Abstract: The invention provides antagonistic and agonistic anti-human VISTA antibodies and antibody fragments. These antagonist antibodies and antibody fragments may be used to inhibit or block VISTA's suppressive effects on T cell immunity and thereby promote T cell immunity. These agonist antibodies and antibody fragments may be used to potentiate or enhance or mimic VISTA's suppressive effects on T cell immunity and thereby suppress T cell immunity. These antagonist antibodies and antibody fragments are especially useful in the treatment of cancer and infectious conditions. These agonist antibodies and antibody fragments are especially useful in the treatment of autoimmunity, allergy, inflammatory conditions, GVHD, sepsis and transplant recipients. Screening assays for identifying these agonists are also provided.

Abstract: The invention provides agonistic anti-human VISTA antibodies and antibody fragments. These agonist antibodies and antibody fragments may be used to potentiate or enhance or mimic VISTA's suppressive effects on T cell immunity and thereby suppress T cell immunity. These agonist antibodies and antibody fragments are especially useful in the treatment of autoimmunity, allergy, inflammatory conditions, GVHD, sepsis and transplant recipients. Screening assays for identifying these agonists are also provided.

Abstract: The invention provides agonistic anti-human VISTA antibodies and antibody fragments. These agonist antibodies and antibody fragments may be used to potentiate or enhance or mimic VISTA's suppressive effects on T cell immunity and thereby suppress T cell immunity. These agonist antibodies and antibody fragments are especially useful in the treatment of autoimmunity, allergy, inflammatory conditions, GVHD, sepsis and transplant recipients. Screening assays for identifying these agonists are also provided.

Abstract: Improved anti-CD154 antibodies are provided herein which have improved therapeutic potency, in vivo half-life and ablated FcR binding and/or complement binding/activation. The use of these antibodies for inducing tolerance and treating immune diseases including autoimmunity, inflammation, transplant recipients, fibrosis and allergic disorders is disclosed herein.

Abstract: The invention provides antagonistic and agonistic anti-human VISTA antibodies and antibody fragments. These antagonist antibodies and antibody fragments may be used to inhibit or block VISTA's suppressive effects on T cell immunity and thereby promote T cell immunity. These agonist antibodies and antibody fragments may be used to potentiate or enhance or mimic VISTA's suppressive effects on T cell immunity and thereby suppress T cell immunity. These antagonist antibodies and antibody fragments are especially useful in the treatment of cancer and infectious conditions. These agonist antibodies and antibody fragments are especially useful in the treatment of autoimmunity, allergy, inflammatory conditions, GVHD, sepsis and transplant recipients. Screening assays for identifying these agonists are also provided.

Abstract: Improved anti-CD154 antibodies are provided herein which have improved therapeutic potency, in vivo half-life and ablated FcR binding and/or complement binding/activation. The use of these antibodies for inducing tolerance and treating immune diseases including autoimmunity, inflammation, transplant recipients, fibrosis and allergic disorders is disclosed herein.

Abstract: The receptor for VISTA is identified (VSIG8) as well as the use of this receptor in the identification or synthesis of agonist or antagonist compounds, preferably antibodies, polypeptides and fusion proteins which agonize or antagonize the effects of VSIG8 and/or VISTA and/or the VSIG8/VISTA binding interaction. These antagonists may be used to suppress VISTA's suppressive effects on T cell immunity, and more particularly used in the treatment of cancer, or infectious disease. These agonist compounds may be used to potentiate or enhance VISTA's suppressive effects on T cell immunity and thereby suppress T cell immunity, such as in the treatment of autoimmunity, allergy or inflammatory conditions. Screening assays for identifying these agonists and antagonist compounds are also provided.

Abstract: The present invention is directed to the use of VISTA agonists alone or in association with other immune inhibitors, preferably another inhibitor of humoral immunity such as an iNOS/NO promoter or nitric oxide or a PD-1 or PD-L1 agonist or a CD40 antagonist for the treatment or prevention of conditions wherein the suppression of humoral immunity is therapeutically beneficial. The present invention is further directed to the use of VISTA antagonists alone or in association with other immune agonists, preferably another enhancer of humoral immunity such as iNOS/NO inhibitor or a PD-1 or PD-L1 antagonist or anti-CTLA-4 antibody or a CD40 agonist for the treatment or prevention of conditions wherein the enhancement of humoral immunity is therapeutically beneficial. Also, the invention relates to the use of VISTA antagonists alone or in association with another immune agonist, e.g., an iNOS/NO inhibitor or a CD40 agonist to promote the efficacy of therapeutic and prophylactic vaccines, e.g.