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Application of Long-term cultured Interferon-γ Enzyme-linked Immunospot Assay for Assessing Effector and Memory T Cell Responses in Cattle
Published on: July 11, 2015
Evaluation of a commercially available immunoassay for assessing adequacy of passive transfer in calves
Maisie E Dawes1, Jeff W Tyler, Douglas Hostetler
1Department of Veterinary Medicine and Surgery College of Veterinary Medicine, University of Missouri, Columbia 65211, USA.
Objective:
To evaluate diagnostic utility of a commercially available immunoassay for assessing adequacy of passive transfer of immunity in neonatal calves.
Design:
Prospective study.
Animals:
123 calves.
Procedure:
Blood and serum samples were obtained from the calves prior to 2 weeks of age. The immunoassay was performed, along with refractometry and an 18% sodium sulfite turbidity test. Serum IgG concentration was determined with a radial immunodiffusion assay. Sensitivity and specificity of the immunoassay, refractometry, and the sodium sulfite test were calculated by comparing results with results of the radial immunodiffusion assay.
Results:
Sensitivity and specificity of the blood IgG immunoassay were 0.93 and 0.88, respectively, compared with 1.00 and 0.53 for the sodium sulfite test. For refractometry, sensitivity and specificity were 0.71 and 0.83, respectively, when a serum total solids concentration of 5.2 g/dl was used as the cutoff between positive and negative test results.
Conclusions And Clinical Relevance:
Results suggest that the immunoassay performs well in detecting calves with inadequate passive transfer of immunity.

