Detection of geographic isolates of Anaplasma marginale, using polyclonal bovine antisera and microfluorometry

Geographically separate United States isolates of Anaplasma marginale were differentiated, using polyclonal bovine antiserum and microfluorometry. Both isolate-common and restricted antigen-specific antibodies were apparent in sera of splenectomized calves after resolution of infection, as judged by the capability of the antisera to recognize heterologous isolate antigens to a lesser extent than homologous antigens. Furthermore, absorption of the antisera with homologous antigens removed homologous and heterologous reactions, whereas heterologous absorptions resulted in the capability to discriminate the tailed or appendage-associated isolates (Virginia and Washington) from the tail-less isolate (Florida).