AIM:To characterize the anticancer function of cytokine-induced killer cells(CIK)and develop an adoptiveimmunotherapy for the patients with primary hepatocellularcarcinoma(HCC),we evaluated the proliferation rate,phenotype and the antitumor activity of human CIK cellsfrom healthy donors and HCC patients in vitro and in vivo.METHODS:Peripheral blood mononuclear cells(PBMC)fromhealthy donors and patients with primary HCC were incubatedin vitro and induced into CIK cells in the presence of variouscytokines such as interferon-gamma(IFN-γ),interleukin-1(IL-1),IL-2,and monoclonal antibody(mAb)against CD3.The phenotype and characterization of CIK cells wereidentified by flow cytometric analysis.The cytotoxicity of CIKcells was determined by ~(51)Cr release assay.RESULTS:The CIK cells were shown to be a heterogeneouspopulation with different cellular phenotypes.Thepercentage of CD3~+/CD56~+ positive cells,the dominanteffector cells,in total CIK cells from healthy donors andHCC patients,significantly increased from 0.1-0.13% at day0 to 19.0-20.5% at day 21 incubation,which suggested thatthe CD3~+ CD56~+ positive cells proliferated faster than othercell populations of CIK cells in the protocol used in thisstudy.After 28 day in vitro incubation,the CIK cells frompatients with HCC and healthy donors increased by morethan 300-fold and 500-fold in proliferation cell number,respectively.CIK cells originated from HCC patientspossessed a higher in vitro antitumor cytotoxic activity onautologous HCC cells than the autologous lymphokine-activated killer(LAK)cells and PBMC cells.In in vivoanimal experiment,CIK cells had stronger effects on theinhibition of tumor growth in Balb/c nude mice bearing BEL-7402-producing tumor than LAK cells(mean inhibitory rate,84.7% vs 52.8%,P<0.05)or PBMC(mean inhibitoryrate,84.7% vs 37.1%,P<0.01).CONCLUSION:Autologous CIK cells are of highly efficientcytotoxic effector cells against primary hepatocellularcarcinoma cells and might serve as an alternative adoptivetherapeutic strategy for HCC patients. AIM: To characterize the anticancer function of cytokine-induced killer cells (CIK) and develop an adoptive immunotherapy for the patients with primary hepatocellular carcinoma (HCC), we evaluated the proliferation rate, phenotype and the antitumor activity of human CIK cells from healthy donors and HCC patients in vitro and in vivo. METHODS: Peripheral blood mononuclear cells (PBMC) from healthy donors and patients with primary HCC were incubated in vitro and induced into CIK cells in the presence of various cytokines such as interferon-gamma (IFN-γ), interleukin-1 ( IL-1), IL-2, and monoclonal antibody (mAb) against CD3. The phenotype and characterization of CIK cells were identified by flow cytometric analysis. Cytotoxicity of CIK cells was determined by ~ (51) Cr release assay. cells were shown to be heterogeneouspopulation with different cellular phenotypes.Thepercentage of CD3 ~ + / CD56 ~ + positive cells, the dominanteffector cells, in total CIK cells from healthy donors andHCC patients, signif icantly increased from 0.1-0.13% at day 0 to 19.0-20.5% at day 21 incubation, which suggested that the CD3 ~ + CD56 ~ + positive cells proliferated faster than other populations of CIK cells in the protocol used in this study. After 28 days in vitro incubation of the CIK cells from patients with HCC and healthy donors increased by morethan 300-fold and 500-fold in proliferation cell number, respectively. CIK cells originated from HCC patients captured a higher in vitro antitumor cytotoxic activity on autologous HCC cells than the autologous lymphokine-activated CIK cells had stronger effects on the inhibition of tumor growth in Balb / c nude mice bearing BEL-7402-producing tumors than LAK cells (mean inhibitory rate, 84.7% vs 52.8% , P <0.05) or PBMC (mean inhibitory rate, 84.7% vs 37.1%, P <0.01) .CONCLUSION: Autologous CIK cells are of highly efficient cytotoxic effector cells against primary hepatocellular carcinoma cells and might serve as an alternativeadoptive therapeutic strategy for HCC patients.