Modified lipopolysaccharides and process of preparation
AssigneeRibi ImmunoChem Research, Inc.
InventorsKent R. Myers, Alex T. Truchot
Life of this patent
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Abstract
Modified lipopolysaccharides, particularly de-3-0-acylated monophosphoryl lipid A and de-3-0-acylated diphosphoryl lipid A, are provided by an alkaline hydrolysis under controlled conditions which removes only the .beta.-hydroxymyristic acyl residue that is ester-linked to the reducing-end glucosamine at position 3. The modified products are less endotoxic and maintain their antigenic and immuno-stimulating properties.
Claims26
A method for modifying a lipopolysaccharide to selectively remove only the .beta.-hydroxymyristic acyl residue that is ester-linked to the reducing-end glucosamine at position 3 of said lipopolysaccharide, which comprises subjecting said lipopolysaccharide to alkaline hydrolysis sufficient only to remove .beta.-hydroxymyristic acid from position 3 without removal of other fatty acids from the lipopolysaccharide molecule and recovering said lipopolysaccharide free of said residue.
A method for removing from lipid A or monophosphoryl lipid A, only the .beta.-hydroxymyristic acyl residue that is ester-linked to the reducing-end glucosamine at position 3 of said lipid A, which method comprises the steps of:
- (a) dissolving said lipid A in an inert organic solvent;
- (b) saturating said solvent with an aqueous buffer comprised of an alkaline compound, at a pH of from about 10 to about 13;
- (c) flash evaporating said solvent under a vacuum at a temperature of between about 40.degree. C. and about 60.degree. C.;
- and
- (d) recovering said lipid A.
A lipopolysaccharide from which the .beta.-hydroxymyristic acyl group has been removed from position 3.
An essentially pure lipopolysaccharide compound of the formula:
- ##STR5## wherein R.sup.1 is selected from the group consisting of hydrogen and the core component of enterobacterial lipopolysaccharide, with the O-antigen present, R.sup.2 is selected from the groups H and PO.sub.3 H.sub.2, and R.sup.3 is selected from the group consisting of H, .beta.-hydroxymyristoyl, and a 3-acyloxyacyl residue having the formula:
- ##STR6## and wherein X and Y have a value of from 0 up to about 20.
An essentially pure lipopolysaccharide compound of the formula:
- ##STR7## wherein R.sup.1 is selected from the group consisting of hydrogen and the core component of enterobacterial lipopolysaccharide, without the O-antigen present, R.sup.2 is selected from the groups H and PO.sub.3 H.sub.2, and R.sup.3 is selected from the group consisting of H, .beta.-hydroxymyristoyl, and a 3-acyloxyacyl residue having the formula:
- ##STR8## and wherein X and Y have a value of from 0 up to about 20.
A pharmaceutical composition comprising a substantially pure, modified lipopolysaccharide, having no .beta.-hydroxymyristic acyl residue that is ester-linked to the reducing-end glucosamine at position 3, and a pharmaceutically acceptable carrier.
Dependencies are inferred from the claim text.