Background: Understanding tumor antigen expression and its correlation with the cell cycle may help in designing immunotherapy by monoclonal antibodies. Therefore, we studied the in vitro expression of sarcoma-associated antigens p102 and p200 in the G, S, and G2/M phases of sarcoma cell lines.
Methods: The expression of human cell surface sarcoma-associated antigens p102 and p200 was studied in 13 human sarcoma cell lines, using flow cytometry.
Results: p102 was detected by monoclonal antibody 19-24-6 in all 13 sarcoma cell lines, and p200 was detected by monoclonal antibody 29-13-17 in five of 13. p102 antigen expression was 1.4- to 3.4-fold higher (p < 0.001) than p200 expression. Although sarcoma cell lines showed a wide range of p102/p200 antigen expression, over 99% of the entire in vitro and in vivo cell population was found to be p102- and/or p200-positive. In three cell lines, p102 expression was cell cycle-dependent, with relative fluorescence intensity ranging from 13.8% to 23.9% higher at the G1 phase than at the G2/M phase. In three cell lines, the expression of p200 at the GI phase was 22.4% to 40.9% percent higher than at the G2/M phase.
Conclusions: The heterogeneity and cell cycle dependence of p102/p200 antigen expression in sarcoma cells suggest that monoclonal antibodies 19-24-6 and 29-13-17 might be applied to the immunotherapy of sarcoma.