Time filter

Source Type

da Hora V.P.,Queensland Institute of Medical Research | da Hora V.P.,Federal University of Pelotas | da Hora V.P.,Grande Rio University | Conceicao F.A.,Federal University of Pelotas | And 3 more authors.
Vaccine | Year: 2011

The heat-labile enterotoxin of Escherichia coli (LT) consists of an enzymatically active A subunit (LTA) and a pentameric B subunit (LTB). LT has been extensively studied as a potent modulator of immune responses but wild-type LT is toxic and therefore unsuitable for clinical use. Approaches pursued to avoid the toxicity associated with the use of the native toxin while retaining its adjuvant properties have included isolationof subunit B (LTB) and construction ofnon-toxic LT AB complex mutants, such asLTK63 mutant. Here we review the immunomodulatory characteristics of LTB and LTK63 and their potential as mucosal and parenteral vaccine adjuvants. © 2010 Elsevier Ltd.


Wood M.J.,University of Queensland | Wood M.J.,The Queensland Institute of Medical Research | Wood M.J.,Royal Brisbane and Womens Hospital | Powell L.W.,University of Queensland | And 5 more authors.
Hepatology | Year: 2012

The risk of hepatic fibrosis and cirrhosis in hereditary hemochromatosis relates to the degree of iron loading, but iron alone does not explain the variability in disease penetrance. This study sought to identify clinical cofactors that increase the risk of progressive liver disease. We identified 291 patients from our database who were homozygous for the C282Y mutation in HFE and had undergone a liver biopsy with quantification of hepatic iron concentration (HIC) and fibrosis staging. Data were collected from a retrospective chart review, including age, gender, alcohol consumption, medical therapy, smoking history, metabolic risk factors, mobilizable iron, and laboratory results. Male gender, excess alcohol consumption, HIC, and the presence of diabetes were independently associated with increasing fibrosis stage in multivariate analysis. Of these, the presence of diabetes showed the strongest association (odds ratio, 7.32; P = 0.03). The presence of steatosis was associated with higher fibrosis scores, but this was of borderline statistical significance. Risk factors for hepatic steatosis were male gender, impaired glucose tolerance, and increased body mass index. Conclusion: The presence of diabetes was associated with more severe hepatic fibrosis independent of iron loading, male gender, and alcohol consumption. The mechanism for this association is unknown and deserves further evaluation; however, it is possible that diabetes produces an additional hepatic oxidative injury from hyperglycemia. Thus, management of such cofactors in patients with hemochromatosis is important to reduce the risk of liver injury and fibrosis. © 2012 American Association for the Study of Liver Diseases.


McMillan D.J.,The Queensland Institute of Medical Research | Bessen D.E.,New York Medical College | Pinho M.,University of Lisbon | Ford C.,New York Medical College | And 3 more authors.
PLoS ONE | Year: 2010

Background:Streptococcus dysgalactiae subspecies equisimilis (SDSE) is an emerging global pathogen that can colonize and infect humans. Although most SDSE isolates possess the Lancefield group G carbohydrate, a significant minority have the group C carbohydrate. Isolates are further sub-typed on the basis of differences within the emm gene. To gain a better understanding of their molecular epidemiology and evolutionary relationships, multilocus sequence typing (MLST) analysis was performed on SDSE isolates collected from Australia, Europe and North America. Methodology/Principal Findings:The 178 SDSE isolates, representing 37 emm types, segregate into 80 distinct sequence types (STs) that form 17 clonal complexes (CCs). Eight STs recovered from all three continents account for >50% of the isolates. Thus, a small number of STs are highly prevalent and have a wide geographic distribution. Both ST and CC strongly correlate with group carbohydrate. In contrast, eleven STs were associated with >1 emm type, suggestive of recombinational replacements involving the emm gene; furthermore, 35% of the emm types are associated with genetically distant STs. Data also reveal a history of extensive inter- and intra-species recombination involving the housekeeping genes used for MLST. Sequence analysis of single locus variants identified through goeBURST indicates that genetic change mediated by recombination occurred ~4.4 times more frequently than by point mutation. Conclusions/Significance: A few genetic lineages with an intercontinental distribution dominate among SDSE causing infections in humans. The distinction between group C and G isolates reflects recent evolution, and no long-term genetic isolation between them was found. Lateral gene transfer and recombination involving housekeeping genes and the emm gene are important mechanisms driving genetic variability in the SDSE population. © 2010 McMillan et al.


Engwerda C.R.,The Queensland Institute of Medical Research | Engwerda C.R.,University of Queensland | Minigo G.,Charles Darwin University | Amante F.H.,The Queensland Institute of Medical Research | And 2 more authors.
Trends in Parasitology | Year: 2012

A system for experimentally induced blood stage malaria infection (IBSM) with Plasmodium falciparum by direct intravenous inoculation of infected erythrocytes was developed at the Queensland Institute of Medical Research (QIMR) more than 15 years ago. Since that time, this system has been used in several studies to investigate the protective effect of vaccines, the clearance kinetics of parasites following drug treatment, and to improve understanding of the early events in blood stage infection. In this article, we will review the development of IBSM and the applications for which it is being employed. We will discuss the advantages and disadvantages of IBSM, and finish by describing some exciting new areas of research that have been made possible by this system. © 2012.


Bettington M.,University of Queensland | Bettington M.,The Queensland Institute of Medical Research | Walker N.,University of Queensland | Clouston A.,University of Queensland | And 5 more authors.
Histopathology | Year: 2013

Approximately 30% of colorectal carcinomas develop via a serrated neoplasia pathway, named for the pattern of crypts in the precursor polyps. Molecular abnormalities consistently involve methylation of CpG islands [CpG island methylator phenotype (CIMP)] of low degree (CIMP-L) or high degree (CIMP-H), and activating mutations of the mitogen-activated protein kinase pathway components BRAF or KRAS. Microsatellite instability (MSI) of a high level (MSI-H) is often present, allowing for a molecular classification of serrated pathway carcinoma as: (i) BRAF mutant/CIMP-H with either a) MSI-H or b) microsatellite stable (MSS); and (ii) KRAS mutant/CIMP-L/MSS. Precursor polyps include sessile serrated adenoma (SSA), characterized by proximal location, crypt architectural disturbance, and BRAF mutation. Microvesicular hyperplasic polyp (MVHP) probably precedes the development of SSA, and borderline lesions between MVHP and SSA occur. Cytological dysplasia in SSA portends advanced genetic abnormality and a high risk of progression to carcinoma. The traditional serrated adenoma has a predilection for the left colon, tubulovillous architecture, eosinophilic cytoplasm, and frequent KRAS mutation. Serrated morphology carcinoma is a new World Health Organization subtype with well-differentiated, mucinous or trabecular patterns. It has frequent KRAS or BRAF mutations and a poor prognosis. This review provides an insight into the histology and molecular mechanisms driving these serrated pathway lesions. © 2012 Blackwell Publishing Ltd.


Good M.F.,The Queensland Institute of Medical Research | Good M.F.,Griffith University | Doolan D.L.,The Queensland Institute of Medical Research
Immunity | Year: 2010

The concept of a malaria vaccine has sparked great interest for decades; however, the challenge is proving to be a difficult one. Immune dysregulation by Plasmodium and the ability of the parasite to mutate critical epitopes in surface antigens have proved to be strong defense weapons. This has led to reconsideration of polyvalent and whole parasite strategies and ways to enhance cellular immunity to malaria that may be more likely to target conserved antigens and an expanded repertoire of antigens. These and other concepts will be discussed in this review. © 2010 Elsevier Inc.


Wykes M.N.,The Queensland Institute of Medical Research | Horne-Debets J.,The Queensland Institute of Medical Research
International Journal for Parasitology | Year: 2012

Malaria, caused by . Plasmodium spp., is responsible for over 200. million infections worldwide and 650,000 deaths annually. Until recently, it was thought that blood-stage parasites survived and replicated in hepatocytes and red blood cells exclusively. We recently showed that blood-stage parasites could infect, survive and replicate within plasmacytoid dendritic cells of the spleen and that these cells could release infective parasites. Here we discuss the implications of this novel niche in the spleen. © 2012 .


Koyama M.,The Queensland Institute of Medical Research
Blood | Year: 2013

Donor T cells play pivotal roles in graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effects following bone marrow transplantation (BMT). DNAX accessory molecule 1 (DNAM-1) is a costimulatory and adhesion molecule, expressed mainly by natural killer cells and CD8(+) T cells at steady state to promote adhesion to ligand-expressing targets and enhance cytolysis. We have analyzed the role of this pathway in GVHD and GVL. The absence of DNAM-1 on the donor graft attenuated GVHD in major histocompatibility complex (MHC)-mismatched and MHC-matched BMT following conditioning with lethal and sublethal irradiation. In contrast, DNAM-1 was not critical for GVL effects against ligand (CD155) expressing and nonexpressing leukemia. The effects on GVHD following myeloablative conditioning were independent of CD8(+) T cells and dependent on CD4(+) T cells, and specifically donor FoxP3(+) regulatory T cells (Treg). The absence of DNAM-1 promoted the expansion and suppressive function of Treg after BMT. These findings provide support for therapeutic DNAM-1 inhibition to promote tolerance in relevant inflammatory-based diseases characterized by T-cell activation.


Wykes M.N.,The Queensland Institute of Medical Research
Trends in Parasitology | Year: 2012

Dendritic cells (DCs), the sentinels of immunity, reside in almost every organ of the body. These cells are responsible for initiating immune responses against infectious agents. DCs are divided into different subsets based on their biological functions, with plasmacytoid DCs (pDCs) and conventional DCs (cDCs) being two major populations. The ability of DCs to protect against malaria infection was recently questioned when pDCs were reported to be a reservoir for rodent . Plasmodium spp. in the spleen. This opinion article explores how the occupation of pDCs by the parasite may corrupt immunity against malaria. © 2012 Elsevier Ltd.


Rishi G.,The Queensland Institute of Medical Research | Rishi G.,University of Queensland | Crampton E.M.,The Queensland Institute of Medical Research | Wallace D.F.,The Queensland Institute of Medical Research | And 2 more authors.
PLoS ONE | Year: 2013

The hemochromatosis associated proteins HFE and Transferrin Receptor 2 (TFR2) have been shown to be important for the proper regulation of hepcidin. A number of in vitro studies using transient overexpression systems have suggested that an interaction between HFE and TFR2 is required for the regulation of hepcidin. This model of iron sensing which centers upon the requirement for an interaction between HFE and TFR2 has recently been questioned with in vivo studies in mice from our laboratory and others which suggest that Hfe and Tfr2 can regulate hepcidin independently of each other. To re-examine the postulated interaction between Hfe and Tfr2 we developed a novel expression system in which both proteins are stably co-expressed and used the proximity ligation assay to examine the interactions between Hfe, Tfr1 and Tfr2 at a cellular level. We were able to detect the previously described interaction between Hfe and Tfr1, and heterodimers between Tfr1 and Tfr2; however no interaction between Hfe and Tfr2 was observed in our system. The results from this study indicate that Hfe and Tfr2 do not interact with each other when they are stably expressed at similar levels. Furthermore, these results support in vivo studies which suggest that Hfe and Tfr2 can independently regulate hepcidin. © 2013 Rishi et al.

Loading The Queensland Institute of Medical Research collaborators
Loading The Queensland Institute of Medical Research collaborators