Abstract: Methods and compositions relating to anti-CD22 antibodies with high binding affinity, and immunoconjugates comprising the anti-CD22 antibody linked to a therapeutic agent such as a Pseudomonas exotoxin or a detectable label. The invention provides diagnostic methods, and means to inhibit the growth of malignant B cells.

Abstract: The invention provides mutated Pseudomonas exotoxins (PE) that have reduced immunogenicity compared to PEs containing the native sequence. The PEs of the invention have one or more individual mutations of positions of the native sequence of PE that reduce antibody binding to one or more PE epitopes. Nucleic acids encoding the mutated PEs, chimeric molecules comprising them, compositions comprising the chimeric molecules and methods of using them, are also provided.

Abstract: Recombinant immunotoxins are fusion proteins composed of the Fv domains of antibodies fused to bacterial or plant toxins. RFB4 (Fv)-PE38 is an immunotoxin that targets CD22 expressed on B cells and B cell malignancies. The present invention provides antibodies and antibody fragments that have improved ability to bind the CD22 antigen of B cells and B cell malignancies compared to RFB4. Immunotoxins made with the antibodies and antibody fragments of the invention have improved cytotoxicity to CD22-expressing cancer cells. Compositions that incorporate these antibodies into chimeric immunotoxin molecules that can be used in medicaments and methods for inhibiting the growth and proliferation of leukemia and lymphoma cells.

Abstract: Methods and compositions relating to anti-CD22 antibodies with high binding affinity, and immunoconjugates comprising the anti-CD22 antibody linked to a therapeutic agent such as a Pseudomonas exotoxin or a detectable label. The invention provides diagnostic methods, and means to inhibit the growth of malignant B cells.

Abstract: The invention provides mutated Pseudomonas exotoxins (PE) that have reduced immunogenicity compared to PEs containing the native sequence. The PEs of the invention have one or more individual mutations of positions of the native sequence of PE that reduce antibody binding to one or more PE epitopes. Nucleic acids encoding the mutated PEs, chimeric molecules comprising them, compositions comprising the chimeric molecules and methods of using them, are also provided.

Abstract: Methods and compositions relating to recombinant anti-CD22 antibodies with high binding affinity, and immunoconjugates comprising the anti-CD22 antibody linked to a therapeutic agent such as a Pseudomonas exotoxin or a detectable label. The invention provides diagnostic methods, and means to inhibit the growth of malignant B cells.

Abstract: CD30 is a receptor expressed on cells of Hodgkin's disease and certain leukemias. The extracellular portion of CD30 is cleaved, releasing a form known as sCD30. The invention relates in part to the discovery that a residual, extracellular “stalk” of CD30 remains after cleavage of sCD30. The stalk provides an advantageous and previously unrecognized target for immunotoxins. The invention provides antibodies that bind to the CD30 stalk or to epitopes destroyed upon the cleavage of CD30 which results in the stalk. The invention further provides new anti-CD30 antibodies that form effective immunotoxins and are particularly suitable for making disulfide stabilized Fv (“dsFv”)-immunoconjugates. The dsFv immunoconjugates can be used as reagents to label CD30-expressing cancer cells or to inhibit the growth of CD30-expressing cancer cells. Moreover, the invention provides anti-CD30 antibodies that activate complement-dependent cytotoxicity.

Abstract: CD30 is a receptor expressed on cells of Hodgkin's disease and certain leukemias. The extracellular portion of CD30 is cleaved, releasing a form known as sCD30. The invention relates in part to the discovery that a residual, extracellular “stalk” of CD30 remains after cleavage of sCD30. The stalk provides an advantageous and previously unrecognized target for immunotoxins. The invention provides antibodies that bind to the CD30 stalk or to epitopes destroyed upon the cleavage of CD30 which results in the stalk. The invention further provides new anti-CD30 antibodies that form effective immunotoxins and are particularly suitable for making disulfide stabilized Fv (“dsFv”)-immunoconjugates. The dsFv immunoconjugates can be used as reagents to label CD30-expressing cancer cells or to inhibit the growth of CD30-expressing cancer cells. Moreover, the invention provides anti-CD30 antibodies that activate complement-dependent cytotoxicity.

Abstract: Disclosed herein are methods of using previously unknown soluble forms of CD22 (sCD22) present in the serum of subjects with B-cell leukemias and lymphomas to assess tumor burden in the subjects. Also disclosed are methods of diagnosing or prognosing development or progression of a B-cell lymphoma or leukemia in a subject, including detecting sCD22 in a body fluid sample taken or derived from the subject, for instance serum.

Abstract: Recombinant immunotoxins are fusion proteins composed of the Fv domains of antibodies fused to bacterial or plant toxins. RFB4 (Fv)-PE38 is an immunotoxin that targets CD22 expressed on B cells and B cell malignancies. The present invention provides antibodies and antibody fragments that have improved ability to bind the CD22 antigen of B cells and B cell malignancies compared to RFB4. Immunotoxins made with the antibodies and antibody fragments of the invention have improved cytotoxicity to CD22-expressing cancer cells. Compositions that incorporate these antibodies into chimeric immunotoxin molecules that can be used in medicaments and methods for inhibiting the growth and proliferation of leukemia and lymphoma cells.