The long term objectives of this study are to determine the pathogenesis of macular disease associated with ocular histoplasmosis. We will continue to study a primate model developed in our laboratory. Since thousands of Americans are blinded each year by ocular histoplasmosis (OHS), determination of its pathogenesis could lead to substantial improvements in therapy. We have already determined that acute multifocal histoplasmic choroiditis in primates occurs with gradual resolution of active lesions into typical histo scars, retinal pigment epithelial defects, sub-clinical, and """"""""disappearing"""""""" lesions. There is a persistence of chronic inflammation in the choroid for years after the infection (no viable organisms are present). We have recently demonstrated subretinal neovascularization two years after the acute choroiditis, the first time this has been described in a primate model. Following intracarotid challenge with killed H. capsulatum, we have also observed apparent """"""""reactivation"""""""" of choroiditis in some animals. We plan to evaluate this phenomenon in more detail in the current granting period. Our proposed goals are to (1) complete the natural history studies of OHS in primates, (2) detect the antigen which drives the persistent choroiditis by immunofluorescent studies using polyclonal rabbit anti-H. capsulatum antisera, and (3) characterize the immunopathology of reactivation by comparing inflammatory cell types in choroidal lesions before and after antigen challenge using immunocytochemical (monoclonal antibody) techniques to identify helper/inducer T-cells, suppressor/cytotoxic T-cells, B-cells, and macrophages. This study will provide insight into the reactivation response and provide leads to methods to modify this response therapeutically. Ultimately, we feel this study will have direct clinical relevance to the understanding of OHS and its therapy. This is a collaborative study in which the immunocytochemical procedures proposed will be carried out in a modern immunopathology laboratory by fully experienced personnel under the direction of a qualified immunologist.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001883-11
Application #
3256283
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1977-02-01
Project End
1990-01-31
Budget Start
1987-02-01
Budget End
1988-01-31
Support Year
11
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Southern California
Department
Type
Schools of Medicine
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90033
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Anderson, A; Clifford, W; Palvolgyi, I et al. (1992) Immunopathology of chronic experimental histoplasmic choroiditis in the primate. Invest Ophthalmol Vis Sci 33:1637-41
Ormerod, L D; Osborn, K G; Lowenstine, L J et al. (1988) Lymphoid immunohistochemistry of macaque primates. Clin Exp Immunol 74:435-42
Anderson, A; Taylor, C; Azen, S et al. (1987) Immunopathology of acute experimental histoplasmic choroiditis in the primate. Invest Ophthalmol Vis Sci 28:1195-9
Miyashiro, J E; Jester, J V; Delmage, J M et al. (1986) Immunofluorescent detection of Histoplasma capsulatum in primate experimental ocular histoplasmosis. Curr Eye Res 5:833-40
Meyer, P R; Ormerod, L D; Osborn, K G et al. (1985) An immunopathologic evaluation of lymph nodes from monkey and man with acquired immune deficiency syndrome and related conditions. Hematol Oncol 3:199-210
Jester, J V; Smith, R E (1985) Subretinal neovascularization after experimental ocular histoplasmosis in a subhuman primate. Am J Ophthalmol 100:252-8