Figure 3. Immunohistochemical studies for TLR4 and F4/80. A: Unstimulated C3H/HeN mouse peritoneal macrophages were marked with F4/80 staining. Cells were approximately round. B: No staining was seen when under identical experimental conditions when the primary antibody was replaced with normal IgG at the same concentration (negative control). C: The TLR4+ cells of C3H/HeN mice possessed round-ovoid morphology, expressed in the membrane without LPS stimulation.