Prof Ling-Pei Ho
|Technology Exchange:||Cellular immunology, Flow cytometry and Transcript profiling|
|Scientific Themes:||Immunology & Infectious Disease|
|Keywords:||Lungs, Immuneregulation, Natural Killer T (iNKT) cells, Monocytes, Fibrotic lung disease and Influenza virus infection|
Our work is focused on understanding how immune responses in the lungs impact on the mechanisms of injury and repair. We are particularly interested in the role of invariant natural killer T cells (iNKT) and monocytes in immune-regulation and disease pathogenesis.
We have four areas of research that span cellular mechanisms to translational medicine:
- Understanding cellular and molecular interaction of iNKT cells with monocytes
- Examining the contribution of CD1d expression on lung epithelium to mucosal immunity in the lungs
- Examining the contribution of subsets of monocytes to lung injury and resolution of repair
- Using transcriptomics to develop molecular biomarker for predicting outcome in inflammatory lung disease and as a platform for discovery of mechanisms involved in lung immunepathology
These areas of immunology research cross-cut with our focus on the human diseases of idiopathic pulmonary fibrosis, sarcoidosis and severe influenza infection.
|Dr Luzheng Xue||Experimental Medicine Division||University of Oxford||United Kingdom|
|Prof Tao Dong (RDM)||Investigative Medicine Division||University of Oxford||United Kingdom|
New approaches to define factors underlying the immunopathogenesis of pulmonary diseases including sarcoidosis and tuberculosis are needed to develop new treatments and biomarkers. Comparing the blood transcriptional response of tuberculosis to other similar pulmonary diseases will advance knowledge of disease pathways and help distinguish diseases with similar clinical presentations. Hide abstract
The SNP rs12252-C allele alters the function of interferon-induced transmembrane protein-3 increasing the disease severity of influenza virus infection in Caucasians, but the allele is rare. However, rs12252-C is much more common in Han Chinese. Here we report that the CC genotype is found in 69% of Chinese patients with severe pandemic influenza A H1N1/09 virus infection compared with 25% in those with mild infection. Specifically, the CC genotype was estimated to confer a sixfold greater risk for severe infection than the CT and TT genotypes. More importantly, because the risk genotype occurs with such a high frequency, its effect translates to a large population-attributable risk of 54.3% for severe infection in the Chinese population studied compared with 5.4% in Northern Europeans. Interferon-induced transmembrane protein-3 genetic variants could, therefore, have a strong effect of the epidemiology of influenza in China and in people of Chinese descent. Hide abstract
The molecular repertoire of macrophages in health and disease can provide novel biomarkers for diagnosis, prognosis, and treatment. Th2-IL-4–activated macrophages (M2) have been associated with important diseases in mice, yet no specific markers are available for their detection in human tissues. Although mouse models are widely used for macrophage research, translation to the human can be problematic and the human macrophage system remains poorly described. In the present study, we analyzed and compared the transcriptome and proteome of human and murine macrophages under resting conditions (M0) and after IL-4 activation (M2). We provide a resource for tools enabling macrophage detection in human tissues by identifying a set of 87 macrophage-related genes. Furthermore, we extend current understanding of M2 activation in different species and identify Transglutaminase 2 as a conserved M2 marker that is highly expressed by human macrophages and monocytes in the prototypic Th2 pathology asthma. Hide abstract
T-cell responses have been implicated in control and exacerbation of lung injury during influenza A virus (IAV) infection. Hide abstract
Protection against mucosally transmitted infections probably requires immunity at the site of pathogen entry, yet there are no mucosal adjuvant formulations licensed for human use. Polyethyleneimine (PEI) represents a family of organic polycations used as nucleic acid transfection reagents in vitro and DNA vaccine delivery vehicles in vivo. Here we show that diverse PEI forms have potent mucosal adjuvant activity for viral subunit glycoprotein antigens. A single intranasal administration of influenza hemagglutinin or herpes simplex virus type-2 (HSV-2) glycoprotein D with PEI elicited robust antibody-mediated protection from an otherwise lethal infection, and was superior to existing experimental mucosal adjuvants. PEI formed nanoscale complexes with antigen, which were taken up by antigen-presenting cells in vitro and in vivo, promoted dendritic cell trafficking to draining lymph nodes and induced non-proinflammatory cytokine responses. PEI adjuvanticity required release of host double-stranded DNA that triggered Irf3-dependent signaling. PEI therefore merits further investigation as a mucosal adjuvant for human use. Hide abstract
Neuropathology in multiple sclerosis is closely linked to presence of macrophages in the CNS. Both M1 (inflammatory) and M2 (alternatively activated, noninflammatory) macrophages are found in the inflamed CNS and thought to differentiate from infiltrating monocytes. It is unclear whether the balance of M1 and M2 macrophages can be altered and whether this affects disease outcome. We show in this article that Ly6C(hi) inflammatory monocytes are the early and dominant infiltrating cells in the CNS during experimental autoimmune encephalomyelitis, a model for the acute phase of multiple sclerosis. Activation of invariant NKT (iNKT) cells reduced the frequency of Ly6C(hi) monocytes and increased the proportion of M2 macrophages in the CNS with associated improvement in neurologic impairment. In contrast, iNKT-deficient mice showed higher numbers of Ly6C(hi) monocytes, reduced M2, and much more severe disease. Adoptive transfer of M2-enriched cells to iNKT-deficient mice markedly improved neurologic impairment. In vitro and in vivo experiments showed that iNKT cells promote differentiation of monocytes to M2 macrophages in an IL-4 and CD1d-dependent process. These findings indicate that infiltrating Ly6C(hi) inflammatory monocytes are early players in acute neuroinflammation and that their frequency and differentiation can be influenced by activation of iNKT cells with resultant improvement in disease outcome. Hide abstract
Nature,2012. IFITM3 restricts the morbidity and mortality associated with influenza
Little is known of how a strong immune response in the lungs is regulated to minimize tissue injury during severe influenza A virus (IAV) infection. Here, using a model of lethal, high-pathogenicity IAV infection, we first show that Ly6C(hi)Ly6G(-) inflammatory monocytes, and not neutrophils, are the main infiltrate in lungs of WT mice. Mice devoid of iNKT cells (Jα18(-/-) mice) have increased levels of inflammatory monocytes, which correlated with increased lung injury and mortality (but not viral load). Activation of iNKT cells correlated with reduction of MCP-1 levels and improved outcome. iNKT cells were able to selectively lyse infected, MCP-1-producing monocytes in vitro, in a CD1d-dependent process. Our study provides a detailed profile and kinetics of innate immune cells in the lungs during severe IAV infection, highlighting inflammatory monocytes as the major infiltrate and identifying a role for iNKT cells in control of these cells and lung immune-pathology. Hide abstract
CD1d is a MHC I like molecule which presents glycolipid to natural killer T (NKT) cells, a group of cells with diverse but critical immune regulatory functions in the immune system. These cells are required for optimal defence against bacterial, viral, protozoan, and fungal infections, and control of immune-pathology and autoimmune diseases. CD1d is expressed on antigen presenting cells but also found on some non-haematopoietic cells. However, it has not been observed on bronchial epithelium, a site of active host defence in the lungs. Here, we identify for the first time, CD1D mRNA variants and CD1d protein expression on human bronchial epithelial cells, describe six alternatively spliced transcripts of this gene in these cells; and show that these variants are specific to epithelial cells. These findings provide the basis for investigations into a role for CD1d in lung mucosal immunity. © 2011 Benam et al. Hide abstract
Approximately 60 to 70% of patients with pulmonary sarcoidosis have disease that resolves spontaneously; the rest follow a chronic course with varying levels of fibrosis. It is unclear why some patients progress and if treatment affects outcome. Hide abstract
The cause of severe disease in some patients infected with pandemic influenza A virus is unclear. Hide abstract
Invariant NKT (iNKT) cells have an indubitable role in antiviral immunity, although the mechanisms by which these cells exert their functions are not fully elucidated. With the emerging importance of high-pathogenicity influenza A virus infections in humans, we questioned whether iNKT cells contribute to immune defence against influenza A virus and whether activation of these cells influences outcome. We show that activation of iNKT cells with alpha-galactosylceramide (alpha-GC) during influenza virus infection transiently enhanced early innate immune response without affecting T cell immunity, and reduced early viral titres in lungs of C57BL/6 mice. This is accompanied by a better disease course with improved weight loss profile. Temporal changes in iNKT cells in the liver, blood and lungs suggest activation and migration of iNKT cells from the liver to the lungs in mice that were administered alpha-GC. Improvement in viral titres appears dependent on activation of iNKT cells via the intraperitoneal route since intranasal administration of alpha-GC did not have the same effect. We conclude that activation of iNKT cells enhances early innate immune response in the lungs and contribute to antiviral immunity and improved disease course in influenza A virus infection. Hide abstract
Sarcoidosis is a multisystem disorder that predominantly involves the lungs, characterised by a T-helper 1 (Th1) biased CD4-positive T-cell response and granuloma formation, for which the explanation is unknown. A newly identified subset of T-cells with immunoregulatory functions, CD1d-restricted natural-killer T (NKT) cells, has been shown to protect against disorders with increased CD4-positive Th1 responses in animals. We explored whether abnormalities in these cells are implicated in the pathogenesis of sarcoidosis. Hide abstract
J Immunol, 172 (12), pp. 7350-7358. Read abstract2004. CD4(-)CD8alphaalpha subset of CD1d-restricted NKT cells controls T cell expansion.
Valpha24 invariant (Valpha24i) CD1d-restricted NKT cells are widely regarded to have immune regulatory properties. They are known to have a role in preventing autoimmune diseases and are involved in optimally mounted immune responses to pathogens and tumor cells. We were interested in understanding how these cells provide protection in autoimmune diseases. We first observed, using EBV/MHC I tetrameric complexes, that expansion of Ag-specific cells in human PBMCs was reduced when CD1d-restricted NKT cells were concomitantly activated. This was accompanied by an increase in a CD4(-)CD8alphaalpha(+) subset of Valpha24i NKT cells. To delineate if a specific subset of NKT cells was responsible for this effect, we generated different subsets of human CD4(-) and CD4(+) Valpha24i NKT clones and demonstrate that a CD4(-)CD8alphaalpha(+) subset with highly efficient cytolytic ability was unique among the clones in being able to suppress the proliferation and expansion of activated T cells in vitro. Activated clones were able to kill CD1d-bearing dendritic or target cells. We suggest that one mechanism by which CD1d-restricted NKT cells can exert a regulatory role is by containing the proliferation of activated T cells, possibly through timely lysis of APCs or activated T cells bearing CD1d. Hide abstract
Control of lung innate immune response during influenza A virus infection by airway epithelial CD1d
Influenza A virus (IAV) infection continues to pose a major threat to the human population. Whilst a large amount of effort has been invested in prevention of infection via vaccination, less is known of how to prevent or modulate lung injury caused by the disease. A key contributor to pathology is undoubtedly the innate immune response and commonly cited ‘cytokine storm’ in severe infection. However, it is unclear why this occurred and how this could be modulated. Our laboratory has shown that ...
High density mapping of the immune landscape in fibrotic lungs
Progressive organ fibrosis is a major cause of morbidity and mortality. Lung fibrosis is a devastating disease with a very poor outcome and no treatment, caused by persistent deposition of extracellular matrix by myofibroblasts. Immune cells control the generation and maintenance of these myofibroblasts but little is known of the global perturbance of immune response in the human lungs during fibrogenesis. The studies will focus on two diseases - idiopathic pulmonary fibrosis (IPF), a severe ...
Can “exhausted” influenza specific T cell be managed at site of infection?
For most human virus infections, the course of disease is largely influenced by the T cell response. Numerous factors influence the quality of the T cell response to viral infections, including the microenvironment of the infection site, the type of cells infected, the variability of the virus and host factors.Pre-existing memory T cells are known to play an important role in influenza virus infection. This has been demonstrated by our own work (Wilkinson et al Nature Medicine 2013; Lee et al, ...