Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
2001-03-28
2002-12-03
Mertz, Prema (Department: 1646)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C530S387100, C530S387900, C530S388230, C530S388200
Reexamination Certificate
active
06489126
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a gene and a novel membrane protein encoded by said gene, and more specifically, relates to a gene encoding a novel membrane protein polypeptide having pre-B cell growth-supporting ability, a vector containing said gene, transformants transformed by said vector and a method for producing the novel membrane protein polypeptide by using said gene.
The present invention further relates to a monoclonal antibody recognizing a novel membrane protein polypeptide having pre-B cell growth-supporting ability.
The gene of the present invention encodes a novel membrane protein polypeptide enhancing pre-B cell growth-supporting ability on the surface of synovial cells derived from patients with rheumatoid arthritis (RA). In the present invention, a homogeneous and purified novel membrane protein polypeptide having pre-B cell growth-supporting ability can be produced in large quantities by transforming appropriate host cells with a suitable vector in which the gene of the present invention is inserted. Thus, according to the present invention, it becomes possible to identify rheumatoid arthritis (RA), and also prepare reagents for the clinical diagnosis thereof.
BACKGROUND ART
Inflammatory cells in the synovial membrane and the synovial fluid of patients with rheumatoid arthritis (RA) are derived from peripheral blood and the migration of these cells to synovial membranes has not been explicated perfectly yet, but it is believed to be caused by a complicated interaction between chemical signals given to cells and protein (adhesion molecule) on cell membranes.
Various studies upon the significance of membrane proteins in arthritis have been performed. For example, it is known that an intercellular adhesion molecule-1 (hereinafter referred to as ICAM-1) is expressed on the inner layer of the synovial membrane and the blood vessel of the synovial membrane of patients with rheumatoid arthritis (RA), which is a ligand of a T cell surface molecule LFA-1 and causes both adhesion and migration of cells in the blood vessel wall [Hale et al.; Arthritis Rheum., 32:22 (1989), and Haynes et al.; Springer Semin. Immunopathol., 11:163 (1989)]
Similarly, it is suggested that a vasocellular adhesion molecule-1 (hereinafter referred to as VCAM-1), which is a ligand of integrin VLA-4 expressed on T lymphoid cells (memory cells in particular) and monocytes, is expressed on the synovial membrane and fibroblast-like synovial cells of rheumatoid arthritis (RA) and osteoarthritis, [Morales-Ducret et al.; J. Immunol., 149:1424 (1992)], and further that a membrane protein called VAP-1 is expressed on the endothelial vein of a synovial membrane and may work as a specific recognition structure of leukocytes [Salmi et al.; Science, 257, 1407 (1992)].
The present inventors have engaged in extensive studies with a view to investigating the function of the bone marrow microenvironments in disorders causing abnormalities of B cells, and have found that the pre-B cell growth-supporting ability of bone marrow stromal cells derived from patients with rheumatoid arthritis (RA) and multiple myeloma (MM) is enhanced in comparison with that of healthy donor-derived bone marrow stromal cells and that the direct contact of pre-B cells with stromal cells might play an essential role in this supporting ability. And the present inventors have established novel stromal cell lines (RASV5-5, MMSV3-3) containing a molecule enhancing the growth of pre-B cells by cell-lining stromal cells of patients, and have found that the pre-B cell growth-supporting activity of these stromal cell lines is most likely caused by unknown adhesion molecules different from known stem cell factors (SCF), ICAM, CD44, VCAM-1, LFA-1&agr;, LFA-1&bgr;, NCAM and FLAM-1 [J. Immunol., 149:4088 (1992)].
Further, since it has been suggested that the synovial cell line SynSV6-14 established from the synovial cell derived from patients with rheumatoid arthritis (RA) has pre-B cell growth-supporting ability similarly to the stromal cell line RASV5-5 derived from the bone marrow of patients with rheumatoid arthritis (RA), the present inventors have obtained a novel monoclonal antibody which responds to these cell lines but does not respond to the stromal cell line NFSV1-1 derived from the human bone marrow having no pre-B cell growth-supporting ability, and at the same time have succeeded in cloning genes encoding its antigen membrane protein (Bst-1) (Japanese Patent Application No. 5-141178/1993).
DISCLOSURE OF THE INVENTION
The present inventors have obtained a novel mouse monoclonal antibody RS38 which responds to SynSV6-14 but does not respond to the healthy bone marrow stromal cell line NFSV1-1 and recognizes a membrane protein different from the above Bst-1 at the process of producing various mouse monoclonal antibodies recognizing a membrane protein expressed on the synovial cell derived from patients with rheumatoid arthritis (RA) but not expressed on the cell derived from healthy donors. subsequently, the present inventors have succeeded in isolating clones encoding a novel membrane protein responding to said RS38, according to screening a cDNA library prepared from a synovial cell line derived from patients with rheumatoid arthritis (RA) by using the RS38 antibody, which has led to the completion of the present invention.
That is, the present invention is directed to provide a novel membrane protein polypeptide having pre-B cell growth-supporting ability, a gene encoding said polypeptide, a vector containing said gene, transformants transformed by said vector and a method for producing a novel membrane protein by using said gene.
Further, the present invention is directed to provide a monoclonal antibody recognizing a novel membrane protein having pre-B cell growth-supporting ability.
The present invention for accomplishing the above object consists of the following (1)-(7).
(1) A novel membrane protein polypeptide containing an amino acid sequence shown in sequence No. 1 of the sequence table or a part of the amino acid sequence and being expressed on the synovial membrane of patients with rheumatoid arthritis.
(2) A DNA encoding a polypeptide containing an amino acid sequence shown in sequence No. 1 of the sequence table or a part of the amino acid sequence.
(3) The DNA according to the above (2), characterized by containing a base sequence which hybridizes the base sequence shown in sequence No. 2 of the sequence table or a base sequence derived from said base sequence having at least one amino acid residue substituted, removed or added partially.
(4) A recombinant vector containing the DNA according to the above (2) or (3).
(5) A prokaryotic or eukaryotic host cell, characterized by being transformed with the recombinant vector according to the above (4).
(6) A method for producing the polypeptide containing an amino acid sequence shown in sequence No. 1 of the sequence table or a part of the amino acid sequence, characterized by culturing the host cell according to the above (5).
(7) A monoclonal antibody recognizing a polypeptide containing an amino acid sequence shown in sequence No. 1 of the sequence table or a part of the amino acid sequence.
Subsequently, the present invention will be described in detail.
The monoclonal antibody of the present invention may be prepared in the following manner essentially.
That is, the antibody of the present invention may be prepared by using a synovial cell derived from patients with rheumatoid arthritis (RA) having pre-B cell growth-supporting ability as an antigen, immunizing it according to an ordinary immunization method, cell-fusing the immunized cell according to an ordinary cell fusion method and cloning the fused cell according to an ordinary cloning method.
More specifically, as a preferable method for producing the monoclonal antibody of the present invention may be exemplified a method comprising using the cell line SynSV6-14, derived from the synovial membrane of patients with rheumatoid arthritis (RA) and established
Hirano Toshio
Kaisho Tsuneyasu
Hirano Toshio
Mertz Prema
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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