Chemistry: molecular biology and microbiology – Vector – per se
Reexamination Certificate
2000-07-17
2003-04-08
Priebe, Scott D. (Department: 1632)
Chemistry: molecular biology and microbiology
Vector, per se
C435S325000, C435S455000, C514S04400A
Reexamination Certificate
active
06544781
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a viral vector construct derived from Epstein-Barr virus (EBV) that targets B-lymphocytes. The viral vector of the invention has a transgene inserted in the EBV major internal repeat region (IR1), for gene delivery and persistent gene expression in B-lymphocytes in vitro and in vivo.
2. Related Art
The terms “gene transfer” and “gene therapy” have been used to describe a variety of methods for delivering genetic material to a cell using viral or non-viral based vector systems. Substantial attention has been given to human gene therapy. The transfer of genetic material to a cell may one day become one of the most important forms of medicine. A variety of public and private institutions now participate in research and development related to the use of genetic material in therapeutic applications. Hundreds of human gene transfer protocols are being conducted at any given time with the approval of the Recombinant DNA Advisory Committee (RAC) and the National Institutes of Health (NIH). Most of these protocols focus on therapy, while others involve marking and non-therapeutic applications. The therapeutic protocols are primarily concerned with infectious diseases, monogenic diseases, and cancer. Gene-based therapies are now expanding into fields such as cardiovascular disease, autoimmune disease, and neurodegenerative disease. The availability of a safe and efficient gene delivery and expression system is essential to the success and efficacy of gene-based therapy.
One method of delivering a gene of interest to a target cell of interest is by using a viral-based vector. Techniques for the formation of vectors or virions are generally described in “Working Toward Human Gene Therapy,” Chapter 28 in
Recombinant DNA,
2
nd Ed.,
Watson, J. D. et al., eds., New York: Scientific American Books, pp. 567-581 (1992). An overview of viral vectors or virions that have been used in gene therapy can be found in Wilson, J. M.,
Clin. Exp. Immunol.
107(Suppl. 1):31-32 (1997), as well as Nakanishi, M.,
Crit. Rev. Therapeu. Drug Carrier Systems
12:263-310(1995); Robbins, P. D., et al.,
Trends Biotechnol.
16:35-40 (1998); Zhang, J., et al.,
Cancer Metastasis Rev.
15:385-401 (1996); and Kramm, C. M., et al.,
Brain Pathology
5:345-381 (1995). Such vectors may be derived from viruses that contain RNA (Vile, R. G., et al.,
Br. Med Bull.
51:12-30 (1995)) or DNA (Ali M., et al.,
Gene Ther.
1:367-384 (1994)).
Specific examples of viral vector systems that have been utilized include: retroviruses (Vile, R. G., supra; U.S. Pat. Nos. 5,741,486 and 5,763,242); adenoviruses (Brody, S. L., et al.,
Ann. N.Y. Acad. Sci.
716: 90-101 (1994); Heise, C. et al.,
Nat. Med.
3:639-645 (1997)); adenoviral/retroviral chimeras (Bilbao, G., et al.,
FASEB J.
11:624-634 (1997); Feng, M., et al.,
Nat. Biotechnol.
15:866-870 (1997)); adeno-associated viruses (Flotte, T. R. and Carter, B. J.,
Gene Ther.
2:357-362 (1995); U.S. Pat. No. 5,756,283); herpes simplex virus I or II (Latchman, D. S.,
Mol. Biotechnol.
2:179-195 (1994); U.S. Pat. No. 5,763,217; Chase, M., et al.,
Nature Biotechnol.
16:444-448 (1998)); parvovirus (Shaughnessy, E., et al.,
Semin Oncol.
23:159-171 (1996)); reticuloendotheliosis virus (Donburg, R.,
Gene Therap.
2:301-310 (1995)). Other viruses that can be used as vectors for gene delivery include poliovirus, papillomavirus, vaccinia virus, Epstein-Barr virus (EBV), and lentivirus, as well as hybrid or chimeric vectors incorporating favorable aspects of two or more viruses (Nakanishi, M.,
Crit. Rev. Therapeu. Drug Carrier Systems
12:263-310 (1995); Zhang, J., et al.,
Cancer Metastasis Rev.
15:385-401 (1996); Jacoby, D. R., et al.,
Gene Therapy
4:1281-1283 (1997); Robertson, E. S., et al.,
Proc.Natl Acad.Sci.USA
93:11334-11340(1996)). Guidance in the construction of gene therapy vectors and the introduction thereof into affected animals for therapeutic purposes may be obtained in the above-referenced publications, as well as U.S. Pat. Nos. 5,631,236, 5,688,773, 5,691,177, 5,670,488, 5,529,774, and 5,601,818.
The viral vectors mentioned above each have advantages and disadvantages. For example, retroviruses have the ability to infect cells and have their genetic material integrated into the host cell with high efficiency. The development of a helper virus free packaging system for retrovirus vectors was a key innovation in the development of this vector system for human gene therapy. Retroviral helper virus free packaging systems generally employ the creation of a stable producer cell line that expresses a selected vector. The relatively small size of the retroviral genome (approximately 11 kb), and the ability to express viral genes without killing cells, allows for the production of a packaging cell line that synthesizes all the proteins required for viral assembly. Producer lines are made by introducing the retroviral vector into such a packaging cell line.
On a down side, however, numerous difficulties with retroviruses have been reported. For example, most retroviral vectors are not capable of gene transfer to postmitotic (nondividing) cells and thus are not applicable to the nervous system because most of the cells in the adult nervous system, especially neurons, are quiescent or postmitotic. In addition, outbreaks of wild-type virus from recombinant virus-producing cell lines have also been reported, with the vector itself causing a disease.
Difficulties have been noted with other viral vectors as well. Adenovirus vectors can only support limited long-term (2 months) gene expression, they appear to be gradually lost from neural cells, and moreover, they can cause both cytopathic effects and an immune response (Le Gal La Salle, G., et al.,
Science
259:988-990 (1993); Davidson et al.,
Nat. Genet.
3:219-223 (1993); Yang, Y., et al.,
J. Virol.
69:2004-2015 (1995)). Adeno-associated virus vectors cause minimal cytopathic effects and can support at least some gene expression for up to 4 months, but gene transfer is inefficient and these vectors can accept only about 4 kb of foreign DNA (Kaplitt, M. G., et al.,
Nat. Genet.
8:148-154 (1994)).
Vectors based on herpes simplex virus (HSV), and especially HSV-1, have shown promise as potent gene delivery vehicles for several reasons: the virus has a very large genome and thus can accommodate large amounts of foreign DNA (greater than 30 kb), the virus can persist long-term in cells, and can efficiently infect many different cell types, including post-mitotic neural cells (Breakefield, X. O., et al., “Herpes Simplex Virus Vectors for Tumor Therapy,” in
The Internet Book of Gene Therapy: Cancer Gene Therapeutics,
R. E. Sobol and K. J. Scanlon, eds., Appleton and Lange, Stamford, Conn., pp. 41-56 (1995); Glorioso, J. C., et al., “Herpes Simplex Virus as a Gene-Delivery Vector for the Central Nervous System,” in Viral Vectors:
Gene Therapy and Neuroscience Applications,
M. G. Kaplitt and A. D. Loewy, eds., Academic Press, New York, pp. 1-23 (1995)).
Two types of HSV-1 vector systems are known: recombinant and amplicon. Recombinant HSV-1 vectors (Wolfe, J. H. et al.,
Nat. Genet.
1:379-384 (1992)) are created by inserting genes of interest directly into the 152 kb viral genome, thereby mutating one or more of the approximately 80 viral genes, and concomitantly reducing cytotoxicity. In contrast, HSV-1 amplicons are bacterial plasmids containing only about 1% of the 152 kb HSV-1 genome. They are packaged into HSV-1 particles (virions) using HSV-1 helper virus. HSV-1 amplicons contain: (i) a transgene cassette with a gene of interest; (ii) sequences that allow plasmid propagation in
E. coli,
such as the origin of DNA replication colE1 and the ampicillin resistance gene; and (iii) non-coding elements of the HSV-1 genome, in particular an origin of DNA replication (ori) and a DNA cleavage/packaging signal (pac), to support replication and subsequent packaging of the amplicon DNA into virions in the presence of helper functions (Spaete, R.
Chiocca E. Antonio
Hochberg Fred
Jiang Xiaoqun
Kieff Elliott
Wang Fred
Paras, Jr. Peter
Priebe Scott D.
Sterne Kessler Goldstein & Fox PLLC
The General Hospital Corporation
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