Monoclonal Antibodies Against Wilms' tumor (WT1)
Scientists at The Wistar Institute have created monoclonal antibodies that react with the Wilms' tumor (WT1) protein. These antibodies can be used diagnostically in a variety of malignancies that over-express the WT1 protein. In particular, they can be used for distinguishing mesotheliomas from other tumors or nonmalignant conditions that affect the pleura. In addition, the antibodies may be used to monitor disease activity in acute leukemias.
The wt1 gene was originally identified as a candidate tumor suppressor gene by researchers investigating the causes of Wilms' tumor, a childhood kidney tumor. The gene codes for the WT1 protein, which has the structural features of a DNA-binding transcription factor. The WT1 protein has been shown to be over-expressed in a variety of tumors.
Three monoclonal antibodies have been developed, designated 6F-H2, 6F-H7, 6F-H17, and the isotype for each is IgG1.
The hybridomas producing these antibodies resulted from the fusion of spleen cells from mice immunized with a peptide comprising the N-terminal 173 amino acids of the WT1 protein and cells of the myeloma fusion partner P3x63AG8/653. This N-terminal region of the WT1 protein has little sequence homology to any other known protein. The resulting antibodies do not cross react with other transcription factors containing the zinc finger motif. Consequently, these monoclonal antibodies are more specific than either polyclonal or monoclonal antibodies to WT1 that have been produced by other researchers.
All three monoclonal antibodies work in a variety of applications including ELISA, immunofluorescence, immunoprecipitation, and immunoblotting (i.e., Western blot) assays. H2 has been used in immunohistology on frozen sections as well as on formalin-fixed, paraffin-embedded sections.
United States Patents, Nos. 5,622,835 and 5,633,142, have been issued.