Neural activity from the acutely infected HSV-1 rabbit cornea

Herpes simplex virus type 1 (HSV-1) infections of the human cornea are often accompanied by abnormal sensations. In this study, a combination of physiological and structural methods was used to examine the innervation of the corneas of rabbits with HSV-1 lesions of varying severity. Degeneration of the plexiform neural layer adjacent to dendritic lesions and surrounding normal neurology provided a basis for the limited physiological changes. Extensive degeneration of the corneal innervation at all levels occurred within the anesthetic area of the geographic lesion. Abnormal physiological activity characterized by hyperexcitability and loss of stimulus specificity were included in the physiological profile. Collateral sprouts seen in the geographic lesion were suggested as an anatomical substrate for the abnormal neural activity. Thus, the neural changes could be associated with the severity of HSV-1 lesions.     

Both CD4+ and CD8+ T cells are involved in protection against HSV-1 induced corneal scarring

AIM: To determine the relative impact of CD4+ T cells and CD8+ T cells in protecting mice against ocular HSV-1 challenge. METHODS: CD4+ T cell knockout mice (CD4-/- mice), CD8+ T cell knockout mice (CD8-/- mice), and mice depleted for CD4+ or CD8+ T cells by antibody (CD4+ depleted and CD8+ depleted mice), were examined for their ability to withstand HSV-1 ocular challenge. The parental mice for both knockout mice were C57BL/6J. RESULTS: These results suggest that: (1) both CD4+ deficient mice (CD4-/- and CD4+ depleted mice) and CD8+ deficient mice (CD8-/-, and CD8+ depleted mice) developed significantly more corneal scarring than their C57BL/6J parental strain; (2) the duration of virus clearance from the eyes of the CD4+ deficient mice was 4 days longer than that of the CD8+ deficient mice; and (3) the severity of corneal scarring in the CD4+ deficient mice was approximately twice that of the CD8+ deficient mice. CONCLUSIONS: It was reported here that: (1) CD4+ and CD8+ T cells were both involved in protection against lethal ocular HSV-1 infection; and (2) CD4+ and CD8+ T cells were both involved in protection against HSV-1 induced corneal scarring.     

The role of TH1 and TH2 cytokines in HSV-1-induced corneal scarring

Objective: The study was to evaluate the diagnostic efficacy of nested polymerase chain reaction (nPCR) using primers targeting B1 gene of Toxoplasma gondii (T. gondii) with Witmer Desmonts coefficient (WDC) technique in intraocular fluids of clinically suspected toxoplasma retino choroiditis (TRC) patients. Materials and Methods: Two hundred and seventy eight specimens from 189 patients (25 TRC patients and 164 controls) consisting of 189 serum samples and 89 intraocular fluids were included in the study. The clinical specimens were categorized into TRC patients (typical TRC lesion-group I &; atypical TRC lesion-group II) and controls (voluntary blood donors-group III, patients undergoing uncomplicated cataract surgery-group IV, ocular inflammation of nontoxoplasma origin-group V). Detection of anti T. gondii IgG and IgM antibodies in serum samples and intraocular fluids were performed and WDC was calculated by the standard method. The standardized nPCR was applied on the 89 intraocular fluids. Results: Clinical diagnosis of TRC based on fundus examination was considered to be the “gold standard.” Anti T. gondii IgG/IgM antibodies were detected in serum by ELISA in 95.6% of 25 clinically suspected TRC patients (gp I and II), 28% of gp III, 40.4% of gp IV, and in 58.3% of gpV. Witmer Desmont's coefficient was positive in 72.7% (16/22) and nPCR in 59.1% (13/22) of TRC patients (gp I and II). Both WDC and nPCR were negative in all the controls. The difference in sensitivity of WDC and nPCR was not statistically significant (p = 0.5247). Conclusions: Though both WDC and nPCR were reliable diagnostic techniques for ocular toxoplasmosis, nPCR is more acceptable because of the amount of specimen(s) required, rapidity, cost effectiveness, and direct evidence of T. gondii DNA in the intraocular fluids.     

CD8+ T cell-mediated delayed rejection of orthotopic guinea pig cornea grafts in mice deficient in CD4+ T cells

PURPOSE: To determine the immunopathogenesis of delayed orthotopic corneal xenograft rejection in mice deficient in the xenoreactive CD4+ T cells that mediate acute rejection. METHODS: CB.17 SCID and BALB/c mice were used as recipients of orthotopic cornea grafts obtained from strain 13 guinea pigs. Before transplantation, SCID recipients, which do not normally reject guinea pig cornea grafts, were reconstituted with spleen cells (whole, CD4-depleted, CD4/CD8-depleted) or purified CD8+ T cells from normal BALB/c donors. Graft survival was assessed by clinical examination, and median survival times (MST) were calculated. Lymphocytes from mice that rejected guinea pig cornea grafts were analyzed in vitro for their capacity to respond to guinea pig xenoantigens and to lyse guinea pig target cells. RESULTS: SCID mice reconstituted with whole spleen cells from BALB/c donors rejected guinea pig corneas with a vigor identical with that of normal BALB/c mice (MST = 15 and 14 days, respectively), whereas SCID mice reconstituted with CD4-depleted BALB/c spleen cells rejected guinea pig corneas in a delayed fashion (MST = 27 days), as did SCID mice reconstituted with purified CD8+ T cells from BALB/c donors. Although CD8+ T cells from rejector mice failed to lyse guinea pig target cells in vitro, the T cells proliferated and secreted IFN-gamma in response to in vitro stimulation with guinea pig xenoantigens. CONCLUSIONS: Guinea pig cornea xenografts that avoid acute rejection in CD4+ T cell-depleted mice are vulnerable to rejection by CD8+ T cells. Effector CD8+ T cells destroy corneal xenografts through release of proinflammatory mediators (IFN-gamma) rather than by cytotoxicity.     

Timolol induces HSV-1 ocular shedding in the latently infected rabbit

Timolol iontophoresis into the eye can induce herpes simplex virus type 1 (HSV-1) shedding in rabbits latently infected with HSV-1 strain McKrae. Anodal iontophoresis of 0.01% timolol was done at 0.8 mAmp for 8 min once a day for 3 consecutive days. Viral shedding was determined by the presence of HSV-1 in the preocular tear film obtained by eye swabs. In two experiments, iontophoresis of 0.01% timolol resulted in all eyes (18/18) shedding HSV-1 for an average duration of 4.3 days. When 5.0% timolol was applied topically to rabbit eyes supersensitized by iontophoresis of 6-hydroxydopamine (6-HD), all eyes (10/10) shed virus for an average duration of 2.9 days. All eyes (12/12) receiving iontophoresis of 6-HD, pre- and posttreatment with topical application of 5.0% timolol, and posttreatment with topical application of 1.0% epinephrine shed virus for an average duration of 3.6 days. Eyes treated with topical application of 5.0% timolol alone showed no difference in HSV-1 ocular shedding, compared with untreated eyes. We concluded that both iontophoresis of 0.01% timolol and topical application of 5.0% timolol to adrenergically supersensitized eyes induced HSV-1 shedding reliably and with a high frequency, and that topically applied timolol does not block the HSV-1 ocular shedding induced by epinephrine in adrenergically supersensitized eyes.     

Bacterial DNA confers neuroprotection after optic nerve injury by suppressing CD4+CD25+ regulatory T-cell activity

PURPOSE: Protective autoimmunity attenuates secondary degeneration after central nervous system (CNS) injury. Such neuroprotection is achieved via activation of autoimmune CD4(+)CD25(-) effector T cells (Teffs) or suppression of naturally occurring CD4(+)CD25(+) regulatory T cells (Tregs). In this study the ability of bacterial DNA, characterized by unmethylated CpG islands, to downregulate Treg activity and therefore, to confer neuroprotection was investigated. METHODS: The effects of CpG on suppressive activity of mouse Tregs were studied by coculturing Tregs with Teffs and measuring proliferation by radiolabeled thymidine. The neuroprotective effects of CpG-mediated Treg suppression was examined in rats after optic nerve crush. RESULTS: Teff proliferation in response to T-cell receptor stimuli was significantly reduced when the Teffs were cocultured with Tregs, compared with Teff activation when cultured alone. Treating Tregs with CpG reduced their suppressive activity and restored Teff proliferation to baseline levels. CpG injection in rats with optic nerve crush conferred significant neuroprotection compared with that in untreated control rats (118 +/- 8 cells/mm(2) vs. 69 +/- 5 cells/mm(2), respectively; mean +/- SEM; P < 0.05). CpG-mediated neuroprotection was accompanied by significantly increased T-cell infiltration at the injury site. Similar CpG treatment of athymic nude rats yielded no neuroprotection, further suggesting a T-cell-dependent mechanism of CpG action. CONCLUSIONS: These findings strongly support the notion that alleviation of Treg suppression after injury benefits neuronal survival. Bacterial DNA attenuation of Treg suppressive activity may represent an evolutionary adaptation that curbs the amplified infection risk after CNS trauma, due to blood-brain barrier breakdown. This study may prompt development of new neuroprotective therapies aimed at the immune system, to benefit the injured CNS.     

Spontaneous ocular shedding of HSV-1 in latently infected rabbits

The unscarified corneas of rabbits were inoculated with 50 microliter of 2-4 X 10(6) PFU/ml of herpes simplex virus, type 1 (HSV-1), McKrae strain in 10 separate experiments over a 12-month period. Sixty of 104 (57.7%) rabbits survived to postinoculation (PI) day 20. These sixty rabbits were swabbed with dacron-tipped swabs for twenty consecutive days (PI days 20-39). The tear film collected on the swabs was immediately placed in tissue culture tubes with confluent primary rabbit kidney (RK) cell monolayers. The RK monolayers were monitored for cytopathic effects indicative of HSV-1. Fifty-eight of the sixty rabbits (96.7%) inoculated had at least one positive episode. Ninety-three of the 120 eyes (77.5%) of the latently infected rabbits had at least one positive episode. Virus was detected in 72 of the 93 positive eyes (77.4%) between PI days 20 and 29 and in 21 of the 93 positive eyes (22.5%) between PI days 31-39. A total of 2400 swabs were taken and 324 were positive (13.5%). All of the 58 positive rabbits were used later for ocular induction of HSV-1 and all 116 eyes of the latently infected rabbits shed virus for at least four consecutive days during induction.     

Th1/Th2细胞因子在小鼠真菌性角膜炎中的表达

目的 通过检测Th1/Th2细胞因子在小鼠真菌性角膜炎中的表达水平,探讨机体免疫在该病发展中的作用. 方法应用角膜表层镜法建立Balb/c小鼠茄病镰刀菌性角膜炎模型,在感染后第1、3、5、7天,裂隙灯显微镜观察角膜炎特点;HE染色观察角膜病理变化;半定量RT-PCR和ELISA检测角膜中Thl细胞因子(IFN-γL-12)及Th2细胞因子(IL-4、IL-10)基因mRNA和蛋白的表达,半定量RT-PCR检测T-bet基因mRNA的表达;直线相关分析检测T-bet mRNA与IFN-比值的相关性. 结果角膜接种菌液后,早期角膜浸润混浊进行性加重,第5天后新生血管大量生长;HE染色可见第1、3天在角膜缘、角膜基质及前房中有大量的炎症细胞浸润,第5天后炎症细胞减少,角膜基质中纤维细胞逐渐增多;RT-PCR与ELISA检测结果表明,Thl细胞因子(IFN-γL-12)和Th2细胞因子(IL-4、IL-10)基因mRNA及蛋白在角膜接种菌液后均出现表达,且IFN-γL-12的表达显著强于IL-4、IL-10;IFN-γ/IL-4比值在第3天达最高值,而后逐渐降低;T-bet mRNA在第3天达最高值;T-bet mRNA的表达与IFN-γ/IL-4比值呈正相关(P＜0.05). 结论在真菌性角膜炎中,Thl/Th2型免疫应答共同参与调节机体的抗真菌免疫,但以Th1型应答为主;角膜感染真菌后第3天机体的免疫力达最强.     

Isolation of the human T-cell leukemia/lymphotropic virus type III from the cornea

Corneoscleral donor tissue from a donor with a positive serum antibody to HTLV-III but without the overt clinical signs of the acquired immune deficiency syndrome (AIDS) was cultured for the presence of the human T-cell leukemia/lymphotropic virus type III (HTLV-III). The virus was isolated from the two corneal specimens in this patient after the tissue had been stored for four days in McCarey-Kaufman medium. The presence of HTLV-III was confirmed by the detection of viral core proteins (approximately 24,000 protein, termed P24 gag), by immunofluorescence of a touch preparation of the corneal epithelium as well as in cells cultured in vitro. The percentage of immunofluorescent cells detected by HTLV-III anti-P24 antibody ranged between 2% and 3%. These findings emphasize the possibility of transmission of this virus via corneal transplantation surgery. Although no documented cases of AIDS have occurred in corneal transplant recipients, serologic screening of donors before the use of the tissue for transplantation is advisable.     

TGF-β1 对角膜上皮移植后CD4+、CD8+、CD25+、CD71+的影响

目的 :角膜移植排斥反应是角膜移植失败的主要原因。方法 :为有效控制角膜移植术后排斥反应的发生 ,提高角膜移植成功率 ,我们观察了TGF β1对BALB/c小鼠角膜上皮移植术后外周血淋巴细胞亚群CD 4 、CD 8、CD 2 5、和CD 71活化的影响。研究中采用CD 4 、CD 8、CD 2 5、CD 71、免疫荧光标记及流式细胞仪检测技术 ,对BALB/c小鼠角膜上皮移植术后 12d的外周血中CD 4 、CD 8、CD 2 5、CD 71的表达进行分析。结果 :BALB/c小鼠角膜上皮移植术后 12d的外周血中CD 4 CD 2 5、CD 8CD 2 5、CD 4 CD 71、及CD 8CD 71双阳性的T淋巴细胞均有显著升高 ;术后经TGF β1治疗后 ,上述细胞的数量明显受到抑制。结论 :TGF β1可抑制特异性抗原介导的 ,以及非特异性炎症诱导的移植排斥反应     

Corneal nerve disruption reactivates virus in rabbits latently infected with HSV-1

Trauma, inflammation, and neuronal stimulation or damage can reactive latent herpes simplex virus type 1 (HSV-1). The innervation density of the corneal epithelium is 300-600 times that of skin and, therefore, corneal nerve disruption could provide a strong stimulus for HSV-1 reactivation. This study has documented HSV-1 ocular reactivation following three methods of corneal nerve disruption in rabbits. Twenty HSV-1 latently infected rabbits (26 eyes) were divided into three groups: 7 rabbits received uniocular cryogenic injury, 7 rabbits underwent uniocular anterior superficial keratectomy, and 6 rabbits had binocular transection of the corneal nerves at the corneoscleral limbus which, in contrast to the other treatments, produced minimal epithelial change. Opposite eyes in the first two groups of rabbits were left undisturbed to serve as HSV-1 infected controls. Three additional rabbits, not infected with HSV-1, underwent gold chloride impregnation of the corneal nerves for light microscopic documentation of corneal nerve damage induced by each procedure. On all HSV-1 infected eyes, daily HSV-1 ocular cultures were obtained for 7 consecutive days. All three procedures resulted in marked corneal nerve destruction and degeneration. HSV-1 shedding occurred in 5/7 (71%) of the eyes that underwent cryogenic lesioning; in 5/7 (71%) of the eyes that underwent anterior keratectomy; and in 8/12 (67%) of the eyes that had the corneal nerves transected at the corneoscleral limbus. Only 4 (29%) of the 14 control eyes had positive HSV-1 ocular cultures. This investigation provides strong evidence that corneal nerve disruption is correlated with ocular HSV-1 reactivation.     

Engagement of TLR2 reverses the suppressor function of conjunctiva CD4+CD25+ regulatory T cells and promotes herpes simplex virus epitope-specific CD4+CD25- effector T cell responses

PURPOSE. The authors recently reported that Foxp3(+)CD4(+) CD25(+(Bright)) "natural" regulatory T cells (nT(reg) cells) are abundant in rabbit conjunctiva and suppress herpes simplex virus (HSV)-1-specific CD4(+) and CD8(+) effector T cells (T(eff) cells). However, little is known about the overall regulatory mechanisms of these nT(reg) cells. The authors investigate the regulation of conjunctiva-resident nT(reg) cells through Toll-like receptors (TLRs) and their effect on ocular mucosal T(eff) cell immunity. METHODS. CD4(+)CD25(+) nT(reg) cells were purified from naive rabbit conjunctivas, and their TLR expression profile was determined. The effects of TLR engagement on nT(reg) cell-mediated suppression of CD4(+) T(eff) cells were determined in vitro and in vivo. RESULTS. The authors found that conjunctiva-resident nT(reg) cells express high levels of TLR2 and TLR9; exposure to the TLR2 ligand lipoteichoic acid (LTA) led to the increased activation and proliferation of nT(reg) cells, and the addition of autologous APCs further increased nT(reg) cell expansion; in contrast, the TLR9 ligand CpG(2007) inhibited the proliferation of nT(reg) cells, and the addition of autologous APCs had no effect on such inhibition; nT(reg) cells treated with LTA, but not with CpG(2007), expressed IFN-γ and IL-10 mRNA, but not TGF-β; consistent with in vitro data, rabbits immunized by topical ocular drops of HSV-gD peptides + TLR2 ligand (LTA) displayed enhanced CD4(+)CD25(-) T(eff) cell immune responses when compared with HSV-gD peptides + TLR9 ligand (CpG(2007)). CONCLUSIONS. Although conjunctiva-resident CD4(+)CD25(+) nT(reg) cells express high level of TLR2 and TLR9, their suppressive function is more significantly reversed after the administration of TLR2 ligand (LTA; P < 0.005) than of TLR9 ligand (CpG(200); P > 0.005). These findings will likely help optimize the topical ocular administration of immunotherapies.