Development of a sensitive and specific time resolved fluorimetric immunoassay for the bovine acute phase protein...

Haptoglobin (Hp) is recognised as a major acute phase protein in the bovidae and its presence in serum is used as an indicator of inflammation. A mouse monoclonal antibody (1D9) specific for bovine Hp was labelled with a lanthanide (Eu) chelate and used to develop a competitive immunoassay. This competitive immunoassay allowed direct measurement of Hp in serum and was validated for intra- and interassay coefficients of variation (below 8%). Cross-reactivity with other serum proteins was measured (less than 0.1%) and limits of detection for Hp in serum were established for adult male (0.344 microgram/ml) and adult female cattle (1.589 micrograms/ml). The immunoassay was compared with an established haptoglobin-haemoglobin binding assay.