Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Herpetic stromal keratitis (HSK) appears to represent an immunopathologic response in the cornea of the eye to HSV-1. T cells of the CD4+ subset were shown to be involved in the mediation of HSK, but how they subserve an immunopathologic role is uncertain. In the present report, we have isolated cells from eyes in the active phase of HSK and studied their cytokine profile after culture in vitro or stimulation with Ag or nonspecific mitogens. Inflammatory cells recovered from eyes consist of polymorphonuclear leukocytes, macrophages, and lymphocytes. As reported before, all the lymphocyte recovered were of the CD4+ phenotype. After stimulation in vitro with Ag or mitogen the cytokines IL-2, IFN-gamma, and TNF-alpha/beta were produced, but not the cytokines IL-4 and IL-10. Thus, on the basis of cytokine profile, ocular lymphocytes were identified as Th1 cells. Ocular cells were also stimulated with PMA and shown to produce IL-1. The results were discussed in terms of the possible means by which the Th1 cells induce tissue damage in HSK as well as in terms of the possible means by which a preferential accumulation of Th1 cell occurs in the eye.
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PMID:Predominance of Th1 cells in ocular tissues during herpetic stromal keratitis. 135 34

Herpetic stromal keratitis (HSK) has an immune-mediated pathogenesis that involves T cells that have a type 1 cytokine profile. IFN-gamma is suspected to be the type 1 cytokine involved in ocular pathology, and to test this notion more directly the pathogenesis of HSK was compared in mice deficient in the IFN-gamma gene (gamma knockout or gko) and control mice (wild-type littermates or BALB/c mice). The clinical course of HSK in gko mice closely paralleled that in control mice, yet virus persisted in the corneas of gko mice for an extended period of time, severe periocular skin lesions developed, and gko mice were far more susceptible to encephalitis. Delayed-type hypersensitivity to viral Ag was present, though diminished, in knockout mice, and serum herpes simplex virus-specific IgG isotypes indicated a Th2 shift. No differences existed in proliferative responses to in vitro Ag stimulation in gko vs control mice nor in T cell or proinflammatory cytokine mRNA levels in the corneas of infected mice. However, up-regulation of Th2 cytokine mRNA did occur in in vitro Ag-stimulated gko immune splenocytes. Histopathologic lesions were not statistically different between any of the groups of mice analyzed. These observations indicate that although IFN-gamma plays an important role in the clearance of virus from the eye, the pathogenesis of HSK lesions most likely involves additional cytokines, inflammatory mechanisms, or immune responses to nonviral Ags.
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PMID:Characterization of herpes simplex virus type-1 infection and herpetic stromal keratitis development in IFN-gamma knockout mice. 756 Nov 4

Inflammation of the corneal stroma (stromal keratitis) is a serious complication of infection with the nematode parasite Onchocerca volvulus. Because stromal keratitis is believed to be immunologically mediated in humans, we used a murine model to examine the role of T cells and T helper cell cytokines in the immunopathogenesis of these eye lesions. BALB/c mice immunized subcutaneously and injected intrastromally with soluble O. volvulus antigens (OvAg) developed pronounced corneal opacification and neovascularization. The corneal stroma was edematous and contained numerous eosinophils and mononuclear cells. Stromal keratitis in immunized mice was determined to be T cell dependent based on the following observations: (a) T cell-deficient nude mice immunized and injected intrastromally with OvAg fail to develop corneal pathology; and (b) adoptive transfer of spleen cells from OvAg-immunized BALB/c mice to naive nude mice before intrastromal injection of OvAg results in development of keratitis. OvAg-stimulated lymph node and spleen cell cytokine production was dependent on CD4 cells and included interleukin (IL)-4 and IL-5, but not interferon gamma, indicating a predominant T helper type 2 cell-like response. Inflamed corneas from immunized BALB/c mice and from reconstituted nude mice had greatly elevated CD4 and IL-4 gene expression compared with interferon gamma. Mice in which the IL-4 gene was disrupted failed to develop corneal disease, demonstrating that IL-4 is essential in the immunopathogenesis of O. volvulus-mediated stromal keratitis.
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PMID:Interleukin 4 and T helper type 2 cells are required for development of experimental onchocercal keratitis (river blindness). 756 96

Interleukin-8 (IL-8) is a proinflammatory cytokine released at sites of tissue damage by various cell types. One important function of IL-8 is to recruit neutrophils into sites of inflammation and to activate their biological activity. Stromal keratitis induced by herpes simplex virus type 1 (HSV-1) is characterized by an initial infiltration of neutrophils. This study was carried out to determine whether cells resident in the cornea synthesize IL-8 after virus infection. Pure cultures of epithelial cells and keratocytes established from human corneas were infected with HSV-1, and the medium overlying the cells was subsequently assayed for IL-8 by an enzyme-linked immunosorbent assay. Cytokine mRNA levels in cell lysates were monitored by Northern (RNA) blot analysis. It was found that virus infection of keratocyte cultures led to the synthesis of IL-8-specific mRNA with more than 30 ng of IL-8 made per 10(6) cells. Neither UV-inactivated virus nor virus-free filtrates collected from HSV-1-infected keratocytes could induce IL-8 protein or mRNA, suggesting that viral gene expression was needed for induction of IL-8 gene expression. Unlike keratocytes, HSV-1-infected epithelial cells failed to synthesize IL-8 protein or mRNA. However, these cells readily produced both molecules following tumor necrosis factor alpha stimulation. HSV-1 had similar titers in both cell types. Thus, the failure to induce IL-8 synthesis was not due to an inability of the virus to replicate in epithelial cells. The capacity of HSV-1-infected corneal keratocytes to synthesize IL-8 suggests that these cells can contribute to the induction of the acute inflammatory response seen in herpes stromal keratitis.
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PMID:Induction of interleukin-8 gene expression is associated with herpes simplex virus infection of human corneal keratocytes but not human corneal epithelial cells. 768 2

Corneal infection with herpes simplex virus in mice induces an inflammatory response in the stroma (herpetic stromal keratitis (HSK)) that appears to represent an immunopathologic reaction in which T cells of the CD4+ subset act as the essential participants. To assess the role of T cell cytokines at different clinical phases of HSK, corneas and draining lymph node (DLN) cells were collected and the levels of mRNA thought to be representative of type 1 and type 2 T cells were quantitated by reverse transcription-PCR. In the corneas collected before the onset of clinical disease, IFN-gamma and IL-4 mRNA were detectable, with levels of IFN-gamma 5- to 15-fold higher than IL-4. During the onset and peak expression of clinical disease, type 1 cytokines IFN-gamma and IL-2 were predominant in the corneas, and IL-4 levels were either very low or undetectable. Neither IL-10 nor IL-5 mRNA was present. After 3 wk postinfection, when some animals with mild disease began to recover, high levels of type 2 cytokine mRNA, particularly IL-10, were present. In addition, only during the recovery phase was IL-10 mRNA present in DLN samples. Levels of transcriptional activity for cytokine mRNA during clinical HSK were higher in corneas than in the corresponding DLN samples. The results indicate that IL-10 may be involved in HSK resolution and that the stimuli for cytokine induction in the cornea may differ from those in the DLN.
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PMID:T cell cytokine mRNA expression during the course of the immunopathologic ocular disease herpetic stromal keratitis. 772 30

Herpes simplex virus (HSV) ocular virulence has been associated with strain sensitivity to mouse interferon (IFN)-alpha/beta. To identify the region of the virus genome associated with heightened resistance to this cytokine, intertypic recombinants were constructed using the intact genome of avirulent, IFN-sensitive HSV type 1 (strain 35) and XbaI-digested DNA from virulent, IFN-resistant HSV type 2 (strain 186). An intertypic recombinant, designated HSV-R4, was isolated which grew to titres 10- to 100-fold higher than HSV-1(35) in mouse ocular tissue in vivo, and induced stromal keratitis. The recombinant which was several orders of magnitude more resistant to mouse IFN-alpha/beta than HSV-1(35) had a genome composed of HSV-1(35) DNA except for a 12 kb fragment (0.15 to 0.23 map units) derived from HSV-2(186). To define the IFN resistance locus further, three overlapping subclones of this 12 kb fragment were constructed from the HSV-2(186) genome and subjected to marker rescue experiments. The cloned BamHI D fragment was the only subclone that promoted HSV-1(35) ocular growth in vivo. An intertypic recombinant, designated HSV-R(BD), was isolated from the 35 x 186 BamHI D transfection progeny pool. This recombinant, in contrast to HSV-1(35), was several orders of magnitude more resistant to mouse IFN-alpha/beta inhibition in vitro, grew 10- to 100-fold better in mouse ocular tissue in vivo, and caused severe necrotizing stromal keratitis in BALB/c mice. Analysis of the recombinant genome indicated that the HSV-2 genetic information responsible for IFN resistance of HSV-R(BD) was located within the BamHI D fragment, most likely mapping to that region containing three partial open reading frames designated UL14, UL15 and UL16. The products encoded by this region remain to be identified.
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PMID:Mapping the genetic region coding for herpes simplex virus resistance to mouse interferon alpha/beta. 824 49

Corneal infection of BALB/c mice with herpes simplex virus type 1 results in a chronic inflammatory response in the stroma termed herpetic stromal keratitis (HSK). This disease is considered to be immunopathological and mediated primarily by CD4+ T cells of the type 1 cytokine profile. However, the nature of the antigens, virus or host derived, which drive the inflammatory response remains in doubt. In this study, the relevance of infection with replicating virus for the subsequent development of HSK was evaluated with immunocompetent mice as well as with SCID mice reconstituted with herpes simplex virus-immune CD4+ T cells. In the corneas of immunocompetent mice, infectious virus, viral antigen, and mRNA expression were detectable for only a brief period of time (< or = 7 days postinfection), and all were undetectable by the time clinical lesions were evident (10 to 15 days). Viral replication, however, was necessary for the development of HSK in both models, since infection with UV-inactivated virus or with mutant viruses which were incapable of multiple rounds of replication in vivo failed to induce HSK. The inactivated and mutant viral preparations did, however, stimulate T-cell immune responses in immunocompetent mice. The results are discussed in terms of possible involvement of host antigens exposed in response to transient progeny virion replication in the immune-privileged cornea.
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PMID:Viral replication is required for induction of ocular immunopathology by herpes simplex virus. 852 13

Herpetic stromal keratitis (HSK) has an immunopathological basis, thought primarily to involve a CD4+ T cell-mediated immune response to viral antigen. Other cell types, however, particularly those involved in nonspecific immunity, such as natural killer (NK) cells or neutrophils, may also contribute to tissue destruction in the cornea. The reconstituted SCID mouse model of HSK provides a powerful system in which to study the interactions of the innate and adaptive immune responses to herpes simplex virus type 1 corneal infection. In the present study, reconstituted SCID mice depleted of NK cells had a reduced incidence and severity of clinical and histopathological HSK. The levels of T cell cytokine protein and message in restimulated splenocytes and cytokine message in corneas did not differ between experimental groups. However, significantly fewer neutrophils were seen within the inflamed corneas of NK-depleted SCID mice. Therefore, endogenous NK cells may indirectly influence the severity of HSK in reconstituted SCID mice by affecting neutrophil migration into the cornea.
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PMID:The role of the innate immune system in the reconstituted SCID mouse model of herpetic stromal keratitis. 867 36

Corneal inflammation similar to human onchocercal keratitis can be induced in mice by subcutaneous immunization of a soluble extract of Onchocerca volvulus (OvAg) followed by direct injection of OvAg into the corneal stroma. Previous studies have shown that corneal pathology is associated with increased systemic and corneal Th2 cytokine expression and that IL-4 gene knockout (IL-4-/-) mice develop less severe or no O. volvulus-mediated keratitis. The current study examined the contribution of Th2 cytokines to the diminished OvAg-induced corneal immunopathology observed in IL-4-/- mice. IL-4-/- mice (129Sv x C57B1/6), wild-type F2 littermates (IL-4+/+), and C57B1/6 mice were sensitized by repeated subcutaneous immunization with OvAg. Ten days after the final immunization, mice were sacrificed, spleens were removed, and cells were incubated with OvAg. Cells from immunocompetent C57B1/6 and IL-4+/+ mice produced IL-4 and IL-5, but no IFN-gamma, whereas cells from IL-4-/- mice had elevated IFN-gamma and no IL-4. Interestingly, cells from these animals produced levels of IL-5 protein equivalent to those of C57B1/6 and IL-4+/+ mice. To determine cytokine production in corneas during the onset of onchocercal keratitis, OvAg-immunized mice were injected intracorneally with OvAg, and cytokine gene expression in the cornea was determined by RT-PCR. Temporal analysis of cytokine gene expression in corneas of immunocompetent mice showed that the Th2-associated cytokines IL-4, IL-5, IL-10, and IL-13 were produced within 1 day of intrastromal injection, with sustained elevations for 10 days. Maximal IFN-gamma mRNA levels were not detected until Day 10. This was in contrast to IL-4-/- mice in which IFN-gamma appeared at Day 1 and remained elevated for at least 10 days. Moreover, in corneas from IL-4-/- mice, all Th2 cytokines with the exception of IL-4 were up-regulated and expressed with kinetics similar to that of IL-4+/+ littermates. Histologically, corneas from IL-4-/- mice were less edematous and contained fewer eosinophils and other inflammatory cells than those from immunocompetent controls. As there was no difference in peripheral eosinophil levels, these data indicate that the diminished severity of onchocercal keratitis in IL-4-/- mice is not due to failure to develop systemic or local Th2 cytokine responses or to produce eosinophils, but that IL-4 may be involved in recruitment of eosinophils and other inflammatory cells into the corneal stroma.
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PMID:Onchocerca volvulus-mediated keratitis: cytokine production by IL-4-deficient mice. 893 77

Corneal inflammation (keratitis) is a major cause of visual impairment in Onchocerca volvulus infection. Previous studies showed that onchocercal keratitis can be induced in mice following s.c. immunization and intracorneal injection with soluble O. volvulus Ags (OvAg), and that the inflammatory response is dependent on T cells and IL-4. Since recombinant IL-12 impairs IL-4-dependent, Th2-mediated responses in other parasitic infections and in models of allergic asthma, the present study was undertaken to determine the effect of IL-12 on onchocercal keratitis. Mice were injected i.p. with IL-12 or saline at the time of initial sensitization to OvAg. Surprisingly, IL-12 treatment caused significant exacerbation of corneal pathology, which was associated with increased eosinophil and mononuclear cell infiltration into the corneal stroma. Consistent with the well-documented effect of IL-12 on Th1 cell development, corneas of IL-12-treated animals had elevated expression of the Th1 cytokine IFN-gamma and diminished expression of the Th2 cytokines IL-4, IL-5, IL-10, and IL-13. However, corneas from these animals also had marked elevation of alpha- and beta-chemokines known to be active on eosinophils and mononuclear cells, including IFN-gamma-inducible protein (IP)-10, macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, JE/monocyte chemotactic protein-1, RANTES (regulated upon activation, normal T expressed and secreted), and eotaxin. Together, these data indicate that IL-12 exacerbates OvAg-mediated corneal pathology by enhancing chemokine expression and recruitment of inflammatory cells.
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PMID:IL-12 exacerbates helminth-mediated corneal pathology by augmenting inflammatory cell recruitment and chemokine expression. 899


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