Methods of treating tumors using natural killer cell lines

Abstract

This invention relates to a natural killer cell line termed NK-92. The invention provides a vector for transfecting a mammalian cell which includes a nucleic acid sequence encoding a cytokine that promotes the growth of NK-92. Additionally, the invention provides an NK-92 cell, or an NK-92 cell modified by transfection with a vector conferring advantageous properties, which is unable to proliferate and which preserves effective cytotoxic activity. The invention further provides a modified NK-92 cell that is transfected with a vector encoding a cytokine that promotes the growth of NK-92 cells. The cell secretes the cytokine upon being cultured under conditions that promote cytokine secretion, and furthermore secretes the cytokine in vivo upon being introduced into a mammal. In a significant embodiment, the cytokine is interleukin 2. The present invention also provides methods of purging cancer cells from a biological sample, of treating a cancer ex vivo in a mammal, and of treating a cancer in vivo in a mammal employing a natural killer cell, such as NK-92 itself, an NK-92 cell which is unable to proliferate and which preserves effective cytotoxic activity, or natural killer cells transfected with a vector encoding a cytokine.

Description

RELATED APPLICATION [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09 / 403,910, filed on Oct. 27, 1999, which was based on, and claimed benefit of, U.S. Provisional Application Ser. No. 60 / 045,885, filed on Apr. 30, 1997.FIELD OF THE INVENTION [0002] This invention relates to natural killer cells and their use in the treatment of pathologies related to cancer or viral infections. Specifically, a particular cell line, NK-92, and modifications thereof, are disclosed. These cells are shown to be highly effective in the treatment of these pathologies. BACKGROUND OF THE INVENTION [0003] Certain cells of the immune system have cytotoxic activity against particular target cells. Cytotoxic T lymphocytes (CTLs) are specifically directed to their targets via antigen-derived peptides bound to MHC class I-specific markers. Natural killer (NK) cells, however, are not so restricted. NK cells, generally representing about 10-15% of circulating lymphocytes, bin...

AI Technical Summary

Benefits of technology

[0014] In significant embodiments of this population, the physical treatment renders them non-proliferative yet does not significantly diminish the cytotoxicity of the cells, and in particularly significant embodiments, the treatment is irradiation. In additional important embodiments the cells have been transfected by a vector that encodes a cytokine promoting the growth of the cells. The cells secrete the cytokine both upon being cultured under conditions that promote cytokine secretion or in vivo upon being introduced into a mammal. In particularly important embodiments of this aspect of the invention, the cytokine is interleukin 2. In still further important embodiments, the NK-92 cells are the cells NK-92MI, modified by transfection with the vector MFG-hIL-2 encoding, and the cells NK-92CI modified by transfection with the vector pCEP4-LTRhIL-2 encoding interleukin-2. The NK-92MI and NK-92CI cell lines have been in the American Type Culture Collection under the designations CRL-2408 and CRL-2409, respectively. In additional important embodiments, the NK-92 cells are transfected by a vector including a sequence that encodes a cellular component responsive to an agent such that, when the NK-92 cell so transfected takes up the agent, the cell is inactivated. In particularly important embodiments thereof, the agent is acyclovir or gancyclovir. In yet additional embodiments, the cell population is transfected with a vector encoding a cancer cell receptor molecule.

[0015] The present invention also provides a method of purging cells related to a pathology from a biological sample including the steps of (i) obtaining a biological sample from a mammal that is suspected of containing cells related to the pathology, and (ii) contacting the sample with a medium comprising NK-92 or modified NK-92 natural killer cells, wherein the modified NK-92 cells have been modified by a physical treatment or by transfection with a vector. In significant embodiments of this method, the pathology is a cancer, or is an infection by a pathogenic virus such as human immunodeficiency virus (HIV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), or herpes virus. In additional important embodiments, the modified NK-92 cells have undergone a physical treatment that renders them non-proliferative, yet which does not significantly diminish their cytotoxicity, or have been transfected with a vector, or they have been treated by any combination of these modifications. In significant embodiments of this method, the vector encodes a cytokine that promotes the growth of the cells, a protein that is responsive to an agent, a cancer cell receptor molecule, or a combination of these coding sequences. In a further embodiment, the medium also includes a cytokine that promotes the growth of the cells. The sample, once purged of cancer cells, may be further treated, including, for example, being returned to the mammal from which it was obtained. In important embodiments of the method, the biological sample is blood or bone marrow, the mammal is a human, and/or the natural killer cell is immobilized on a support.

[0016] The invention additionally provides a method of treating a pathology ex vivo in a mammal including the steps of (i) obtaining a biological sample suspected of containing cells related to the pathology from the mammal; (ii) contacting the biological sample with a me

Problems solved by technology

This purging treatment is expensive and can cause serious side effects.

In spite of the advantageous properties of NK cells in killing tumor cells and virus-infected cells, they remain difficult to work with and to apply in immunotherapy.

It is difficult to expand NK cells ex vivo that maintain their tumor-targeting, tumoricidal, and viricidal capabilities in vivo.

This remains a major obstacle to their clinical use in adoptive cell immunotherapy (Melder et al., Cancer Research 48:3461-3469 (1988); Stephen et al., Leuk.

Studies of the mechanisms whereby NK cells exert their tumoricidal and viricidal effects are also limited by difficulties in enriching the NK cell fractions without compromising their biological functions and in obtaining pure NK cells that are not contaminated by T cells or other immune effector cells.

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