Propagation and purification of rat Pneumocystis carinii in short-term cell culture

A short-term cell culture is used to propagate and purify rat-derived Pneumocystis carinii (Pc). An aliquot of pelleted material washed out of the lungs of rats with moderate to severe Pc pneumonia is cultured for 7 to 10 days on the adherent mink lung cell line Mv 1 Lu, and the rest of the material is frozen down in medium with 10% glycerol. Although it has not been established that substantial multiplication of Pc occurs in culture, the Pc organisms harvested from the supernatant at the end of the culture period are relatively free of both host and feeder cells. This is in marked contrast with the lung wash inoculum in which the Pc organisms are heavily contaminated with rat cells and enmeshed in a highly sticky material. Lung wash preparations frozen down in glycerol and stored at -70 degrees C for as long as 6 months or more can be successfully cultured upon thawing with no apparent loss of viability of the Pc organisms.