Acanthamoeba keratitis is a sight-threatening disease that is caused by Invasion of the eye by a free-living amoeba of the genus Acanthamoeba. Since its initial description in 1973, the incidence of Acanthamoeba keratitis has steadily increased. In spite of significant improvement in the diagnosis of Acanthamoeba keratitis, progress in developing and utilizing effective antimicrobial agents for treating this disease have been disappointing. Moreover, the emergence of drug resistance poses a serious problem in the management of Acanthamoeba infections. The long range goal of the present project is to develop effective strategies for preventing and treating Acanthamoeba keratitis. A growing body of evidence suggests that the mammalian immune system, if properly activated, is capable of preventing and controlling ocular Acanthamoeba infections as well as infections produced by other microorganisms. Therefore, a secondary and equally Important, long range goal of this project is to gain a better understanding of the immune effector mechanisms that protect the cornea from infectious agents. In order to develop effective immunotherapeutic modalities, it is necessary to fully characterize and evaluate the immunobiology of Acanthamoeba keratitis. The present application seeks to characterize and evaluate the immunobiology of experimental Acanthamoeba keratitis in a Chinese hamster model of this disease.
Three specific aims will be addressed. The first specific aim will characterize the protective immunity to Acanthamoeba keratitis that is induced by oral and topical administration of Acanthamoeba antigens. The second specific aim will characterize the systemic and local ocular immune responses that are induced by corneal infections in Chinese hamsters. Preliminary studies indicate that the presence of Langerhans cells in corneas exposed to Acanthamoeba-laden contact lenses prevents the development of Acanthamoeba keratitis. Therefore, the third specific aim will evaluate the role of corneal Langerhans cells in the resistance to Acanthamoeba keratitis.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY009756-04
Application #
2711074
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1995-08-01
Project End
1999-07-31
Budget Start
1998-08-01
Budget End
1999-07-31
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Texas Sw Medical Center Dallas
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
City
Dallas
State
TX
Country
United States
Zip Code
75390
Alizadeh, Hassan; Tripathi, Trivendra; Abdi, Mahshid et al. (2014) Pathogenic strains of Acanthamoeba are recognized by TLR4 and initiated inflammatory responses in the cornea. PLoS One 9:e92375
Tripathi, Trivendra; Alizadeh, Hassan (2014) Role of protease-activated receptors 2 (PAR2) in ocular infections and inflammation. Receptors Clin Investig 1:
Tripathi, Trivendra; Abdi, Mahshid; Alizadeh, Hassan (2014) Protease-activated receptor 2 (PAR2) is upregulated by Acanthamoeba plasminogen activator (aPA) and induces proinflammatory cytokine in human corneal epithelial cells. Invest Ophthalmol Vis Sci 55:3912-21
Tripathi, Trivendra; Alizadeh, Hassan (2014) Significance of arachidonic acid in ocular infections and inflammation. Inflamm Cell Signal 1:
Tripathi, Trivendra; Abdi, Mahshid; Alizadeh, Hassan (2013) Role of phospholipase A? (PLA?) inhibitors in attenuating apoptosis of the corneal epithelial cells and mitigation of Acanthamoeba keratitis. Exp Eye Res 113:182-91
Tripathi, Trivendra; Smith, Ashley Dawn; Abdi, Mahshid et al. (2012) Acanthamoeba-cytopathic protein induces apoptosis and proinflammatory cytokines in human corneal epithelial cells by cPLA2? activation. Invest Ophthalmol Vis Sci 53:7973-82
Alizadeh, Hassan; Neelam, Sudha; Cavanagh, H Dwight (2009) Amoebicidal activities of alexidine against 3 pathogenic strains of acanthamoeba. Eye Contact Lens 35:1-5
Alizadeh, Hassan; Li, Haochuan; Neelam, Sudha et al. (2008) Modulation of corneal and stromal matrix metalloproteinase by the mannose-induced Acanthamoeba cytolytic protein. Exp Eye Res 87:286-91
Alizadeh, Hassan; Neelam, Sudha; Niederkorn, Jerry Y (2007) Role of activated macrophages in Acanthamoeba keratitis. J Parasitol 93:1114-20
Alizadeh, Hassan; Neelam, Sudha; Niederkorn, Jerry Y (2007) Effect of immunization with the mannose-induced Acanthamoeba protein and Acanthamoeba plasminogen activator in mitigating Acanthamoeba keratitis. Invest Ophthalmol Vis Sci 48:5597-604

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