[Induction and measurement of delayed hypersensitivity to OK-432]

This study was performed intending to demonstrate whether delayed hypersensitivity (DH) to OK-432 might augment the antitumor effect of intratumoral injection of OK-432. In this preliminary report, we showed that 1) DH to OK-432 was inducible in BALB/c mice by injecting 2KE of OK-432 with Freund's incomplete adjuvant into foot pads 2) DH was assayed by direct macrophage migration inhibition test (MIT) of Harrington's microdroplet method using 100 micrograms/ml of Su-M protein extracted from OK-432 as in vitro test antigen 3) the highest MI was observed in the second week after sensitization 4) strong and stable DH was induced after the second sensitization at the interval of two weeks.