Title:  Herpes simplex virus ORF P is a repressor of viral protein synthesis

United States Patent:  6,383,738

Assignee:  Arch Development Corporation (Chicago, IL)

Filed:  December 7, 1998

The present invention is directed to methods and compositions relating to the treatment of herpes simplex virus infections and the screening of compounds for activity that inhibit or promote viral latency. The previously identified ORF P gene product now has been shown to interact with certain eukaryotic splicing factors and, in a cell infected with a herpesvirus containing a derepressed ORF P gene, ORF P can limit the splicing of at least two viral products. Given this function, it now is possible to screen for inhibitors and inducers of ORF P and, further, provide methods for maintaining and preventing viral latency.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide methods for the treatment of HSV infections, and compositions therefor. More specifically, it is an object of the present invention to provide methods that inhibit, induce or maintain latency of herpesvirus infections. It also is an object of the present invention to provide methods for the identification of compositions that will inhibit, induce or maintain latency of HSV infections.

In satisfying these objectives, there is provided, in a first embodiment, a method for inducing latency in a herpesvirus infected cell comprising the step of increasing the level of ORF P polypeptide in the cell. The herpesvirus may be a herpes simplex virus and, more particularly, a type 1 herpes simplex virus or a type II herpes simplex virus. The cell may be a human cell and, in a preferred embodiment, a human cell located in a human subject.

Increasing the level of ORF P may comprise providing an ORF P polypeptide to the cell, for example, by contacting the cell with an ORF P polypeptide. Alternatively, providing may comprise contacting the cell with a nucleic acid encoding an ORF P polypeptide. Preferably, the nucleic acid is under the transcriptional control of a promoter active in eukaryotic cells, for example, a herpesvirus promoter. The nucleic acid may further be contained in a replication-deficient vector, such as a replication-deficient herpesvirus vector. The herpesvirus vector may be contained in an infectious herpesvirus particle, where contacting is performed under conditions that permit infection of the cell by the herpesvirus particle. This method may further comprise a step of administering an anti-viral agent to the cell.

In another embodiment, there is provided a method for preventing latency in a herpesvirus infected cell comprising the step of decreasing the level of ORF P polypeptide in the cell. The herpesvirus may be a herpes simplex virus and, more particularly, a type 1 herpes simplex virus or a type II herpes simplex virus. The cell may be a human cell and, in a preferred embodiment, a human cell located in a human subject. Decreasing ORF P may comprise providing to the cell an antisense construct, wherein the antisense construct inhibits transcription or translation of an ORF P gene. The antisense construct may comprise an oligonucleotide that targets a 5'-untranslated region or a translational start site for ORF P. Alternatively, decreasing may comprise inhibiting translational processing of the ORF P polypeptide. In another alternative, decreasing may comprise providing to the cell an antibody that binds immunologically to the ORF P polypeptide. Preferably, the antibody is a monoclonal antibody.

In still another embodiment, there is provided a method for inhibiting the splicing of a RNA transcript comprising the step of contacting the transcript with an ORF P polypeptide. The RNA transcript may be produced in an in vitro transcription system or it may be produced in a cell. The ORF P is produced recombinantly and it may be produced in the same cell as the RNA transcript. The recombinant ORF P may be under the control of an inducible promoter.

In still yet another embodiment, there is provided a method for isolating a splicing factor comprising the steps of (a) providing an ORF P polypeptide; (b) contacting the ORF P polypeptide with a cell extract containing a splicing factor; and (c) isolating the ORF P polypeptide-splicing factor complex. Preferably, the ORF P polypeptide is bound to a support.

In still yet a further embodiment, there is provided a method for isolating an SM antigen comprising the steps of (a) providing an ORF P polypeptide; (b) contacting the ORF P polypeptide with a cell extract containing an SM antigen; and (c) isolating the ORF P polypeptide-SM antigen complex. Preferably, the ORF P polypeptide is bound to a support.

Claim 1 of 14 Claims

What is claimed is:

1. A method for inducing latency in a herpesvirus infected cell in vitro comprising the step of increasing the level of ORF P polypeptide in said cell, wherein ORF P is expressed at a level sufficient to induce latency in said herpesvirus infected cell.

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