Prospective evaluation of a monoclonal antibody in diagnosis of Pneumocystis carinii pneumonia.

To evaluate the ability of a mouse monoclonal antibody, 2G2, directed against human Pneumocystis carinii, to detect the organism in clinical specimens, a prospective study of the antibody in an indirect immunofluorescent assay was undertaken. P carinii was rapidly detected in thirteen of fourteen bronchoalveolar lavage specimens positive by toluidine-blue-O stain, none of eleven lavage specimens negative by toluidine-blue-O, neither of two impression smears of histologically negative open-lung biopsy specimens, and both of two impression smears of histologically positive necropsy specimens. Immunofluorescence with monoclonal antibody 2G2 is a rapid, simple, and specific technique for detection of P carinii in clinical specimens.