Abstract
Purpose :
The goal of these studies is to determine if the avascular lens contains resident immune cells and to investigate the potential response of lens resident immune cells to sterile injury caused by cataract surgery wounding.
Methods :
To identify lens resident immune cells, uninjured mouse and chicken whole eye cryostat sections as well as human pediatric cataract surgery lens tissue were labeled for immune cell markers (CD45, β2 integrin or Major Histocompatibility Complex (MHC)II). To determine the response of lens resident immune cells to sterile injury, ex vivo mock cataract surgery cultures were prepared from isolated chick lenses and labeled for immune cell markers and vimentin following injury. All samples were analyzed by high resolution confocal imaging and 3D structural images were created by Imaris software using z-stack confocal images to reveal the spatial organization of resident immune cells within the lens tissue.
Results :
3D structural images revealed that CD45+ resident immune cells were nestled among the lens equatorial epithelium in the E18.5 mouse lens. Professional antigen presenting resident immune cells expressing MHCII were found interdigitated among the lens equatorial epithelium of E15 chick lenses, which have the potential to engage an adaptive immune response. 3D structural views of the ex vivo lens mock cataract surgery model also showed MHCII+ resident immune cells with extended dendritic tails inserted between the lens epithelial cells. In response to sterile injury induced by cataract surgery, vimentin-enriched CD45+ resident immune cells with an activated morphology appeared to be emerging from niches located among the lens epithelium. Similarly, in human lens tissue CD45+ resident immune cells were observed extending dendritic-like processes between the lens epithelial cells. Furthermore, in response to mock cataract surgery vimentin-rich CD45, β2 and MHCII positive resident immune cells migrated and populated the wounded edge of the ex vivo cultures where they can mediate the repair response to sterile injury.
Conclusions :
These studies provide the first evidence that resident immune cells are a shared feature of lens tissue where they are poised to be the first responders to injury/pathogenesis as well as the initiators of an adaptive immune response to maintain lens tissue homeostasis.
This is a 2020 ARVO Annual Meeting abstract.