Hereford cattle protected against Boophilus microplus with antigens purified by immunoaffinity chromatography from larval and adult ticks.

Tick larvae (Boophilus microplus) were extracted, fractionated by gel filtration and ion-exchange chromatography, and the fractions assayed by enzyme-linked immunosorbent assay (ELISA) against sera from cattle immunized and protected by antigens from the mid-gut of adult ticks. Unfractionated, whole larval extracts and selected reactive components were used to vaccinate cattle; they decreased the number of ticks dropped after challenge, but the effect of treatment was not significant. Antigens purified from crude larval extracts by affinity chromatography, using immunoglobulin ligands from an immune steer vaccinated with tick mid-gut antigens, also failed to protect cattle. However, tick extracts from both larval and adult ticks, which were first separated into membrane-associated and soluble fractions and then purified by exposure to the affinity ligands, protected cattle greater than 80% against subsequent challenge with ticks.