Transport of hydrophobized fragments of antibodies through the blood-brain barrier.

Hydrophobized and non-hydrophobized Fab fragments of human antibodies against gliofibrillar acid protein (GFAP) and brain specific alpha 2-glycoprotein (alpha 2GP) were used to study their penetration through the blood-brain barrier (BBB). These Fab fragments were modified by stearoyl chloride in reversed micelles of aerosol OT in octane (one or two fatty acid residues attached to protein molecule). Modified and non-modified 125I-labelled Fab fragments were intracardially administered to rats. The amount of label accumulated in brain was 55% higher than the total amount in all other organs. In contrast, non-hydrophobized Fab fragments did not penetrate through the BBB. We assume that the artificial hydrophobization of Fab fragments can increase their capability to penetrate through the cell membranes and, in particular, the BBB.