University of Illinois

Massachusetts Institute of Technology

Daniel W Pack

Kyekyoon Kim

Cory Berkland

Robert Samuel Langer

Halong N Vu

Joshua Ramsey

The present invention is a mutant retroviral protease which confers an increase in retroviral stability. Retroviruses expressing the instant mutant retroviral protease exhibit at least a 2-fold increase in infectivity half-life as compared to wild-type retrovirus. Unexpectedly, a Gly119Glu mutation in the protease enhances retroviral stability in the presence of various wild-type envelope proteins including wild-type amphotropic, ecotropic and 10A1 murine leukemia viruses. The improved stability of the mutant retrovirus leads to more facile virus production and enhanced infection efficiency.

Stable retrovirus and methods of use

A method of forming particles comprises accelerating a stream comprising a liquid; and vibrating the stream, to form particles. The particle may have a diameter that is smaller than the diameter of the nozzle used to form the stream, allowing for the formation of micro- and nano-sized particle.

Microparticles

The present invention provides improved cell delivery compositions. In particular, the invention provides biocompatible endosomolytic agents. In a preferred embodiment, the endosomolytic agents are also biodegradable and can be broken down within cells into components that the cells can either reuse or dispose of. Preferred endosomolytic agents include cationic polymers, particularly those comprised of biomolecules, such as histidine, polyhistidine, polylysine or any combination thereof. Other exemplary endosomolytic agents include, but are not limited to, other imidazole containing compounds such as vinylimidazole and histamine. More particularly preferred are those agents having multiple proton acceptor sites and acting as a &ldquo;proton sponge&rdquo;, disrupting the endosome by osmolytic action. In preferred embodiments, the endosomolytic agent comprises a plurality of proton acceptor sites having pKas within the range of 4 to 7, which endosomal lysing component is polycationic at pH 4. The present invention also contemplates the use of these endosomolytic agents as delivery agents by complexation with the desired compound to be delivered. Thus, the present invention also acts as a cell delivery system comprising an endosomolytic agent, a delivery agent, and a compound to be delivered.

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Champaign, IL, United States of America

Daniel W Pack