Population structure of rat-derived Pneumocystis carinii in Danish wild rats.

The rat model of Pneumocystis carinii pneumonia is frequently used to study human P. carinii infection, but there are many differences between the rat and human infections. We studied naturally acquired P.

Experimental corticosteroid induction of Pneumocystis carinii pneumonia in piglets.

Animal models of Pneumocystis carinii (Pc) pneumonia (PCP) play a central role in research on the Pc microorganism itself and the disease, especially the pathogenesis and the host defence. The classic rat model with corticosteroid-induced reactivation of a latent infection has been most widely used. In our search for alternative non-rodent models, six 31/2-week-old piglets were injected intramuscularly with methylprednisolone acetate, at 18 mg/kg body weight, once a week for 6 weeks.

Cultured rat and purified human Pneumocystis carinii stimulate intra- but not extracellular free radical production in human neutrophils.

The production of free radicals in human neutrophils was studied in both Pneumocystis carinii derived from cultures of L2 rat lung epithelial-like cells and Pneumocystis carinii purified from human lung. Using the cytochrome C technique, which selectively measured extracellular superoxide generation, hardly any free radical production was observed after stimulation with cultured rat-derived P. carinii.

Different ultrastructural morphology of Pneumocystis carinii derived from mice, rats, and rabbits.

Pneumocystis carinii (PC) is a fungus present in the lungs of many mammal species. Even though studies of the genome, the isoenzymes, and the antigens have proved some host-species-linked heterogeneity, the existence of distinct Pneumocystis species or subspecies has still not been accepted. Comparative studies of the ultrastructural morphology of pneumocysts derived from several host species may support evidence of host-species-linked heterogeneity.