M1-like macrophages stimulated with L-MTP-PE require IFN-γ for anti-tumor activity. M1-like Macrophages were activated with LPS + IFN-γ, L-MTP-PE + IFN-γ, L-MTP-PE alone, L-PBS + IFN-γ or L-PBS alone. Tumor cell numbers of (A) HOS-143b (n = 3–5) and (B) OHS (n = 2–4) were assessed after two-day co-culture with activated macrophages and statistically analyzed relative to the control by ANOVA and Dunnett’s post test as indicated. (C) Surface expression of Fcγ receptors (CD64, CD32 and CD16), HLA-DR and CD86 was analyzed on M1-like macrophages after activation with LPS + IFN-γ, L-MTP-PE + IFN-γ, L-MTP-PE alone, L-PBS + IFN-γ or L-PBS alone. Representative data of two experiments are depicted.