Upregulation of DF3,in Association with ICAM-1 and MHC Class II by IFN-γ in Short-Term Human Mammary Carcinoma Cell Cultures

This study was designed to determine whether in vitro exposure of isolated short-term human primary and metastatic breast tumor cell cultures to interferon-γ (IFN-γ) could enhance expression of the breast tumor associated DF3 antigen in association with the intercellular adhesion molecule 1 (ICAM-l) and MHC class II molecules. Cell cultures were established from primary solid tumors and metastatic cells as previously described (Sgagias et al., 1995). Data show that recombinant human IFN-γ treatment, in vitro, dramatically increased the breast tumor associated DF3 antigen, in association with ICAM-l, and MHC class II antigens in primary breast cancer cell cultures. All primary breast tumor cell cultures constitutively expressed high levels of HLA-class I antigen. Metastatic breast cancer cell cultures expressed high levels of DF3 and recombinant human IFN-γ treatment, in vitro, upregulated ICAM-l and MHC class II antigens before and after passage of the metastatic cells through the nude mouse. Metastatic breast cancer cells similar to primary breast cancer cells constitutively expressed high levels of MHC class I antigens. In addition, three LAK cell lines significantly lysed the primary and the metastatic breast tumor cell cultures to the same degree before and after passage of the metastatic cancer cells through the nude mouse. These data indicate the upregulation of the breast tumor associated DF3 antigen in vitro after IFN-γ treatment and its persistence in vivo, after passage of the metastatic breast cancer cells through the nude mouse. The ability of IFN-γ to upregulate the breast tumor associated DF3 antigen in association with the ICAM-l and HLA class II antigens may play an important role in eliciting an immune response which may contribute to the immunodiagnosis, and immunotherapy of breast cancer.