Acquired Immunity to Pathogenic Fungi in Gnotobiotic Animals.

摘要

Fungal infections were studied in germfree and conventional guinea pigs, rats and mice. The response of flora-defined and conventional nude (congenitally athymic) mice to pathogenic fungi was also investigated. In brief dermatophyte skin infections on conventional guinea pigs were of much shorter duration (2 1/2 times) than comparable infections on germfree guinea pigs. Dermatophyte infections on the skin of guinea pigs were associated with an impairment (suppression) of in vitro lymphocyte blastogenesis to mitogens and dermatophyte antigens. The suppressor, also present in infected gnotobiotic guinea pigs appeared to be a serum component that disappeared from serum when the fungal load on the skin was diminished. Germfree and conventional rats did not undergo chronic skin infections when challenged with dermatophytes that produced full-blown infections in guinea pigs. The dermatophytes did not colonize the gastrointestinal tract of germfree rats or guinea pigs. Scanning electron microscopy (SEM), light microscopy, and quantitative culture of microorganisms in intestinal contents were used to determine the effects of oral tetracycline, the bacterial flora and thymus-dependent immune compentency on the capacity of Candida albicans to colonize and infect the gastrointestinal tract of four groups of mice: (a) thymus-intact conventional mice, (b) conventional athymic mice, (c) flora-defined athymic mice and (d) thymus-intact bacteria-free mice.