The negative acute phase response of serum transthyretin following Streptococcus suis infection in the pig

Transthyretin (TTR) is a serum protein which is a negative acute phase reactant in humans and levels of TTR are routinely measured as an indicator of health status. Such tests have yet to be established for the pig. In order to measure serum TTR in the pig during an acute phase response an assay was developed using anti-human TTR antibodies which cross reacted with porcine TTR. The assay had a detection limit of 32 mu g/mL while the mean concentration of transthyretin measured in healthy pig serum was 302 +/- 8 mu g/mL ( n = 63). There was no significant difference in the serum concentration of TTR in three different age groups from 10 to 25 weeks. Following Streptococcus suis type 2 infection transthyretin showed a negative acute phase response with serum concentrations reaching a significantly lower level at two days following infection.