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Her-2 (p185(erbB-2)) is a transmembrane tyrosine kinase receptor, which is encoded by the Her-2/neu proto-oncogene. Her-2 is overexpressed on 30% of highly malignant breast cancers. Monoclonal antibodies (MAbs) against Her-2 inhibit the growth of Her-2-overexpressing tumor cells and this occurs by a variety of mechanisms. One such MAb, Herceptin(More)
A human Burkitt lymphoma (Daudi) has been grown in the mutant mouse called C.B-17 SCID. Twenty-eight days after s.c. injection of Daudi cells, a palpable tumor grew only at the site of injection in all injected mice. In contrast, after intravenous (i.v.) or intraperitoneal (i.p.) injection, macroscopic, disseminated tumors developed. Following i.v.(More)
In 1997, a chimeric anti-CD20 monoclonal antibody (mAb) (Rituxan) was approved for the treatment of low-grade/follicular B-cell lymphoma. Rituxan has a long half-life and low immunogenicity, and it mediates effector function. Rituxan induces apoptosis in some tumor cell lines in vitro. Previous studies with mAbs that react with neoplastic B cells have(More)
Severe combined immunodeficient (SCID) mice injected intravenously with a human Burkitt's lymphoma cell line (Daudi) develop disseminated lymphoma (SCID/Daudi), which is fatal in 100% of the mice. Early treatment of these mice with either an immunotoxin (IT) cocktail (consisting of anti-CD19-ricin A chain plus anti-CD22-ricin A chain) or chemotherapy(More)
In this report, we extend our previous findings that IgG or F(ab')2 fragments of HD37 anti-CD19 antibody (Ab) in combination with the immunotoxin (IT), RFB4-anti-CD22-deglycosylated ricin A chain (dgA) (but neither reagent alone), prolonged the survival of SCID mice with disseminated human Daudi lymphoma (SCID/Daudi mice) to 1 year at which time they still(More)
Vascular leak syndrome is a major and often dose-limiting side effect of immunotoxins and cytokines. We postulated that this syndrome is initiated by damage to vascular endothelial cells. Our earlier studies identified a three-amino acid motif that is shared by toxins, ribosome-inactivating proteins, and interleukin-2, all of which cause this problem. We(More)
We have previously demonstrated that an anti-CD19 monoclonal antibody (MAb; HD37) inhibits the function of the P-glycoprotein (P-gp) pump in a multidrug-resistant (MDR) B-lymphoma cell line, Namalwa/MDR1, and that this effect is not due to the recognition of a cross-reactive epitope on P-gp. In this study, we have used the same cell line to define the(More)
The antitumor effects of two anti-CD22 ricin A chain-containing immunotoxin (IT) constructs were compared in mice with severe combined immunodeficiency disease with human Daudi cell tumors (SCID-Daudi mice). SCID-Daudi mice develop disseminated lymphoma that clinically resembles African Burkitt's lymphoma, i.e., extranodal disease including infiltration of(More)
Monoclonal antibodies (mAbs) that exert antitumor activity can do so by virtue of their effector function and/or their ability to signal growth arrest or cell death. In this study, we demonstrate that mAbs which have little or no signaling activity-i.e., anti-CD19, CD20, CD21, CD22 and Her-2-can become potent antitumor agents when they are converted into(More)
The antitumor activities of immunotoxins (ITs) constructed with deglycosylated ricin A chain (dgA) and either anti-CD19 (HD37) or anti-CD22 (RFB4) monoclonal antibodies were compared in SCID mice with disseminated human Daudi lymphoma (SCID/Daudi). As reported previously, after intravenous injection with Daudi cells, SCID mice develop disseminated lymphoma,(More)