FURTHER CHARACTERIZATION OF IGA IN CHICKEN SERUM AND SECRETIONS WITH EVIDENCE OF A POSSIBLE ANALOG OF MAMMALIAN SECRETORY COMPONENT

  • 1 January 1976
    • journal article
    • research article
    • Vol. 31  (3) , 407-417
Abstract
Immunochemical studies of the intestinal secretory immune system of the chicken led to further characterization of IgA [immunoglobulin A] in bile, intestinal contents and serum. A component was detected in late Sephadex G-200 fractions of cecal and intestinal contents which showed partial identity with bile, intestinal and a high MW fraction of serum IgA. This component showed similar sedimentation characteristics to bovine serum albumin in sucrose density gradients, a fast electrophoretic mobility on polyacrylamide gel and is a possible analogue of mammalian secretory component (SC). Fractionation of serum from birds affected with infectious synovitis revealed 2 molecular classes of IgA. Comparative double diffusion studies produced a reaction of complete identity between bile IgA and high MW serum IgA (15S) and partial identity with low MW serum IgA (7S), suggesting a lack of an SC determinant on the latter. A spur of partial identity between 15S and 7S serum IgA was also observed. Although no direct structural homology with mammalian [porcine, bovine, caprine] or human IgA could be demonstrated by immunological cross-reactivity, the similarities of molecular characteristics, particularly emphasized by the presence of a secretory component, favor a functional analogy between the secretory immune system of the fowl and mammalian species.