There has been much discussion regarding the classification of Pneumocystis jirovecii, formerly known as P. carinii.
P. carinii is found only in rat lungs, and P. jirovecii is a pathogen found only in humans. P. jirovecii was erroneously classified as a protozoan when, in actuality, it is a yeast-like fungus.
Pneumocystis pneumonia (PCP) or pneumocystosis causes pneumonia in human immunodeficiency virus (HIV) patients, immunosuppressed patients, and organ transplant recipients. In infected lungs, P. jirovecii is visualized as homogeneous rings corresponding to individual fungal cyst walls in intra-alveolar spaces.
P. jirovecii mouse monoclonal clone 3F6, is an IgM, kappa isotype antibody that requires proteolytic-induced epitope retrieval (PIER) pretreatment with pepsin or heat-induced epitope retrieval (HIER) pretreatment with citrate buffer for demonstration of P. jirovecii.
