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Updated: Aug 8, 2026
Ex Vivo Organotypic Corneal Model of Acute Epithelial Herpes Simplex Virus Type I Infection
Published on: November 3, 2012
Immunization with specific polysaccharide antigen reduces alterations in corneal proteoglycans during experimental
C D Georgakopoulos1, A M Exarchou, S P Gartaganis
1Department of Ophthalmology, School of Medicine, University of Patras, Greece, and Department of Laboratory Medicine, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Purpose:
Staphylococcus epidermidis is a leading cause of bacterial keratitis associated with corneal damage. Corneal integrity is closely associated with matrix macromolecules, such as proteoglycans (PGs) and collagen. The aim of this study was to examine whether active immunization (AI) using a major immunogenic polysaccharide determinant of slime (20-kDa PS) as antigen, and passive immunization (PI) after administration of specific antibodies toward 20-kDa PS affect the distribution of PGs as well as corneal lesions in an experimental model of slime-producing S. epidermidis keratitis.
Methods:
For AI, seven rabbits were immunized with 20-kDa PS, whereas for PI, seven rabbits received specific antibodies against 20-kDa PS. Lesions were graded clinically for a 21-day period. Levels of 20-kDa PS antibodies in serum and aqueous humor in both immunization groups were determined by ELISA. The distribution of certain extracellular matrix PGs during corneal healing was analyzed immunohistochemically.
Results:
Levels of specific anti-20-kDa PS antibodies in serum and aqueous humor obtained after either AI or PI were significantly higher as compared with those in the respective nonimmunized control groups (p<0.001). Clinical grading showed that both AI and PI rabbits had a significantly less corneal damage as compared with infected nontreated rabbits. Immunohistochemical analyses for PGs exhibited significant differences to the wounded regions as compared with noninfected corneal tissue. Accumulation of keratan sulfate PGs and decorin was observed in the corneal stroma of infected rabbits and of heparan sulfate PGs around the new-formed vessels. This phenomenon was significantly reduced in immunized animals in accordance with macroscopically decreased corneal damage observed in these animals.
Conclusions:
Results of this study suggest a key role of 20-kDa PS and its antibodies as prophylactic and therapeutic agents in keratitis caused by slime-producing S. epidermidis.
Insights
Active and passive immunization against Staphylococcus epidermidis slime (20-kDa PS) reduced corneal lesions and altered proteoglycan distribution in experimental keratitis. This suggests the 20-kDa PS and its antibodies are promising agents for treating bacterial keratitis.
Area of Science:
- Ophthalmology
- Microbiology
- Immunology
Background:
- Staphylococcus epidermidis is a primary cause of bacterial keratitis, leading to significant corneal damage.
- Corneal integrity relies on matrix macromolecules like proteoglycans (PGs) and collagen.
- Slime-producing S. epidermidis strains pose a particular challenge in treating keratitis.
Purpose of the Study:
- To investigate the effects of active immunization (AI) and passive immunization (PI) using the 20-kDa polysaccharide (PS) of S. epidermidis slime on corneal lesions.
- To examine the impact of AI and PI on proteoglycan distribution during the healing of experimental keratitis.
- To assess the role of antibodies against the 20-kDa PS in managing S. epidermidis-induced keratitis.
Main Methods:
- Rabbits underwent AI with 20-kDa PS or PI with anti-20-kDa PS antibodies.
- Corneal lesions were clinically graded over 21 days.
- Antibody levels were measured by ELISA, and PG distribution was analyzed immunohistochemically.
Main Results:
- Both AI and PI groups showed significantly higher levels of specific antibodies in serum and aqueous humor compared to controls.
- Immunized rabbits exhibited significantly reduced corneal damage compared to non-treated infected rabbits.
- PG accumulation (keratan sulfate, decorin, heparan sulfate) in corneal stroma and around new vessels was significantly reduced in immunized animals.
Conclusions:
- The 20-kDa PS and its specific antibodies demonstrate significant prophylactic and therapeutic potential.
- These findings highlight the crucial role of the 20-kDa PS in S. epidermidis keratitis pathogenesis and immune response.
- Targeting the 20-kDa PS offers a promising strategy for developing new treatments for bacterial keratitis.
