Pneumocystis carinii in vitro. A study by scanning electron microscopy

M. J. Murphy, L. L. Pifer, W. T. Hughes

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The nomenclature used to describe the various stages in the life cycle of Pneumocystis carinii differs among authors. The following terms, based on the size of the organism, are used here: Sporozite refers to membrane bounded intracystic bodies and those in the process of being released from the cyst. Those 'budding' from the cyst measure an average of 1 μ in diameter. Trophozoite refers to the extracystic form from the point of detachment from the cyst and is therefore smaller than the cyst, measuring an average of 3 μ in diameter. Cyst refers to pleomorphic cells which may be round, oval, or with single or multiple surface concavities. They average 5.5 μ in diameter, with a range of 4 to 8 μ in diameter. Pneumocystis carinii is a parasitic microorganism which induces an often fatal pneumonitis in a variety of compromised patients (e.g., premature infants, those with congenital immune deficiency disorders, those therapeutically immune suppressed, etc.). Organisms derived from murine sources were cultivated in vitro on monolayers of primary embryonic chick epithelial lung cells. The infected cultures were then examined by scanning electron microscopy. An examination of the surface ultrastructure revealed pleomorphic organisms which were not only attached to host cells with anchoring fibers but also connected to other parasites via fine fibrils. Another type of fine fibril was observed which may play a role in the organism's nutrition.

Original languageEnglish (US)
Pages (from-to)387-403
Number of pages17
JournalAmerican Journal of Pathology
Issue number2
StatePublished - Jan 1 1977

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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