Abstract: A method for preparing a cell sheet having a durable strength in practical use with good reproducibility within a period of time as short as possible, regardless of a culture medium additive or a type of culture vessel to be used is provided. The method for producing a cell sheet comprises a step of culturing mesenchymal stem cells in a medium containing an ascorbic acid species at 0.3 mM or higher and a ROCK (Rho-associated coiled-coil forming kinase) inhibitor to prepare mesenchymal stem cells in a sheet-like form in a culture vessel, wherein the ascorbic acid species is a water-soluble ascorbic acid derivative or a mixture of a water-soluble ascorbic acid derivative and ascorbic acid.

Abstract: It is an object of the present invention to provide a method for efficiently producing a B cell population comprising B cells that recognize a specific antigen. According to the present invention, provided is a method for producing a B cell population, comprising: a step (c) of culturing a cell population comprising B cells together with a specific antigen in the absence of IL-21, in the absence of IL-4, and in the presence of a cytokine other than IL-21 and IL-4, while giving stimulation mediated by CD40 and a BAFF receptor to the cells; and a step (d) of culturing the cell population comprising B cells, while giving stimulation mediated by has to the cells, so as to obtain a B cell population comprising B cells that recognize the specific antigen.

Abstract: A method for producing a transgenic cell, may include contacting, in vitro, (i) a virus comprising: a chimeric protein of an antibody-binding protein and a vesicular stomatitis virus G (VSV-G) protein; and a foreign gene, with (ii) a target cell and an antibody specific to the target cell, and/or a target cell comprising a membrane antibody, to infect the target cell with the virus.

Abstract: It is an object of the present invention to provide a method for easily producing an antigen-specific B cell population comprising IgG-positive B cells specific to a specific antigen. The present invention provides a method for producing a B cell population, comprising culturing B cells, in which the expression of a Bach2 gene has been increased, in the presence of a means for acting on CD40 and/or a BAFF receptor.

Abstract: It is an object of the present invention to provide a method for easily producing an antigen-specific B cell population comprising IgG-positive B cells specific to a specific antigen. The present invention provides a method for producing a B cell population, comprising culturing B cells, in which the expression of a Bach2 gene has been increased, in the presence of a means for acting on CD40 and/or a BAFF receptor.

Abstract: It is an object of the present invention to provide a method for efficiently producing a B cell population comprising B cells that recognize a specific antigen. According to the present invention, provided is a method for producing a B cell population, comprising: a step (c) of culturing a cell population comprising B cells together with a specific antigen in the absence of IL-21, in the absence of IL-4, and in the presence of a cytokine other than IL-21 and IL-4, while giving stimulation mediated by CD40 and a BAFF receptor to the cells; and a step (d) of culturing the cell population comprising B cells, while giving stimulation mediated by has to the cells, so as to obtain a B cell population comprising B cells that recognize the specific antigen.

Abstract: It is an object of the present invention to provide a method for easily producing an antigen-specific B cell population comprising IgG-positive B cells specific to a specific antigen. The present invention provides a method for producing a B cell population, comprising culturing B cells, in which the expression of a Bach2 gene has been increased, in the presence of a means for acting on CD40 and/or a BAFF receptor.

Abstract: A method for producing a transgenic cell, may include contacting, in vitro, (i) a virus comprising: a chimeric protein of an antibody-binding protein and a vesicular stomatitis virus G (VSV-G) protein; and a foreign gene, with (ii) a target cell and an antibody specific to the target cell, and/or a target cell comprising a membrane antibody, to infect the target cell with the virus.

Abstract: The present invention provides to a polyethylene glycol-modified feline-derived protein which is obtained by chemically modifying a feline-derived protein with polyethylene glycol. The feline-derived protein is produced by a method comprising any or a combination of extracting the protein from somatic cells of a transgenic bird and/or an egg laid thereby, purifying and activating the same. The transgenic bird has a foreign gene containing a sequence encoding a feline-derived protein.

Abstract: An object of the present invention is to develop techniques to create novel engineered protein ligands that maximize the binding capacity and binding efficiency to a target molecule of affinity separation matrices on which the protein ligands are immobilized. The present invention provides protein ligands (variants) that can be immobilized on carriers in a manner shown in schematic FIG. 1(4)-(15), as well as antibody affinity separation matrices obtained by immobilizing such a protein ligand on a water-insoluble carrier. The affinity separation matrices are characterized by their excellent binding capacity and binding efficiency to a target molecule.

Abstract: It is an object of the present invention to provide a method for easily producing an antigen-specific B cell population comprising IgG-positive B cells specific to a specific antigen. The present invention provides a method for producing a B cell population, comprising culturing B cells, in which the expression of a Bach2 gene has been increased, in the presence of a means for acting on CD40 and/or a BAFF receptor.

Abstract: The present invention provides to a polyethylene glycol-modified feline-derived protein which is obtained by chemically modifying a feline-derived protein with polyethylene glycol. The feline-derived protein is produced by a method comprising any or a combination of extracting the protein from somatic cells of a transgenic bird and/or an egg laid thereby, purifying and activating the same. The transgenic bird has a foreign gene containing a sequence encoding a feline-derived protein.

Abstract: An object of the present invention is to develop techniques to create novel engineered protein ligands that maximize the binding capacity and binding efficiency to a target molecule of affinity separation matrices on which the protein ligands are immobilized. The present invention provides protein ligands (variants) that can be immobilized on carriers in a manner shown in schematic FIG. 1(4)-(15), as well as antibody affinity separation matrices obtained by immobilizing such a protein ligand on a water-insoluble carrier. The affinity separation matrices are characterized by their excellent binding capacity and binding efficiency to a target molecule.

Abstract: The present invention has for its object to provide a transgenic bird with a foreign gene containing a feline-derived protein-encoding sequence as transferred therein, and a method of producing the same. The present invention provides a method of producing a feline-derived protein by using a transgenic bird with a method which comprises infecting an avian embryo with a replication defective retrovirus vector containing a foreign gene by microinjection thereof into the early heart or blood vessel formed in the embryo and allowing the embryo to hatch.