Isolation and Characterization of Serum Immunoglobulins from kalbasu (Labeo calbasu) (Hamilton, 1822)

The Ig (Ig) from the serum of kalbasu (Labeo calbasu, Cyprinidae) was isolated and characterized during the present investigation. Kalbasu of 500-800 g size were immunized with Bovine Berum Albumin (BSA) to prepare immune sera. The Ig was isolated from the immune sera by an immunoaffinity column of BSA-Sepharose 4B. The purity and homogeneity of the isolated sample were confirmed by observing a single band in native gradient polyacrylamide gel electrophoresis. This also indicated the presence of only single type of Ig in kalbasu. The molecular weight of native Ig molecule was determined from the gel to be ~857 kDa. In Sodium dodecyl sulphate polyacrylamide gel electrophoresis (E), the constituent heavy (H) and light (L) polypeptide chains of the Ig molecules were identified. There were only one type of H chain with a molecular weight of ~78 kDa and two types of L chain with molecular weights of ~27 kDa and ~26 kDa. The antiserum against the kalbasu Ig was raised in a rabbit and adsorbed with 10% kalbasu liver tissue homogenate in order to enhance its specificity. By an indirect ELISA standardized using this adsorbed rabbit antiserum, the normal serum Ig concentration in kalbasu was estimated to be ~2.82 mg.ml^-1 (n=22), which is around 8% of the total serum proteins.