Application de l'ultracentrifugation en gradient de densité à l'analyse des immunoglobulines

The ultracentrifugation method in linear density gradient of sucrose, proposed by McEwen (1967), was applied to the study of serum immunoglobulins and immunoglobulins preparations for therapeutic use. The gradient content was analysed at the end of centrifugation by continuous u.v. spectrophotometry. So, it was possible to measure the standard sedimentation coefficient s20,w for each peak and to determine the respective percentages of each type of separated macromolecules. This method has many advantages. It is less expensive than classical analytical ultracentrifugation. It allows simultaneous analysis of several samples with a good accuracy and recovering of fractions for specific, biological assays of the molecule to be studied. This method is suitable for every macromolecule (proteins, viruses, etc.) and has a wide spectrum of application in immunology.