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This study was initiated to investigate the mechanism of action of a new indomethacin derivative, indomethacin-phenylalanine (indo-Phe) in human monocytes. We determined the effect of indo-Phe on the induction by LPS of prostaglandin-E2 (PGE2) and interleukin-1beta (IL-1beta) production in human monocytes. Indomethacin and indo-Phe inhibited the PGE2 synthesis in treated and untreated IL-1beta or LPS-treated monocytes. Furthermore, in IL-1beta and LPS-treated monocytes, prostaglandin G/H synthase-1 (PGHS-1) protein expression was down-regulated with indomethacin or its indo-Phe analog whereas the level of the inducible protein (PGHS-2) was up-regulated. We analyzed the effect of indomethacin and indo-Phe on the expression of IL-1beta protein in LPS-treated monocytes and found that indo-Phe blocked the LPS-induction of IL-1beta synthesis while indomethacin did not. These differential effects of indomethacin and indo-Phe suggest that two independent ways are involved in the stimulation of monocytes by LPS: the PGHS-2 protein induction and the IL-1beta secretion.

It has been reported in the literature that Neisseria gonorrhoeae DNA is modified by the methyltransferases (MTases) M· Ngo I, M· Ngo II, and M· Ngo III, as well as three other cytosine MTases and one adenine MTase, even if the corresponding restriction endonucleases are not present. We envisioned the possibility of cloning one of the N. gonorrhoeae MTase-encoding genes for use as a species-specific DNA probe. We therefore undertook a survey of methylation patterns of several clinical isolates of N. gonorrhoeae and N. meningitidis as well as ATCC strains of other Neisseriae. We found, from digestion patterns with isoschizomers, one N. gonorrhoeae strain that lacked M· Ngo III. All N. meningitidis strains (save one) were resistant to digestion with Nla IV thus possessing an MTase like Ngo V, and one was resistant to Sst II, thus having an Ngo III-like MTase. None were resistant to isoschizomers of Ngo I, Ngo III and NgoIIV . Some other Neisseriae had an MTase with Nla IV ( Ngo V) specificity, but none had Ngo I, II, III or IV specificity, except for the Branhamella -like N. caviae-ovis group and N. lactamica where these specificities were present in at least one strain of this group. Therefore, among the Neisseriae other than N. caviae only M· Ngo I is N. gonorrhoeae -specific.