Increased expression of interferon-inducible genes in macaque lung tissues during simian immunodeficiency virus infection

Type I interferon and HIV: Subtle balance between antiviral activity, immunopathogenesis and the microbiome

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Induction and action of IFN during acute and chronic HIV-1 infection.

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Host and viral factors influencing IFN response in HIV-1 infected patients.

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Type I IFN and IFNα subtypes signatures and their antiviral activity during HIV-1 infection.

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The microbiome and intestinal IFN responses relationship in HIV-1 infection and disease.

Type I interferon (IFN) response initially limits HIV-1 spread and may delay disease progression by stimulating several immune system components. Nonetheless, persistent exposure to type I IFN in the chronic phase of HIV-1 infection is associated with desensitization and/or detrimental immune activation, thereby hindering immune recovery and fostering viral persistence. This review provides a basis for understanding the complexity and function of IFN pleiotropic activity in HIV-1 infection. In particular, the dichotomous role of the IFN response in HIV-1 immunopathogenesis will be discussed, highlighting recent advances in the dynamic modulation of IFN production in acute versus chronic infection, expression signatures of IFN subtypes, and viral and host factors affecting the magnitude of IFN response during HIV-1 infection. Lastly, the review gives a forward-looking perspective on the interplay between microbiome compositions and IFN response.

Interferon-α Subtypes As an Adjunct Therapeutic Approach for Human Immunodeficiency Virus Functional Cure

Human immunodeficiency virus (HIV) establishes life-long latency in infected individuals. Although highly active antiretroviral therapy (HAART) has had a significant impact on the course of HIV infection leading to a better long-term outcome, the pool of latent reservoir remains substantial even under HAART. Numerous approaches have been under development with the goal of eradicating the latent HIV reservoir though with limited success. Approaches that combine immune-mediated control of HIV to activate both the innate and the adaptive immune system under suppressive therapy along with “shock and kill” drugs may lead to a better control of the reactivated virus. Interferon-α (IFN-α) is an innate cytokine that has been shown to activate intracellular defenses capable of restricting and controlling HIV. IFN-α, however, harbors numerous functional subtypes that have been reported to display different binding affinities and potency. Recent studies have suggested that certain subtypes such as IFN-α8 and IFN-α14 have potent anti-HIV activity with little or no immune activation, whereas other subtypes such as IFN-α4, IFN-α5, and IFN-α14 activate NK cells. Could these subtypes be used in combination with other strategies to reduce the latent viral reservoir? Here, we review the role of IFN-α subtypes in HIV infection and discuss the possibility that certain subtypes could be potential adjuncts to a “shock and kill” or therapeutic vaccination strategy leading to better control of the latent reservoir and subsequent functional cure.

Early treatment with reverse transcriptase inhibitors significantly suppresses peak plasma IFNα in vivo during acute simian immunodeficiency virus infection

Innate interferons (IFN) are comprised of multiple Type I and III subtypes. The in vivo kinetics of subtype responses during human immunodeficiency virus (HIV) infection is not well defined. Using the acute simian immunodeficiency virus (SIV) infection model, we show that plasma IFNα levels peak at day 10 post-infection (pi) after which they rapidly declined. The mRNA expression of Type I and III IFN subtypes were significantly elevated in the lymph nodes (LN) at day 10 pi. Though the expression levels of all subtypes declined by day 14-31 pi, numerous subtypes remained elevated suggesting that ongoing viral replication in LN continues to drive induction of these subtypes. Interestingly, treatment with reverse transcriptase (RT) inhibitors at day 7 pi significantly suppressed plasma IFNα responses by day 10 pi that significantly correlated with cell-associated SIV DNA loads suggesting that RT byproducts such as viral DNA likely plays a role in driving IFN responses during acute SIV infection. Quantification of Type I and III subtype transcripts in sorted subsets of LN CD4+ and CD8+ T cells, CD14+/CD14- monocytes/macrophages, and total CD11c/CD123+ dendritic cells (DC) at day 10 pi showed that DC expressed ∼3-4 log more subtype transcripts as compared to the other subsets. Taken together, our results provide new insights into the kinetics of innate interferon responses during early stages of infection, and provide evidence that DC's are a major in vivo source of innate IFN during acute SIV infection.

Infection with equine infectious anemia virus vaccine strain EIAVDLV121 causes no visible histopathological lesions in target organs in association with restricted viral replication and unique cytokine response

The live equine infectious anemia virus (EIAV) vaccine strain EIAV_DLV121 was developed by in vitro attenuation of a virulent strain, EIAV_LN40, in the 1970s, and it has been demonstrated to induce protective immunity under laboratory and natural EIAV infection conditions. The detailed biological features of this attenuated virus remain to be further investigated. Experimental inoculation with EIAV_DLV121 did not result in clinical symptoms even with immunosuppressive treatment in our previous studies. Here, we further investigated whether the replication of the vaccine strain EIAV_DLV121 in experimentally infected horses causes histopathological lesions to develop in the targeted organs. Both the lungs and the spleen have been demonstrated to support EIAV replication. By evaluating the gross macroscopic and histological changes, we found that EIAV_DLV121 did not cause detectable histopathological lesions and that it replicated several hundred times more slowly than its parental virulent strain, EIAV_LN40, in tissues. Immunochemical assays of these tissues indicated that the primary target cells of EIAV_DLV121 were monocytes/macrophages, but that EIAV_LN40 also infected alveolar epithelial cells and vascular endothelial cells. In addition, both of these viral strains promoted the up- and down-regulation of the expression of various cytokines and chemokines, implicating the potential involvement of these cellular factors in the pathological outcomes of EIAV infection and host immune responses. Taken together, these results demonstrate that the EIAV vaccine strain does not cause obvious histopathological lesions or clinical symptoms and that it induces a unique cytokine response profile. These features are considered essential for EIAV_DLV121 to function as an effective live vaccine.

ISG15 expression correlates with HIV-1 viral load and with factors regulating T cell response

Given the multifactorial nature of action of type I interferon (IFN) in HIV-1 infection and the need to firmly establish the action of key components of IFN pathways, we compared the IFN stimulated gene (ISG)15 expression with that of other well-characterized ISGs, evaluating its relationship with immunosuppressive factors regulating T-cell response in HIV-1 patients. PBMC from 225 subjects were included: healthy donors (n=30), naïve (n=93) and HAART treated HIV-1 subjects (n=102). Levels of ISG15-mRNA, ISG56-mRNA, APOBEC3G/3F-mRNA, TRAIL-mRNA, IDO-mRNA, proviral load andISG15 (rs15842 and rs1921) SNPs were evaluated by using TaqMan assays. We found that ISG15, ISG56, APOBEC3G/3F levels were increased in untreated HIV-1 patients compared to healthy donors, being ISG15 the highest ISG expressed. The amount of ISG15 correlated with viral load and with CD4+ T cell counts whereas no relationship was found between all ISGs analyzed and proviral load or HIV-1 tropism. ISG15 expression was reduced following long-term antiretroviral therapy. In addition, ISG15 levels were correlated with those of TRAIL and IDO in HIV-1 viremic patients. Lastly, ISG15 SNPs had no influence on ISG15 levels. We demonstrates that ISG15 is elevated in viremic HIV-1 patients and is associated with high TRAIL and IDO levels.

Characterization of chemokine and chemokine receptor expression during Pneumocystis infection in healthy and immunodeficient mice

We examined gene expression levels of multiple chemokines and chemokine receptors during Pneumocystis murina infection in wild-type and immunosuppressed mice, using microarrays and qPCR. In wild-type mice, expression of chemokines that are ligands for Ccr2, Cxcr3, Cxcr6, and Cxcr2 increased at days 32-41 post-infection, with a return to baseline by day 75-150. Concomitant increases were seen in Ccr2, Cxcr3, and Cxcr6, but not in Cxcr2 expression. Induction of these same factors also occurred in CD40-ligand and CD40 knockout mice but only at a much later time-point, during uncontrolled Pneumocystis pneumonia (PCP). Expression of CD4 Th1 markers was increased in wild-type mice during clearance of infection. Ccr2 and Cx3cr1 knockout mice cleared Pneumocystis infection with kinetics similar to wild-type mice, and all animals developed anti-Pneumocystis antibodies. Upregulation of Ccr2, Cxcr3, and Cxcr6 and their ligands supports an important role for T helper cells and mononuclear phagocytes in the clearance of Pneumocystis infection. However, based on the current and prior studies, no single chemokine receptor appears to be critical to the clearance of Pneumocystis.

Simian immunodeficiency virus infection potently modulates chemokine networks and immune environments in hilar lymph nodes of cynomolgus macaques

BACKGROUND

Chemokines provide critical immune cell homing and activation signals that if altered could affect the inflammatory milieu and cellular composition of lymphoid tissues. During HIV-1 and simian immunodeficiency virus (SIV)-infection, the virus triggers an increase in inflammation or activation, leading to immunodeficiency and development of opportunistic infections, such as in the lungs-a massive interface between the host and the environment.

METHODS

Chemokine, cytokine, and chemokine receptor expression profiles were determined using real-time reverse transcriptase-polymerase chain reaction and in situ hybridization in hilar lymph nodes (HiLNs) from cynomolgus macaques at different stages after infection with SIV/DeltaB670. Immunostaining of tissue sections and flow cytometric analysis of cryopreserved cells were used to examine cellular compositions of lymph nodes.

RESULTS

Interferon-gamma, type 1 chemokine, and cognate chemokine receptor mRNAs were upregulated, whereas type 2 and homeostatic chemokine and chemokine receptor mRNAs were down-regulated in HiLNs after SIV infection. Local SIV and interferon-gamma levels were positively correlated with type 1 chemokine levels but negatively correlated with type 2 and homeostatic chemokine levels. Using in situ hybridization, Pneumocystis carinii rRNA was detected in lung-draining lymph nodes from animals with P. carinii pneumonia. Changes in the cellular composition of HiLNs included decreased proportions of CD4 cells and dendritic cells and increased proportions of CD8, CXCR3, and CCR5 cells.

CONCLUSIONS

SIV infection of cynomolgus macaques dramatically alters the cellular homing signals of lung-draining lymph nodes, which correlated with changes in the immune cellular composition. These changes could contribute to the loss of immune function that defines AIDS.

Interleukin-21 up-regulates interleukin-21R expression and interferon gamma production by CD8+ cells in SHIV-infected macaques

Interleukin-21 (IL-21) is produced primarily by CD4+ T cells and regulates immunity against human/simian immunodeficiency virus (HIV/SIV) infection. Activated CD8+ cells and their secreted interferon-gamma (IFN-γ) are crucial for the control of acute HIV/SIV infection. However, whether IL-21 can regulate IFN-γ production by CD8+ cells remains controversial. Rhesus macaques (RMs, n = 8) were infected with SHIV and the levels of plasma IL-21, IFN-γ and the frequency of peripheral blood activated T cells were measured longitudinally. Following infection with SHIV, the levels of plasma IL-21 and IFN-γ increased, peaked at 17 days postinfection and declined later. Furthermore, IL-21 induced IL-21 receptor (IL-21R) and IFN-γ, perforin, but not granmyze B, expression in CD8+ cells from four selected SHIV-infected RMs. The regulatory effect of IL-21 on CD8+ cell function appeared to be associated with increased levels of STAT3, but not STAT5, phosphorylation in CD8+ cells from SHIV-infected RMs. In parallel, treatment with soluble IL-21R/Fc, an inhibitor of IL-21-induced activation of JAK1/3 and STAT3, abrogated IL-21-induced STAT3 activation and IFN-γ production in CD8+ cells from SHIV-infected RMs in vitro. Our data indicated that IL-21 was a positive regulator of IFN-γ-secreting CD8+ cells and increased the STAT3 phosphorylation, regulating T-cell immunity against acute SHIV infection in RMs. Our findings may provide a new basis for the development of immunotherapies for the control of SHIV/HIV infection.

Macaque paneth cells express lymphoid chemokine CXCL13 and other antimicrobial peptides not previously described as expressed in intestinal crypts

CXCL13 is a constitutively expressed chemokine that controls migration of immune cells to lymphoid follicles. Previously, we found CXCL13 mRNA levels increased in rhesus macaque spleen tissues during AIDS. This led us to examine the levels and locations of CXCL13 by detailed in situ methods in cynomolgus macaque lymphoid and intestinal tissues. Our results revealed that there were distinct localization patterns of CXCL13 mRNA compared to protein in germinal centers. These patterns shifted during the course of simian immunodeficiency virus (SIV) infection, with increased mRNA expression within and around follicles during AIDS compared to uninfected or acutely infected animals. Unexpectedly, CXCL13 expression was also found in abundance in Paneth cells in crypts throughout the small intestine. Therefore, we expanded our analyses to include chemokines and antimicrobial peptides (AMPs) not previously demonstrated to be expressed by Paneth cells in intestinal tissues. We examined the expression patterns of multiple chemokines, including CCL25, as well as α-defensin 6 (DEFA6), β-defensin 2 (BDEF2), rhesus θ-defensin 1 (RTD-1), and Reg3γ in situ in intestinal tissues. Of the 10 chemokines examined, CXCL13 was unique in its expression by Paneth cells. BDEF2, RTD-1, and Reg3γ were also expressed by Paneth cells. BDEF2 and RTD-1 previously have not been shown to be expressed by Paneth cells. These findings expand our understanding of mucosal immunology, innate antimicrobial defenses, homeostatic chemokine function, and host protective mechanisms against microbial translocation.

Vpu-deficient HIV strains stimulate innate immune signaling responses in target cells

Acute virus infection induces a cell-intrinsic innate immune response comprising our first line of immunity to limit virus replication and spread, but viruses have developed strategies to overcome these defenses. HIV-1 is a major public health problem; however, the virus-host interactions that regulate innate immune defenses against HIV-1 are not fully defined. We have recently identified the viral protein Vpu to be a key determinant responsible for HIV-1 targeting and degradation of interferon regulatory factor 3 (IRF3), a central transcription factor driving host cell innate immunity. IRF3 plays a major role in pathogen recognition receptor (PRR) signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Here we interrogate the cellular responses to target cell infection with Vpu-deficient HIV-1 strains. Remarkably, in the absence of Vpu, HIV-1 triggers a potent intracellular innate immune response that suppresses infection. Thus, HIV-1 can be recognized by PRRs within the host cell to trigger an innate immune response, and this response is unmasked only in the absence of Vpu. Vpu modulation of IRF3 therefore prevents virus induction of specific innate defense programs that could otherwise limit infection. These observations show that HIV-1 can indeed be recognized as a pathogen in infected cells and provide a novel and effective platform for defining the native innate immune programs of target cells of HIV-1 infection.

Vpu mediates depletion of interferon regulatory factor 3 during HIV infection by a lysosome-dependent mechanism

HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV.

Generalized immune activation and innate immune responses in simian immunodeficiency virus infection

PURPOSE OF REVIEW

Chronic immune activation is a key factor driving the immunopathogenesis of AIDS. During pathogenic HIV/simian immunodeficiency virus (SIV) infections, innate and adaptive antiviral immune responses contribute to chronic immune activation. In contrast, nonpathogenic SIV infections of natural hosts such as sooty mangabeys and African green monkeys (AGMs) are characterized by low immune activation despite similarly high viremia. This review focuses on the role of innate immune responses in SIV infection.

RECENT FINDINGS

Several studies have examined the role of innate immune responses to SIV as potential drivers of immune activation. The key result of these studies is that both pathogenic SIV infection of macaques and nonpathogenic SIV infections of natural hosts are associated with strong innate immune responses to the virus, high production of type I interferons by plasmacytoid dendritic cells, and upregulation of interferon-stimulated genes (ISGs). However, SIV-infected sooty mangabeys and AGMs (but not SIV-infected macaques) rapidly downmodulate the interferon response within 4-6 weeks of infection, thus resulting in a state of limited immune activation during chronic infection.

SUMMARY

Studies in nonhuman primates suggest that chronic innate/interferon responses may contribute to AIDS pathogenesis. Further, the ability of natural host species to resolve innate immune responses after infection provides a novel avenue for potential immunotherapy.

The simian immunodeficiency virus targets central cell cycle functions through transcriptional repression in vivo

A massive and selective loss of CD4+ memory T cells occurs during the acute phase of immunodeficiency virus infections. The mechanism of this depletion is poorly understood but constitutes a key event with implications for progression. We assessed gene expression of purified T cells in Rhesus Macaques during acute SIVmac239 infection in order to define mechanisms of pathogenesis. We observe a general transcriptional program of over 1,600 interferon-stimulated genes induced in all T cells by the infection. Furthermore, we identify 113 transcriptional changes that are specific to virally infected cells. A striking downregulation of several key cell cycle regulator genes was observed and shared promotor-region E2F binding sites in downregulated genes suggested a targeted transcriptional control of an E2F regulated cell cycle program. In addition, the upregulation of the gene for the fundamental regulator of RNA polymerase II, TAF7, demonstrates that viral interference with the cell cycle and transcriptional regulation programs may be critical components during the establishment of a pathogenic infection in vivo.

Simian immunodeficiency virus infection alters chemokine networks in lung tissues of cynomolgus macaques: association with Pneumocystis carinii infection

Infection by HIV-1 frequently leads to pulmonary complications, including alterations to local immune environments. To better understand these alterations, we have examined in detail the patterns and levels of expression of chemokine, cytokine, and chemokine receptor mRNAs in lung tissues from 16 uninfected or simian immunodeficiency virus (SIV)/DeltaB670 infected cynomolgus macaques at different stages of infection. Among the most up-regulated immune genes were interferon (IFN)-gamma, IFN-gamma-inducible CXCR3 ligands, and CCR5 ligands, as well as the cognate chemokine receptors. These changes were greatest in animals with clear Pneumocystis carinii coinfection. Immunohistochemistry and in situ hybridization revealed monocytes/macrophages to be the predominant type of cell infiltrating into lung tissues and serving as the major cellular source of chemokines. To explore the causes of chemokine alterations, we treated macaque lung cells with IFN-gamma, lipopolysaccharide, Poly(I:C), and P. carinii in vitro, and results revealed that these stimuli can induce the expression of CXCR3 ligand and/or CCR5 ligand mRNAs. Taken together, these studies provide a comprehensive definition of the chemokine networks available to modulate cellular recruitment to lung tissues during SIV infection and implicate both cytokines (IFN-gamma) and pathogens (SIV and P. carinii) as contributors to increased expression of pro-inflammatory chemokines.

Nonpathogenesis of simian immunodeficiency virus infection is associated with reduced inflammation and recruitment of plasmacytoid dendritic cells to lymph nodes, not to lack of an interferon type I response, during the acute phase

Divergent Toll-like receptor 7 (TLR7) and TLR9 signaling has been proposed to distinguish pathogenic from nonpathogenic simian immunodeficiency virus infection in primate models. We demonstrate here that increased expression of type I interferon in pathogenic rhesus macaques compared to nonpathogenic African green monkeys was associated with the recruitment of plasmacytoid dendritic cells in the lymph nodes and the presence of an inflammatory environment early after infection, instead of a difference in the TLR7/9 response.

Elevated levels of innate immune modulators in lymph nodes and blood are associated with more-rapid disease progression in simian immunodeficiency virus-infected monkeys

Cytokines and chemokines are critical for establishing tissue-specific immune responses and play key roles in modulating disease progression in simian immunodeficiency virus (SIV)-infected macaques and human immunodeficiency virus (HIV)-infected humans. The goal here was to characterize the innate immune response at different tissue sites and to correlate these responses to clinical outcome, initially focusing on rhesus macaques orally inoculated with SIV and monitored until onset of simian AIDS. Cytokine and chemokine mRNA transcripts were assessed at lymph nodes (LN) and peripheral blood cells utilizing quantitative real-time PCR at different time points postinfection. The mRNA expression of four immune modulators-alpha interferon (IFN-alpha), oligoadenylate synthetase (OAS), CXCL9, and CXCL10-was positively associated with disease progression within LN tissue. Elevated cytokine/chemokine expression in LN did not result in any observed beneficial outcome since the numbers of CXCR3(+) cells were not increased, nor were the SIV RNA levels decreased. In peripheral blood, increased OAS and CXCL10 expression were elevated in SIV(+) monkeys that progress the fastest to simian AIDS. Our results indicate that higher IFN-alpha, OAS, CXCL9, and CXCL10 mRNA expression in LN was associated with rapid disease progression and a LN environment that may favor SIV replication. Furthermore, higher expression of CXCL10 and OAS in peripheral blood could potentially serve as a diagnostic marker for hosts that are likely to progress to AIDS. Understanding the expression patterns of key innate immune modulators will be useful in assessing the disease state and potential rates of disease progression in HIV(+) patients, which could lead to novel therapy and vaccine approaches.

Interferon-gamma-mediated pathways and in vitro PBMC proliferation in HIV-infected patients

HIV infection is characterized by progressive immunodeficiency: HIV-infected peripheral blood mononuclear cells (PBMCs) cannot properly react to stimulation with allo-antigens and mitogens. In this study, we examined interferon-gamma (IFN-gamma)-mediated pathways and the proliferative response of mitogen-stimulated HIV-infected PBMCs in vitro. PBMCs of 30 HIV-infected patients were stimulated with the mitogens concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogen (PWM). Mitogen stimulation induced expression of IFN-gamma, GTP cyclohydrolase I (GCH-I), and indoleamine (2,3)-dioxygenase (IDO) resulting in enhanced neopterin formation and tryptophan degradation by HIV-infected and control PBMCs. IFN-gamma concentrations correlated with neopterin levels and tryptophan degradation. Proliferative responses to PHA and PWM cytokine were lower in HIV patients, with IFN-gamma formation predicting proliferative responses. Higher mRNA expression of IFN-gamma, GCH-I and IDO after 6 h was related to better proliferative responses in HIV-infected PBMCs. In conclusion, induction of IFN-gamma and subsequent enzymes appears to importantly influence the proliferative response of HIV-infected PBMCs in vitro, suggesting a prominent role of the cytokine in the development of immunodeficiency.

Multiple roles for chemokines in the pathogenesis of SIV infection

Chemokines are small chemoattractant cytokines involved in homeostatic and inflammatory immune cell migration. These small proteins have multiple functional properties that extend beyond their most recognized role in controlling cellular migration. The complex immunobiology of chemokines, coupled with the use of subsets of chemokine receptors as HIV-1 and SIV entry co-receptors, suggests that these immunomodulators could play important roles in the pathogenesis associated with infection by HIV-1 or SIV. This review provides an overview of the effects of pathogenic infection on chemokine expression in the SIV/macaque model system, and outlines potential mechanisms by which changes in these expression profiles could contribute to development of disease. Key challenges faced in studying chemokine function in vivo and new opportunities for further study and development of therapeutic interventions are discussed. Continued growth in our understanding of the effects of pathogenic SIV infection on chemokine expression and function and the continuing development of chemokine receptor targeted therapeutics will provide the tools and the systems necessary for future studies of the roles of chemokines in HIV-1 pathogenesis.

Minimal conjunctival limbal autograft for total limbal stem cell deficiency

PURPOSE

To report the results of one 60 degrees conjunctival limbal autograft (CLAU) combined with amniotic membrane (AM) transplantation for an eye with total limbal stem cell deficiency (LSCD).

METHODS

One eye of a patient with chronic total LSCD and symblepharon caused by chemical burn was subjected to symblepharon lysis, removal of pannus from corneal surface, AM transplantation to cover the conjunctival and corneal surfaces as a permanent graft, one 60 degrees CLAU to the superior limbal area, and insertion of ProKera as a temporary AM patch to cover the CLAU.

RESULTS

After surgery, corneal epithelialization over the AM was evident adjacent to the CLAU on day 6, progressed to pass the horizontal midline by day 11, and was completed by day 18. During a follow-up of 1 year, the corneal surface remained stable and smooth, and the stroma considerably regained clarity with regression of midstromal vascularization. The best-corrected visual acuity improved from 20/400 to 20/50. The conjunctival inflammation completely resolved, and the fornices were deep.

CONCLUSIONS

One 60 degrees CLAU combined with AM transplantation as both a permanent graft and a temporary patch can restore the entire corneal surface in an eye with total LSCD caused by chemical burn.

Antiviral therapy during primary simian immunodeficiency virus infection fails to prevent acute loss of CD4+ T cells in gut mucosa but enhances their rapid restoration through central memory T cells

Gut-associated lymphoid tissue (GALT) is an early target of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) and a site for severe CD4+ T-cell depletion. Although antiretroviral therapy (ART) is effective in suppressing HIV replication and restoring CD4+ T cells in peripheral blood, restoration in GALT is delayed. The role of restored CD4+ T-cell help in GALT during ART and its impact on antiviral CD8+ T-cell responses have not been investigated. Using the SIV model, we investigated gut CD4+ T-cell restoration in infected macaques, initiating ART during either the primary stage (1 week postinfection), prior to acute CD4+ cell loss (PSI), or during the chronic stage at 10 weeks postinfection (CSI). ART led to viral suppression in GALT and peripheral blood mononuclear cells of PSI and CSI animals at comparable levels. CSI animals had incomplete CD4+ T-cell restoration in GALT. In PSI animals, ART did not prevent acute CD4+ T-cell loss by 2 weeks postinfection in GALT but supported rapid and complete CD4+ T-cell restoration thereafter. This correlated with an accumulation of central memory CD4+ T cells and better suppression of inflammation. Restoration of CD4+ T cells in GALT correlated with qualitative changes in SIV gag-specific CD8+ T-cell responses, with a dominance of interleukin-2-producing responses in PSI animals, while both CSI macaques and untreated SIV-infected controls were dominated by gamma interferon responses. Thus, central memory CD4+ T-cell levels and qualitative antiviral CD8+ T-cell responses, independent of viral suppression, were the immune correlates of gut mucosal immune restoration during ART.

Mucosal innate immune response associated with a timely humoral immune response and slower disease progression after oral transmission of simian immunodeficiency virus to rhesus macaques

Mucosal transmission is the predominant mode of human immunodeficiency virus (HIV) infection worldwide, and the mucosal innate interferon response represents an important component of the earliest host response to the infection. Our goal here was to assess the changes in mRNA expression of innate mucosal genes after oral simian immunodeficiency virus (SIV) inoculation of rhesus macaques (Macaca mulatta) that were followed throughout their course of disease progression. The SIV plasma viral load was highest in the macaque that progressed rapidly to simian AIDS (99 days) and lowest in the macaque that progressed more slowly (>700 days). The mRNA levels of six innate/effector genes in the oral mucosa indicated that slower disease progression was associated with increased expression of these genes. This distinction was most evident when comparing the slowest-progressing macaque to the intermediate and rapid progressors. Expression levels of alpha and gamma interferons, the antiviral interferon-stimulated gene product 2'-5' oligoadenylate synthetase (OAS), and the chemokines CXCL9 and CXCL10 in the slow progressor were elevated at each of the three oral mucosal biopsy time points examined (day 2 to 4, 14 to 21, and day 70 postinfection). In contrast, the more rapidly progressing macaques demonstrated elevated levels of these cytokine/chemokine mRNA at lymph nodes, coincident with decreased levels at the mucosal sites, and a decreased ability to elicit an effective anti-SIV antibody response. These data provide evidence that a robust mucosal innate/effector immune response is beneficial following lentiviral exposure; however, it is likely that the anatomical location and timing of the response need to be coordinated to permit an effective immune response able to delay progression to simian AIDS.