Characterization of immune responses of cattle to erythrocyte stroma, Anaplasma antigen, and dodecanoic acid-conjugated Anaplasma antigen: humoral immunity.

Normal erythrocyte antigen (sonically disrupted erythrocyte stroma; SES) and two anaplasma antigens (sonically disrupted anaplasma antigen; SAA, and French pressure cell-disrupted anaplasma antigen; FAA) were prepared from normal and Anaplasma marginale-infected blood. Portions of SAA and FAA antigens were chemically modified by conjugation with dodecanoic acid (SAADA and FAADA). Eleven cattle were vaccinated with SES, SAA, SAADA, or FAADA. Five weeks later, the 11 cattle, together with 3 controls, were challenge exposed with A marginale. The anti-anaplasma antibody response and the antierythrocyte-antibody response (including the blood group isoantibody response) were evaluated. Only SAA-vaccinated cattle developed anti-anaplasma antibody before challenge exposure. Isoantibodies were developed by 1 of the 3 SAADA-vaccinated cows and 1 of the 2 FAADA-vaccinated cows, as well as by all 3 SAA-vaccinated cows. After challenge exposure, all cattle developed anti-anaplasma antibody and antierythrocyte autoantibody.