Blood group serology of the pig
The serology of the pig has been investigated firstly in terms of specific antigen/antibody reactions and secondly on a more general basis of the protein constituents of porcine serum. The antigen/antibody reactions studied have been those involved in red blood cell typing and serum immunoglobulin allotyping. These two approaches have been correlated by using red cell typing reactions and immuno-diffusion in gel, immuno-electro- phoretic, specific staining, passive haemagglutination, haemagglutination inhibition, gel filtration, ion exchange and starch gel electrophoretic techniques. In order to achieve this correlation, it has been necessary to partially separate and identify a large number of pig serum components on the basis of molecular size, electrical charge and specific staining characteristics. These components not only include those involved in well established systems of pig serum protein biochemical polymorphism such as haemopexin, transferrin, serum amylase, prealbumin, caeruloplasmin and slow oc g-globulin But also additional constituents such as fast and slow lipoprotein, variable«: -globulin, complement components, haptoglobin and the porcine immunoglobulins Ig M, Ig A, Ig G^^ and Ig Gg. A provisional investigation of the porcine A-0 blood group system has also been initiated.More specifically the following conclusions have been established. Antibodies reacting with pig red blood cell typing factors by the direct agglutination, haemolytic and indirect sensitation (Ooombs) test have been demonstrated in the 19 S, 7 S and intermediate fractions on Sephadex G200 fractionation. These reactivities have been partially correlated with porcine Ig M, Ig G and only tentatively with Ig A. The heterogeneity of distribution of these reactivities within the 7 S peak of G200 fractionation suggests the possibility of novel sub-classes of Ig G on a molecular size and/or steric hindrance to gel filtration basis.Iso-immune precipitins against pig immunoglobulin allotypes have been produced using a double emulsion (water-oil- water-WOW) type of adjuvant incorporating whole pig serum.The reactions are demonstrated by double diffusion (Ouchterlony) and immuno-electrophoretic procedures in agar gel. The late hyperimmune precipitin has Ig G^ characteristics. Antibodies with two specificities anti factor 1 and anti factor 2 have been investigated.Allotype factor 1 occurs on Ig G molecules with a full range of electrophoretic mobility from to y g* Factor 2 has a more restricted distribution on Ig G-^ molecules. These factors are therefore termed porcine Ig G - allotype factor 1 and porcine Ig G-, - allotype factor 2 or P. Ig G - Al and P. Ig G-j - A2.In the pig A-0 blood type system the failure of neonatal piglets’ cells to type as A positive with conventional typing techniques has been shown to be a property of their serum, or iii.of their cells and serum, hut not of their cells alone. It is not caused hy a quantitative lack of A blood group substance in the serum.In adult pigs a provisional investigation has established that all pigs typing as 0 negative by direct test possess an antibody accessible but non-haemolisable cryptantigenic form of 0 on their red cells.