Monoclonal antibodies to angiotensin-converting enzyme: a powerful tool for lung and vessel studies.

We obtained a series (12 clones) of hybridomas, which produce monoclonal antibodies (Mab) to 5 different epitopes of the angiotensin-converting enzyme (ACE) molecule. These antibodies may be used to (1) map antigenic structure of ACE, including the study of immunologic heterogeneity of ACE from different organs and tissues; (2) study the immunohistochemical distribution of ACE in human tissues, including the diagnosis of sarcoidosis; (3) develop an ACE immunoassay, and (4) prepare an immunosorbent for large-scale ACE isolation and for ACE-apheresis. One of the antibodies, 9B9, when injected into the circulation of rat and monkey, accumulated with high specificity in the lungs as compared with either normal mouse IgG or other organs and blood. The highly specific and nontoxic accumulation of Mab 9B9 suggests that it also may be used for gamma scintigraphy visualization of the pulmonary vascular bed, detection of lung injury and as a vector for targeted drug delivery to the lung.