Abstract: The present invention relates to methods and compositions for the prevention and treatment and prevention of immune system disorders, including cancer, AIDS, asthmatic disorders, autoimmune diseases, organ transplant rejection and chronic viral diseases such as HCV or HBV infections. The therapeutic methods of the invention comprise administering molecules that modulate the activity of 8F4, thereby modulating costimulation of T cells. The present invention further provides monoclonal antibodies against the 8F4 molecule and hybridoma cells which produce said monoclonal antibodies. Pharmaceutical compositions comprising molecules that modulate the activity of 8F4 are also provided.

Abstract: A polypeptide (8F4 molecule) with a T-cell costimulating biological activity is disclosed, as well as monoclonal antibodies against said 8F4 molecule and hybridoma cells which produce the monoclonal antibodies, the use as medicaments of substances which inhibit the biological activity of the disclosed 8F4 polypeptide, in particular monoclonal antibodies, natural or synthetic ligands, agonists or antagonists, in particular for preventing or treating diseases which involve the immune system, the use of said 8F4 molecule or cells containing said 8F4 molecule as medicaments, in particular for preventing or treating diseases which involve the immune system, and the use of substances which specifically recognize the disclosed polypeptide, in particular monoclonal antibodies, natural or synthetic ligands, agonists or antagonists, for diagnosing diseases which involve the immune system.

Abstract: The present invention provides methods of suppressing demyelinating inflammatory disorders in a patient by administering to the patient a compound that inhibits binding of B7RP-1 to ICOS or inhibits signaling through the B7RP-1 pathway. Various therapeutic regimens are provided. Methods of identifying such compounds are also provided. The present invention further provides kits and pharmaceutical compositions useful in the present methods.

Abstract: A polypeptide (8F4 molecule) with a T-cell costimulating biological activity is disclosed, as well as monoclonal antibodies against said 8F4 molecule and hybridoma cells which produce the monoclonal antibodies, the use as medicaments of substances which inhibit the biological activity of the disclosed 8F4 polypeptide, in particular monoclonal antibodies, natural or synthetic ligands, agonists or antagonists, in particular for preventing or treating diseases which involve the immune system, the use of said 8F4 molecule or cells containing said SF4 molecule as medicaments, in particular for preventing or treating diseases which involve the immune system, and the use of substances which specifically recognize the disclosed polypeptide, in particular monoclonal antibodies, natural or synthetic ligands, agonists or antagonists, for diagnosing diseases which involve the immune system.

Abstract: The present invention relates to methods and compositions for the prevention and treatment and prevention of immune system disorders, including cancer, AIDS, asthmatic disorders, autoimmune diseases, organ transplant rejection and chronic viral diseases such as HCV or HBV infections. The therapeutic methods of the invention comprise administering molecules that modulate the activity of 8F4, thereby modulating costimulation of T cells. The present invention further provides monoclonal antibodies against the 8F4 molecule and hybridoma cells which produce said monoclonal antibodies. Pharmaceutical compositions comprising molecules that modulate the activity of 8F4 are also provided.