In vitro attachment of Pneumocystis carinii from mouse and rat origin

Abstract

The attachment of Pneumocystis carinii to lung cells could play a role in the pathophysiology of P carinii pneumonia. The trophozoite attaches to type I alveolar epithelial cells. Physical, chemical, and extracellular matrix factors, involved in the mouse-or rat-derived P carinii attachment to fibroblastic cells in culture, were examined using a new model of in vitro adherence. The development of parasite filopodia penetrating deeply the host cell cytoplasm was observed using transmission electronic microscopy. Killed P carinii organisms were unable to attach to cultured cells. Also, parasites were unable to attach to killed target cells. The P carinii in vitro attachment was partially inhibited by cytochalasin B. In contrast, the parasite attachment was not affected when the target cell cytoskeleton was altered. In our work conditions, sialic acids were not involved in the attachment process. Present results showed that fibronectin (Fn) plays a role in the parasite attachment, and suggest that a specific Fn-binding receptor is present at the surface of mouse-derived P carinii organisms.

In uterotransmission ofPneumocystis cariniisp. f.Oryctolagi

“…Parasite extracts were filtered through sterile stainless steel (250 and 30 μm) and through Nucleopore filters (10 and 8 µm) (Cofralab, Gradignan, France). The number of P. carinii was assessed in lung extract smears stained with TBO as previously described (Aliouat et al, 1993).…”

Pneumocystis carinii f. sp. hominis Is Not Infectious for SCID mice

“…Ten weeks postinfection, all SCID mice were euthanized and lungs were removed for microscopic and Pneumocystis PCR analysis. Both parasite inocula and lung samples were stained with toluidine blue O, which stains cystic forms, and methanol-Giemsa, which stains cytoplasm and nuclear structures of all Pneumocystis stages, as previously described (1). Animal experiments were performed according to the conditions stipulated in European guidelines (7).…”

Hypobaric hypoxia-related impairment of pulmonary surfactant proteins A and D did not favourPneumocystis cariniiFrenkel 1999 growth in non-immunocompromised rats

“…Parasite extraction from tissue lung and purification were performed as previously (Aliouat et al, 1993). These methods revealed efficient in obtaining viable and infectious P. carinii organisms (Anonyme, 1996;DurandJoly et al, 2002).…”

“…The total number of cystic forms (intermediate or late sporocytes and cysts) was calculated as previously described (Aliouat et al, 1993;Anonyme, 1996;Durand-Joly et al, 2002).…”