Bone Marrow–Derived Cells in Normal Human Corneal Stroma

Abstract

To examine the normal human corneal stroma for the presence of bone marrow-derived cells. Methods: Thirty-four corneas from donors aged 56 to 71 years were used. The stroma of the donor corneas was examined immunohistochemically by fluorescent microscopy. CD45-positive and-negative cells were separated from collagenase-digested stroma by magnetic beads, and the expression of toll-like receptor 4 was analyzed. Results: CD45-positive cells were mainly found in the anterior stroma of the central and paracentral cornea as well as all stromal layers of the peripheral cornea (n=5). These cells uniformly expressed CD11b, CD11c, CD14, and HLA-DR antigen but not CD3, CD19, CD56, or CD66, indicative of bone marrow-derived monocyte lineage cells, which can include monocytes, macrophages, or den-dritic cells. CD45-positive cells isolated with magnetic beads accounted for 6.0% of total stromal cells (n=20). Stromal CD45-positive cells, but not CD45-negative cells, expressed toll-like receptor 4 by flow cytometry and reverse-transcriptase polymerase chain reaction. Conclusion: Our findings demonstrate that DR antigenpositive bone marrow-derived monocyte lineage cells exist in the anterior and peripheral posterior stroma of normal human cornea. Clinical Relevance: These cells may play a role in the innate and adaptive immune responses in the human cornea.

Involvement of C-C Chemokine Ligand 2-CCR2 Interaction in Monocyte-Lineage Cell Recruitment of Normal Human Corneal Stroma

“…For separation of CD45-positive and CD45-negative cells, the stroma from three to five corneas was processed simultaneously. The average number of CD45-positive cells per cornea was 10.5 Ϯ 0.9 ϫ 10 3 (mean Ϯ SD), as described elsewhere (1). Average BMC rate per isolated cells from corneal stroma was 91 Ϯ 7% (mean Ϯ SD; n ϭ 5) in our preliminary study.…”

“…H uman leukocyte Ag DR-positive bone marrow-derived cells (BMCs) 3 of the monocyte lineage, which include monocytes, macrophages, and dendritic cells, exist in the normal human corneal stroma (1). These cells are mainly distributed in the anterior stroma of the central and paracentral cornea as well as all stromal layers of the peripheral cornea and may play a role in the innate and adaptive immune responses (1).…”

“…These cells are mainly distributed in the anterior stroma of the central and paracentral cornea as well as all stromal layers of the peripheral cornea and may play a role in the innate and adaptive immune responses (1). Constitutive BMCs have been reported in normal mouse corneal stroma (2,3).…”

Characteristic Morphology and Distribution of Bone Marrow Derived Cells in the Cornea

“…On the other hand, some GFP(1) cells in the corneal stroma were not immunostained for Iba1 and their lineages were not determined. Some previous reports showed the existence of antigen presenting dendritic cells in normal murine and human cornea (Hamrah et al, 2003a,b;Nakamura et al, 2005;Yamagami et al, 2006). We failed to detect the signal of the dendritic cell marker CD11c.…”

Pattern recognition receptors in microbial keratitis

“…47,49,50 A picture now emerges of a stratified resident myeloid population in the human cornea, with major histocompatibility complex (MHC) II + /CD45 + bone marrow-derived cells present throughout all layers of the peripheral stroma, as well as in the anterior stroma of the central cornea. 51 Classification of cell surface markers has enabled cell lineage identification: myeloid-derived dendritic cells (DCs) are considered CD11c + , while monocyte-derived lineages, including LCs, are CD14 + . 52 Hamrah et al 53 observed that some murine DCs in the periphery of the anterior stroma also express MHC II, CD80, and CD86, but the DCs located in the centre present an immature, MHC II − CD80 − CD86 − phenotype until inflammation is induced.…”