Different Innate Immune Responses in BALB/c and C57BL/6 Strains following Corneal Transplantation.

PURPOSE: To investigate immunological differences and the role of CD38+/F4/80 + M1 macrophages in C57BL/6J- and BALB/c-recipient mouse corneal transplantation models. METHODS: Allogeneic transplantation was performed crosswise in BALB/c mice and C57BL/6J mice; syngeneic transplantation was performed in both strains. Anterior chamber depth (ACD) was measured before and central corneal thickness (CCT) was measured both before and after transplantation. In vivo graft rejection was monitored using anterior eye segment optical coherence tomography (ASOCT) evaluating the CCT and grading of corneal oedema using a well-established clinical score (CS). Histology of corneal grafts was performed 18 or 21 days after surgery. Immunohistochemistry with anti-F4/80 antibody and anti-CD38 antibody was used for detecting M1 macrophages within the grafts. RESULTS: High CS and CCT values after allogeneic transplantation persisted in both BALB/c (n = 18) and C57BL/6J recipients (n = 20). After syngeneic transplantation, CS and CCT values increased in both models in the early phase after surgery due to the surgical trauma. Surprisingly, in the syngeneic C57BL/6J model, high CCT values persisted. Furthermore, anterior synechiae developed in C57BL/6 recipients after both syngeneic and allogeneic transplantation, whereas BALB/c recipients showed almost no synechiae - even though C57/BL6J animals tended to have a deeper anterior chamber (281 ± 11 pixels [mean ± SD]) compared with BALB/c animals of the same age (270 ± 9 pixels [mean ± SD]). Immunohistochemistry revealed numerous CD38+/F4/80 + M1 macrophages in grafts of C57BL/6J recipients following both syngeneic and allogeneic transplantation. However, in BALB/c-recipient mice only sparse M1 macrophages were detectable (CD38 + M1 macrophages relative to all F4/80 + cells: 75 vs. 17% [after allogeneic transplantation] and 66 vs. 17% [after syngeneic transplantation]; p < 0.05). CONCLUSIONS: Allogeneic corneal transplants are rejected in BALB/c as well as C57BL/6J mice, but tissue alterations with anterior synechiae are more pronounced in C57BL/6J recipients. Following syngeneic transplantation, C57BL/6J-recipient animals show a persistent graft swelling with increased numbers of CD38+/F4/80 + M1 macrophages in grafted tissue, in contrast to the common model using BALB/c-recipient mice. Our data strongly suggest that strain-dependent differences convey different innate immune responses in BALB/c and C57BL/6J strains. Accordingly, in murine keratoplasty experiments, the mouse line of both donor and recipient animals must be carefully considered. C57BL/6J-recipient mice might be particularly suited to study corneal graft rejection in a clinical setting considered "high risk."

The involvement of anti-inflammatory protein, annexin A1, in ocular toxoplasmosis.

PURPOSE: The aim of this study was to evaluate the expression of the protein annexin A1 (ANXA1), a potent endogenous regulator of the inflammatory process, in ocular toxoplasmosis. METHODS: C57BL/6 female mice were infected using intravitreal injections of either 10(6) tachyzoites of Toxoplasma gondii (RH strain; T. gondii) or PBS only (control groups). After 24, 48, and 72 h, animals were sacrificed and their eyes were harvested for histopathological, immunohistochemical, and ultrastructural immunocytochemical analysis of ANXA1. Human retinal pigment epithelial (RPE) cells (ARPE-19) were infected in vitro with T. gondii and collected after 60, 120, 240 min, and 24 h. RESULTS: Compared with non-infected eyes, an intense inflammatory response was observed in the anterior (24 h after infection) and posterior segments (72 h after infection) of the infected eye, characterized by neutrophil infiltration and by the presence of tachyzoites and their consequent destruction along with disorganization of normal retina architecture and RPE vacuolization. T. gondii infection was associated with a significant increase of ANXA1 expression in the neutrophils at 24, 48, and 72 h, and in the RPE at 48 and 72 h. In vitro studies confirmed an upregulation of ANXA1 levels in RPE cells, after 60 and 120 min of infection with T. gondii. CONCLUSIONS: The positive modulation of endogenous ANXA1 in the inflammatory and RPE cells during T. gondii infection suggests that this protein may serve as a therapeutic target in ocular toxoplasmosis.

Total protein concentration and T-cell suppression activity of aqueous humour before and after penetrating keratoplasty.

PURPOSE: We wished to determine whether immune privilege parameters assayed in aqueous humour (AqH) are relevant to the fate of penetrating keratoplasty (PK) in humans. METHODS: AqH was collected in 28 patients before PK (prospective cohort), in 6 patients with no history of graft rejection undergoing cataract surgery after PK (acceptors), in another 6 patients undergoing treatment of an acute endothelial immune reaction (rejectors), and in 65 controls undergoing uncomplicated cataract extraction. AqH was tested for total protein concentration and the ability to suppress T-cell activation. RESULTS: AqH protein concentrations of acceptors and rejectors post-PK were elevated (2.7 ± 0.8 and 2.7 ± 0.7 mg/ml, respectively) compared with pre-PK AqH level and cataract controls (1.0 ± 0.1 mg/ml, P = 0.01). All AqH samples suppressed T-cell activation, irrespective of source and timing of AqH removal. CONCLUSION: Assays of immune privilege markers in AqH suggest that PK surgery may result in a sustained loss of integrity of the blood-aqueous barrier. Although trends were evident, values of immune privilege markers determined pre- and post-PK were not statistically significantly different between the study groups. However, further prospective studies determining additional immune privilege markers have to be conducted in order to find out whether these markers might serve as predictive parameters for immune reactions following PK.

Fibrosis in the anterior segments of the eye.

The anterior segment of the eye ball, i. e., cornea and conjunctiva, serves as the barrier to the external stimuli. Cornea is transparent and is a "window"of the light sense, while conjunctiva covers the sclera, the main part of the eyeshell. Fibrosis/scarring in cornea potentially impairs vision by the reduction of its transparency and the alteration of the regular curvature. Fibrotic reaction in conjunctiva is also of a clinical importance because inflammatory fibrosis in this tissue affects the physiology of the cornea and also of a problem post-eye surgery. In this review we discuss on the topic that is quite critical in vision. Although various growth factors are considered to be involved in, focus was put on the roles of transforming growth factorß (TGFß).

[Diseases of the outer eye in rheumatoid arthritis]. / Erkrankungen des äusseren Auges bei rheumatoider Arthritis.

Eye involvement is a frequent finding in patients with rheumatoid arthritis and may represent the leading clinical manifestation of disease. In this context, all components of the visual organ might be affected. The main spectrum of eye involvement comprises keratoconjunctivitis sicca, episcleritis and scleritis as well as ulcerative keratitis. As with the underlying disease, autoimmune reactions based on a patient's genetic predisposition are assumed to be of significance in disease pathogenesis. Emerging evidence also points to additional morphological and physiological ocular characteristics in the pathogenesis of the various ocular pathologies. This article gives an overview of clinical aspects, pathogenetic background as well as therapeutic options for ocular involvement in rheumatoid arthritis.

Relevance of animal models to human uveitis.

Uveitis represents a wide spectrum of intraocular inflammatory conditions and includes various autoimmune and infectious etiologies. The relevance of animal models of uveitis to human diseases remains a key issue with major implications for the translational research and development of therapeutic strategies. Histopathological findings in patients with Vogt-Koyanagi-Harada disease, birdshot retinochoroidopathy and anterior uveitis are correlated to those observed in different animal models. Even though evidence based on histopathology is usually irrefutable, similar features may be due to different disease mechanisms. Analysis of triggering factors, determination of cellular populations and immune microenvironment should prevail over clinical phenotype evaluation. There is a controversy in correlating the clinical finding of nummular chorioretinal scars, commonly referred to as Dalen-Fuchs nodules, seen in the periphery of fundus in patients with chronic Vogt-Koyanagi-Harada disease with histologic observations made on such enucleated eyes. Although histopathology of the lesions consisted of focal chorioretinal scars with loss of RPE, there was no consensus about the histologic nature of the nummular chorioretinal scars, particularly whether they represent Dalen-Fuchs nodules. Based on the immunogenetic background, there may be different forms of one specific disease with variable phenotypic expression. This review discusses the importance of experimental models in the light of immunologic alterations and histopathological features in human uveitic entities.

Contact lenses and associated anterior segment disorders: dry eye disease, blepharitis, and allergy.

This article discusses the use of contact lenses in patients suffering from dry eye and ocular allergy. The diagnosis of dry eye is outlined along with the relationship between contact lenses, the tear film, and the ocular surface. A practical approach to the recognition and management of the dry eye patient wishing to wear contact lenses is presented. In addition, a consideration of a careful strategy to identify patients with ocular allergy and manage the use of contact lenses in these patients is developed with an emphasis on the avoidance of complications.

Role of swarming migration in the pathogenesis of bacillus endophthalmitis.

PURPOSE: Bacillus cereus causes one of the most rapidly blinding forms of bacterial endophthalmitis. Migration of B. cereus throughout the eye during endophthalmitis is a unique aspect of this disease that may contribute to intraocular virulence. This study was conducted to analyze the contribution of swarming and intraocular migration to the pathogenesis of experimental endophthalmitis. METHODS: Eyes were injected intravitreally with 100 colony-forming units (CFU) of either wild-type, nonswarming, or swarming-complemented strains of B. cereus. Pathogenicity was compared throughout the course of infection by biomicroscopy, histology, electroretinography, and bacterial and inflammatory cell quantitation. RESULTS: Wild-type, nonswarming, and swarming-complemented B. cereus strains grew to a similar number in the vitreous throughout the course of infection. Unlike the wild-type and swarming-complemented strains, the nonswarming mutant did not migrate to the anterior segment during infection. The rate of decrease in retinal responses of eyes infected with the all strains was similar, resulting in near complete elimination of retinal function by 12 hours. All Bacillus strains caused similar degrees of posterior segment inflammation and retinal destruction. However, the accumulation of inflammatory cells in the anterior chamber, hyphemae, and corneal ring abscesses did not occur in eyes infected with the nonswarming mutant. CONCLUSIONS: The deficiency in swarming had little effect on retinal function loss or the overall course or severity of experimental B. cereus endophthalmitis. However, a deficiency in swarming prevented Bacillus from migrating to the anterior segment, leading to less severe anterior segment disease.

An intravital and confocal microscopic study of the distribution of intracameral antigen in the aqueous outflow pathways and limbus of the rat eye.

In a previous investigation into the fate of fluorescently labelled antigen (Ag) injected into the anterior chamber (AC) of the rat eye, a large number of Ag+ cells were noted in the conventional and non-conventional aqueous humour outflow pathways together with the external limbus. The aim of this study was to investigate the precise distribution and phenotype of these cells and compare their ability to capture fluorescent-labelled protein (bovine serum albumin, BSA, and ovalbumin, OVA) and polysaccharides (dextran, Dx) injected into the AC. The density of Ag+ cells in the iris and limbus was investigated using in vivo video fluorescence microscopy 24 hr post-injection. The distribution and phenotype of Ag+ cells in ocular tissues was analysed by confocal microscopy of frozen sections and in iris and corneoscleral/limbal wholemounts from animals sacrificed 24 hr post injection. The general distribution of labelled Ag was equivalent in OVA, BSA and Dx injected animals. Antigen-bearing cells were observed within the iris, iridocorneal angle, pre-equatorial choroid and around limbal/episcleral vessels. Localization of Ag+ cells and free Ag in the anterior segment suggests that substances of these molecular weights (40-70 kDa) leave the eye through the conventional and non-conventional aqueous outflow pathways. The cells that internalized BSA, OVA or Dx in ocular tissues were of a similar phenotype, namely, ED1+, ED2+, occasionally ED3+ and predominantly MHC class II-, thus suggesting that they are of the macrophage phenotype. However, a few Ag+ MHC class II+ dendriform cells (putative DC) were also observed in the iris, trabecular meshwork, choroid and episclera. In conclusion our data reveal that the majority of intracamerally injected soluble Ag retained in the eye is taken up by resident macrophages not only in the iris but in all tissues lining the AC of the eye.

Ocular immune privilege and CTL tolerance.

The introduction of antigens into the anterior chamber (AC) of the eye, an immune-privileged site, induces immune responses that effectively eliminate ocular pathogens while minimizing tissue damage that can cause blindness. This specialized immune response, termed AC associated immune deviation (ACAID) is thought to be an evolutionary compromise to preserve the delicate microanatomy of the eye while maintaining ocular immune responses. The injection of soluble antigen in the AC of mice results in systemic tolerance characterized by reduced priming for antigen-specific delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) responses. Similarly, the injection of histo incompatible tumors into the AC of mice reduces priming for DTH responses specific to minor antigens. However, robust tumor-specific CTL responses are induced systemically following this treatment that are capable of eliminating a subsequent injection of the same tumors in the skin or the opposite eye. Interestingly, CTL responses induced by administration of tumors in the AC fail to eliminate the primary ocular tumor. In this review, we compare and contrast CTL responses generated by the injection of soluble or tumor-associated antigens in the AC and discuss mechanisms employed to induce ocular CTL tolerance.

[A study of total IgE in inflammatory pathologies of the eye anterior segment]. / Issledovanie obshchego IgE pri vospalitel'nykh zabolevaniiakh perednego otdela glaza.

The paper contains data on comparative research of the IgE content in blood serum and lachrymal fluid in patients with ophthalmoherpes and with other inflammatory diseases of the eye. A higher IgE level was found in blood serum and lachrymal fluid in cases of ophthalmoherpes as well as in lachrymal fluid in cases of allergic, Chlamydia and fungus diseases of the eye. The data obtained can be used in the diagnostics of allergic eye diseases as well as in elaborating complex treatment methods for herpetic, Chlamydia and fungus lesions of the anterior eye segment. A detection of the local allergenic effect of acaricide drugs exerted on the conjunctiva and eyelids makes it obligatory to consider the above fact while treating patients with demodectic blepharoconjunctivitis.

Blood mononuclear cells induce regulatory NK T thymocytes in anterior chamber-associated immune deviation.

Injection of antigen into the anterior chamber (AC) of the eye, an immunologically privileged site, is associated with the induction of immune deviation, as evidenced by T helper cell (Th) 1 to Th2 cell polarization. We recently demonstrated that AC-associated immune deviation (ACAID) is a thymus-dependent phenomenon initiated by the formation of regulatory alpha,beta T-cell receptor-positive CD4(-) CD8(-) thymocytes (THYregs). In this study, the afferent and efferent limbs of this immunoregulatory loop were traced from peripheral blood to the thymus and then to the spleen by adoptive-transfer assays. The results demonstrate that (1) F4/80(+) CD1(+) peripheral blood mononuclear cells from mice whose ACs were injected with trinitrophenol-bovine serum albumin induce the appearance of natural killer (NK) 1.1(+) THYreg in naïve recipients within 24 h of intravenous infusion; (2) these NK THYregs induce (or generate) suppressor-effector T cells in the spleens of adoptive recipients; (3) these suppressor-effector spleen cells, but not the NK THYregs themselves, directly inhibit the expression of delayed-type hypersensitivity in sensitized recipients; and (4) peripheral blood mononuclear cells from AC-injected mice do not induce ACAID in thymectomized recipients. These results confirm our hypothesis that ACAID is a model of centrally induced dominant tolerance mediated by CD-1-dependent NK T cells of recent thymic origin. The results also provide evidence of a novel tolerance induction pathway by which blood-borne antigen-presenting cells generated by antigen injection into an immunologically privileged site transport antigen to the thymus and induce the formation and export of THYreg.

[Immunological status and its changes in children during surgery on anterior eye segment]. / Immunologicheskii status i ego izmeneniia u detei pri provedenii operatsii na perednem otrezke glaznogo iabloka.

Nonspecific and specific immunity values were studied in 70 children before and in various periods after 74 operations on the anterior segment of the eyeball. In children with persistent autosensitization to ocular tissue autoantigens (alpha-crystalline and S-antigen) postoperative uveitis presented as an immunocomplex disease with signs of exhaustion of the functional potential of the phagocytosis and complement systems. In children without autosensitization uveitis was associated with immunity activation. Phagocytosis system and cooperation of lymphocyte subpopulations, including normal killers (CD16+), play an important role in prevention of sensitization to ocular tissue autoantigens. Therefore, complex immunological examinations of children before surgery and regular check-ups after it will help differentiate immunodeficiency from compensatory immunosuppression preventing autoimmune disease, which is important in prescription of immunostimulating therapy.

Recurrent intraocular inflammation in endotoxin-induced uveitis.

PURPOSE: Endotoxin-induced uveitis (EIU) in rats and mice peaks 24 hours after endotoxin injection and is commonly assumed to be a monophasic disease. This study examined intraocular inflammation at later time points to determine whether endotoxin injection can induce recurrent intraocular inflammation in strains of mice with high or moderate levels of susceptibility to EIU. METHODS: EIU was elicited in two mouse strains with high (C3H/HeN) and moderate (FVB/N) susceptibility, by means of intraperitoneal injections of Salmonella typhimurium endotoxin. Inflammatory cells in the anterior and posterior segments of the eye were counted by a masked observer on histologic sections of eyes from 1 to 17 days after endotoxin injection. RESULTS: A bimodal distribution of inflammatory cell infiltration was noted in eyes from C3H/HeN mice. As previously reported, inflammation peaked at 24 hours after endotoxin injection. However, a second, more pronounced peak of intraocular inflammation occurred approximately 5 days after endotoxin injection. FVB/N mice had a single peak of intraocular inflammation 4 days after injection. CONCLUSIONS: Endotoxin injection in C3H/HeN elicits recurrent intraocular inflammation. The previously unrecognized second peak of inflammation is more severe than the initial inflammatory disease. Studies on this second inflammatory peak may be useful in determining the pathogenesis of recurrent uveitis in humans.

Endotoxin-induced uveitis is partially inhibited by anti-IL-8 antibody treatment.

PURPOSE: To examine the potential therapeutic effect of a neutralizing anti-IL-8 monoclonal antibody in endotoxin-induced uveitis (EIU) in the rabbit. METHODS: An anti-IL-8 antibody (WS-4) was injected intravitreal 2 hours before, simultaneously with, or 6 hours after endotoxin challenge in rabbits. Eyes were examined for clinical signs of inflammation, and aqueous humor (AH) was sampled to study cellular infiltration and protein content. Leukocyte subset analysis was performed on Giemsa-stained AH cytospins. Histologic grading of inflammation was performed on hematoxylin-eosin-stained sagittal sections of enucleated eyes. In separate experiments, animals received the anti-IL-8 antibody simultaneously with the endotoxin challenge, before repeated anterior chamber paracentesis was performed (at 6, 12, 24, 48, and 72 hours after injection) to estimate the kinetics and durability of changes in total cell count and protein concentration in AH. RESULTS: Anti-IL-8 therapy caused a decrease in the clinical and histologic grade of inflammation in EIU. The mean cell count in the AH at the peak of inflammation (24 hours) in eyes receiving endotoxin only was 6419+/-1165/microl (mean +/- SE) compared to 2546+/-573/microl in rabbits treated simultaneously with 250 microg of anti-IL-8 antibody (P < 0.05). The protein concentration in the AH was not significantly altered by anti-IL-8 treatment. Kinetic analysis of the leukocyte count in the AH demonstrated persistent inhibition of leukocyte accumulation (range, 60%-91% compared to control eyes) by the anti-IL-8 antibody administered simultaneously with endotoxin. This inhibition was sustained for up to 72 hours after injection. CONCLUSIONS: Anti-IL-8 antibody treatment partially blocks EIU in rabbits. A consistent decrease in the recruitment of polymorphonuclear leukocytes into the anterior chamber was obtained when neutralizing antibody was injected simultaneously with endotoxin. These findings suggest that IL-8 contributes to the chemotactic signal for the recruitment of leukocytes in EIU.

Effects of experimental ocular inflammation on ocular immune privilege.

PURPOSE: To determine whether the inflammation of endotoxin-induced uveitis (EIU) and experimental autoimmune uveoretinitis (EAU) alters key in vivo and in vitro parameters of ocular immune privilege. METHODS: For EIU induction, C3H/HeN mice received 200 microg lipopolysaccharide (LPS). For EAU induction, B10.A mice were immunized with 50 microg interphotoreceptor retinoid-binding protein (IRBP) mixed with complete Freund's adjuvant. Aqueous humor (AqH) was collected at periodic intervals and assayed for leukocyte content and the ability to suppress or enhance T-cell proliferation. Eyes with EAU were assessed for the capacity to support anterior chamber (AC)-associated immune deviation (ACAID) induction after injection of ovalbumin (OVA). RESULTS: Inflammation within the anterior segment in EIU peaked at 12 to 24 hours and was detected from 10 days onward in EAU. In AqH of EIU, protein content rose within 4 hours, followed by infiltrating leukocytes. EIU AqH promptly lost its capacity to suppress T-cell proliferation and became mitogenic for T cells. In AqH of EAU, protein and leukocyte content rose at 11 days and continued to remain elevated thereafter. Whereas 11-day EAU AqH failed to suppress T-cell proliferation, AqH at later time points reacquired immunosuppressive properties. Injection of OVA into the AC of eyes of mice with EAU failed to induce ACAID. CONCLUSIONS: The intraocular inflammation of EIU and EAU disrupted important parameters of immune privilege, ranging from breakdown of the blood- ocular barrier, to loss of an immunosuppressive microenvironment, to abrogation of ACAID. Because AqH from inflamed EAU reacquired the ability to suppress T-cell proliferation, the authors conclude that the capacity to regulate immune expression and inflammation can be a property even of inflamed eyes.

Cellular localisation and dynamics of nitric oxide synthase expression in the rat anterior segment during endotoxin-induced uveitis.

The present study examined the temporal pattern and cellular localisation of nitric oxide synthase in Endotoxin-Induced Uveitis (EIU). Lewis rats (n=40) received a single footpad injection of 200 microg of bacterial lipopolysaccharide. Animals were killed at 0, 2, 4, 6, 12, 24, 48 and 72 hr after injection and ocular tissues prepared as iris-ciliary body wholemounts or frozen sections of the anterior segment. The expression of constitutive nitric oxide synthase (cNOS) and inducible nitric oxide synthase (iNOS) was investigated at all time points by immunohistochemistry. A further group of animals (n=6) were killed at the peak of the disease (12 hr) and the cellular co-localisation of iNOS on resident and infiltrating immune cells was investigated by double immunohistochemistry utilising the biotinylated monoclonal antibodies ED1, ED2 and Ox6. Expression of cNOS on iris vessels did not alter during the course of EIU. Quantitative analysis of iris-ciliary body wholemounts revealed the first evidence of iNOS+ at 2 hr which increased dramatically at 4 and 6 hr with a peak at 12 hr. The expression of iNOS in the early phase of the disease (2-6 hr) was associated with small round marginating and newly extravasated cells that on morphological criteria were most likely neutrophils and monocytes. At 12 hr, cells of more mixed morphologies began to express iNOS and double labelling revealed 70% of these cells were also ED1(+) (a lysosomal antigen present in monocytes/macrophages and dendritic cells), 52% were Ox6(+) (MHC class II) (dendritic cells, activated macrophages and some T-cells) and 19% were ED2(+) (pan-specific resident tissue macrophages). Expressed in an alternative manner, 10% of the total ED1(+) cell population, 11% of the ED2(+) cells and 44% of Ox6(+) cells co-expressed iNOS. Expression of iNOS decreased significantly by 24 hr to near baseline levels and was absent by 48 and 72 hr. Within the ciliary processes iNOS+ dendriform cells were noted at 6 hr and accumulations of many small round iNOS+ cells were present at 12 hr. The ciliary epithelium did not at any time express iNOS at the protein level detectable by immunohistochemistry. The results of this study suggest that iNOS expression early in EIU is associated with infiltrating or newly recruited neutrophils and monocytes/macrophages in the iris whereas later in the disease resident tissue macrophages and MHC class II+ cells (activated macrophages and putative dendritic cells) in the iris and ciliary body may synthesise nitric oxide. The role of this late phase of nitric oxide synthesis may include lymphocytostasis and immunosuppression as proposed in other tissue sites. The outcome of the present study may help in planning therapeutic strategies using NOS inhibitors.

Immunoreactivity of exfoliation material for the cell adhesion-related HNK-1 carbohydrate epitope.

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.