Abstract: The invention provides novel glucocorticosteroids, glucocorticosteroid-linkers and antibody drug conjugates (ADC's) comprising an antibody or antibody fragment which binds to an antigen expressed on immune cells, optionally an antigen expressed on human immune cells. In some instances the ADCs comprise an anti-human VISTA (V-region Immunoglobulin-containing Suppressor of T cell Activation (1)) antibody or anti-VISTA antigen-binding antibody fragment which binds to VISTA expressing cells at physiologic pH having a short serum half-life (?24-72 or 24-48 or 12-24 hours or less in a human VISTA knock-in rodent or ((?1-3.5 days or less in a human or non-human primate). In some instances these ADCs have a rapid onset of action and are potent for prolonged duration as they are very effectively internalized by immune cells in large amounts where they are cleaved releasing large amounts of active steroid payload.

Abstract: The invention provides anti-VISTA antibody drug conjugates which may be used for targeted delivery of anti-inflammatory agents such as steroids to immune cells, e.g., myeloid cells. The invention also provides methods of using anti-VISTA antibody drug conjugates in the treatment of inflammatory and/or autoimmune conditions and/or for alleviating the toxicity of anti-inflammatory agents such as steroids.