Adenosine, AMP, and protein phosphatase activity in sandfly saliva

Oren Katz*, John N. Waitumbi, Ronnie Zer, Alon Warburg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


As they probe the skin for blood, sand flies inject saliva that prevents hemostasis. Sand fly saliva also promotes leishmaniasis by suppressing immunologic functions of macrophages. Saliva of Phlebotomus papatasi, the vector of Old World cutaneous leishmaniasis, contains adenosine and AMP. We show that Ph. papatasi saliva as well as pure adenosine down-regulate the expression of the inducible nitric oxide (NO) synthase gene in activated macrophages. In addition Ph. papatasi, but not Lutzomyia longipalpis, saliva inhibits the production of NO. Taken together, these data suggest that salivary adenosine is responsible for the down-regulation of NO synthesis. Saliva of both genera Phlebotomus and Lutzomyia contains significant levels of endogenous protein phophatase-1/2A-like activity that is heat labile, inhibitable by okadaic acid and calyculine a, and does not require divalent cations.

Original languageAmerican English
Pages (from-to)145-150
Number of pages6
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number1
StatePublished - Jan 2000


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