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Title: Sensitivities of human monocytes and epithelial cells to pneumolysin are different
Authors: Hirst, Robert A.
Yesilkaya, Hasan
Clitheroe, Edwin
Rutman, Andrew
Dufty, Nicola
Mitchell, Timothy J.
O'Callaghan, Christopher L.
Andrew, Peter W.
First Published: Feb-2002
Publisher: American Society for Microbiology
Citation: Infection and Immunity, 2002, 70(2), pp.1017-1022
Abstract: The Streptococcus pneumoniae pore-forming toxin, pneumolysin, is an important virulence factor in pneumococcal pneumonia. The effect of pneumolysin on human lung epithelial and monocyte cell viability was compared. Pneumolysin caused a dose-dependent loss of viability of human lung epithelial (A549 and L132) and monocyte (U937 and THP-1) cell lines. Analysis of the dose-response curves revealed similar log 50% inhibitory concentration (pIC50) values for A549, L132, and THP-1 of 0.12 +/-0.1, 0.02 +/-0.04, and 0.12 +/- 0.13 hemolytic units (HU), respectively, but U937 cells showed a significantly greater pIC50 of 0.42 +/- 0.12 HU. Differentiation of A549 and L132 with phorbol ester or THP-1 with gamma interferon had no effect on their sensitivity to pneumolysin. However, a significant decrease in the potency of pneumolysin against U937 cells followed gamma interferon treatment. The Hill slopes of the inhibition curves were greater than unity, indicating that pneumolysin may act with positive cooperativity. Analysis of pneumolysin-treated THP-1 cells by electron microscopy revealed membrane lesions of between 100 and 200 nm in diameter.
Type: Article
Description: Copyright © 2002, American Society for Microbiology. Also available from the publisher's website at
Appears in Collections:Published Articles, Dept. of Infection, Immunity and Inflammation

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