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.

Systems, compositions, and methods for the treatment of a liver disorder is disclosed. The systems, compositions, and methods include use of activated T regulatory cells for alleviating, treating, or reducing a liver disorder. The T regulatory cells may be allogeneic T regulatory cells that may be present in an amount of about 510.sup.5 to 210.sup.6 cells. The liver disorder needing treatment may be hepatitis, cirrhosis, chronic liver disease, acute liver disease, or liver failure.

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.

The present invention provides a method for producing recombinant growth factors using an algal expression system, which offers advantages over traditional platforms, and the algae-derived growth factors can be used to formulate cell culture media for mammalian cells without the risk of pathogen contamination or endotoxins.