Cross-bred cattle protected against Hyalomma anatolicum anatolicum by larval antigens purified by immunoaffinity chromatography.

Antigens from larvae of Hyalomma anatolicum anatolicum were extracted and purified by immunoaffinity chromatography using immunoglobulin ligands from cross-bred animals immunized with soluble larval antigen. Affinity-purified antigen (Aff-TLE) and a total larval extract (TLE) were used to immunize cross-bred (Bos indicus x Bos taurus) cattle. The group immunized with Aff-TLE rejected 71.6% of larvae and 77.3% of nymphs. However, the rejection percentages were lower in the TLE-immunized group. No significant changes in the feeding period, moulting percentages or moulting period of engorged larvae and nymphs were recorded. There was, however, a significant decrease in the number of resultant nymphs p < 0.01) and adults (p < 0.01) in the ticks fed on the Aff-TLE-immunized group. The Aff-TLE antigen was 93.3% purified. SDS-PAGE analysis identified a 39 kDa protein, reported for the first time, as the antigen responsible for the induction of resistance in the host.