Characterization of a novel mouse monoclonal antibody, clone 1E8.33, highly specific for human procollagen 11A1, a tumor-associated stromal component.

A novel IgG1, κ mouse monoclonal antibody (clone 1E8.33) to human procollagen 11A1 has been generated. This antibody is poorly mutated, essentially in germ line configuration; its complementarity determining regions (CDRs) are especially rich in tyrosine and serine residues. The epitope recognized is encompassed in the YNYGTMESYQTEAPR amino acid stretch within the variable region of human procollagen 11A1. Human procollagens 5A1 and 11A1 are very similar. However, this antibody does not cross-react with human procollagen 5A1. In human breast tumors, only the activated peritumoral myofibroblasts show a strong intracytoplasmic staining with this antibody. As procollagen 11A1 is overexpressed in the stroma of human tumors with desmoplastic reaction, this antibody represents a valuable tool for diagnostic purposes.