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

T-cell activation in the absence of costimulation is futile because T-cells deprived of costimulatory signals enter a state of unresponsiveness or anergy. The interaction of 4-1BB and 4-1BB ligand (4-1BBL) activates an important costimulatory pathway with diverse and important roles in immune regulation. Signals relayed through 4-1BB generate strong CD8(+) T-cell responses rather than CD4(+) T-cell responses; this action results in cytokine induction and promotes T-cell survival. In recent years, 4-1BB-mediated immune regulation has gained great significance because of the seemingly contradictory dual roles of agonistic anti-4-1BB in vivo disease models. To date, agonistic 4-1BB monoclonal antibody has shown therapeutic potential against a variety of tumors, CD4(+) T-cell-mediated autoimmune diseases, and chronic graft-versus-host disease. In addition, blockade of 4-1BB/4-1BBL interaction has produced therapeutic effects against coxsackievirus-induced myocardial inflammation, herpetic stromal keratitis, and graft rejection. We propose that the dual roles of agonistic anti-4-1BB--an enhanced effector function and a suppressor function--are mediated by a novel CD11c(+)CD8(+) T-cell population.
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PMID:Immunotherapy targeting 4-1BB and its ligand. 1644 48

Various mechanisms of peripheral T cell tolerization have evolved to avoid responses mediated by autoreactive T cells that have not been eliminated in the thymus. In this study, we investigated the peripheral conditions of Ag presentation required to induce T cell tolerance when the predominant APCs are B cells. We show that transient Ag presentation, in absence of inflammation and in a self-context, induces CD4(+) T cell activation and memory formation. In contrast, chronic Ag presentation leads to CD4(+) T cell tolerance. The importance of long-lasting Ag presentation in inducing tolerance was also confirmed in the herpes stromal keratitis autoimmune disease model. Keratogenic T cells could be activated or tolerized depending on the APC short or long persistence. Thus, when APCs are B cells, the persistence of the Ag presentation itself is one of the main conditions to have peripheral T cell tolerance.
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PMID:Induction of peripheral T cell tolerance by antigen-presenting B cells. I. Relevance of antigen presentation persistence. 1654 36

STAT5 proteins are components of the common growth hormone and interleukin 2 family of cytokines' signaling pathway. Mutations in the STAT5b gene, described in 2 patients, lead to growth hormone insensitivity that resembles Laron syndrome. Clinical immunodeficiency was also present, although immunologic defects have not been well characterized thus far. Here we describe a 16-year-old girl who suffered generalized eczema and recurrent infections of the skin and respiratory tract since birth. She also suffered severe chronic lung disease and multiple episodes of herpetic keratitis. Clinical features of congenital growth hormone deficiency were observed, such as persistently low growth rate, severely delayed bone age, and postnatal growth failure resulting from growth hormone resistance. This combined phenotype of growth hormone insensitivity and immunodeficiency was attributable to a homozygous C-->T transition that resulted in a nonsense mutation at codon 152 in exon 5 of the STAT5b gene. This novel mutation determined a complete absence of protein expression. The main immunologic findings were moderate T-cell lymphopenia (1274/mm3), normal CD4/CD8 ratio, and very low numbers of natural killer (18/mm3) and gammadelta T (5/mm3) cells. T cells presented a chronically hyperactivated phenotype. In vitro T-cell proliferation and interleukin 2 signaling were impaired. CD4+ and CD25+ regulatory T cells were significantly diminished, and they probably contributed to the signs of homeostatic mechanism deregulation found in this patient. This new case, in accordance with 2 previously reported cases, definitely demonstrates the significant role of the STAT5b protein in mediating growth hormone actions. Furthermore, the main immunologic findings bring about an explanation for the clinical immunodeficiency features and reveal for the first time the relevant role of STAT5b as a key protein for T-cell functions in humans.
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PMID:Characterization of immunodeficiency in a patient with growth hormone insensitivity secondary to a novel STAT5b gene mutation. 1703 May 97

Herpes stromal keratitis (HSK) is an immunopathological disease regulated by Th1 CD4 T cells, which require APC and costimulation within the infected cornea to mediate disease. Recent studies suggest the OX40:OX40 ligand (OX40L) interaction enhances effector cell cytokine secretion at inflammatory sites. OX40(+) cells were detected in HSV-1-infected mouse corneas as early as 3 days postinfection (dpi), prior to the onset of HSK, and their frequency increased through 15 dpi, when all mice exhibited severe HSK. OX40L(+) cells were first detected at 7 dpi, coincident with the initiation of HSK. It is interesting that the OX40L(+) cells did not coexpress MHC Class II or the dendritic cell (DC) marker CD11c. Our findings demonstrate rapid infiltration of activated (OX40(+)) CD4(+) T cells into HSV-1-infected corneas and expression of OX40L on MHC Class II-negative cells but surprisingly, not on MHC Class II(+) CD11c(+) DC, which are present in the infected corneas and required for HSK. Moreover, neither local nor systemic treatment of mice with a blocking antibody to OX40L or with a blocking fusion protein altered the course of HSK significantly, possibly as a result of a lack of OX40L expression on functional APC.
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PMID:Expression and function of the OX40/OX40L costimulatory pair during herpes stromal keratitis. 1718 58

CD4(+), CD8(+), immunoglobulin status and ocular lesions of some onchocerciasis-infected rural Nigerians as manifested by the presence of microfilariae in their skin snips and some chronic symptoms of the parasitic infestation were evaluated. The highest mean CD4(+) and mean microfilarial (mff) load of 560 +/- 20.46 unit cells/microl and 20 mff/mg were recorded among the individuals within the second decade of life, while the least mean CD4+ and mff load of 307.20 +/- 11.23 unit cell/microl and 6.5 mff/mg occurred among volunteers after 60 years of age. The highest mean CD8(+) of 388.00 +/- 23.71 unit cells/microl occurred at the third decade of life. The individuals above 60 years had the least mean CD8(+) of 350.25 +/- 11.90 unit cells/microl. The volunteers had mean CD4(+) of 372.45 +/- 109.02 unit cells/microl and mean CD8(+) of 359.42 +/- with an overall CD4(+):CD8(+) ratio of 1.04. The mean CD4(+) and mean CD8(+) had positive correlation with the mean microfilarial load (r = 0.52 and r = 0.40), respectively. The mean IgE, IgG, lgA, IgM, and IgD were 2,074.82 +/- 823.09, 19.36 +/- 2.49, 3.88 +/- 0.26, 3.59 +/- 0.38, and 0.29 +/- 0.19 mg/dl, and these immunoglobulins negatively correlated with the mean microfilarial load at r = -0.02, r = -0.15, r = -0.82, r = -0.37, and r = 0.26, respectively. Among these immunoglobulins evaluated, only mean IgE (2,074.82 +/- 823 ng/ml) was statistically different from the control subjects (0 mg/dl) at t = 3.39, P < 0.05. In all, the prevalence of the visual impairment and lesions were low. Among the six visual lesions, namely, cataract, choroidoretinitis, iridocyclitis, glaucoma, sclerosing keratitis, and optic atrophy encountered in Egoro-Eguare, only optic atrophy and sclerosing keratitis was reported among the children. The female adults had the highest prevalence of reduced vision 20(43.5%). Also, the prevalence of choroidoretinitis (2.2%) and iridocyclitis (2.2%) were the least prevalent ocular lesions reported among these female adults. The depletion of the CD4(+) contributed to the low prevalence of visual impairment and lesions in this locality. The depleted CD4(+), CD8(+), and the lower values of IgA, IgM, and IgG contributed in the maintenance of chronicity of onchocerciasis in Egoro-Eguare, Nigeria.
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PMID:CD4(+), CD8(+), immunoglobulin status and ocular lesions among some onchocerciasis-infected rural Nigerians. 1720 2

Ocular infection with herpes simplex virus (HSV) causes a vision-impairing inflammatory reaction called herpetic stromal keratitis. In murine models, herpetic stromal keratitis lesions appear to be immunopathologic, mediated by CD4(+) T cells of Th1 phenotype. To provide insight about cytokine networks and signaling events involved in the development of aggressor CD4(+) T cells, ocular HSV infection was followed in mice deficient in Stat4 (Stat4(-/-) mice), the signal transducer for the cytokine interleukin-12 (IL-12). After ocular HSV infection of Stat4(-/-) and control BALB/c mice, clinical, histologic, and immunologic analyses were carried out. Further, to evaluate the involvement of Stat4 in the development of this aggressor population, naive CD4(+) T cells from Stat4(-/-) and BALB/c mice were adoptively transferred to C.B-17 SCID mice 1 day after corneal infection. Although Stat4(-/-) mice demonstrated increased susceptibility to lethal encephalitis and facial lesions, interestingly, these mice had less severe stromal keratitis in comparison to control animals. Adoptive transfer of naive CD4(+) T cells from Stat4(-/-) mice failed to produce disease in infected SCID recipients. The data imply a significant role of Stat4-mediated signaling events in the generation of an aggressor CD4(+) T cell population in stromal keratitis pathogenesis.
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PMID:Role of Stat4-mediated signal transduction events in the generation of aggressor CD4+ T cells in herpetic stromal keratitis pathogenesis. 1726 45

Herpes simplex virus (HSV) infection of the cornea culminates in an immunopathological lesion (stromal keratitis--SK) that impairs vision. This report shows that HSV infection results in IL-23 up-regulation, but if this response fails to occur, as was noted in p19-/- mice, the severity of lesions, their incidence and the level of viral induced angiogenesis were significantly increased compared to wild-type (WT) animals (p<0.05). The higher disease severity in p19-/- mice appeared to be the consequence of an increased IL-12 response that in turn led to the induction of higher numbers of IFN-gamma producing CD4(+)T cells, the principal orchestrators of SK. Our results indicate that the severity of HSV induced immunopathological lesions may be mainly the consequence of IL-12 driven Th1 T cell reactions rather than the action of IL-17 producing cells controlled by IL-23.
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PMID:Enhanced viral immunoinflammatory lesions in mice lacking IL-23 responses. 1832 11

Two prominent anti-inflammatory mechanisms involved in controlling HSV-1-induced corneal immunopathology (stromal keratitis or SK) are the production of the cytokine IL-10 and the activity of natural regulatory T cells (nTregs). It is not known whether, under in vivo conditions, IL-10 and nTregs influence the corneal pathology independently or in concert. In the current study using wild-type and IL-10(-/-) animals, we have assessed the activity of nTregs in the absence of IL-10 both under in vitro and in vivo conditions. The IL-10(-/-) animals depleted of nTregs before ocular infection showed more severe SK lesions as compared with the undepleted IL-10(-/-) animals. In addition, nTregs purified from naive WT and IL-10(-/-) animals were equally able to suppress the proliferation and the cytokine production from anti-CD3-stimulated CD4(+)CD25(-) T cells in vitro. Furthermore, intracellular cytokine staining results indicated that nonregulatory cells expressing B220 and CD25 markers were the major IL-10-producing cell types in the lymphoid tissues of HSV-infected mice. In contrast, in the infected corneas, cells with the CD11b(+)Gr1(+) phenotype along with a minor population of Foxp3(-)CD4(+) and a few F4/80(+) cells produced IL-10. Our current investigations indicate that at least two independent anti-inflammatory mechanisms are involved in limiting the corneal lesions in SK, both of which may need to be modulated to control SK therapeutically.
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PMID:IL-10 and natural regulatory T cells: two independent anti-inflammatory mechanisms in herpes simplex virus-induced ocular immunopathology. 1842 53

Generating and using regulatory T cells (Tregs) to modulate inflammatory disease represents a valuable approach to therapy but has not yet been applied as a means to control virus-induced immunopathological reactions. In this report, we developed a simplified technique that used unfractionated splenocytes as a precursor population and showed that stimulation under optimized conditions for 5 days with solid-phase anti-CD3 monoclonal antibody in the presence of transforming growth factor beta (TGF-beta) and interleukin-2 could induce up to 90% of CD4(+) T cells to become Foxp3(+) and able to mediate suppression in vitro. CD11c(+) dendritic cells were intricately involved in the conversion process and, once modified in the presence of TGF-beta, could convert Foxp3(-) CD4(+) cells into Foxp3(+) CD4(+)cells by producing TGF-beta. The converted cells had undergone cell division, and the majority of them expressed activation markers along with surface molecules that would facilitate their migration into tissue sites. The primary reason for our study was to determine if such in vitro-converted Tregs could be used in vivo to influence the outcome of a virus-induced immunoinflammatory lesion in the eye caused by herpes simplex virus infection. We could show in three separate models of herpetic stromal keratitis that adoptive transfers of in vitro-converted Tregs effectively diminished lesion severity, especially when given in the initial phases of infection. The suppression effect in vivo appeared to be polyspecific. The protocol we have developed could provide a useful additional approach to control virus-induced inflammatory disease.
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PMID:In vitro-generated antigen-specific CD4+ CD25+ Foxp3+ regulatory T cells control the severity of herpes simplex virus-induced ocular immunoinflammatory lesions. 1848 Apr 41

Herpetic stromal keratitis (HSK) is an immune reaction related to herpes simplex virus (HSV) corneal infection, and has many important immunological aspects. CD4(+) T lymphocytes, especially Th1 cells, are the principal mediators for HSK. In addition, neutrophils and antigen-presenting cells play vital roles in HSK. CD8(+) T lymphocytes, B cells, and natural killer cells all participate in the pathogenesis of HSK under certain circumstances. Many molecules are involved in the pathogenesis of HSK. Th1 cytokines such as interleukin 2 (IL-2), IL-12 and interferon gamma, and inflammatory cytokines such as IL-1alpha and IL-6 are especially important ones. Among various chemokines that take part in HSK, MIP-1alpha is one of the most important aggravating factors. Vaccination therapy against HSK has been developed; glycoprotein D is a particularly promising candidate. However, the possibility of HSK exacerbation due to vaccination is the final problem to be solved before vaccination can be clinically applied to HSK. Molecular mimicry theory and bystander activation theory are the two new autoimmune theories that have been advocated. Since genuine autoimmune HSK without HSV growth can hardly be the case in clinical practice, some part of these new theories remains controversial. In the future, better understanding of the pathogenesis of HSK is essential to resolve the paradox between suppressing the immune reaction to avoid corneal scarring and preventing viral proliferation.
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PMID:Immunological aspects of herpetic stromal keratitis. 1858 59


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