Structural and biological relationships of low molecular weight interferon inducers

Mucopolysaccharidosis and lipidosis in rats treated with tilorone analogues

The experimental immunomodulatory agent tilorone was previously reported to induce generalized mucopolysaccharidosis (lysosomal storage of sulfated glycosaminoglycans) and lipidosis in rats. While lipidosis is a side effect common to many cationic amphiphilic compounds, none of them except tilorone has been known to cause mucopolysaccharidosis in intact animals. The purpose of the present histochemical and ultrastructural study was to examine whether or not mucopolysaccharidosis can be induced by tilorone analogues. Three analogues were selected and administered to rats in short-term and subchronic experiments, and liver, spleen, kidney, and cornea were examined. The analogues caused generalized cellular lesions which had the same histochemical and cytological characteristics and the same distribution as the lesions produced by tilorone. The results show that the ability to induce mucopolysaccharidosis is not a unique property of tilorone; this drug side effect should be taken into account when developing new drugs with molecular structures resembling that of tilorone.

N,N-diethylaminoalkoxy-4,7-phenanthrolines and 1,8-diazaflourene derivatives, a novel class of potential interferon inducers and antiviral agents: interactions with nucleic acids in vitro and cellular activities

Tilorone aza-analogues, derivatives of 4,7-phenanthroline and 1,8-diazafluorene, were examined as DNA-complexing agents by spectral and electrophoretic methods. The binding process includes at least two types of interactions: electrostatic and, possibly, intercalation. Complex formation with the denatured DNA was also observed, but its nature remained unsolved. Binding and thermodynamic parameters were determined. All ligands studied showed weak antiviral activity and essentially no interferon induction when assayed in vitro and in vivo. It was concluded that interferon induction by tilorone may involve specific cell receptors or intermediaries.

Augmentation of murine natural killer cell activity by manganese chloride

Natural killer (NK) cell activity of spleen cells from male CBA/J mice was augmented by a single parenteral injection of MnCl2 administered 1 day prior to testing by in vitro and in vivo isotope release assays. Increased cytotoxic activity was observed in vitro against both NK-sensitive (YAC-1) and NK-resistant (EL-4) target cells. NK activity was also enhanced in normally low (A/J) and intermediately (C57Bl/6J) reactive strains of mice. Augmentation of NK activity by MnCl2 was accompanied by an increase in circulating interferon (IFN) levels.

The interaction of tilorone and RMI 9563DA with the complement system

RMI 9563DA inhibited the classical complement pathway in rat serum in vitro with an 150 of 51 micrograms/ml in diluted serum and 750 micrograms/ml in undiluted serum. Tilorone was much less active than RMI 9563DA in diluted serum and was inactive in undiluted serum. No complement inhibition could be detected in vivo following a near lethal dose of RMI 9563DA (25 mg/kg i.v.). Thus, complement inhibition is not the mechanism by which these compounds exert their anti-inflammatory activity. Both compounds increase serum hemolytic complement activity 24 h after administration to rats. With RMI 9563DA, this effect is entirely due to the local irritancy produced by s.c. administration of the compound. Tilorone, however, has a specific effect on complement synthesis which may be related to its ability to induce interferon.

Suppression of experimental allergic encephalomyelitis by interferon

Experimental allergic encephalomyelitis (EAE) is an experimental, T-cell dependent, autoimmune disease of the central nervous system that can be induced in most mammals by the injection of myelinated neural tissue in complete Freund's adjuvant. Relatively small doses, 10(4.6) Units/kg, of rat interferon (IFN), specific activity 10(7.6) Units/kg, delayed the onset of the disease and significantly ameliorated the severity of EAE symptoms observed in Lewis rats. Injection of IFN at 10(5.6) U/Kg suppressed hind limb paralysis in 70 to 80% of the rats.