Korean J Pathol.  2001 Dec;35(6):496-505.

Apoptosis of Alveolar Cells in Pneumocystis Carinii Pneumonia: Application of Electron Microscopic Terminal Deoxynucleotidyl Transferase-Mediated dUTP-Biotin Nick End Labeling Method

• Kang KH
• Kim SP
• Kwon KY

Abstract

BACKGROUND
Pneumocystis carinii (P. carinii) attaches to alveolar cells and causes injury to the epithelial cells by direct toxic effects or inhibition of epithelial growth and replication. Although respiratory cell damage or death is a common feature in P. carinii pneumonia, there has been little reports about expression of apoptosis of the lung tissue in the literatures.
METHODS
We examined expression of fibronectin and vitronectin in the interaction between P. carinii and alveolar cells, and in situ terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling (TUNEL) expression of apoptosis in the respiratory cells by immunohistochemistry and pre-embedding immunoelectron microscopy.
RESULTS
Light microscopic (LM) and electron microscopic (EM) immunohistochemical stains for the fibronectin and vitronectin showed strong expressions on the pellicles and tubular extensions of P. carinii and weak expression along the surfaces of type I alveolar cells. LM and EM TUNEL stains showed positive expression in the nuclei of alveolar cells, apoptotic bodies in the cytoplasm of alveolar macrophages and cellular debris in alveolar spaces.
CONCLUSIONS
P. carinii induces injury and apoptosis of alveolar cells after attachment of the organisms to host cells, and alveolar macrophages enhance the clearance of apoptotic bodies of alveolar cells as well as phagocytosis and degradation of P. carinii.

Keyword

Pneumocystis carinii; In situ nick-end labeling; Apoptosis; Microscopy; immunoelectron

MeSH Terms

Apoptosis*
Biotin
Coloring Agents
Cytoplasm
Epithelial Cells
Fibronectins
Immunohistochemistry
In Situ Nick-End Labeling
Lung
Macrophages, Alveolar
Microscopy
Microscopy, Immunoelectron
Phagocytosis
Pneumocystis carinii*
Pneumocystis*
Pneumonia
Pneumonia, Pneumocystis*
Vitronectin
Biotin
Coloring Agents
Fibronectins
Vitronectin