Proliferation of rat Pneumocystis carinii on cells sheeted on microcarrier beads in spinner flasks.

A method of growing rat Pneumocystis carinii with human embryonic lung fibroblasts (HEL-299 cells) sheeted onto microcarrier beads has been developed. This method allows production of large quantities of P. carinii organisms with very little contamination of host cells. A fivefold increase in the numbers of organisms was achieved, as determined by organism count, antigen detection, and DNA quantification. The majority of organisms produced by this method are trophozoites.