The present invention relates to proteins or polypeptides, referred to herein as isolated and/or recombinant mammalian (e.g., human) IP-10/Mig receptor proteins designated CXC Chemokine Receptor 3 (CXCR3) and variants thereof, including those characterized by selective binding of one or more chemokines (e.g., IP-10 and/or Mig), and/or the ability to induce a cellular response (e.g., chemotaxis, exocytosis). Antibodies reactive with CXCR3 receptors can be produced using the proteins or variants thereof or host cells comprising same as immunogen.