TNF and infection: Infection of gingival fibroblasts with a clinical P. gingivalis strain harboring the G231N, E232T, N235D variant isolated from advanced PD donor (G231N, E232T, N235D+ adv) or with a laboratory mutant of the G231N, E232T, N235D variant introduced to the ATCC 33277 P. gingivalis strain (ATCC T2) upregulated the expression of TNF-α (Figure 3A) and IL-6 (Figure 3B).