Isolation and characterization of serum immunoglobulin classes of the ostrich (Struthio camelus)

Immunoglobulins were separated from ostrich sera by ammonium sulfate precipitation and ion-exchange chromatography. Two classes of immunoglobulin could be identified, corresponding to IgG and IgM of other species, based on elution profiles from ion-exchange columns and molecular mass estimation on gel-filtration chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). On SDS-PAGE, the heavy chains of IgG and IgM were shown to have molecular masses of 67.5 kDa and 65 kDa, respectively, and the light chains common to both were shown to have a molecular mass of 27 kDa. The ostrich immunoglobulins were not recognized by monoclonal and polyclonal antibodies against immunoglobulins of many species of animals tested, nor by antibodies against chicken immunoglobulins.