INFLUENCE OF LAK CELLS ON EXPRESSION OF HLA-DR ANTIGEN ON LARYNGEAL CARCINOMA CELL-LINE IN NEW CULTURE SYSTEMS

We demonstrated the enhancement of HLA-DR antigen expression on cultur ed laryngeal carcinoma cells (Hep 2) by in vitro cultivation with LAK cells using flow cytometric and immunohistological analysis. For in vi tro cultivation of tumor cells with LAK cells, we used newly developed experimental systems (the Transwell double-dish system and experiment al three-dimensional tumors). In flow cytometric analysis, expression of HLA-DR antigen on tumor cells was compared before and after co-cult ivation with LAK cells. When tumor cells were cultured separately with LAK cells in a Transwell Petri dish and the expression of HLA-DR anti gen on tumor cells was analyzed by flow cytometry, the expression of H LA-DR antigen on tumor cells was increased in a dose-dependent manner related to the number of LAK cells used. Furthermore, when anti-interf eron-gamma monoclonal antibody was added to the experimental system, e nhancement of HLA-DR antigen expression was blocked. These findings we re consistent with immunohistological studies, in which experimental t hree-dimensional Hep 2 cell tumors were established in double-layered agar with/without being co-cultivated with LAK cells. The expression o f HLA-DR antigen in this system was significantly increased when compa red to such expression before cultivation with LAK cells. These findin gs suggested that the culture systems employed in this study could be a possible model for examining solid tumor in vivo biological response s. This enhanced expression of HLA-DR antigen may also represent one o f the multifactorial responses seen with adoptive LAK cell immunothera py for solid tumors.