Composition of viral vectors in lecithin liposomes, preparation method and treatment methods
A composition is provided which comprises a recombinant viral particle comprising a capsid, wherein the viral particle is encapsulated into an anionic liposome comprising lecithin and polyethylene glycol (PEG). A method for preparing and purifying the encapsulated viral particles is provided as well. Methods for treating patients by using the encapsulated viral particles are provided as well.
1. A method of preparing a formulation comprising a viral particle encapsulated in an anionic liposome, wherein the viral particle is a recombinant adenovirus, the method comprising:
a) preparing a mixture by dissolving lecithin, cholesterol and PEG in an organic solvent;
b) drying the mixture under vacuum to form a dry lipid film;
c) mixing the dried lipid film with recombinant adenovirus particles and hydrating the dried lipid film by exposing it to a physiological solution, and thereby forming multilamellar vesicles;
d) sonicating said vesicles and thereby forming a formulation with recombinant adenovirus particles encapsulated in the anionic liposomes;
e) binding non-encapsulated recombinant adenovirus particles with an antibody; and
f) separating the encapsulated recombinant adenovirus particles from the non-encapsulated recombinant adenovirus particles bound to the antibody by magnetic immunoprecipitation with magnetic beads linked to protein G; and thereby extracting the non-encapsulated recombinant adenovirus particles from the formulation.
2. The method of claim 1 , wherein the organic solvent is chloroform.
3. The method of claim 1 , wherein the binding is conducted with anti-hexon IgG, anti-penton IgG or anti-fiber IgG.
4. The method of claim 1 , wherein the adenovirus is Ad5.
5. The method of claim 1 , wherein a PEG-folate complex is further added to the mixture of step a).
6. A formulation comprising a recombinant adenoviral particle encapsulated in an anionic liposome, wherein the formulation is obtained by the method of claim 1 .
7. A method of treating a cancer patient, the method comprising administering to the cancer patient a formulation prepared by the method of claim 1 , the formulation comprising a recombinant Ad5 adenoviral particle encapsulated in an anionic liposome comprising lecithin, cholesterol, PEG, and a folate moiety, said formulation being purified from non-encapsulated recombinant Ad5 adenoviral particles by binding of the non-encapsulated recombinant Ad5 adenoviral particles with an antibody and immunoprecipitating the non-encapsulated recombinant Ad5 adenoviral particles bound to the antibody with magnetic beads linked to protein G.
8. The method of claim 7 , wherein the patient is a metastatic cancer patient.
9. The method of claim 7 , wherein the patient is afflicted with a cancer selected from the group consisting of lung cancer, cervical cancer and breast cancer.
10. The method of claim 7 , wherein the patient is a cancer patient, and wherein the cancer is an epithelial cancer.
11. The method of claim 7 , wherein the patient is a cancer patient whose cancer cells express a folate receptor.