Corneal Antigens Research Articles

Antibody response to herpes simplex virus-1 is increased in autoimmune encephalitis.

Antibody response to herpes simplex virus-1 is increased in autoimmune encephalitis.

Clinical significance of detecting organ-specificsensitization in patients with long-term chronic posttraumatic uveitis

Purpose: to assess the clinical significance of detecting organ-specific sensitization in chronic posttraumatic uveitis (CPTU) based on a comparative analysis of data from the leukocyte migration inhibition test (LMIT) and histological examination.Materials and methods. We examined 54 patients aged 17-82 with CPTU who underwent surgical removal of the eyeball (by enucleation/evisceration). To detect organ-specific sensitization, the LMIT in whole blood with extracts of corneal, lens, and uvearetinal tissue antigens was used. The eyes were subjected to histological examination after removal.Results. A positive response in LMIT was detected in 35.2 % of patients with CPTU. Pathomorphological signs of immune inflammation were found in 55.5 % of cases (30 eyes). In 23 eyes (42.6 %), the morphological picture was characterized by atrophic, fibrous and dystrophic changes in tissues. Based on the data from a comparative analysis of LMIT results and histological studies, we showed that in 16 cases out of 30 (53.3 %), morphologically confirmed immune inflammation was accompanied by sensitization to antigens of eye shells.Conclusions. In half of the cases, a productive inflammation, detected in CPTU during histological examination, was associated with the development of specific sensitization to eye tissue antigens. This result is important and should be considered when choosing how the patient should be managed, including targeted diagnostics and immunotropic therapy. The negative organ-specific response of LMIT in patients with chronic CPTU and intraocular inflammation confirmed by pathomorphological signs suggests a possible involvement of additional mechanisms of the inflammatory process, which requires further research.

Biology of peripheral ulcerative keratitis

Peripheral ulcerative keratitis (PUK) is a progressive peripheral thinning of the corneal stroma caused by proinflammatory mediators' release from corneal limbal vasculitis. The clinical presentation is an epithelial defect with a crescent-shaped stromal inflammation. Its exact pathophysiologic mechanisms of PUK remain partially understood, but the overall understanding of the fundamental processes that mediate and effect corneal immunity has continued to expand over the past 25 years.The unique anatomical and physiological characteristics of the periphery in relation to collagen bundles and peripheral corneal vascular arch contribute to the occurrence of this type of ulcer in this region, in addition to the concentration of complement and immunoglobulins. There is a relevant participation of the adjacent conjunctiva. Both cell-mediated immunity and humoral immunity are implicated in the pathogenesis of PUK, and the postulated mechanisms are autoimmune reactions to corneal antigens, deposition of circulating immune complexes and hypersensitivity reactions to foreign antigens. These immunocomplexes are deposited in limbic vessels resulting in the activation of the classical pathway of the complement system and, consequently, in the chemotaxis of inflammatory cells and in the release of several pro-inflammatory cytokines, which allow the production and release of matrix metalloproteinases. The release of inflammatory cytokines by infiltrating cells may induce keratocyte activation, which could then generate more release of a variety of cytokines, such as the neutrophil calgranulin C, thus facilitating an autoimmune response to the protein and precipitating an antibody- and cell-mediated hyperimmune reaction in the peripheral cornea.

Central bacterial corneal ulcers of prolonged course. Immunological aspects and tactics of etiopathogenetic treatment

Purpose: to describe the characteristic clinical signs and to study the causes of the development of an unfavorable prolonged course of bacterial corneal ulcers of central localization, and to improve treatment effectiveness. Material and methods. A total of 289 patients with central bacterial corneal ulcers were examined. Two types courses of bacterial corneal ulcer were distinguished: favorable (acute and subacute) and unfavorable (prolonged subacute and prolonged chronic forms). Blood (122 samples) and scrapings from corneal ulcers (110 samples) were examined in a nested polymerase chain reaction (PCR) to detect deoxyribonucleic acid (DNA) of simple herpes virus (HSV) 1 and 2 types, virus Epstein–Barr (VEB), human herpes virus (HHV)-6, and HHV-7. To detect autoimmune sensitization to the corneal antigens, migration inhibition reaction of leukocytes (MIRL, 215 samples) was used. Results. In patients with unfavorable course of the disease, blood and corneal HHV DNA was detected in 88.7 % of cases, while with a favorable course only 10 % of cases showed the presence of HHV DNA (р < 0.002). In all patients, HHV type 6 was predominating. Autosensitivity to corneal antigens was detected in 8 (10.4 %) out of 77 patients at the end of the first week of the disease, and as the disease progressed, the number of patients with an autoimmune component increased to reach 63.2 % (48 of 76). The inclusion of antiviral and immunosuppressive drugs into the routine treatment plan led to complete epithelialization of the cornea within 5–10 days. Сonclusion. The protracted course of bacterial corneal ulcers was found to be caused by a mixed herpes-bacterial infection, which is corroborated by the effectiveness of the modified treatment tactics.

Kinetics of Corneal Antigen Presenting Cells in Experimental Dry Eye Disease

ObjectiveTo evaluate dry eye disease (DED)-induced alterations in subsets of corneal antigen presenting cells (APCs) in a mouse model of experimental DED.Methods and AnalysisSeven to 8-week-old female C57BL/6 mice were...

Treatment with mPEG-SPA improves the survival of corneal grafts in rats by immune camouflage

We investigated the immune camouflage effects of methoxy polyethylene glycol succinimidyl propionate (mPEG-SPA) on corneal antigens and explored a novel approach for reducing corneal antigenicity, thereby decreasing corneal graft rejection. Importantly, this approach did not alter normal local immunity. Corneal grafts were treated with mPEG-SPA 5KD or 20KD (3% W/V), which could shield major histocompatibility antigen class I molecules (RT1-A) of corneal grafts. Skin grafts of Wistar rats were transplanted to SD rats. Then the splenic lymphocytes were isolated from SD rats. Subsequently, the lymphocytes were co-cultured with autologous corneal grafts or untreated corneal grafts and PEGylated grafts treated with mPEG-SPA 5KD or 20KD obtained from the counterpart skin donors, which were used as autologous control, allogeneic control, mPEG-SPA 5KD group and mPEG-SPA 20KD group, respectively. Lymphocyte proliferation was lower in mPEG-SPA 5KD group and mPEG-SPA 20KD group than in the allogeneic control. SD rats with corneal neovascularisation were used as recipients for high-risk corneal transplantation and were randomly divided into four groups: autologous control, allogeneic control, mPEG-SPA 5KD group and mPEG-SPA 20KD group. The recipients received corneal grafts from Wistar rats. Corneal graft survival was prolonged and graft rejection was reduced in the mPEG-SPA 5KD group and the mPEG-SPA 20KD group compared to the allogeneic control. Thus, we think that mPEG-SPA could immunologically camouflage corneal antigens to prolong corneal grafts survival in high-risk transplantation.

Kératoconjonctivite vernale atopique sévère et Xolair : à propos d’un cas

Peripheral ulcerative keratitis (PUK) is a progressive peripheral thinning of the corneal stroma caused by proinflammatory mediators' release from corneal limbal vasculitis. The clinical presentation is an epithelial defect with a crescent-shaped stromal inflammation. Its exact pathophysiologic mechanisms of PUK remain partially understood, but the overall understanding of the fundamental processes that mediate and effect corneal immunity has continued to expand over the past 25 years.The unique anatomical and physiological characteristics of the periphery in relation to collagen bundles and peripheral corneal vascular arch contribute to the occurrence of this type of ulcer in this region, in addition to the concentration of complement and immunoglobulins. There is a relevant participation of the adjacent conjunctiva. Both cell-mediated immunity and humoral immunity are implicated in the pathogenesis of PUK, and the postulated mechanisms are autoimmune reactions to corneal antigens, deposition of circulating immune complexes and hypersensitivity reactions to foreign antigens. These immunocomplexes are deposited in limbic vessels resulting in the activation of the classical pathway of the complement system and, consequently, in the chemotaxis of inflammatory cells and in the release of several pro-inflammatory cytokines, which allow the production and release of matrix metalloproteinases. The release of inflammatory cytokines by infiltrating cells may induce keratocyte activation, which could then generate more release of a variety of cytokines, such as the neutrophil calgranulin C, thus facilitating an autoimmune response to the protein and precipitating an antibody- and cell-mediated hyperimmune reaction in the peripheral cornea.

Soluble antigen traffics rapidly and selectively from the corneal surface to the eye draining lymph node and activates T cells when codelivered with CpG oligonucleotides

The transport of antigen to the secondary lymphoid tissue is a central component in the initiation of the adaptive immune response. The mechanism of antigen delivery to the DLN from the avascular cornea has not been fully explored. Previous studies in the mouse have shown that cell-associated corneal antigen is delivered within 6 h to the eye draining SM DLN via DCs and macrophages. In this study, we used a system in which antigen and the processed p-MHCII complexes derived from the antigen could be tracked in vivo. We report that soluble antigen applied to an abraded cornea in the mouse is transported rapidly (within 30 min) to the SM DLN, where a proportion is taken up by resident DCs and presented as p-MHCII complexes, while the larger part is cleared by 8 h. At a later time, a second wave of antigen transport in migratory DCs enters the DLN and participates in further continued antigen presentation. With the use of an antigen-specific TCR transgenic mouse system, we demonstrate that T cell activation does not occur during the early stages of soluble antigen delivery to LN, even though p-MHCII complexes are generated. Antigen-specific T cell activation occurs in the later, presumed cell-associated phase but requires codelivery of a "danger" signal, such as the TLR ligand CpG. We suggest that the early delivery of soluble antigen is more likely to induce T cell nonresponsiveness (anergy) unless presented in the context of an innate-immune cell activation (danger) signal.

Immunohistochemical and immunopathologic characterization of superficial stromal immune-mediated keratitis in horses

To describe the immunopathologic characteristics of superficial stromal immune-mediated keratitis (IMMK) immunopathologically by characterizing cellular infiltrate in affected corneas of horses. 10 client-owned horses with IMMK. Immunohistochemical staining was performed on keratectomy samples with equine antibodies against the T-cell marker CD3 and B-cell marker CD79a (10 eyes) and the T-helper cytotoxic marker CD4 and T-cell cytotoxic marker CD8 (6 eyes). Percentage of positively stained cells was scored on a scale from 0 (no cells stained) to 4 (> 75% of cells stained). Equine IgG, IgM, and IgA antibodies were used to detect corneal immunoglobulin via direct immunofluorescence (10 eyes). Serum and aqueous humor (AH) samples from 3 horses with IMMK were used to detect circulating and intraocular IgG against corneal antigens via indirect immunofluorescence on unaffected equine cornea. Percentage scores (scale, 0 to 4) of cells expressing CD3 (median, 2.35 [range, 0.2 to 3.7]; mean ± SD, 2.36 ± 1.08) were significantly greater than scores of cells expressing CD79a (median, 0.55 [range, 0 to 1.5]; mean, 0.69 ± 0.72). All samples stained positively for CD4- and CD8-expressing cells, with no significant difference in scoring. All samples stained positively for IgG, IgM, and IgA. No serum or AH samples collected from horses with IMMK reacted with unaffected equine cornea. Pathogenesis of superficial stromal IMMK included cell-mediated inflammation governed by both cytotoxic and helper T cells. Local immunoglobulins were present in affected corneas; however, corneal-binding immunoglobulins were not detected in the serum or AH from horses with IMMK.

Augenentzündungen bei entzündlichen Systemerkrankungen: Keratitis

Systemic inflammatory diseases are associated with keratitis. In addition to the much less frequently occurring non-ulcerative keratitis, ulcerative inflammation of the corneal periphery is common in systemic inflammatory diseases. Significant systemic inflammatory diseases in this context are autoimmune connective tissue diseases (including rheumatoid arthritis, systemic lupus erythematosus or primary vasculitides such as polyarteritis nodosa or Wegener's granulomatosis), systemic autoimmune dermatological disorders (such as the cicatrising pemphigoid or Stevens-Johnson syndrome) and autoimmune diseases of the lacrimal system (such as the lacrimal gland involvement in primary Sjogren's syndrome or in graft-versus-host disease). In severe cases of peripheral ulcerative keratitis intensive topical therapy is initially combined with a systemic high-dose steroid therapy. In further progressing ulceration, surgery may help to preserve or restore the integrity of the eye and may suppress the autoimmune response by shielding the corneal antigens from blood and the lymphatic system. Systemic immune modulating therapy has to be done in close consultation with the rheumatologist.

Adoptive Transfer of Donor Corneal Antigen-specific Regulatory T Cells Can Prolong Mice Corneal Grafts Survival

To explore the effects of adoptive transferring T regulatory cells (T reg cells) stimulated by donor corneal antigen (Ag) to prevent corneal transplantation immune rejection in mice. C57BL/6 mice were used as donors and BALB/c mice as recipients. Corneal Ag was harvested by homogenization and centrifugation. Bone marrow dendritic cells (DCs) from BALB/c mice were cultured with stimulation of granulocyte-macrophage colony-stimulating factor and interleukin-4 for 5 days. Then, donor corneal Ag was added to obtain donor corneal Ag-loaded DCs. The DCs were used to stimulate CD4+CD25+ and CD4+CD25+ T cells from the recipient to yield Ag-stimulated T reg cells. Penetrating keratoplasty was performed in the mice. The recipients were randomly divided into 3 groups receiving 0.1 mL of phosphate-buffered saline, 1 × 10(6) naive T reg cells, and Ag-stimulated T reg cells, respectively, given by retroorbital injection at the end of surgery. The allografts were observed, and histopathological examination was performed 15 days after surgery. : The corneal Ag mainly comprised 2 proteins with molecular weight 54 and 42 kD, respectively. Corneal Ag-loaded DCs expressed higher levels of CD11c, CD80, and CD86 than bone marrow precursor cells. Both CD4CD25 and CD4+CD25+ T cells showed vigorous proliferative responses to corneal Ag-loaded DCs. Mean survival time of the mice corneal allografts in phosphate-buffered saline, naive T reg cells, and Ag-stimulated groups was 8.1 ± 1.1, 14.3 ± 2.0, and 23.3 ± 2.6 days, respectively (P < 0.01 among groups). Histopathological examination revealed less inflammatory cells infiltration in Ag-stimulated than in naive mice. : Adoptive transfer of donor corneal Ag-specific T reg cells prolonged survival time of corneal allografts in our mouse model, which might suggest a useful approach to cellular immunotherapy for corneal transplantation immune rejection.

Mooren's Ulcer following Extracapsular Cataract Extraction

Prior cataract surgery is a recognized risk factor for the development of Mooren''s ulcer, but the demographic and clinical features of a large cohort of such patients have not been described. The authors performed a retrospective review of demographic and clinical data from 14 eyes in 13 patients who developed Mooren's ulcer following extracapsular cataract extraction at Aravind Eye Hospital in Madurai, South India. Eight (62%) of the 13 patients were men and 5 (39%) were women. The median age in our population was 65 years, with a range of 45 to 85 years. The median number of months from surgery to the onset of Mooren's ulcer was 19, with a range of 4 to 156 months. Of the 14 eyes with prior cataract surgery, the location of the ulcer was at or contiguous with the wound in 10 eyes (71%), which was 2.5 times more likely than other circumlimbal locations, and only one patient (8%) had bilateral disease. Mooren''s ulcer may occur following extracapsular cataract extraction and when it does it is most likely to be unilateral and contiguous with the wound. These findings support the notion that exposure of normally concealed corneal antigens may contribute to the pathogenesis of Mooren''s ulcer in some patients.

Circulating cornea specific antibodies and keratoplasty

The presence of corneal antibodies in blood sera was investigated in 130 patients by immunoblotting analysis. Sera were obtained from patients before the first keratoplasty, repeated corneal transplantation or keratoplasty of the other eye. Baseline levels of antibodies in 15 healthy blood donors served to establish a positivity threshold. Patients were divided according to diagnosis and number of keratoplasties. Corneal antigens were prepared from donor corneas not suitable for surgery. Hyperimmune sera obtained by immunization of rabbits were used as positive controls. Significant increase in corneal antibodies specific to epithelial antigens was found in patients (62.5% positive) with keratitis of microbial origin. The presence of circulating antibodies to endothelial or stromal proteins was without significant changes. Depending on the number of keratoplasties no statistical difference in corneal antibodies production was observed. The group of patients with increased anti-corneal antibodies already before transplantation had to take immunosuppressive and anti-inflammatory therapy after keratoplasty.

TGF-β2 and corneal antigen co-cultured antigen presenting cell and graft rejection in a mouse model

目的 建立小鼠同种异体角膜移植模型,观察静脉注入抗原递呈细胞对术后免疫排斥的影响.方法 建立BALB/c→C57BL/6小鼠角膜移植模型.随机分2组,静脉注入耐受型或普通抗原递呈细胞.根据植片混浊评分,判断植片排斥情况.随机取两组小鼠脾脏检测CD4+ NKT百分比和IL-10质量分数.结果 与对照组相比,实验组移植排斥出现晚(19 d±1.6 d,P＝0.009).术后脾脏CD4+NKT百分比、IL-10质量分数相对恒定.结论 小鼠角膜移植术后耐受型抗原递呈细胞静脉注射可延长植片存活时间。

Angiogenesis and Lymphangiogenesis—Implications for Corneal Immunity

It is now widely acknowledged that vasculogenesis and immunogenic inflammation are intricately related in many tissues. However, less understood is to what extent blood (heme) angiogenesis (HA) and lymphangiogenesis (LG) are differentially regulated, and in turn contribute potentially to different aspects of adaptive immunity generated to corneal antigens. Herein, we will provide a brief synopsis of relevant work in this field by focusing particularly on the differential regulation of immunity by these two distinct vasculogenic processes in the cornea, illustrating that in spite of significant redundancies in the mechanisms that induce these vascular processes in the cornea, there are also important distinctions in what aspects of immunity are promoted by them.keywords

Alpha-internexin as a Corneal Autoantigen in Spontaneous Autoimmune Keratitis Mouse Model

The purpose of this study was to identify target antigens of autoimmune keratitis with a disease-prone mouse model. BALB/c nude mice grafted with embryonic rat thymi (TG nude mice) develop various organ-localized autoimmune lesions, including keratitis. A hybridoma producing a monoclonal antibody (OT-20), specific for corneal epithelium was established by using spleen cells from this model mouse of keratitis, and the target of OT-20 was identified by immunoblot analysis. Then, using the antigen, T-cell proliferation and cytokine production by TG nude mice with keratitis were examined. Immunoblot analysis revealed alpha-internexin to be the target antigen of OT-20 that specifically recognizes corneal epithelium. Sera from TG nude mice with keratitis reacted with alpha-internexin on Western blot analysis, and the T cells of these mice on stimulation with alpha-internexin exhibited proliferation responses and produced IL-2, IFN-gamma, and TNF-alpha, but not IL-4 or IL-5. These results suggest that alpha-internexin is one of the corneal antigens associated with keratitis, developing spontaneously in TG-nude mice, with a probable pathogenic role.

Corneal Antigen Presentation: Molecular Regulation and Functional Implications

Presentation of corneal antigens for induction of adaptive immune responses is mediated by corneal antigen-presenting cells (APC), including those that infiltrate the cornea in response to inflammatory stimuli and, to a lesser extent, those that reside in the cornea and up-regulate activation markers in response to inflammation. Significant progress has been made in the last decade in dissecting the molecular mechanisms that mediate APC infiltration into the cornea. However, it has recently been determined that exit of APC out of the cornea is critical for induction of T cells that normally reside outside of the cornea in lymphoid reservoirs. Much less is understood about the molecular regulation of APC egress from the cornea, but our laboratory has recently discovered that APC access to afferent lymphatics and draining lymph nodes requires signaling mediated by VEGFR-3. We describe herein the functional implication of APC trafficking and the prospects for novel immunomodulatory strategies based on regulating APC migration.

The role of eye‐associated lymphoid tissue in corneal immune protection

Because the cornea is optimized for refraction, it relies on supporting tissues for moistening and nutrition and in particular for immune protection. Its main support tissue is the conjunctiva, in addition to the lacrimal gland, the latter which provides soluble mediators via the tear film. The cornea and conjunctiva constitute a moist mucosal surface and there is increasing evidence that apart from innate defence mechanisms, also lymphoid cells contribute to the normal homeostasis of the corneal surface. A Medline-based literature search was performed in order to review the existing literature on the existence, composition and functions of mucosa-associated lymphoid tissue (MALT) at the ocular surface for corneal protection. The existence of lymphoid cells at the ocular surface and appendage has been known for many years, but for a long time they were believed erroneously to be inflammatory cells. More recent research has shown that in addition to the known presence of lymphoid cells in the lacrimal gland, they also form MALT in the conjunctiva as conjunctiva-associated lymphoid tissue (CALT) and in the lacrimal drainage system as lacrimal drainage-associated lymphoid tissue (LDALT). Together this constitutes an eye-associated lymphoid tissue (EALT), which is a new component of the mucosal immune system of the body. When the topographical distribution of CALT is projected onto the ocular surface, it overlies the cornea during eye closure and is hence in a suitable position to assist the corneal immune protection during blinking and overnight. It can detect corneal antigens and prime respective effector cells, or distribute protective factors as secretory IgA.

Occupational rhinitis and asthma induced by corneal antigens in surgeons and close surgical assistants following Lasik

Occupational rhinitis and asthma induced by corneal antigens in surgeons and close surgical assistants following Lasik

Immune response to intragraft antigen in draining lymph nodes after corneal transplantation is mediated by interleukin-12.

To examine the molecular basis of immunity generated to intragraft antigens and determine whether it differs between acceptor and rejector hosts, we used a novel in vitro system to assay the T cell response to a specific antigen, ovalbumin (OVA), in the graft. OVA-containing corneas were orthotopically grafted into syngeneic or allogeneic hosts. Draining cervical lymph nodes (cLN) were assayed for OVA-specific T cell proliferation and cytokine production. In addition, cytokine production was assayed in cultures of antigen-presented cells (APC) isolated from cLN cultured with OVA-specific DO11.10 T cells and OVA. OVA-specific immunity was detected only in the draining cLN of mice following allogeneic, but not syngeneic, grafting, and this immunity was evident well before any demonstrable alloresponse in the graft. In addition, cLN cells from mice that accepted their corneal allografts produced significantly less interferon-gamma (IFN-gamma) when stimulated in culture than cells harvested from cLN of rejector hosts. Moreover, APC isolated from cLN of acceptor hosts produced significantly lower levels of IL-12. These data suggest that the induction of immunity to corneal antigens in the draining cLN occurs via an interleukin-12 (IL-12) and IFN-gamma-dependent mechanism. Targeting this process may serve as an effective immunomodulatory strategy in corneal transplantation.