Liposome composition for lupus assay
AssigneeThe Liposome Company, Inc.
InventorsAndrew S. Janoff, Marc J. Ostro, Alan L. Weiner, Gerald Weissmann, James R. Seibold
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Abstract
An immunoassay utilizing a novel liposome composition in which there is incorporated a stabilizing or destabilizing component and an antigen. The presence of cognate antibodies in test samples is detected by the alteration of the supramolecular structure of the liposomes resulting in changes in stabilization. Destabilization can be detected, and in certain cases, caused by, the addition of magnesium or calcium ions. Increased stabilization can be detected by the polymerization of bilayer components in response to ultraviolet light. Antibody-antigen interactions at the liposome surface mediate the stabilization/destabilization response.
Claims57
A method for detecting antibodies in serum, comprising:
- (a) contacting serum, for a period of time at least sufficient to permit equilibration of binding between an antigen and its cognate antibody, with liposomes having a multicomponent bilayer comprising a flexible double tailed phospholipid and a destabilization component, wherein at least one of the liposome membrane constituents is an antigen;
- (b) exposing the liposomes to conditions which cause destabilization of the liposomes in the absence of cognate antibodies directed against the antigen and which do not cause destabilization of the liposomes in the presence of the cognate antibodies;
- (c) detecting any destabilization of the liposome,
- the method being performed under conditions non-inhibiting to the binding between the antigen and its cognate antibody.
A method for detecting antibodies in serum, comprising:
- (a) contacting serum, for a period of time at least sufficient to permit equilibration of binding between an antigen and its cognate antibody, with liposomes having a multicomponent bilayer comprising a flexible double tailed phospholipid and a destabilization component, wherein at least one of the liposome membrane constituents is an antigen;
- (b) exposing the liposomes to conditions which do not cause destabilization of the liposomes in the absence of cognate antibodies directed against the antigen and which cause destabilization of the liposomes in the presence of the cognate antibodies;
- (c) detecting any destabilization of the liposome,
- the method being performed under conditions non-inhibiting to the binding between the antigen and its cognate antibody.
A liposome composition comprising liposome vesicles, said vesicles having (i) a multicomponent liposome bilayer comprising a flexible double tailed phosphatidylcholine and a lipid antigen for SLE antibodies in a molar ratio of from about 1:7 to about 9:1, respectively, and (ii) a colorimetric indicator entrapped within said liposome.
A method for preparing liposomes having a compound entrapped therein, comprising:
- (a) forming a dispersion of at least one amphipathic lipid in an organic solvent;
- (b) forming an aqueous mixture containing a compound to be entrapped in the liposomes;
- (c) injecting the dispersion into the aqueous mixture heated to a temperature above the boiling point of the organic solvent to form, as the organic solvent escapes, a suspension of liposomes having said compounds entrapped therein;
- and
- (d) exposing the suspension to a vacuum produced by a water aspirator for from about one to five hours to remove excess remaining organic solvent.
A method for detecting antibodies in serum, comprising:
- (a) contacting serum, for a period of time at least sufficient to permit equilibration of binding between an antigen and its cognate antibody, with liposomes having a multicomponent bilayer comprising a diacetylenic phospholipid and an antigen;
- (b) exposing the liposomes to ultraviolet light;
- and
- (b) detecting any polymerization of the liposome membrane,
- the method being performed under conditions non-inhibiting to the binding between the antigen and its cognate antibody.
Dependencies are inferred from the claim text.