The HNK-1 carbohydrate epitope in the anterior segment of the eye. The inner connective tissue layer of the human ciliary body as a distinct element.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to M Uusitalo.
Explore the source record for details and available documents.
AIMS--The study was carried out to search for labelling similar to that of intraocular exfoliation material in the conjunctiva by light microscopy using lectin and immunohistochemistry. METHODS--Ten formalin fixed and paraffin embedded conjunctival biopsy specimens both from patients with and without exfoliation syndrome were studied with a panel of 11 lectins and with three monoclonal antibodies to the HNK-1 carbohydrate epitope, all of which react with intraocular exfoliation material. RESULTS--The lectin binding profile was essentially the same in specimens from patients with and without exfoliation syndrome. The superficial epithelium reacted similarly with Phaseolus vulgaris (PHA-E), Caragana arborescens (CAA), Helix pomatia (HPA), concanavalin A (ConA), and wheat germ (WGA) agglutinins. Binding was also detected with peanut (PNA) and Bauhinia purpurea (BPA) agglutinins, particularly in patients with exfoliation. The basement membrane generally reacted with Ricinus communis (RCA-I), PHA-E, Vicia villosa (VVA), ConA, and Lens culinaris (LCA) agglutinins. The stroma was weakly labelled with RCA-I, PHA-E, ConA, and LCA. Lectin binding to the vascular endothelium was moderate with RCA-I, PHA-E, CAA, ConA, LCA, and WGA. Inconsistent labelling was also detected with PNA, BPA, and Erythrina cristagalli agglutinin (ECA). The subendothelial region reacted weakly but consistently with PHA-E, ConA, and LCA, and inconsistently with PNA. Pretreatment with neuraminidase did not change that pattern. Antibodies to the HNK-1 epitope reacted only with myelinated stromal nerve branches. CONCLUSION--No evidence of abnormal deposits in any specimen was found. The carbohydrate composition of intraocular exfoliation material may differ from that of exfoliation-like fibres often detected in the conjunctiva by electron microscopy.
PURPOSE: To analyze the cytoskeletal development in neuroectodermally derived epithelial and muscle cells of the human eye during the second and third trimesters of pregnancy. METHODS: Nine formalin-fixed, paraffin-embedded fetal autopsy eyes from the 13th to 40th week of gestation were studied with eight monoclonal antibodies (mAbs) to intermediate filaments and alpha-smooth muscle actin (alpha SMA) by the avidin-biotinylated-peroxidase complex method. RESULTS: The epithelium of the iris reacted with mAbs Vim 3B4 and V9 to vimentin in all eyes. Reactivity with mAb CAM 5.2 to cytokeratin (CK) 8 and mAb CY-90 and KS-B17.2 to CK 18 disappeared from the iris epithelium by the 28th gestational week. mAb 1A4 to alpha SMA labeled its anterior layer from the 28th week on. mAbs DE-U-10 and D33 to desmin labeled dilator fibers by the 37th week, and focal reactivity for CK 8 and 18 concurrently appeared. The developing iris sphincter reacted for alpha SMA in all eyes. It was labeled increasingly for desmin from the 18th week on, whereas initial reactivity for vimentin gradually disappeared after the 22nd week. mAbs to vimentin, CK 8, and CK 18 labeled the ciliary epithelium and the retinal pigment epithelium in all eyes, except for lack of CK 8 and 18 in the nonpigmented ciliary epithelium at the 13th week. The ciliary muscle reacted uniformly for vimentin and alpha SMA and from the 16th week on for desmin. CONCLUSIONS: The results highlight the individuality of cytoskeletal profiles in the neuroectodermal epithelial and muscle cells of the eye and clarify the formation of the peculiar cytoskeleton typical of the adult human eye. They also offer a framework for detecting cytoskeletal changes in developmental anomalies of the eye after the first trimester of pregnancy.
Explore the source record for details and available documents.
BACKGROUND: A previous study revealed the HNK-1 epitope in the human ciliary body beneath the ciliary epithelium. The molecules bearing this 3-sulphoglucuronic acid-containing oligosaccharide epitope in the eye remain unknown. As chondroitin sulphate proteoglycan (CSPG) and tenascin are potential candidates as bearers of the HNK-1 epitope, their distribution in the human eye was compared with that of the HNK-1 epitope. METHODS: Fifty-five formalin-fixed, paraffin-embedded human eyes, including 20 normal eyes and 35 eyes with exfoliation syndrome or glaucoma, were studied immunohistochemically with monoclonal antibody (MAb) CS-56 to CSPG, MAb TN2 to tenascin, and MAbs HNK-1 and VC1.1 to the HNK-1 epitope. Additionally, four frozen lens capsules with exfoliation material were studied by indirect immunofluorescence. RESULTS: A population of dendritic cells in the inner connective tissue layer of the ciliary body and exfoliation material were immunoreactive with antibodies to the HNK-1 epitope, but no labelling for CSPG and tenascin was seen in them, including frozen sections. The inner surface of the nonpigmented ciliary epithelium was reactive for the HNK-1 epitope, and at the ora serrata also for CSPG. In some eyes with glaucoma, immunoreaction for CSPG and tenascin was seen beneath the epithelium and endothelium of the cornea. The nerve fibre layer of the retina was labelled for tenascin. In the sclera, all antibodies labelled the ground substance, and in some large blood vessels immunoreaction for CSPG and tenascin was seen subendothelially. CONCLUSION: Apart from the sclera, the distribution of CSPG and tenascin was different form that of the HNK-1 epitope, suggesting that this carbohydrate epitope may not be borne by these molecules in the human ciliary body.
Possible changes in the expression of the HNK-1 carbohydrate epitope in the inner connective tissue layer of the human ciliary body, located between the ciliary epithelium and muscle, was studied using 2 formalin-fixed, paraffin-embedded eyes with exfoliation syndrome, 33 eyes with different types of glaucoma, and 21 morphologically normal control eyes. A strong immunoreaction delineating cell process was observed in this layer with monoclonal antibodies HNK-1 and VC1.1 recognizing the HNK-1 epitope in control specimens, whereas partly granular immunoreaction was present in eyes with exfoliation syndrome. Exfoliation material was also immunoreactive. In all types of advanced glaucoma, the immunoreaction was mostly granular in nature and greatly diminished. No difference in HNK-1 immunoreactivity between control and glaucoma eyes was seen in the retina and ciliary epithelium. Elevated intraocular pressure, either directly or by decreasing blood flow to the ciliary body, may cause degenerative or metabolic changes in the inner connective tissue layer cells that bear or secrete molecules sharing the HNK-1 epitope. The partly granular immunoreactivity in eyes with exfoliation syndrome only indicates changes in this epitope even without an increase in intraocular pressure.
The expression of the cell adhesion-related HNK-1 carbohydrate epitope in the retina and ciliary body was studied in different vertebrates and in man. A series of eyes from 4 fish, 5 bird, and 9 mammalian species was analyzed by immunohistochemistry with monoclonal antibodies (MAb) HNK-1 and VC1.1 to the HNK-1 epitope, and with MAb SY38 to synaptophysin. Additionally, 7 morphologically normal human eyes were studied. In all fishes, as well as in baboons and man, the radial glia and all retinal layers except the photoreceptor cell layer were immunoreactive for the HNK-1 epitope. In all birds, the nerve fiber layer and both plexiform layers were labelled. In nonprimate mammals only the plexiform layers were immunoreactive. Fine differences in this general immunoreaction pattern were seen in different species. Mab SY38 labeled both plexiform layers of mammals only. In the ciliary body, immunoreaction for the HNK-1 epitope was seen in the inner connective tissue layer only in man, but the ciliary nerves were labelled in all species except the mouse and rat. The HNK-1 epitope seems to be phylogenetically conserved in the retina, where the HNK-1 immunoreactive plexiform layers possibly are overlapped with HNK-1 reactive radial glial cells in fishes and primates. Instead in the inner connective tissue layer of the ciliary body, the HNK-1 epitope is not phylogenetically conserved.
Explore the source record for details and available documents.
OBJECTIVE: To study the presence of the HNK-1 epitope in exfoliation material. METHODS: Twenty-six formalin-fixed, paraffin-embedded human eyes with exfoliation syndrome and 30 control eyes were studied immunohistochemically with monoclonal antibodies HNK-1 and VC1.1 to the HNK-1 epitope. RESULTS: Exfoliation material reacted consistently with antibodies to the HNK-1 epitope. The zonular lamella of the lens, inner surface of the nonpigmented ciliary epithelium, and inner connective tissue layer of the ciliary body were also labeled, but the lens capsule, epithelium, and zonules were not immunoreactive. Several blood vessels of the iris showed granular immunoreaction beneath the endothelium in all exfoliation eyes and in 11 (37%) of 30 control eyes, representing older age groups. CONCLUSIONS: The zonular lamella, nonpigmented ciliary epithelium, or the inner connective tissue layer may be responsible for the HNK-1 epitope in exfoliation material. Since this epitope is shared by many cell-adhesion molecules, its presence in exfoliation material might be of pathogenetic significance to the formation of the deposits.
PURPOSE: To characterize the nature and the developmental distribution of the HNK-1 epitope in the inner connective tissue layer of the human ciliary body, located between the ciliary epithelium and muscle with two monoclonal antibodies to the HNK-1 epitope common to many cell adhesion molecules. METHODS: Nine fetal (gestational age 13-40 wk) and 32 postnatal human eyes (age 3 mo to 78 yr) were studied by immunohistochemistry with monoclonal antibodies HNK-1 and VC1.1 to the HNK-1 epitope. Antibodies to cytoskeletal elements were used to characterize the cells in this region. RESULTS: The HNK-1-immunopositive cells appeared underneath the pigment epithelium of the pars plicata by the 20th gestational week, spread into the pars plana after the 28th week, and reached the ora serrata during the first year of life. The immunoreaction was constantly present in all adult eyes examined; they were sharply demarcated from the iris, ciliary muscle, and choroid. The HNK-1-positive subepithelial layer was not labeled with monoclonal antibodies V9 or Vim 3B4 to vimentin, monoclonal antibodies CAM 5.2 and CY-90 to cytokeratin 8 and 18, or monoclonal antibodies DE-U-10 and D33 to desmin in adult eyes, but was uniformly positive for vimentin in fetal eyes. The HNK-1 epitope was distributed along cell membranes or adjacent extracellular matrix of stromal cells. CONCLUSION: The HNK-1-positive stromal region is a constant and conspicuous element of the human eye that may have a role in structurally stabilizing the ciliary body, perhaps in relation to accommodation or aqueous secretion.