ABSTRACT
I. Introduction Pneumocystis jiroveci (formerly called Pneumocystis carinii f.sp. hominis) is an important cause of pneumonia in patients with HIV, cancer, and organ transplantation as well as in other immunocompromised hosts [1]. Although research on Pneumocystis has been hindered by the lack of a continuous in vitro cultivation system, animal models and molecular techniques have provided a lot of information about the immunological features of this infection. The principal experimental models have included congenitally immunodeficient mice or rats, mice rendered immunodeficient by genetic manipulation, and mice or rats immunosuppressed with exogenous agents (e.g., corticosteroids, antibodies to CD4 cells) [2]. These animals also produce a ready supply of Pneumocystis organisms.
