Augmentation of chemotherapeutically induced remission of a murine leukemia by a chemical immunoadjuvant.

The effect of combining chemotherapy and immunostimulation, induced by a chemical, against a murine lymphoid leukemia was investigated. When tetramisole or levamisole were used following one administration of 1,3-bis(2-chloroethyl)-l-nitrosourea, a significantly higher percentage of long-term surviviors occurred in contrast to the groups of animals treated with drug or immunostimulant alone. The administration of chemical immunostimulator was effec tive at any time during 1, 3-bis(2-chloroethyl)-l-nitrosourea-induced remission. Low doses of the chemicals were as effective as higher doses in evoking this synergistic response. The role of chemical immunostimulators in combination with antitumor drugs is discussed.