Table I.

Percentage inhibition of PMN apoptosis by TLR agonistsa

Percentage Inhibitionb
Whole BloodIsolated PMN
PBS00
LPS (TLR4)87.4 ± 2.4c70.3 ± 7.8c
PGN (TLR2)81.8 ± 7.3c69.1 ± 4.9c
R-848 (TLR7/8)83.5 ± 4.1c66.7 ± 1.9c
CpG-DNA (TLR9)75.2 ± 4.0c65.1 ± 3.2c
Pam3CSK4 (TLR1/2)60.2 ± 5.8cd57.3 ± 2.3c
MALP-2 (TLR2/6)58.1 ± 6.6cd49.3 ± 5.8cd
Flagellin (TLR5)16.1 ± 7.212.7 ± 5.4
Loxoribine (TLR7)10.6 ± 4.513.6 ± 3.2
  • a Whole blood or isolated PMN were incubated in 24-well tissue cultures plates at 37°C with 5% CO2 for 8 h with PBS or TLR agonists at the following optimal concentrations: LPS, 10 ng/ml (TLR4); PGN, 1 μg/ml (TLR2); R-848, 10 μg/ml (TLR7/8); CpG-DNA, 100 μg/ml (TLR9); Pam3CSK4, 500 ng/ml (TLR1/2); MALP-2, 10 ng/ml (TLR2/6); flagellin, 100 ng/ml (TLR5); or loxoribine, 100 μM (TLR7). PMN were identified by using a FITC anti-CD15 Ab. Apoptosis was quantified by staining with allophycocyanin-annexin V and 7-AAD as described in Materials and Methods.

  • b Results are expressed as the percentage inhibition of PMN apoptosis [1 − (% of total annexin V+ PMN in TLR agonist-treated sample/% of total annexin V+ PMN in PBS-treated sample)] × 100. Values are means ± SEM (n = 5).

  • c Significantly different from sample incubated with PBS (percentage inhibition of PMN apoptosis = 0) and samples incubated with flagellin or loxoribine (p < 0.05).

  • d Significantly different from samples incubated with LPS, PGN, R848, or CpG (p < 0.05).