The molecular weight ratio of monomethoxypolyethylene glycol (mPEG) to protein determines the immunotolerogenicity of mPEG proteins

Immunotolerogenic activity of monomethoxypolyethylene glycol- (mPEG) conjug ated proteins is a beneficial property in protein pharmaceutics. However, p rocedures for the preparation of tolerogenic mPEG proteins have not yet bee n defined. We prepared mPEG proteins with different mPEG contents using thr ee proteins, hen egg lysozyme, ovalbumin and bovine gamma globulin, and the ir tolerogenicities to antigen-specific T and B cell responses were examine d. We found the most appropriate ratio of tolerance induction to be 1.5-2.0 , which is the molecular weight ratio of conjugated total mPEGs to protein. This value may assist in the preparation of tolerogenic mPEG proteins.