Genetic Diversity of Pneumocystis carinii Derived from Infected Rats, Mice, Ferrets, and Cell Cultures

ABSTRACT. The degree of strain and/or species diversity among Pneumocystis carinii isolates is unknown. As a first approach to the study of P. carinii genetic relatedness, we compared the pulsed field gel electrophoretic karyotypes of P. carinii derived from lung homogenates of three immunosuppressed host animals: rats transtracheally inoculated with P. carinii -infected rat lung; mice transtracheally inoculated with P. carinii -infected mouse lung; and ferrets which developed reactivated latent P. carinii pneumonia. Rat P. carinii propagated on HEL299 cells was also examined. Karyotypes of P. carinii DNA from both rat lung homogenate and cell culture were identical (14 bands, 315–680 kb). In contrast, mouse and ferret P. carinii DNA karyotypes were each distinctly different from the rat P. carinii samples (mouse P. carinii 15 bands, 315–610 kb; ferret P. carinii nine bands, 410–760 kb). Three distinct rat P. carinii gene probes reacted with both Southern-transferred rat and mouse P. carinii DNA but not with ferret P. carinii DNA. Thus, P. carinii from rat, mouse, and ferret are genetically diverse. The results are consistent with recently reported antigenic and nucleic acid sequence differences among P. carinii isolates recovered from different hosts.     

Quantitative Differences In Phagocytosis and Degradation of Pneumocystis By Alveolar Macrophages In Aids and Non-Hiv Patients In Vivo

Broncholaveolar lavage (BAL) specimens (n= 213) from AIDS and non-HIV immunosuppressed patients were investigated for the presence of Pneumocystis carinii infection by fluorescence microscopy of Papanicolaou-stained slides. Alveolar casts, extracellular pneumocysts and phagocytosed cysts and their degradation products in pulmonary alveolar macrophages were identified. the number of phagocytosed pneumocysts within human pulmonary alveolar macrophages was recorded and correlated with the number of extracellular cysts and alveolar casts, in both groups of patients. Both phagocytic and degradation capacity were depressed in AIDS patients. This observation may explain the large number of extracellular organisms found in BAL specimens of AIDS patients compared with non-HIV-positive immunocompromised individuals.