Recombinant Thyrotropin (TSH)
Standard for the Next Generation of Canine TSH Immunoassays With Improved Sensitivity
Overall, this research project completed the genetic phase of the project and are reproducibly producing reasonable quantities of recombinant canine TSH in vitro and purifying it with high recovery to high purity. In the future, this standard can serve as a reproducible standard for all available canine TSH assays. Although the researchers did not succeed with the development of a permanent cell line expression canine TSH, the transient expressions in PEAK cells and purification procedures have resulted in hundreds of micrograms of pure canine TSH devoid of contaminating LH and FSH. The data support the importance of the lack of standard cross-contamination with these more abundant but structurally related pituitary glyoprotein hormones. The research also pursued the promising development of antibody titers against TSH in 2 immunized mice. Unfortunately, neither of the animals resulted in a successful result: the positive hybridomas from one mouse were contaminated in the UGA monoclonal antibody facility, and the positive clones from the other mouse did not result in permanently positive clones.
In summary, using the currently available pairing of the 14H9 monoclonal antibody with a limited quantity of anti-cTSH polyclonal antibody, the researchers have developed a canine TSH immunoassay with an IRMA format, but the assay in this format does not appear to be more sensitive than the current commercial canine TSH assay. However, the use of highly purified recombinant canine TSH does provide an improvement over the use of pituitary source TSH inevitably contaminated by LH and FSH. Such contamination provided by pituitary source glycohormones could theoretically be more problematic for accurate measurement of TSH in the cycling bitch.
Co-sponsored with the AKC Canine Health Foundation, Grant Number: 0002434
Duncan Ferguson, DVM, PhD
University of Georgia