Figure 2. Bar diagram representing optical densities as a measure of positive reactivity of patient sera to 108 synthetic peptides spanning whole molecules of P. gingivalis HSP60 and human HSP60, respectively. The number indicates each patient. Fifteen antigenic peptides that showed positive signals in more than four out of six patients were designated as B-cell epitopes of P. gingivalis HSP60. In the same manner, B-cell epitopes of human HSP60 were identified.