Bactericidal properties of murine intestinal phospholipase A2.

SS Harwig, L Tan, XD Qu, Y Cho… - The Journal of …, 1995 - Am Soc Clin Investig
SS Harwig, L Tan, XD Qu, Y Cho, PB Eisenhauer, RI Lehrer
The Journal of clinical investigation, 1995Am Soc Clin Investig
We purified a molecule from the murine small intestine that killed both Escherichia coli and
Listeria monocytogenes, and identified it as intestinal phospholipase A2 (iPLA2) by NH2-
terminal sequencing and enzymatic measurements. The ability of iPLA2 to kill. L.
monocytogenes was greatly enhanced by 5 mM calcium, inhibited by EGTA and abolished
after reduction and alkylation, suggesting that enzymatic activity was required for iPLA2-
mediated bactericidal activity. A mouse-avirulent phoP mutant, S. typhimurium 7953S, was …
We purified a molecule from the murine small intestine that killed both Escherichia coli and Listeria monocytogenes, and identified it as intestinal phospholipase A2 (iPLA2) by NH2-terminal sequencing and enzymatic measurements. The ability of iPLA2 to kill. L. monocytogenes was greatly enhanced by 5 mM calcium, inhibited by EGTA and abolished after reduction and alkylation, suggesting that enzymatic activity was required for iPLA2-mediated bactericidal activity. A mouse-avirulent phoP mutant, S. typhimurium 7953S, was 3.5-fold more susceptible to iPLA2 than its isogenic virulent parent, S. typhimurium 14028S (estimated minimal bactericidal concentrations 12.7 +/- 0.5 micrograms/ml vs. 43.9 +/- 4.5 micrograms/ml P < 0.001). Overall, these findings identify iPLA2 as part of the antimicrobial arsenal that equips Paneth cells to protect the small intestinal crypts from microbial invasion. Because iPLA2 is identical to Type 2 phospholipase A2 molecules found in other sites, including spleen, platelets and inflammatory exudate cells, this enzyme may also contribute to antibacterial defenses elsewhere in the body.
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