Selective killing of human monocytes by an immunotoxin containing partially denatured mistletoe lectin I

The in vitro activity of an immunotoxin (IT) prepared by conjugating the monocyte specific RoMo-1 monoclonal antibody and partially inactivated Mistletoe lectin I (dMLI) containing inactivated B chain has been initially characterized. It is shown that while not affecting other mononuclear cells viability, this IT is capable of selectively destroying human monocytes after 24 h exposure thus resulting in the abrogation of monocyte support for PHA reactivity in mononuclear cell preparations. Therefore it seems to be possible to use this non-sugar binding holotoxin for immunotoxin preparation.