Inhibition of human acute lymphoblastic leukemia cells by immunotoxins: potentiation by chloroquine

Immunotoxins containing pokeweed antiviral protein and monoclonal antibodies against human T cells or human transferrin receptor efficiently killed acute lymphoblastic leukemia cells. Chloroquine specifically enhanced the rate of protein synthesis inhibition by immunotoxin. Depending on its concentration, chloroquine (10 to 100 micromolar) reduced by up to 65-fold the amount of immunotoxin required to inhibit protein synthesis in the target cells 50 percent.