PURIFICATION OF GOAT IMMUNOGLOBULIN G1 (IGG1) AND IGG2 ANTIBODIES BY USE OF STREPTOCOCCUS-DYSGALACTIAE CELLS WITH FC-RECEPTORS

The application of stabilised streptococcal cells for the purification of both immunoglobulin 1 (IgG1) and IgG2 subclasses from goat sera wa s evaluated. Guanidinium chloride extracted, lyophilised cells of the Lancefield Group C Streptococcus dysgalactiae Sd strain showed strong binding to goat IgG, reaching a capacity of approximately 1.4 mg IgG p er 100 mg cells (dry weight). The IgG preparation obtained was of high quality. In immunoelectrophoretic analysis the preparation appeared t o consist of pure IgG, whereas the high pressure liquid chromatography (HPLC) gel filtration and immunoblot analyses showed a very slight co ntamination (less than 1.3% of the total probe) with alpha(2)-macroglo bulin. The presence of both IBG subclasses in the preparation was veri fied by HPLC ion exchange chromatography. The adsorption procedure pro ved to be efficient and easy to perform without advanced technical equ ipment and the cells were reusable. As these streptococcal cells bind both IgG subclasses, this method presents an economical way for the sm all scale purification of goat IgG. Additionally the streptococcal cel ls may conveniently substitute Protein A bearing Staphylococcus aureus cells in various immunological assays.