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FP5

APP IN PIG PRODUCTIO Report Summary

Project ID: QLK5-CT-2001-02219
Funded under: FP5-LIFE QUALITY
Country: United Kingdom

ELISA for porcine transthyretin

For the first time, a method to measure the levels of transthyretin in porcine serum has been developed. It shows that TTR is a negative acute phase reactant in pig.

Immunoblotting and mass spectrometry demonstrated that commercially available sheep polyclonal antiserum raised to human transthyretin cross reacted with porcine TTR. This cross reactivity is probably due to the 85% amino acid sequence homology between porcine and human transthyretin protein sequences and the lack of glycosylation of TTR. The specific antibody was used to develop an assay for measuring transthyretin in pig serum. Using this assay TTR in porcine sera can be measured in a consistent and reproducible manner with acceptable precision.

Following Strep.suis infection transthyretin showed a negative acute phase response with serum levels falling significantly two days following treatment then returning to pretreatment values after 5 days. The fall in levels of TTR during the acute phase response was relatively small compared to the increases found in other acute phase proteins such as SAA. However, it is consistent with drops in human transthyretin levels following infection reported previously (Ferard et al. 2002).

The assay we have developed for TTR may have the disadvantage of relying on passively adsorbing the antigen to a surface in competition with all the other serum proteins. This, on the other hand may be less of a drawback considering that TTR concentrations vary only slightly. However, the detection limit might be lowered significantly by using a sandwich ELISA with antibodies raised to purified porcine transthyretin to trap the TTR. We are presently developing such an ELISA.

In conclusion, we have developed a means to measure TTR in pig serum and demonstrated that the concentration of this protein in serum falls in response to infection. This assay was used to measure TTR levels in the porcine serum samples provided by other project partners.

More information on the APP IN PIG PRODUCTIO -project can be found at: http://www.gla.ac.uk/appinpigs/

Contact

Peter David ECKERSALL, (Professor)
Tel.: +44-1413305732
Fax: +44-1413302483
E-mail
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