The effectiveness of toxin-neutralizing antibodies is considered to be mediated through the interaction of the variable region of the antibody and the toxin; however, recent studies suggest that the constant region (Fc) of antibodies also influence efficacy.

In this issue of the Journal of Clinical Investigation, Jeffrey Ravetch and colleagues at The Rockefeller University demonstrate that engineering the Fc domain of anti-toxin antibodies increases toxin neutralization activity through enhancing the interaction between toxin-targeting antibodies and the Fc receptor on immune cells. The authors found that mice expressing humanized FcR were better protected from anthrax toxin when given engineered anti-anthrax toxin antibodies.

This study suggests that engineering the Fc domains of antibodies can be used as a strategy to enhance antibody efficacy.

TITLE: Human IgG Fc domain engineering enhances antitoxin neutralizing antibody activity