Production of polyclonal antisera against barramundi (Lates calcarifer Bloch) serum immunoglobulin derived from affinity columns containing mannan-binding protein or staphylococcal protein A

Barramundi (Lates calcarifer Bloch) immunoglobulin (Ig) was purified by affinity chromatography using staphylococcal protein A (SpA) or mannan-binding protein (MBP) as capture ligands. Both ligands realised a pure product, although the SpA column resulted in a higher yield. In common with other teleosts, barramundi Ig appears to be a tetramer made up of two heavy chain (HC) and two light chain (LC) moieties with individual molecular weights (MW), determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), of 24 and 86 kDa, respectively. Gel filtration indicated that the native la molecule had a molecular weight of approximately 929 kDa. Western blot analyses demonstrated that rabbit antiserum raised against the whole MBP fraction was specific for HC and LC Ig components, whereas antisera directed against the HC or LC constituents of the SpA fraction were specific for HC and LC components, respectively. Analyses by flow cytometry and enzyme-linked immunosorbent assay (ELISA) revealed reactivity of all antisera with varying percentages of barramundi lymphocytes and SpA-purified barramundi Ig, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.