3Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) cause significant morbidity and mortality worldwide (18,60,63). Though these E. coli pathotypes are genetically related, many features of their epidemiology, their pathogenesis, and the niches they occupy within the human host are unique. EPEC causes profuse watery diarrhea, primarily in children under the age of 2 years, and mostly affects individuals residing in developing countries. In contrast, adults and children infected by EHEC bacteria can suffer from either bloody or nonbloody diarrhea, and in a small percentage of cases a life-threatening complication known as hemolytic uremic syndrome (HUS) occurs. Many patients with HUS experience long-term renal damage, and they often require dialysis or kidney transplantation. EHEC produces Shiga toxins (Stx), which can cause damage to renal endothelial cells, resulting in HUS, while EPEC bacteria do not possess stx (72). EHEC disease appears in primarily industrialized nations yet causes fewer disease outbreaks in developing countries. This observation has been anecdotally attributed to immunological cross-protection from the related EPEC bacteria prevalent in the less developed regions of the world.There are two additional important differences that distinguish these two E. coli pathotypes. Approximately 10 8 to 10 10 EPEC bacteria are necessary to cause infection in adult human volunteers (6, 27), while the infectious dose for EHEC is far less, estimated to be less than 100 CFU (49). Intriguingly, EPEC infects the small intestine; EHEC infects the large bowel, inflicting bloody diarrhea resulting from damage to the colon. Variants of the outer membrane protein intimin, expressed by both pathotypes, have been implicated as contributors to tissue tropism (103), but whether intimin is the initial adhesin and, secondly, whether other factors contribute to the ability of EPEC to recognize the small bowel and of EHEC to colonize the large bowel are not clearly understood. AE. EPEC and EHEC share genetic and phenotypic similarities, most notably the locus of enterocyte effacement (LEE) pathogenicity island (PAI), encoding a type III secretion system (TTSS), and the ability to form attaching and effacing (AE) intestinal lesions, intimate attachment to the host cell, and formation of "pedestals" cupping individual bacteria (86); for recent reviews, see references 12, 60, and 95. The LEE PAI is essential for disease for both EPEC and EHEC bacteria (27,31,105). The EPEC LEE expressed from a multicopy plasmid transformed into a K-12 laboratory strain of E. coli was necessary and sufficient to form the AE phenotype on human epithelial cells in culture (80). In contrast, the EHEC LEE alone was not sufficient to confer the AE phenotype when expressed in a laboratory strain of E. coli (33), suggesting that factors and/or regulatory proteins necessary for this phenotype exist outside the EHEC LEE. Indeed, TccP (Tir-cytoskeletoncoupling protein [also called EspFu], a protein with 24% amino acid identit...

Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation.

ObjectivesDetermine global skin transcriptome patterns of early diffuse systemic sclerosis (SSc) and how they differ from later disease.MethodsSkin biopsy RNA from 48 patients in the Prospective Registry for Early Systemic Sclerosis (PRESS) cohort (mean disease duration 1.3 years) and 33 matched healthy controls was examined by next-generation RNA sequencing. Data were analysed for cell type-specific signatures and compared with similarly obtained data from 55 previously biopsied patients in Genetics versus Environment in Scleroderma Outcomes Study cohort with longer disease duration (mean 7.4 years) and their matched controls. Correlations with histological features and clinical course were also evaluated.ResultsSSc patients in PRESS had a high prevalence of M2 (96%) and M1 (94%) macrophage and CD8 T cell (65%), CD4 T cell (60%) and B cell (69%) signatures. Immunohistochemical staining of immune cell markers correlated with the gene expression-based immune cell signatures. The prevalence of immune cell signatures in early diffuse SSc patients was higher than in patients with longer disease duration. In the multivariable model, adaptive immune cell signatures were significantly associated with shorter disease duration, while fibroblast and macrophage cell type signatures were associated with higher modified Rodnan Skin Score (mRSS). Immune cell signatures also correlated with skin thickness progression rate prior to biopsy, but did not predict subsequent mRSS progression.ConclusionsSkin in early diffuse SSc has prominent innate and adaptive immune cell signatures. As a prominently affected end organ, these signatures reflect the preceding rate of disease progression. These findings could have implications in understanding SSc pathogenesis and clinical trial design.

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Primary infection with varicella zoster virus (VZV) results in varicella (more commonly known as chickenpox) after which VZV establishes latency in sensory ganglia. VZV can reactivate to cause herpes zoster (shingles), a debilitating disease that affects one million individuals in the US alone annually. Current vaccines against varicella (Varivax) and herpes zoster (Zostavax) are not 100% efficacious. Specifically, studies have shown that 1 dose of varivax can lead to breakthrough varicella, albeit rarely, in children and a 2-dose regimen is now recommended. Similarly, although Zostavax results in a 50% reduction in HZ cases, a significant number of recipients remain at risk. To design more efficacious vaccines, we need a better understanding of the immune response to VZV. Clinical observations suggest that T cell immunity plays a more critical role in the protection against VZV primary infection and reactivation. However, no studies to date have directly tested this hypothesis due to the scarcity of animal models that recapitulate the immune response to VZV. We have recently shown that SVV infection of rhesus macaques models the hallmarks of primary VZV infection in children. In this study, we used this model to experimentally determine the role of CD4, CD8 and B cell responses in the resolution of primary SVV infection in unvaccinated animals. Data presented in this manuscript show that while CD20 depletion leads to a significant delay and decrease in the antibody response to SVV, loss of B cells does not alter the severity of varicella or the kinetics/magnitude of the T cell response. Loss of CD8 T cells resulted in slightly higher viral loads and prolonged viremia. In contrast, CD4 depletion led to higher viral loads, prolonged viremia and disseminated varicella. CD4 depleted animals also had delayed and reduced antibody and CD8 T cell responses. These results are similar to clinical observations that children with agammaglobulinemia have uncomplicated varicella whereas children with T cell deficiencies are at increased risk of progressive varicella with significant complications. Moreover, our studies indicate that CD4 T cell responses to SVV play a more critical role than antibody or CD8 T cell responses in the control of primary SVV infection and suggest that one potential mechanism for enhancing the efficacy of VZV vaccines is by eliciting robust CD4 T cell responses.