Sandwich enzyme-linked immunosorbent assay for quantitative measurement of serum amyloid A protein in horses.

The research involves the use of a sandwich enzyme-linked immunosorbent assay (ELISA) for quantifying the serum amyloid A (SAA) protein concentrations in horses. The results demonstrate that the technique is highly sensitive and reliable.

Research Methodology

• The researchers developed a sandwich ELISA, utilizing an affinity-purified SAA antibody, to measure SAA protein concentration in horses.
• Once the ELISA was established, the researchers tested its accuracy by comparing the results with a frequently used other method, the single radial immunodiffusion test. They found a strong correlation between the two approaches, with a correlation coefficient (r) of 0.95.

Equine SAA Concentration Measurements

• With the new ELISA, the team examined the SAA concentration in healthy horses and discovered that it was high immediately after birth until the horse was two weeks old. Following this period, the concentration fluctuated between 1.0 to 30 micrograms/ml.
• The researchers also looked at the differences between different horse age groups. The mean concentration of SAA in foals, 12 months or younger, was higher (21.23 +/- 12.20) micrograms/ml than the concentration in adults, 18 months or older, (14.93 +/- 9.07) micrograms/ml.

SAA concentration in Mares and Horses with Induced-Inflammation

• For mares in the perinatal period, the SAA concentration stayed within the reference range before parturition, increased shortly after giving birth, peaked on the third postpartum day, and then decreased to the reference range by the end of the first postpartum month.
• In horses where inflammation was experimentally induced, the SAA concentration increased rapidly reaching four to forty times the pre-treatment value on the first day, remaining high for up to six days following the treatment. The concentration then returned to baseline between two to four weeks into the treatment correlating with the disappearance of inflammation symptoms.
• The level of SAA was elevated in most horses that exhibited inflammation signs.

Research Conclusion

Finally, the team concluded that their ELISA technique for measuring SAA in horses was both sensitive and reliable. The findings suggest a significant relationship between SAA concentrations and inflammation, and the potential for monitoring the protein as an indicator of inflammation in equines.