Abstract: Objective To explore the role of platelet-activating factor receptor (PAFR) in adhesion and invasion of phosphorylcholine
(PC)-positive Aggregatibacter actinomycetemcomitans in cultured human umbilical vein endothelial cells (HUVEC).
Methods Cultured HUVECs were pretreated with the PAFR antagonist CV3988 or anti-human PAFR monoclonal antibody for
30 min before infection with PC-positive or -negative A. actinomycetemcomitans strains. The bacterial adhesion and invasion and
cytotoxicity in the cells were examined using MTT assay. Results Pretreatment with PAFR antagonists at 100, 200 and 500
nmol/L significantly reduced the adhesion rate []36.29±3.52)%, (19.04±3.35)% and (7.69±3.19%), respectively] and invasion rate
[(12.12 ± 1.58)% , (7.08 ± 0.29)% and (2.60 ± 2.26)% , respectively] of PC-positive A.actinomycetemcomitans in HUVECs. Similarly,
pretreatment with anti-PAFR antibody also significantly reduced A.actinomycetemcomitans adhesion and invasion in HUVECs
[(50.05 ± 5.28)% and (39.09 ± 6.50)% , respectively]. Pretreatment with PAFR antagonist (200 and 500 nmol/L) and anti-PAFR
antibody (25 μg/mL) significantly increased the viability of HUVECs incubated with PC-positive A.actinomycetemcomitans from
(25.39 ± 9.33)% to (91.12 ± 3.14)% , (94.12 ± 2.15)% and (65.5 ± 1.87)% , respectively, but such pretreatments did not increase the
viability of cells incubated with PC-negative A.actinomycetemcomitans. Conclusions PAFR plays an important role in the
adhesion, invasion, and cytotoxicity of PC-positive A.actinomycetemcomitans in cultured HUVECs.