title: Effect of sex hormones on the immune system of guinea-pigs and on the development of toxoplasmic lesions in non-lymphoid organs.
abstract: The role of cell-mediated immunity in the pathogenesis of toxoplasmic lesions in non-lymphoid organs and its significance in resistance to infection with Toxoplasma gondii were studied in guinea-pigs. Alteration of the sex hormonal environment in both sexes has significant effects on the immunological status of the guinea-pig, changing its reaction to toxoplasmic infection. Thus, gonadectomy appears to enhance delayed hypersensitivity, leading to a greater prominence of lesions in the non-lymphoid organs of gonadectomized male and female animals than in controls. This observation supports the possibility that delayed hypersensitivity plays a major role in the pathogenesis of non-lymphoid, toxoplasmic lesions. Hexoestrol administration for a long period of time induces complete thymic atrophy and severe involution of the thymus-dependent areas of the lymph nodes and spleen, leading to the suppression of cell-mediated immunity and overwhelming disease in those animals infected with Toxoplasma gondii, suggesting that cell-mediated immunity is of importance in resistance to toxoplasmic infection. In view of these findings, the difficulties in the treatment of non-lymphoid toxoplasmic lesions, such as ocular ones, by depressing cellular immunity, are discussed.
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology; D002369:Castration; D005260:Female; D006168:Guinea Pigs; D006589:Hexestrol / Q000494:pharmacology*; D007111:Immunity, Cellular / Q000187:drug effects*; D008099:Liver / Q000473:pathology; D008168:Lung / Q000473:pathology; D008221:Lymphoid Tissue / Q000473:pathology; D008297:Male; D009132:Muscles / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D013154:Spleen / Q000473:pathology; D013950:Thymus Gland / Q000473:pathology; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000473:pathology
chemical_list: D006589:Hexestrol