UP-REGULATION OF DF3, IN ASSOCIATION WITH ICAM-1 AND MHC CLASS-II BY IFN-GAMMA IN SHORT-TERM HUMAN MAMMARY-CARCINOMA CELL-CULTURES

This study was designed to determine whether in vitro exposure of isol ated short-term human primary and metastatic breast tumor cell culture s to interferon-gamma (IFN-gamma) could enhance expression of the brea st tumor associated DF3 antigen in association with the intercellular adhesion molecule 1 (ICAM-1) and MHC class II molecules. Cell cultures were established from primary solid tumors and metastatic cells as pr eviously described (Sgagias et al., 1995). Data show that recombinant human IFN-gamma treatment in vitro, dramatically increased the breast tumor associated DF3 antigen, in association with ICAM-1, and MHC clas s II antigens in primary breast cancer cell cultures. All primary brea st tumor cell cultures constitutively expressed high levels of HLA-cla ss I antigen. Metastatic breast cancer cell cultures expressed high le vels of DF3 and recombinant human IFN-gamma treatment, in vitro, upreg ulated ICAM-1 and MHC class II antigens before and after passage of th e metastatic cells through the nude mouse. Metastatic breast cancer ce lls similar to primary breast cancer cells constitutively expressed hi gh levels of MHC class I antigens. In addition, three LAK cell lines s ignificantly lysed the primary and the metastatic breast tumor cell cu ltures to the same degree before and after passage of the metastatic c ancer cells through the nude mouse. These data indicate the upregulati on of the breast tumor associated DF3 antigen in vitro after IFN-gamma treatment and its persistence in vivo, after passage of the metastati c breast cancer cells through the nude mouse. The ability of IFN-gamma to upregulate the breast tumor associated DF3 antigen in association with the ICAM-1 and HLA class II antigens may play an important role i n eliciting an immune response which may contribute to the immunodiagn osis, and immunotherapy of breast cancer.