Immunological and Genetical Heterogeneity of Pneumocystis carinii

由肺囊虫引起的机会性感染在包括猪、马、雪貂、大鼠、小鼠和人类在内的多种哺乳动物中都有报道。长期以来，来自这些动物的肺囊虫被认为属于唯一的卡氏肺囊虫，这导致了卡氏肺囊虫肺炎是人畜共患病的猜测。在控制的实验条件下，卡氏假单胞杆菌在同一物种的动物之间通过空气传播途径明显传播。然而，来自一个宿主物种的卡氏假单胞菌感染另一个宿主物种的能力尚不清楚。由于这些生物很相似，所以很难在形态学上加以区分。在本研究中，我们对来自不同宿主物种的肺囊虫进行了血清端粒、分裂端粒和酶端粒分析，以研究其表型和基因型的差异。对于血清素分析，我们采用间接荧光抗体技术和Western blot技术，使用来自小鼠、大鼠和人类的抗肺囊虫生物的单克隆和多克隆抗体。血清素和酶型分析清楚地显示了它们的表型差异。用聚合酶链反应对大鼠和小鼠来源的生物体进行分裂体分析，然后用限制性内切酶处理产物，证实了生物体之间的基因型差异。我们能够明确区分大鼠、小鼠和人类肺囊虫有机体的技术和试剂的可用性促使我们重新审视卡氏假体从一个宿主物种到另一个宿主物种的传播问题。

Opportunistic infections caused by Pneumocystis organisms have been reported in a variety of mammals including pigs, horses, ferrets, rats, mice, and humans. Pneumocystis organisms from those animals has long been considered to belong to the only species, Pneumocystis carinii, leading the speculation that P.carinii pneumonia is zoonosis. P.carinii is clearly transmissible between animals of the same species by the airborne route under controlled experimental conditions. However, the ability of P.carinii from one host species to infect members of another species is unclear. Attempts of morphological distinguishment of the organisms were difficult because of their resemblance. In the present study, we performed serodeme, schizodeme and zymodene analyzes to study both phenotype and genotype variation among Pneumocystis organisms from different host species. For serodeme analysis, we employed an indirect fluorescence antibody technique and a Western blot technique with the use of monoclonal and polyclonal antibodies raised against Pneumocystis organisms from mice, rats, and humans. Serodeme and zymodeme analyzes clearly demonstrated the differences of their phenotypes. Schizodeme analysis using polymerase chain reaction with specific primers for rat and mouse-derived organisms followed by treatment of the products by restriction enzymes confirmed genotype differences among organisms. The availability of techniques and reagents with which we could unequivocally distinguish between rats, mice, and human Pneumocystis organisms is prompting us to reexamine the issue of transmission of P.carinii from one host species to another.