Presence of Common Antigens, Including Major Surface Protein Epitopes, Between the Cattle (intraerythrocytic) and Tick Stages of Anaplasma Marginale

Epitopes of major surface proteins of the intraerythrocytic cattle stage of Anaplasma marginale were demonstrated in the midgut stage of the organism within the infective tick host Dermacentor andersoni. These proteins were common to all A. marginale isolates tested and at all stages of parasitemia. Sera from cattle immunized with the tick midgut stage of A. marginale immunoprecipitated multiple-erythrocyte-stage proteins, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The major proteins recognized (primarily greater than 14 and less than 200 kilodaltons [kDa]) included two major-erythrocyte-stage surface proteins of 36 and 105 kDa molecular size. To confirm the presence of common tick and erythrocyte A. marginale antigens with the immunized cattle sera, we purified the 36-kDa erythrocyte-stage protein by monoclonal immunoaffinity chromatography and developed an enzyme-linked immunosorbent assay based on the purified protein. All sera from cattle immunized with tick-stage A. marginale and cattle infected with various isolates of A. marginale developed antibodies to the 36-kDa protein. The potential immunoprophylactic, diagnostic, and epidemiologic value of the major epitopes common to both the invertebrate and mammalian stages of A. marginale, especially the 36-kDa protein, is discussed.