TNF and periodontitis: Although, the latter two reports indicated that sSema4D mediated elevation of TNF-α production by monocytes as well as that of sRANKL production by osteoblasts are, in part, responsible for the increased osteoclastogenesis, respectively, [34,43], we could not find such an effect of Sema4D on the productions of TNF-α or sRANKL in the mouse periodontal tissue induced of periodontitis (Figure 4D).