Generation of monoclonal antibodies that distinguish between mesotheliomas and other tumor of the lung.

The accurate diagnosis of mesothelioma remains difficult despite advances of diagnostic technique. And specific monoclonal antibody (McAb) against mesothelioma have not been reported. In an attempt to develop mesothelioma specific McAb(s), spleen cells from a mouse immunized with isolated tumor cells were fused to a drug resistant mouse myeloma cell lines. Over 200 hybridomas were assayed for their preferential reactivity with mesothelioma cell lines or mesothelioma tumor biopsy tissues. Two monoclonal antibodies 2A3 and 4E1 were identified that bound 6/7 of the mesotheliomas, tested, but did not bind to the majority, 11/13 (for 2A3) and 12/13 (for 4E1), of other lung tumor types. Based upon western blot analysis of one and two-dimensional gels and upon the distribution pattern of the antibody recognized molecule in mesotheliomas and non-mesothelioma lung tumors, 2A3 binds to the cell adhesion molecule CD44. While the specificity of 4E1 has not yet been unequivocally established it appears to recognize a variant form of the CD44 molecule.