Antibody generation through B cell panning on antigen followed by in situ culture and direct RT-PCR on cells harvested en masse from antigen-positive wells.

We describe a method for the generation of high-affinity monoclonal antibodies, which combines the power of natural immune responses with in vitro panning, B cell culture, RT-PCR and expression of the recombinant product. B cells from immunised rabbits were incubated at approximately 1000-10,000 cells per well with solid phase antigen coated on the surface of 96-well ELISA plates. Extensive washing removed non-binding cells as well as those B cells, which bound with low affinity.

CD70 (TNFSF7) is expressed at high prevalence in renal cell carcinomas and is rapidly internalised on antibody binding.

In order to identify potential markers of renal cancer, the plasma membrane protein content of renal cell carcinoma (RCC)-derived cell lines was annotated using a proteomics process. One unusual protein identified at high levels in A498 and 786-O cells was CD70 (TNFSF7), a type II transmembrane receptor normally expressed on a subset of B, T and NK cells, where it plays a costimulatory role in immune cell activation. Immunohistochemical analysis of CD70 expression in multiple carcinoma types demonstrated strong CD70 staining in RCC tissues.