CD30 is a member of the tumor necrosis factor superfamily. In this study, we examined the effect of four anti-CD30 (aCD30) antibodies (Abs) on CD30-positive anaplastic large cell lymphoma-derived cell line, Ki-JK. The aCD30 Abs suppressed [3H]thymidine (TdR) incorporation. With a TdT mediated dUTP-biotin nick end labeling method, apoptosis was detected in Ki-JK cells at day 5 after the addition of aCD30 Ab to the culture. Genistein, an inhibitor of protein tyrosine kinase, had no effect on aCD30 Ab-induced apoptosis. The aCD30 Ab simultaneously induced interleukin-8 (IL-8) secretion in the Ki-JK cells. In culture of the Ki-JK cells with aCD30 Ab for 5 days, the IL-8 concentration of the cell free-supernatant increased to 240 +/- 16 pg/ml, though the concentration was < 12.5 pg/ml without aCD30 Ab. In combination with aCD30 Ab, genistein decreased the concentration of IL-8 in day 5 supernatants. Although, doxorubicin and herbimycin-A suppressed [3H]TdR incorporation and induced apoptosis in the Ki-JK cells, they did not induce IL-8 secretion. Only aCD30 Ab-induced apoptosis was accompanied by IL-8 secretion. IL-8 mRNA was not detected in the Ki-JK cells by reverse transcription-polymerase chain reaction assay. IL-8 mRNA was detected 5 days after adding aCD30 Ab to the culture.