Surface marker expression of HPV-16-positive primary tumor cell lines with and without IFN-γ treatment. The cells were stained with anti-HLA class I antibody (W6/32), anti-HLA-A2 antibody (BB7.2), anti-HLA class II antibody (IVA12), anti-HLA class II antibody (9.3F10), or anti-CD54 (ICAM-1). The results from two experiments are shown because the expression levels of some antigens were different. (A) First experiment. (B) Second experiment.