Abstract: The invention provides a method of promoting the host defense of a patient to a bacterial infection comprising administering to a patient suffering or at risk of a bacterial infection, a pharmaceutical composition comprising an effective amount of the pleiotropic cytokine, thymic stromal lymphopoietin (TSLP) protein or polypeptide in an amount and at a location sufficient to promote the host defense of the patient to the bacterial infection. In a preferred embodiment, the bacterial infection is the infection of the patient with MRSA. The invention also provides a method of treating blood product, which comprises introducing a TSLP protein or polypeptide into such blood product, wherein the blood product is extracorporeal and comprises at least one neutrophil.

Abstract: The invention provides a method of promoting the host defense of a patient to a bacterial infection comprising administering to a patient suffering or at risk of a bacterial infection, a pharmaceutical composition comprising an effective amount of the pleiotropic cytokine, thymic stromal lymphopoietin (TSLP) protein or polypeptide in an amount and at a location sufficient to promote the host defense of the patient to the bacterial infection. In a preferred embodiment, the bacterial infection is the infection of the patient with MRSA. The invention also provides a method of treating blood product, which comprises introducing a TSLP protein or polypeptide into such blood product, wherein the blood product is extracorporeal and comprises at least one neutrophil.

Abstract: The invention provides a method of treating or preventing viral diseases in a mammal comprising administering to the mammal an interleukin (IL)-21 blocking agent in an amount effective to treat or prevent the viral disease in the mammal. Also provided is a method of reducing the activation or recruitment of immune cells in a mammal comprising administering to the mammal an IL-21 blocking agent in an amount effective to reduce the activation or recruitment of immune cells in the mammal. Methods of decreasing the expression of at least one cytokine or at least one protein in a mammal comprising administering to the mammal an IL-21 blocking agent in an amount effective to decrease the expression of the cytokine or the protein are also provided.

Abstract: The invention provides a method for promoting differentiation of a mature naïve B cell or a B cell progenitor into a memory B cell or a plasma cell. The method comprises (a) contacting a population of cells comprising a mature naïve B cell or a B cell progenitor with an agent that activates at least one of JAK1, JAK3, STAT3, STAT5A or STAT5B; wherein the population of cells optionally is contacted with an antigen, and (b) isolating the memory B cell or plasma cell.

Abstract: A method is disclosed herein for inducing differentiation of a B cell progenitor into a memory B cells and/or a plasma cell. The method includes contacting a population of cells including a mature B cell or a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. In one embodiment, the B cell progenitor is an immature B cell. A method is also disclosed for enhancing an immune response. The method includes contacting a population of cells including a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. The memory B cells arid/or the plasma cell are then introduced into the subject to enhance the immune response. A method is also disclosed for treating a subject with a condition comprising a specific deficiency of at least one of memory B cells and plasma cells. A method is disclosed for identifying an agent with a physiological effect on one or more of a memory B cell and a plasma cell differentiation.

Abstract: Methods are disclosed herein for specifically inducing proliferation of CD4+ T cells. The methods are of use in treating immunodeficiencies, such as an immunodeficiency produced by infection with an immunodeficiency virus, such as infection with a human immunodeficiency virus (HIV). The methods include contacting isolated mammalian CD4+ T cells with an effective amount of a thymic stromal derived lymphopoietin (TSLP) polypeptide or a therapeutically effective amount of nucleic acid encoding the TSLP polypeptide, thereby inducing proliferation of the T cells. Methods are also disclosed for treating an IgE mediated disorder, such as asthma. The methods include administering to a subject a therapeutically effective amount of a TSLP antagonist. Transgenic mice are also disclosed herein.

Abstract: A method of treating and/or preventing cancer in a subject, preferably mammalian, more preferably human, by administering in an effective amount IL-21 polypeptide, polynucleotide, vector comprising an IL-21 nucleic acid sequence encoding an IL-21 polypeptide, variants, and fragments thereof, thereby acting as an anti-cancer agent by reducing, ameliorating, and/or eliminating the cancer; and a method of treating and/or preventing cancer in a subject by co-administering the IL-21 polypeptide, polynucleotide, IL-21 vector, variant, and fragments thereof, with an immunotherapeutic and/or chemotherapeutic agent for the treatment and/or prevention of cancer in a subject.

Abstract: A method is disclosed herein for inducing differentiation of a B cell progenitor into a memory B cells and/or a plasma cell. The method includes contacting a population of cells including a mature B cell or a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. In one embodiment, the B cell progenitor is an immature B cell. A method is also disclosed for enhancing an immune response. The method includes contacting a population of cells including a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. The memory B cells and/or the plasma cell are then introduced into the subject to enhance the immune response. A method is also disclosed for treating a subject with a condition comprising a specific deficiency of at least one of memory B cells and plasma cells. A method is disclosed for identifying an agent with a physiological effect on one or more of a memory B cell and a plasma cell differentiation.

Abstract: A transgenic mouse is disclosed herein whose somatic and germ cells comprise a disrupted IL-21 receptor gene, the disruption being sufficient to inhibit the binding of IL-21 to an IL-21 receptor, and a disrupted IL-4 gene, the disruption being sufficient to inhibit the production of IL-4 or the binding of IL-4 to the IL-4 receptor. A mouse homozygous for the disrupted IL-21 receptor gene and homozygous for the disrupted IL-4 gene has diminished B cell function. A method is disclosed for altering a B cell activity. The method includes administering a therapeutically effective amount of an agent that interferes with the interaction of IL-21 with an IL-21 receptor, thereby altering the B cell activity. A method is also disclosed for of treating a subject with Job's disorder or atopic disease. A method is also disclosed for treating or preventing an allergic reaction in a subject. A method is also disclosed for treating a subject with an autoimmune or antibody mediated disorder.

Abstract: A method is disclosed herein for inducing differentiation of a B cell progenitor into a memory B cells and/or a plasma cell. The method includes contacting a population of cells including a mature B cell or a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. In one embodiment, the B cell progenitor is an immature B cell. A method is also disclosed for enhancing an immune response. The method includes contacting a population of cells including a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. The memory B cells and/or the plasma cell are then introduced into the subject to enhance the immune response. A method is also disclosed for treating a subject with a condition comprising a specific deficiency of at least one of memory B cells and plasma cells. A method is disclosed for identifying an agent with a physiological effect on one or more of a memory B cell and a plasma cell differentiation.

Abstract: A transgenic mouse is disclosed herein whose somatic and germ cells comprise a disrupted IL-21 receptor gene, the disruption being sufficient to inhibit the binding of IL-21 to an IL-21 receptor, and a disrupted IL-4 gene, the disruption being sufficient to inhibit the production of IL-4 or the binding of IL-4 to the IL-4 receptor. A mouse homozygous for the disrupted IL-21 receptor gene and homozygous for the disrupted IL-4 gene has diminished B cell function. A method is disclosed for altering a B cell activity. The method includes administering a therapeutically effective amount of an agent that interferes with the interaction of IL-21 with an IL-21 receptor, thereby altering the B cell activity. A method is also disclosed for of treating a subject with Job's disorder or atopic disease. A method is also disclosed for treating or preventing an allergic reaction in a subject. A method is also disclosed for treating a subject with an autoimmune or antibody mediated disorder.

Abstract: Methods are disclosed herein for specifically inducing proliferation of CD4+ T cells. The methods are of use in treating immunodeficiencies, such as an immunodeficiency produced by infection with an immunodeficiency virus, such as infection with a human immunodeficiency virus (HIV). The methods include contacting isolated mammalian CD4+ T cells with an effective amount of a thymic stromal derived lymphopoietin (TSLP) polypeptide or a therapeutically effective amount of nucleic acid encoding the TSLP polypeptide, thereby inducing proliferation of the T cells. Methods are also disclosed for treating an IgE mediated disorder, such as asthma. The methods include administering to a subject a therapeutically effective amount of a TSLP antagonist. Transgenic mice are also disclosed herein.

Abstract: A method is disclosed herein for inducing differentiation of a B cell progenitor into a memory B cells and/or a plasma cell. The method includes contacting a population of cells including a mature B cell or a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. In one embodiment, the B cell progenitor is an immature B cell. A method is also disclosed for enhancing an immune response. The method includes contacting a population of cells including a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. The memory B cells arid/or the plasma cell are then introduced into the subject to enhance the immune response. A method is also disclosed for treating a subject with a condition comprising a specific deficiency of at least one of memory B cells and plasma cells. A method is disclosed for identifying an agent with a physiological effect on one or more of a memory B cell and a plasma cell differentiation.

Abstract: A method is disclosed herein for inducing differentiation of a B cell progenitor into a memory B cells and/or a plasma cell. The method includes contacting a population of cells including a mature B cell or a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. In one embodiment, the B cell progenitor is an immature B cell. A method is also disclosed for enhancing an immune response. The method includes contacting a population of cells including a B cell progenitor with an effective amount of IL-21, and isolating memory B cells or plasma cells. The memory B cells and/or the plasma cell are then introduced into the subject to enhance the immune response. A method is also disclosed for treating a subject with a condition comprising a specific deficiency of at least one of memory B cells and plasma cells. A method is disclosed for identifying an agent with a physiological effect on one or more of a memory B cell and a plasma cell differentiation.

Abstract: Methods are disclosed herein for specifically inducing proliferation of CD4+ T cells. The methods are of use in treating immunodeficiencies, such as an immunodeficiency produced by infection with an immunodeficiency virus, such as infection with a human immunodeficiency virus (HIV). The methods include contacting isolated mammalian CD4+ T cells with an effective amount of a thymic stromal derived lymphopoietin (TSLP) polypeptide or a therapeutically effective amount of nucleic acid encoding the TSLP polypeptide, thereby inducing proliferation of the T cells. Methods are also disclosed for treating an IgE mediated disorder, such as asthma. The methods include administering to a subject a therapeutically effective amount of a TSLP antagonist. Transgenic mice are also disclosed herein.

Abstract: A transgenic mouse is disclosed herein whose somatic and germ cells comprise a disrupted IL-21 receptor gene, the disruption being sufficient to inhibit the binding of IL-21 to an IL-21 receptor, and a disrupted IL-4 gene, the disruption being sufficient to inhibit the production of IL-4 or the binding of IL-4 to the IL-4 receptor. A mouse homozygous for the disrupted IL-21 receptor gene and homozygous for the disrupted IL-4 gene has diminished B cell function. A method is disclosed for altering a B cell activity. The method includes administering a therapeutically effective amount of an agent that interferes with the interaction of IL-21 with an IL-21 receptor, thereby altering the B cell activity. A method is also disclosed for of treating a subject with Job's disorder or atopic disease. A method is also disclosed for treating or preventing an allergic reaction in a subject. A method is also disclosed for treating a subject with an autoimmune or antibody mediated disorder.