PIG-MAP, PORCINE ACUTE-PHASE PROTEINS AND STANDARDIZATION OF ASSAYS IN EUROPE

The pattern of plasma proteins changes greatly following infection, in flammation or tissue injury. The concentration of some proteins referr ed to as acute phase proteins (APPs) significantly increases within ho urs or days after the onset of these processes. In contrast, the conce ntration of other proteins, such as albumin (Alb), called negative acu te phase proteins, decreases. APPs have been extensively studied in ma n and rat, but less so in other species. In recent work, the APPs have been characterised in pigs in response to inflammation following turp entine injection. The concentrations of C reactive protein (CRP) and h aptoglobin (Hp) increase 5-7 times 48 h after the injection. Porcine A lb, alpha-lipoprotein, fetuin and transferrin were negative APP. Final ly, the concentration of alpha(1)-acid glycoprotein and alpha(1)-prote ase inhibitor (alpha(1)-antitrypsin) did not change significantly duri ng the inflammation. In addition to CRP and Hp, a serum alpha(2)-globu lin was observed to be the major acute phase (MAP) protein in pigs. Pi g-MAP is a new mammalian plasma protein, which is the pig counterpart of a recently cloned human serum protein denominated PK-120 or MRP. Pi g-MAP shows promise as a prominent positive APP and has been shown to be a good marker of different pig pathologies. Recent collaboration in an EU-Concerted Action Project (AIR3-CT94-2255) has joined several la boratories involved in pig APP studies in Europe. These groups have be en working on the approach that APP are markers for the presence of in fectious, inflammatory and pathological lesions in animals. The abilit y to monitor the APP concentration in serum of pigs will improve the q uality and safety of the meat produced as well as provide important di agnostic information for animal health and welfare. The serum concentr ation of APP are altered in several diseases supporting that APP can b e used as markers of pig pathologies. Antibody-based techniques (for e xample, ELISA and immunonephelometric assays) have been and will be fu rther developed for the selected porcine APP to accomplish these objec tives. However, an important effort should be made in the future betwe en laboratories and between countries in Europe to standardise assays for porcine proteins and to harmonise the different methods currently used for measuring the porcine APPs.