Abstract: An objective of the present invention is to provide: a cancer stem cell isolated using a cell marker; a substantively homogeneous cancer stem cell population including said cancer stem cell; and a method of preparing said cancer stem cell population. Another objective of the present invention is to provide: a method for separating cancer stem cells with a high proliferative potential and those with a low proliferative potential; a method for inducing cancer stem cells to have a different proliferative potential; and cancer stem cells separated or induced by these separation or induction methods. A further objective of the present invention is to provide: a method of screening for pharmaceuticals using said cancer stem cell or cancer stem cell population; a method for detecting the presence of said cancer stem cell or cancer stem cell population and for identifying or quantifying the same.

Abstract: The purpose of the present invention is to provide: a cancer stem cell mass from which cells incapable of forming cancer are substantially removed and which has a characteristic property of reproducing a layered structure of a cancer tissue; a process for producing the cancer stem cell mass; and use of the cancer stem cell mass. For achieving the purpose, the present inventors grew a human cancer tissue repeatedly in a NOG mouse, separated cancer cells from the grown cancer tissue, and made a comparison of various cancer cell culture processes with each other. As a result, a cancer stem cell composition which is homogeneous and is substantially free of the coexistence of cells capable of forming cancer and cells incapable of forming cancer in a mixed state can be produced successively by employing an attached culture process using a serum-free stem cell culture medium rather than a generally employed floating culture process, and consequently the present invention has been accomplished.

Abstract: An objective of the present invention is to facilitate the acquisition of antibody-producing cells that are infiltrating virus-infected cells, cancer cells, abnormal cells forming a benign hyperplasia, and the like, and to improve the efficiency of the production of antibodies as well as nucleic acids encoding them from the antibody-producing cells. The present inventors discovered that, when cancer tissues comprising infiltrating lymphocytes are transplanted into highly immunodeficient animals that do not have T cells, B cells, and NK cells and further exhibit a low IFN production ability, the differentiation and proliferation of infiltrating lymphocytes are unexpectedly promoted, and the number of plasma cells that produce antibodies recognizing cancer tissues increases dramatically, plasma cells can be separated easily, and antibodies or nucleic acids encoding them can be easily prepared from the plasma cells.

Abstract: An objective of the present invention is to facilitate the acquisition of antibody-producing cells that are infiltrating virus-infected cells, cancer cells, abnormal cells forming a benign hyperplasia, and the like, and to improve the efficiency of the production of antibodies as well as nucleic acids encoding them from the antibody-producing cells. The present inventors discovered that, when cancer tissues comprising infiltrating lymphocytes are transplanted into highly immunodeficient animals that do not have T cells, B cells, and NK cells and further exhibit a low IFN production ability, the differentiation and proliferation of infiltrating lymphocytes are unexpectedly promoted, and the number of plasma cells that produce antibodies recognizing cancer tissues increases dramatically, plasma cells can be separated easily, and antibodies or nucleic acids encoding them can be easily prepared from the plasma cells.

Abstract: An objective of the present invention is to facilitate the acquisition of antibody-producing cells that are infiltrating virus-infected cells, cancer cells, abnormal cells forming a benign hyperplasia, and the like, and to improve the efficiency of the production of antibodies as well as nucleic acids encoding them from the antibody-producing cells. The present inventors discovered that, when cancer tissues comprising infiltrating lymphocytes are transplanted into highly immunodeficient animals that do not have T cells, B cells, and NK cells and further exhibit a low IFN production ability, the differentiation and proliferation of infiltrating lymphocytes are unexpectedly promoted, and the number of plasma cells that produce antibodies recognizing cancer tissues increases dramatically, plasma cells can be separated easily, and antibodies or nucleic acids encoding them can be easily prepared from the plasma cells.

Abstract: Methods for isolating polynucleotides encoding antibodies against lesional tissues are provided, wherein the methods comprise the steps of: (a) isolating a B cell(s) that infiltrates into a lesional tissue of interest; and (b) obtaining an antibody-encoding polynucleotide from the isolated B cell(s). The lesions may be a cancer tissue or such. Antibody genes can be obtained without depending on B cell cloning. Accordingly, it is also possible to obtain genes encoding human-derived antibodies which are difficult to clone. Genes that encode antibodies against cancer can be obtained using cancer tissues as the lesion.