title: Heterogeneous expression of a murine B16 melanoma-associated antigen correlates with cell cycle.
abstract: A murine monoclonal antibody (MM2-3C6) that reacts with a B16 murine melanoma-associated membrane antigen was used to study the relationship of antigen expression to the cell cycle. Dual-parameter flow cytometric measurements of membrane antigen and DNA revealed that antigen-positive cells were present throughout the cell cycle. Peak antigenic expression was noted during the late log phase of the cell growth curve with negligible antigen-negative population. The emergence of a distinct antigen-negative population (30%-40%) was noted in the late stationary phase. Cell cycle analysis indicated that the negative subpopulation was restricted to the G0/G1 phase, thus, demonstrating antigenic heterogeneity within the tumor cell population. Cell sorting was performed to analyze the origin of such heterogeneity. Following two sequential sortings, the antigen-negative cells became antigenic upon reculture. Again, at the late stationary phase, a distinct antigen-negative population (30%-40%) emerged. The sorted antigen-positive cells showed flow cytometric profiles identical to the sorted antigen-negative population upon reculture. Therefore, in this murine model, it appears that antigen expression is cell cycle dependent and such expression seems to be associated with proliferation.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D002469:Cell Separation; D005434:Flow Cytometry; D008545:Melanoma / Q000276:immunology*; D051379:Mice
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface