Expression and analysis of McAbs antigen against human hepatocellular carcinoma

AIM: To analyze the cause of tumor antigen heterogeneity and solve the problem of targeting diagnosis and therapy.METHODS: Using flow cytometry, the expression of McAbs antigen against human hepatocellular carcinoma (HAb18, E₅, F₁₁ and HAb27) was investigated. Analyses of the antigen sites were made quantitatively on the human hepatoma cell lines (SMMC-7721; QGY-7701; BEL-7402; HHCC and 9204). In particular, expression of human hepatoma, its association with antigen HAg18, and its relation s with cell cycle in four human hepatoma cell lines using the methods of indirect immunofluorescence and dual-parameter DNA dyeing were studied.RESULTS: The corresponding antigen of McAbs HAb18, HAb27, E₅ were expressed on the five hepatoma cell lines and F₁ was expressed only on the 7721 and 7701 hepatoma cell lines, but their mean fluorescence intensity showed different values on each cell line. HAb18 and HAb27 showed a relatively high level of expression, while E₅ and F₁₁ showed a lower level of expression. The value of AI (additivity index) was 136% for HAb18 and E₅, 108% for HAb18 and HAb27, and 118.6% for E₅ and H27As AI < 30% shows that both antibodies sites are the same, AI > 40% shows that both anti bodies sites are different, so the HAb18, HAb27 or E₅ McAbs were combined in pairs, showing that their antigen sites were different. Furthermore, HAg18 antigen was expressed very highly and the positive rate of HAg18 was 100% in all the four human hepatoma cell lines. The was a mean intensity fluorescence was 8.237 ± 1.168 for SMMC-7721; 5.627 ± 1.678 for QGY-7701; 4.378 ± 1.525 for BEL-7402 is 4.378 ± 1.525 and 7.38 ± 1.919 for HHCC. However, in the normal human liver cell (QZG), HAg18 antigen showed low expression (0.534 ± 0.018) and its positive rate was only 9%. The relationship between human hepatoma associated antigen HAb18 and the cell cycle was expressed at the lowest level in G₀-G₁ stages, a higher level in S stage and the highest level in G₂-M stage.CONCLUSION: Analysis of the anti-hepatoma McAbs corresponding to antigen may provide the basis for targeted diagnosis and therapy. The expression heterogeneity of human hepatoma-associated antigen HAg18 is related to the stage of cell cycle in the same cell lines, but not related to the stage of cell cycle in different cell lines.