CHEMOTHERAPEUTIC PROFILES OF HUMAN TUMORS IMPLANTED IN SCID MICE SHOWING APPRECIABLE INCONSISTENCIES WITH THOSE IN NUDE-MICE

Sensitivities to antitumor drugs of human tumor xenografts (HTXs) impl anted in C.B-17-scid and in BALB/cA-nu were compared to examine whethe r genetic backgrounds of immune deficiency of the host mice influenced the chemotherapeutic profiles of implanted tumors. In a total of 25 p airs of corresponding experiments with each host mouse strain (5 HTXs x 5 drug treatment groups), we obtained consistent results in 23 (92.0 %) experiments consisting of 10 which were both significantly effectiv e and 13 which were both ineffective, although the remaining two (8.0% ) experiments showed inconsistent results. A human T-cell lymphoma cel l line, LM-2-JCK, implanted in nude mice, was resistant to treatment w ith 65 mg/kg of cyclophosphamide, but this tumor showed sensitivity to the same treatment when implanted in either SCID mice or mice with a recombination activating gene 2 defect [BALB/cA-TgH(Rag2)] suggesting that the genetic immune background of the host mouse should not be ove rlooked as a factor affecting tumors.