Novel protein transfection of primary rat cortical neurons using an antibody that penetrates living cells.

An Ab-based system to deliver functional proteins into neurons was developed using the murine mAb, mAb 3E10. This was achieved by covalently conjugating catalase to the Ab so that the conjugate retained high activity for the degradation of hydrogen peroxide. Three-dimensional fluorescence microscopy was used to demonstrate penetration of the Ab into the nucleus of living primary cortical neurons. The Ab conjugate localized in both the cytoplasm and nucleus. Retention of catalase activity after penetration and distribution of conjugate was demonstrated by reduction in cell death following exposure of treated neurons to hydrogen peroxide. These studies illustrate the potential of this method for the intracellular delivery of therapeutic proteins.