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Growth and serial passage of Pneumocystis carinii in the A549 cell line
Abstract:
Pneumocystis carinii obtained from infected rats and patients was cultured in the A549 cell line, a presumptive alveolar type 2 cell line derived from a human lung carcinoma. Standard criteria were established for organism sampling, quantitation, and growth. The trophozoite form of P. carinii was a more sensitive indicator of growth than was the cyst. Rat P. carinii increased 10-fold in primary culture and could be serially passed three additional times to new cultures; success in growing human P. carinii was limited and appeared to be related to the quality of the specimen received for culture. Growth pattern experiments suggested that close interaction of P. carinii with the cell monolayer is an important step in the life cycle of the organism. Thus, the A549 culture system should be useful for in vitro studies of the immunobiology of P. carinii.
Insights
Researchers cultured Pneumocystis carinii (P. carinii) in A549 cells, finding trophozoites indicate growth better than cysts. This in vitro model aids P. carinii immunobiology studies.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Pneumocystis carinii is an opportunistic pathogen causing pneumonia in immunocompromised individuals.
- Previous studies on P. carinii have been limited by challenges in in vitro cultivation.
- A549 cells, derived from human lung carcinoma, are considered a model for alveolar type 2 cells.
Purpose of the Study:
- To establish and optimize an in vitro culture system for Pneumocystis carinii using the A549 cell line.
- To determine reliable criteria for assessing P. carinii growth and viability in culture.
- To explore the potential of this system for studying P. carinii immunobiology.
Main Methods:
- Culturing P. carinii from infected rats and human patients in A549 cell monolayers.
- Establishing standardized methods for organism sampling, quantitation, and growth assessment.
- Observing growth patterns and comparing the sensitivity of trophozoite and cyst forms as growth indicators.
Main Results:
- Rat-derived P. carinii demonstrated a 10-fold increase in primary culture and supported serial passaging.
- Successful cultivation of human-derived P. carinii was limited, correlating with specimen quality.
- Trophozoites were identified as more sensitive indicators of P. carinii growth than cysts.
- Close interaction between P. carinii and the A549 cell monolayer was observed, suggesting its importance in the organism's life cycle.
Conclusions:
- The A549 cell line provides a viable system for in vitro culture of P. carinii, particularly from rat models.
- This culture system facilitates further investigation into the immunobiology and life cycle of P. carinii.
- Optimized culture conditions and specimen quality are crucial for successful human P. carinii cultivation.