AIM To develop atumor vaccine by fusion of H22hepatocarcinoma cells and DC,and to study its protectiveand therapeutical effect against H22 cell.METHODS:H22-DC vaccine was produced by PEG fusionof H22 and DC induced by cytokine released from splenicmononuclear cells,sorted by CD11c magnetic microbeadmarker.It was injected through the tail vein of the miceand the H_(22)-DC oncogenesis was detected in the liver,spleenand lung.In order to study the therapeutical and protectiveeffect of H_(22)-DC against tumor H_(22),two groups were divided:immune group and therapeutic group.Immune group wasfurther divided into P,D,HD and H subgroups,immunizedby PBS,DC,H_(22)-DC and inactivated H_(22),respectively,andattacked by H_(22)cell.The tumor size,tumor weight,micesurvival time and tumor latent period were recorded andstatistically analyzed;Therapeutical group was divided intothree subgroups of P,D and HD,and attacked by H_(22),thentreated with PBS,DC,and H_(22)-DC,respectively.Pathologyand flow cytometry were also applied to study the mechanismhow the H_(22)-DC vaccine attacked on the H_(22)cell.RESULTS:1.No oncogenesis was found in spleen,lungand liver after H22-DC injection.2.Hybrid vaccine immunizedmice had strongest CTL activity.3.In the immune group,latent period was longer in HD subgroup than that in P,Hand D subgroup;and tumor size and weight were smaller inHD subgroup than that in P,H and D subgroup.4.Intherapeutic group,tumor size was smaller in HD subgroupthan that in P,D subgroup.CONCLUSION:1.H22-DC tumor vaccine is safe withoutoncogenesis in vivo.2.Hybrid vaccine can stimulate potentspecific CTL activity against H22.3.H22-DC vaccine hasdistinctive prophylatic effect on tumor H22 and can inhibitthe tumor growth. AIM To develop atumor vaccine by fusion of H22 hepatocarcinoma cells and DC, and to study its protective and therapeutical effect against H22 cell. METHODS: H22-DC vaccine was produced by PEG fusion of H22 and DC induced by cytokine released from splenic mononuclear cells, sorted by CD11c magnetic It was injected through the tail vein of the mice and the H_ (22) -DC oncogenesis was detected in the liver, spleen and lung. In order to study the therapeutical and protective effect of H_ (22) -DC against tumor H_ (22) , two groups were divided: immune group and therapeutic group. Immuno was was divided into P, D, HD and H subgroups, immunized by PBS, DC, H_ (22) -DC and inactivated H_ 22) cell. Tumor size, tumor weight, micesurvival time and tumor latent period were recorded and statistically analyzed; Therapeutical group was divided intothree subgroups of P, D and HD, and attacked by H_ (22), thentreated with PBS, DC, and H_ (22) -DC, respectively. Pathology and flow cyto metry were also applied to study the mechanismhow the H_ (22) -DC vaccine attacked on the H_ (22) cell.RESULTS: 1.No oncogenesis was found in spleen, lung and liver after H22-DC injection.2.Hybrid vaccine immunizedmice had strongest CTL activity. 3. In the immune group, latent period was longer in HD subgroup than that in P, Hand D subgroup; and tumor size and weight were smaller in HD subgroup than that in P, H and D subgroup. 4. Intherapeutic group , tumor size was smaller in HD subgroupthan that in P, D subgroup. CONCLUSION: 1. H22-DC tumor vaccine is safe without oncogenesis in vivo.2. Hybrid vaccine can stimulate potentspecific CTL activity against H22.3. H22-DC vaccine hasdistinctive prophylatic effect on tumor H22 and can inhibit the tumor growth.