Mouse peritoneal cells activated with a combination of indomethacin, poly I:C and Syncumar inhibit the take of Lewis lung carcinoma in adoptive transfer assay.

Effect of peritoneal cells (PC) from mice treated with a combination of drugs (indomethacin, poly I:C and Syncumar) on the take of Lewis lung (LL) carcinoma was studied in Winn-type adoptive transfer experiments. Transfer of PC from mice given a single intraperitoneal injection of polyinosinic-polycytidylic acid (poly I:C) or indomethacine or Syncumar (100 micrograms of each) per se did not suppress the take of Lewis lung carcinoma in the recipient mice. PC obtained from mice treated with a combination of indomethacin and poly I:C or poly I:C and Syncumar also failed to inhibit the take of the tumour. In contrast, PC collected from mice after a combined treatment with the three drugs (indomethacin + poly I:C + Syncumar) resulted in a 30-60% decrease in tumour take depending on the tumour cell/PC ratio. This effect could not be observed when a single intraperitoneal dose of cyclophosphamide was administered three days before starting of the combined treatment of the donor mice. The effector cells contributing to the tumour inhibitory effect proved to be nonadherent cells, probably large granular lymphocytes (LGL), as their suppressive effect was abrogated after treatment with the lysosomotrop vital dye neutral red.