An adhesion-recovery assay was used to study adhesion of the A. marginale major surface protein (MSP) 1a to gut cells from both tick populations and cultured tick cells. We demonstrated that recombinant @entity526 expressing @entity6476 adhered to cultured and native D. variabilis gut cells, while recombinant @entity526 expressing the Florida MSP1a were not adherent to either tick cell population. The MSP1a of the Florida isolate of A. marginale, therefore, was unable to mediate attachment to tick gut cells, thus inhibiting @entity281 and transmission to @entity291 . This is the first report of MSP1a being responsible for effecting infection and transmission of A. marginale by Dermacentor spp. ticks. The mechanism of @entity281 and transmission of A. marginale is important in formulating control strategies and development of improved vaccines for @entity9187 .

Major surface protein 1a effects @entity281 and transmission of XXXX .

@entity9187 :: ('MESH:D000712', 'Disease') :: ['anaplasmosis'] @entity281 :: ('MESH:D007239', 'Disease') :: ['salivary gland infection', 'tick infection'] @entity6476 :: ('MESH:C537147', 'Disease') :: ['Oklahoma MSP1a'] @entity291 :: ('9913', 'Species') :: ['cattle'] @entity16451 :: ('770', 'Species') :: ['Anaplasma marginale'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli']
@entity16451 :: (770,Species) :: ['Anaplasma marginale']
