SDZ MRL 953, a novel immunostimulatory monosaccharidic lipid A analog with an improved therapeutic window in experimental sepsis
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C Lam1, E Schütze, J Hildebrandt
1Sandoz Forschungsinstitut, Vienna, Austria.
Abstract:
SDZ MRL 953, a new synthetic monosaccharidic lipid A, was investigated in vitro and in vivo for immunopharmacological activities. In experimental models of microbial infections, the compound was highly protective when it was administered prophylactically either once or three times to myelosuppressed or immunocompetent mice. The 50% effective doses of SDZ MRL 953 varied with the infectious agents and the route of its administration. In all cases, the 50% effective doses were about 10(3) times higher than those obtained with endotoxin from Salmonella abortus equi. SDZ MRL 953 was, however, less toxic than lipopolysaccharide by a factor of 10(4) to greater than 7 x 10(5) times in galactosamine-sensitized mice. The compound was also an effective inducer of tolerance to endotoxin. Hence, repeated dosing with the compound induced a transient resistance (greater than or equal to 1 week) to lethal challenges with endotoxin. In vitro, the compound was devoid of intrinsic antimicrobial activity, but it moderately induced the release of cytokines from monocytes and primed human neutrophils for the enhanced production of reactive oxygen metabolites in response to a soluble stimulus. The results presented here suggest that SDZ MRL 953 may be useful in a clinical setting for enhancing resistance to infections, particularly in patients undergoing myelosuppressive chemotherapy or irradiation, and for the prophylaxis of endotoxin shock.
Insights
SDZ MRL 953, a synthetic lipid A, shows significant protective effects against microbial infections in mice. This compound is less toxic than lipopolysaccharide and may aid in preventing endotoxin shock.
Area of Science:
- Immunopharmacology
- Microbiology
- Toxicology
Background:
- Lipid A is a key component of bacterial lipopolysaccharides (LPS) and a potent immune stimulant.
- Synthetic analogs of Lipid A are being developed to harness immunostimulatory properties while mitigating toxicity.
Purpose of the Study:
- To evaluate the immunopharmacological activities of SDZ MRL 953, a novel synthetic monosaccharidic lipid A.
- To assess its efficacy in protecting against microbial infections and its potential for preventing endotoxin shock.
Main Methods:
- In vitro and in vivo studies in experimental models of microbial infections.
- Administration of SDZ MRL 953 to myelosuppressed and immunocompetent mice.
- Toxicity assessment in galactosamine-sensitized mice.
- Evaluation of cytokine release from monocytes and neutrophil priming in vitro.
Main Results:
- SDZ MRL 953 demonstrated high protective efficacy against microbial infections when administered prophylactically.
- The compound exhibited significantly lower toxicity compared to lipopolysaccharide.
- Repeated dosing induced tolerance to endotoxin, conferring resistance to lethal challenges.
- In vitro, SDZ MRL 953 moderately induced cytokine release and primed neutrophils.
Conclusions:
- SDZ MRL 953 possesses potent immunomodulatory and protective activities.
- Its favorable safety profile and efficacy suggest potential clinical applications for infection resistance, especially in immunocompromised patients.
- The compound holds promise for the prophylaxis of endotoxin shock.