Figure 4. Analysis of protein phosphorylation by Western blot analysis. Human gingival fibroblasts were stimulated with LPS from Porphyromonas gingivalis (P-LPS) in the presence or absence of anti-Toll-like receptor 4 (TLR4) monoclonal antibody (anti-TLR4 mAb). (A) The cells were subjected to Western blotting with anti-phosphotyrosine monoclonal antibody. (B) The immunoprecipitate was analyzed with anti-IL-1 receptor-associated kinase (IRAK) monoclonal antibody (Wang et al., 2000a,b).