Alice Gaughan

Latency Associated Peptide Has In Vitro and In Vivo Immune Effects Independent of TGF-β1

Latency Associated Peptide (LAP) binds TGF-β1, forming a latent complex. Currently, LAP is presumed to function only as a sequestering agent for active TGF-β1. Previous work shows that LAP can induce epithelial cell migration, but effects on leukocytes have not been reported. Because of the multiplicity of immunologic processes in which TGF-β1 plays a role, we hypothesized that LAP could function independently to modulate immune responses. In separate experiments we found that LAP promoted chemotaxis of human monocytes and blocked inflammation in vivo in a murine model of the delayed-type hypersensitivity response (DTHR). These effects did not involve TGF-β1 activity. Further studies revealed that disruption of specific LAP-thrombospondin-1 (TSP-1) interactions prevented LAP-induced responses. The effect of LAP on DTH inhibition depended on IL-10. These data support a novel role for LAP in regulating monocyte trafficking and immune modulation.

Key role for CD4 T cells during mixed antibody mediated rejection of renal allografts

We utilized mouse models to elucidate the immunologic mechanisms of functional graft loss during mixed antibody‐mediated rejection of renal allografts (mixed AMR), in which humoral and cellular responses to the graft occur concomitantly. Although the majority of T cells in the graft at the time of rejection were CD8 T cells with only a minor population of CD4 T cells, depletion of CD4 but not CD8 cells prevented acute graft loss during mixed AMR. CD4 depletion eliminated antidonor alloantibodies and conferred protection from destruction of renal allografts. ELISPOT revealed that CD4 T effectors responded to donor alloantigens by both the direct and indirect pathways of allorecognition. In transfer studies, CD4 T effectors primed to donor alloantigens were highly effective at promoting acute graft dysfunction, and exhibited the attributes of effector T cells. Laser capture microdissection and confirmatory immunostaining studies revealed that CD4 T cells infiltrating the graft produced effector molecules with graft destructive potential. Bioluminescent imaging confirmed that CD4 T effectors traffic to the graft site in immune replete hosts. These data document that host CD4 T cells can promote acute dysfunction of renal allografts by directly mediating graft injury in addition to facilitating antidonor alloantibody responses.

CD103 Deficiency Prevents Graft-versus-Host Disease but Spares Graft-versus-Tumor Effects Mediated by Alloreactive CD8 T Cells

Background Graft-versus-host disease (GVHD) remains the main barrier to broader application of allogeneic hematopoietic stem cell transplantation (alloSCT) as a curative therapy for host malignancy. GVHD is mediated by allogeneic T cells directed against histocompatibility antigens expressed by host tissues. Based on previous studies, we postulated that the integrin CD103 is required for CD8-mediated GVHD, but not for graft-versus-tumor effects (GVT). Methodology/Principal Findings We herein provide evidence in support of this hypothesis. To circumvent the potentially confounding influence of donor CD4 T cells, we developed an alloSCT model in which GVHD mortality is mediated by purified CD8 T cells. In this model, host-reactive CD8 T cells receive CD4 T cell help at the time of initial activation but not in the effector phase in which mature CD8 T effectors migrate into host tissues. We show that donor CD8 T cells from wild-type BALB/c mice primed to host alloantigens induce GVHD pathology and eliminate tumors of host origin in the absence of host CD4 T cells. Importantly, CD103 deficiency dramatically attenuated GVHD mortality, but had no detectable impact on the capacity to eliminate a tumor line of host origin. We provide evidence that CD103 is required for accumulation of donor CD8 T cells in the host intestinal epithelium but not in the tumor or host lymphoid compartments. Consistent with these data, CD103 was preferentially expressed by CD8 T cells infiltrating the host intestinal epithelium but not by those infiltrating the tumor, lamina propria, or lymphoid compartments. We further demonstrate that CD103 expression is not required for classic CD8 effector activities including cytokine production and cytotoxicity. Conclusions/Significance These data indicate that CD103 deficiency inhibits GVHD pathology while sparing anti-tumor effects mediated by CD8 T cells, identifying CD103 blockade as an improved strategy for GVHD prophylaxis.

An Anti‐CD103 Immunotoxin Promotes Long‐Term Survival of Pancreatic Islet Allografts

Previous studies using knockout mice document a key role for the integrin CD103 in promoting organ allograft rejection and graft‐versus‐host disease. However, a determination of whether blockade of the CD103 pathway represents a viable therapeutic strategy for intervention in these processes has proven problematic due to the lack of reagents that efficiently deplete CD103+ cells from wild type hosts. To circumvent this problem, we conjugated the nondepleting anti‐CD103 monoclonal antibody, M290, to the toxin, saporin, to produce an immunotoxin (M290‐SAP) that efficiently depletes CD103+ cells in vivo. Herein, we show that M290‐SAP dramatically reduces the frequency and absolute numbers of CD103‐expressing leukocytes in the blood, spleen, mesenteric lymph nodes and intestinal epithelium of treated mice. We further demonstrate that M290‐SAP promotes indefinite islet allograft survival in a fully MHC mismatched mouse model. The prolonged islet allograft survival resulting from M290‐SAP treatment was associated with multiple effects in the host immune system including not only depletion of CD103‐expressing leukocytes, but also an increase in CD4+CD25+FoxP3+ T regulatory cells and a predominance of effector‐memory CD8 T cells. Regardless of the underlying mechanisms, these data document that depletion of CD103‐expressing cells represents a viable strategy for therapeutic intervention in allograft rejection.

IDEA4PS: The Development of a Research-Oriented Learning Healthcare System:

Leveraging opportunities to learn and then improve the delivery of care using experiences throughout the health care system is essential in efforts to transform health care delivery. The authors present the approach of one academic medical center in becoming a research-oriented Learning Healthcare System (ro-LHS). By reframing the role of research in improving outcomes, the organization was able to move beyond its focus on quality improvement to foster a culture in which feedback informs practice and research drives improvement. The patient safety learning laboratory, the Institute for the Design of Environments Aligned for Patient Safety, funded by the Agency for Healthcare Research and Quality, has provided foundational infrastructure to connect stakeholders across the medical center and university and conduct rigorous research in the context of practice. With this new focus, research now informs operations in a cycle of continuous improvement across the authors’ ro-LHS.

Searching for management approaches to reduce HAI transmission (SMART): a study protocol

BackgroundHealthcare-associated infections (HAIs) impact patients’ lives through prolonged hospitalization, morbidity, and death, resulting in significant costs to both health systems and society. Central line-associated bloodstream infections (CLABSIs) and catheter-associated urinary tract infections (CAUTIs) are two of the most preventable HAIs. As a result, these HAIs have been the focus of significant efforts to identify evidence-based clinical strategies to reduce infection rates. The Comprehensive Unit-based Safety Program (CUSP) provides a formal model for translating CLABSI-reduction evidence into practice. Yet, a national demonstration project found organizations experienced variable levels of success using CUSP to reduce CLABSIs. In addition, in Fiscal year 2019, Medicare will expand use of CLABSI and CAUTI metrics beyond ICUs to the entire hospital for reimbursement purposes. As a result, hospitals need guidance about how to successfully translate HAI-reduction efforts such as CUSP to non-ICU settings (clinical practice), and how to shape context (management practice)—including culture and management strategies—to proactively support clinical teams.MethodsUsing a mixed-methods approach to evaluate the contribution of management factors to successful HAI-reduction efforts, our study aims to: (1) Develop valid and reliable measures of structural management practices associated with the recommended CLABSI Management Strategies for use as a survey (HAI Management Practice Guideline Survey) to support HAI-reduction efforts in both medical/surgical units and ICUs; (2) Develop, validate, and then deploy the HAI Management Practice Guideline Survey, first across Ohio hospitals, then nationwide, to determine the positive predictive value of the measurement instrument as it relates to CLABSI- and CAUTI-prevention; and (3) Integrate findings into a Management Practices Toolkit for HAI reduction that includes an organization-specific data dashboard for monitoring progress and an implementation program for toolkit use, and disseminate that Toolkit nationwide.DiscussionProviding hospitals with the tools they need to successfully measure management structures that support clinical care provides a powerful approach that can be leveraged to reduce the incidence of HAIs experienced by patients. This study is critical to providing the information necessary to successfully “make health care safer” by providing guidance on how contextual factors within a healthcare setting can improve patient safety across hospitals.

Induction of CD4+CD25+ T Regulatory Cells with CD103 Depletion

BACKGROUND M290SAP, a murine CD103 antibody conjugated with the immunotoxin saporin, has been found to induce the indefinite acceptance of transplanted pancreatic islets in mice. We sought to understand the underlying mechanism of this alloacceptance, particularly with respect to the CD4 CD25 T regulatory phenotype. METHODS In this study, we established the kinetics of M290SAP and evaluated the requirement of alloantigen for the induction and maintenance of CD4 CD25 T regulatory cells (Tregs). Naive C57BL/6 mice were treated with several doses of M290SAP with and without donor-specific blood or splenocytes. Blood and spleens were collected at specific time points and underwent FACS analysis. RESULTS M290SAP significantly depleted CD103 cells and induced the up-regulation of CD4 CD25 T regulatory population in spleen cell preparations. The combination of alloantigen in the form of donor-specific blood or splenocytes, with M290SAP, further induced the up-regulation of CD4 CD25 Tregs in the spleen compared with either M290SAP alone or alloantigen alone. The generation of CD4 CD25 cells and the depletion of CD103 cells reached a maximum at 7 d and by 3 wk CD103 and CD4 CD25 T regulatory cell populations returned to baseline. When multiple antigenic challenges were administered, the splenic CD4 CD25 cell population was again up-regulated and persisted for 3 wk. CONCLUSION Our data confirm that M290SAP induces the generation of the CD4 CD25 T regulatory phenotype in spleens of naïve mice. Alloantigen further enhances and rejuvenates the CD4 CD25 cell population in mice treated with M290SAP.