Clone 15F9 has been reported to be a monoclonal antibody specific to the mouse gene, ICOS, or Inducible T cell co-stimulator. Other suppliers describe clone 15F9 to be a monoclonal antibody against human SOCS3, or suppressor of cytokine signaling 3. This antibody clone has been reported to also recognize the virus ortholog of the target gene. Indicated applications for antibody clone 15F9 include Western blot and immunohistochemistry.