Compositions and methods to prevent AAV vector aggregation
Compositions and methods are provided for preparation of concentrated stock solutions of AAV virions without aggregation. Formulations for AAV preparation and storage are high ionic strength solutions (e.g. μ˜500 mM) that are nonetheless isotonic with the intended target tissue. This combination of high ionic strength and modest osmolarity is achieved using salts of high valency, such as sodium citrate. AAV stock solutions up to 6.4×10 13 vg/mL are possible using the formulations of the invention, with no aggregation being observed even after ten freeze-thaw cycles. The surfactant Pluronic® F68 may be added at 0.001% to prevent losses of virions to surfaces during handling. Virion preparations can also be treated with nucleases to eliminate small nucleic acid strands on virions surfaces that exacerbate aggregation.
1. A composition for the storage of purified, recombinant adeno-associated virus (AAV) vector particles, comprising:
purified, recombinant AAV vector particles at a concentration exceeding 1×10 13 vg/ml up to 6.4×10 13 vg/ml;
a pH buffer, wherein the pH of the composition is between 7.5 and 8.0; and
excipients comprising one or more multivalent ions selected from the group consisting of citrate, sulfate, magnesium, and phosphate; wherein the ionic strength of the composition is greater than 200 mM, and wherein the purified AAV vector particles are stored in the composition without significant aggregation.
2. The composition of claim 1 , further comprising ethylene oxide/propylene oxide block copolymer Pluronic® F68.
3. The composition of claim 2 , wherein the Pluronic® F68 is present at a concentration of 0.001% (w/v).
4. The composition of claim 1 , wherein the pH buffer is 10 mM Tris, pH 8.0 and the excipients comprise 100 mM sodium citrate.
5. The composition of claim 1 , wherein the purified, recombinant AAV vector particles have an average particle radius (Rh) of less than about 20 nm as measured by dynamic light scattering.
6. The composition of claim 1 , wherein recovery of the purified, recombinant virus particles is at least about 90% following filtration of the composition of said AAV vector particles through a 0.22 μm filter.