Process for preparing immune complexes

In a method for producing an immunogenic complex between an antigen and a polar triterpensaponin having hydrophobic regions, comprising the steps of

• a. solubilizing the antigen with a solubilizing agent to form a complex between the solubilizing agent and the antigen,
• b. contacting the solubilized antigen with a solution containing a polar triterpensaponin having hydrophobic regions present at a concentration of at least the, critical micellar concentration to form a protein-triterpensaponin complex either
• i. by separating the antigen from the solubilizing agent and immediately transferring the separated antigen to the glycoside containing solution, or
• ii. by removing the solubilizing agent after contact has been made with the glycoside containing solution, and
• c. isolating and purifying the protein-glycoside complex which results from said contact,
• wherein the antigen has exposed hydrophobic peptide domains through which the hydrophobic regions of the glycoside bind, said domains being derived from
• i. amphiphatic proteins or peptides which have hydrophobic domains accessible without modification,
• ii. hydrophilic proteins or peptides made amphiphatic through covalent attachment of hydrophobic groups, or
• iii. amphiphatic proteins or peptides having hydrophobic domains being made accessible through chemical means or by heat treatment,
• wherein the solubilizing agent is selected from the group consisting of non-ionic detergents, ionic detergents, Zwitterionic detergents, or detergents based upon gallic acid, and wherein the resulting complex has
• i. a lower sedimentation constant that the corresponding micelles
• ii. a higher sedimentation constant that the corresponding monomeric form of the antigen, and
• iii. an open spherical structure,
• the improvement comprising adding to the solubilized antigen at least one lipid selected from the group consisting of fats, glycerol ethers, waxes, phospholipids, glycolipids, isoprenoids, steroids, and mixtures thereof, in a molar ratio of lipid to antigen of between 0.1:1 to 100:1, prior to contact of the solubilized antigen with the glycoside-containing solution in step b.i. or b.ii.