Chemistry: molecular biology and microbiology – Micro-organism – per se ; compositions thereof; proces of... – Bacteria or actinomycetales; media therefor
Reexamination Certificate
1999-12-30
2003-12-16
Eyler, Yvonne (Department: 1646)
Chemistry: molecular biology and microbiology
Micro-organism, per se ; compositions thereof; proces of...
Bacteria or actinomycetales; media therefor
C435S070100, C435S325000, C435S320100, C536S023500, C536S023100, C536S024300, C530S300000, C530S350000
Reexamination Certificate
active
06664098
ABSTRACT:
BACKGROUND OF THE INVENTION
Human blood and lymph contain various types of cells and each cell plays important roles. For example, the erythrocyte carries oxygen; platelets have hemostatic action; and lymphocytes prevent from infection. These various cells originate from hematopoietic stem cells in the bone marrow. Recently, it has been clarified that the hematopoietic stem cells are differentiated to various blood cells, osteoclasts and mast cells by stimulation of various cytokines in vivo and environmental factors. In the cytokines, there have been found, for example, erythropoietin (EPO) for differentiation to erythrocytes; granulocyte colony-stimulating factor (G-CSF) for differentiation to leukocytes; and platelet growth factor (mpl ligand) for differentiation to megakaryocytes which is a platelet producing cells, and the former two have already been clinically applied.
The undifferentiated blood cells are generally classified into two groups consisting of blood precursor cells which are destined to differentiate to specific blood series and hematopoietic stem cells which have differentiation ability to all series and self-replication activity. The blood precursor cells can be identified by various colony assays, however identification method for the hematopoietic stem cells has not been established. In these cells, stem cell factor (SCF), interleukin-3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-6 (IL-6), interleukin-1 (IL-1), granulocyte colony stimulating factor (G-CSF) and oncostatin M have been reported to stimulate cell differentiation and proliferation.
Trials for expansion of hematopoietic stem cells in vitro have been examined in order to replace bone marrow transplantation for applying hematopoietic stem cell transplantation therapy or gene therapy. However, when the hematopoietic stem cells are cultured in the presence of the above mentioned cytokines, multi-differentiation activities and self-replication activities, which are originally in the position of the hematopoietic stem cells, gradually disappeared and are changed to the blood cell precursors which are only to differentiate to specific series after 5 weeks of cultivation, and multi-differentiation activity which is one of the specific features of the hematopoietic stem cells, is lost (Wagner et al. Blood 86, 512-523, 1995).
For proliferation of the blood precursor cells, single cytokine is not sufficient to effect, but synergistic action of several cytokines are important. Consequently, in order to proliferate the hematopoietic stem cells in maintaining with specific features of the hematopoietic stem cells, it is necessary to add cytokines which suppress differentiation together with the cytokines which proliferate and differentiate the undifferentiated blood cells. In general, many cytokines, which stimulate proliferation or differentiation of cells, are known, but small numbers of cytokines, which suppressed cell differentiation, are known. For example, leukemia inhibitory factor (LIF) has an action of proliferation of mouse embryonic stem cells without differentiation, but it has no action against the hematopoietic stem cells or blood precursor cells. Transforming growth factor (TGF-&bgr;) has suppressive action for proliferation against various cells, but no fixed actions against the hematopoietic stem cells or blood precursor cells.
Not only blood cells but also undifferentiated cells, especially stem cells are thought to be involved in tissue regeneration. These regeneration of tissues and proliferation of undifferentiated cells in each tissue can be applied in various ways by referring to the known reference (Katsutoshi Yoshizato, Regeneration—a mechanism of regeneration, 1996, Yodosha Publ. Co.).
Notch is a receptor type membrane protein, which involves in regulation of nerve cells differentiation found in Drosophila. Homologues of the Notch are found in various animal kinds exceeding to the invertebrate and vertebrate including nematode (Lin-12). Xenopus laevis (Xotch), mouse (Motch) or human (TAN-1).
Ligand of the Notch in Drosophila is known. These are Drosophila Delta (Delta) and Drosophila Serrate (Serrate). Notch ligand homologues are found in various animal kinds as similar to the Notch of receptors (Artavanis-Tsakonas et al., Science 268, 225-232, 1995).
Human Notch homologue, TAN-1 is found widely in the tissues in vivo (Ellisen et al., Cell 66, 649-661, 1991). Three Notch analogous molecules other than TAN-1 are reported (Artavanis-Tsakonas et al., Science 268, 225-232, 1995). Expression of TAN-1 was also observed in CD34 positive cells in blood cells by PCR (Polymerase Chain Reaction) (Milner et al., Blood 83, 2057-2062, 1994). However, in relation to humans, gene and amino acid sequences of human Delta and human Serrate, which are thought to be the Notch ligand, have not been reported as scientific reports in April 1997.
In Drosophila Notch, binding with the ligand was studied and investigated in details, and it was found that the Notch can be bound to the ligand with Ca++ at the binding region, which is a repeated amino acid sequence No. 11 and No. 12 in the amino acid sequence repeat of Epidermal Growth Factor (EGF) like repeating (Fehon et al., Cell 61, 523-534, 1990, Rebay et al., ibid. 67, 687-699, 1991 and International Publication WO 92/19734). EGF-like repeated sequences are conserved in Notch homologues of the other species. Consequently, the same mechanism in binding with ligand is estimated. An amino acid sequence which is called as DSL (Delta-Serrate-Lag-2) near the amino acid terminal, and EGF-like repeated sequence as like in the receptor are conserved in the ligand (Artavanis-Tsakonas et al., Science 268, 225-232, 1995).
EGF-like sequence has been found in thrombomodulin (Jackman et al., Proc. Natl. Acad. Sci. USA 83, 8834-8838, 1986), low density lipoprotein (LDL) receptor (Russell et al., Cell 37, 577-585, 1984), and blood coagulating factor (Furie et al., Cell 53, 505-518, 1988), and is thought to play important roles in extracellular coagulation and adhesion.
Recently, the vertebrate homologues of the cloned Drosophila Delta were found in chicken (C-Delta-1) and Xenopus laevis (X-Delta-1), and it has reported that X-Delta-1 had acted through Xotch in the generation of the protoneuron (Henrique et al., Nature 375, 787-790, 1995 and Chitnis et al., ibid. 375, 761-766, 1995). Vertebrate homologue of Drosophila Serrate was found in rat as rat Jagged (Jagged) (Lindsell et al., Cell 80, 909-917, 1995). According to the Lindsell et al., mRNA of the rat Jagged is detected in the spinal cord of fetal rats. As a result of cocultivation of a myoblast cell line that is forced excess expressed rat Notch with a rat Jagged expression cell line, suppression of differentiation of the myoblast cell line is found. However, the rat Jagged has no action against the myoblast cell line without forced expression of the rat Notch.
A hypothesis has been set up so that Notch and its ligand have an action of differential regulation not only for neuroblasts and myoblasts, but also for various undifferentiated cells, especially blood undifferentiated cells. However, as far as clinical applications in humans, prior known different species such as chicken or Xenopus laevos type Notch ligand have problems with species specificities and antigenicities. Consequently, obtaining prior unknown human Notch ligand is essentially required. The inventor suspected that a molecule having DSL domain and EGF-like domain which are common to Notch ligand molecules and a ligand of the human Notch (TAN-1 etc.), which is a human Delta homologue (hereinafter designates as human Delta) and human Serrate homologue (hereinafter designates as human Serrate), may be found. In addition, these findings may be a candidate for a drug useful for differential regulation of undifferentiated cells.
As a result, in the previous patent application, a gene cloning of three types of molecules including human Delta-1, human Serrate-1 and human Serrate-2 molecules as the human Notch lig
Andres Janet L.
Asahi Kasei Kabushiki Kaisha
Eyler Yvonne
Young & Thompson
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