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Animal model for AIDS immunology, secondary to symptomless infection with Treponema pallidum.


Int Conf AIDS. 1992 Jul 19-24;8(3):36 (abstract no. PuA 6154). Unique

ISSUE/PROBLEM: Lack of animal models for AIDS as seen in humans. DESCRIPTION OF PROJECT: To review syphilis animal models from the work of Brown and Pierce in the 1920s to the present, looking at lesion susceptibility and response to (under)treatment, natural course, the introduction of penicillin, the immunology assumed to be operative, and finally, the so-called symptomless model. RESULTS: This symptomless animal model is described as a lack of serologic response (VDRL) and endarteritis obliterans (the classical lesion). However, in this model a chronic debilitating course and premature death from other infections regularly occurred in those animals which had become infected with Treponema pallidum without the usual reaction. Mice, certain guinea pigs and rabbits, and certain primates could be induced to suffer this way either upon one inoculation or with superinfection, and with or without (adequate) therapy, depending upon the model chosen. DISCUSSION AND CONCLUSIONS: The classical approach to syphilis animal models has not recognized the course of symptomless syphilis. Recent use of PCR, DFA, and techniques to demonstrate actual Treponema pallidum, suggest infection with syphilis has been going on in HIV-infected persons in the absence of the normal and assumed serologic and clinical sensitivity of diagnosis. The epidemiology of syphilis in sexual risk groups is very suggestive: in the United States, specialists in the syphilis field have suggested that up to half a million cases of untreated or inadequately treated and post-secondary syphilis existed in gay males by 1981 and that the new infection rate was at least 100 times the national average. The serology of syphilis is also problematical in HIV-infected persons: in AIDS epicentres, polyclonal activated individuals often selectively lose all syphilis antibody, treponemal and non-treponemal. Deliberate human inoculation with T-pallidum has repeatedly suggested that the non-treponemal tests may not react upon reinfection in the majority of post-secondary syphilitics, whether treated or not. Post-secondary syphilis is confounded by many autoimmune phenomena. Several research tools besides PCR and DFA may help and will be reviewed.

Acquired Immunodeficiency Syndrome/COMPLICATIONS/DIAGNOSIS/ *IMMUNOLOGY Animal *Disease Models, Animal Guinea Pigs Human Mice Primates Rabbits Syphilis/*COMPLICATIONS/DIAGNOSIS/IMMUNOLOGY ABSTRACT


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