Abstract: The present invention provides a method for inhibiting an immune response and a method for inhibiting rejection of transplanted tissues. This method comprises preventing an endogenous molecule on a cell selected from the group consisting of gp39 and CD40 antigens from binding its endogenous ligand and preventing an endogenous molecule on a cell selected from the group consisting of CTLA4, CD28, and B7 antigens from binding its endogenous ligand. The prevention of such molecules from binding their ligand thereby blocks two independent signal pathways and inhibits the immune response resulting in transplanted tissue rejection.

Abstract: A humanized antibody that binds to human 4-1BB and that allows binding of human 4-1BB to a human 4-1BB ligand. In one aspect, the antibody is an IgG4 antibody. Also provided is a method for treating cancer in a subject comprising administering a therapeutically effective amount of the antibody to said subject.

Abstract: A humanized antibody that binds to human 4-1BB and that allows binding of human 4-1BB to a human 4-1BB ligand. In one aspect, the antibody is an IgG4 antibody. Also provided is a method for treating cancer in a subject comprising administering a therapeutically effective amount of the antibody to said subject.

Abstract: A humanized antibody that binds to human 4-1BB and that allows binding of human 4-1BB to a human 4-1BB ligand. In one aspect, the antibody is an IgG4 antibody. Also provided is a method for treating cancer in a subject comprising administering a therapeutically effective amount of the antibody to said subject.

Abstract: The present invention provides isolated modified inosine 5′-monophosphate dehydrogenase (IMPDH) polypeptides. These modified IMPDH polypeptides comprise a substitute oligo-peptide that replaces the subdomain region. The modified polypeptides of the invention bind to an inhibitor, such as MPA, and/or exhibit functional activity of wild-type IMPDH holo-enzyme.

Abstract: The present invention provides a method for inhibiting an immune reponse and a method for inhibiting rejection of transplanted tissues. This method comprises preventing an endogenous molecule on a cell selected from the group consisting of gp39 and CD40 antigens from binding its endogenous ligand and preventing an endogenous molecule on a cell selected from the group consisting of CTLA4, CD28, and B7 antigens from binding its endogenous ligand. The prevention of such molecules from binding their ligand thereby blocks two independent signal pathways and inhibits the immune response resulting in transplanted tissue rejection.

Abstract: The invention provides a method for enhancing the expression of a gene of interest by a cell, the cell (a) comprises a recombinant nucleic acid sequence encoding and (b) is capable of expressing the gene of interest, the method comprising contacting the cell with an amount of a soluble CTLA4 molecule effective to enhance the expression of the gene of interest by the cell.

Abstract: The present invention provides a method for inhibiting an immune reponse and a method for inhibiting rejection of transplanted tissues. This method comprises preventing an endogenous molecule on a cell selected from the group consisting of gp39 and CD40 antigens from binding its endogenous ligand and preventing an endogenous molecule on a cell selected from the group consisting of CTLA4, CD28, and B7 antigens from binding its endogenous ligand. The prevention of such molecules from binding their ligand thereby blocks two independent signal pathways and inhibits the immune response resulting in transplanted tissue rejection.

Abstract: The present invention provides monoclonal antibodies, antigen binding fragment and recombinant binding proteins specific for human gp39. These antibodies are specific for at least eight different epitopes on gp39. Hybridomas secreting specific antibodies which bind to these epitopes are also provided. Further, the present invention discloses the amino acid sequence of immunoglobulin light and heavy chain variable regions which bind to epitopes of gp39 and provide sFv and humanized antibodies which bind gp39. Also, provided are pharmaceutical compositions comprising the monoclonal antibodies, antigen binding fragments and recombinant binding proteins which bind gp39 and methods for using these compositions in diagnosing disease states, inhibiting B cell activation and for treating immunological disorders, such as autoimmune diseases, allergic responses, organ rejection and graft-versus-host disease.