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Opsonization-Enhanced Antigen Presentation by MR1 Activates Rapid Polyfunctional MAIT Cell Responses Acting as an Effector Arm of Humoral Antibacterial Immunity.
Boulouis, C, Gorin, JB, Dias, J, Bergman, P, Leeansyah, E, Sandberg, JK
Journal of immunology (Baltimore, Md. : 1950). 2020;(1):67-77
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Abstract
Mucosa-associated invariant T (MAIT) cells are innate-like antimicrobial T cells recognizing a breadth of important pathogens via presentation of microbial riboflavin metabolite Ags by MHC class Ib-related (MR1) molecules. However, the interaction of human MAIT cells with adaptive immune responses and the role they may play in settings of vaccinology remain relatively little explored. In this study we investigated the interplay between MAIT cell-mediated antibacterial effector functions and the humoral immune response. IgG opsonization of the model microbe Escherichia coli with pooled human sera markedly enhanced the capacity of monocytic APC to stimulate MAIT cells. This effect included greater sensitivity of recognition and faster response kinetics, as well as a markedly higher polyfunctionality and magnitude of MAIT cell responses involving a range of effector functions. The boost of MAIT cell responses was dependent on strongly enhanced MR1-mediated Ag presentation via increased FcγR-mediated uptake and signaling primarily mediated by FcγRI. To investigate possible translation of this effect to a vaccine setting, sera from human subjects before and after vaccination with the 13-valent-conjugated Streptococcus pneumoniae vaccine were assessed in a MAIT cell activation assay. Interestingly, vaccine-induced Abs enhanced Ag presentation to MAIT cells, resulting in more potent effector responses. These findings indicate that enhancement of Ag presentation by IgG opsonization allows innate-like MAIT cells to mount a faster, stronger, and qualitatively more complex response and to function as an effector arm of vaccine-induced humoral adaptive antibacterial immunity.
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Translating in vitro prediction of cytotoxic T cell alloreactivity to hematopoietic stem cell transplantation outcome.
Jöris, MM, Lankester, AC, von dem Borne, PA, Kuball, J, Bierings, M, Cornelissen, JJ, Sijnke, ME, van der Holt, B, van Rood, JJ, Oudshoorn, M, et al
Transplant immunology. 2014;(2-3):59-64
Abstract
INTRODUCTION Previously we developed a weighted amino acid (AA) mismatch score predictive for cytotoxic T cell (CTL) alloreactivity (in vitro CTLp assay) based on the structure of the HLA class I molecule. The aim of this study is to confirm the clinical relevance of the CTLp assay and to validate the AA mismatch score as an alternative and easy to use tool to predict permissible mismatches in hematopoietic stem cell transplantation (HSCT). METHODS We selected patients transplanted with a 9/10 single HLA class I mismatched graft (n=171) at three Dutch HSCT centers. A CTLp assay was performed in 73 donor-recipient pairs. As a control we selected 168 10/10 HLA matched pairs that were matched to the 9/10 single HLA class I mismatched pairs for HSCT year, donor type, patient age and diagnosis. RESULTS We observed that pairs with negative a CTLp assay had statistically significant decreased incidence of mortality after HSCT comparable to that of 10/10 HLA matched pairs. However, the weighted AA mismatch score did not significantly predict any HSCT end point of interest. CONCLUSION Further investigation is needed to unravel the mechanisms involved in causing the beneficial effect of a negative CTLp assay, before other alternative tools to predict HSCT outcome may be developed.
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The role of iron overload and HFE gene mutations in the era of pegylated interferon and ribavirin treatment of chronic hepatitis C.
Sikorska, K, Stalke, P, Izycka-Swieszewska, E, Romanowski, T, Bielawski, KP
Medical science monitor : international medical journal of experimental and clinical research. 2010;(3):CR137-143
Abstract
BACKGROUND Iron overload observed in chronic hepatitis C (CHC) has been suggested to be one of the negative prognostic factors influencing liver disease progression and failure of treatment with recombinant interferon in monotherapy or in combination with ribavirin. The aim of this study was to assess occurrence of iron overload in relation to polymorphism of the HFE and the influence of both these factors on efficacy of antiviral treatment with pegylated interferon and ribavirin in patients with CHC. MATERIAL/METHODS Liver function tests, serum indices of iron metabolism, and HFE mutations were assayed in 152 patients with CHC from Poland. Histopathological examination of the liver biopsy specimen was performed in 138 patients. Sixty-one patients were treated with pegylated interferon alfa-2 and ribavirin. The comparative analysis was performed in 2 groups of patients: those with and those without elevated serum indices of iron metabolism. RESULTS Increased biochemical iron metabolism parameters correlated with older age, higher ALT activity, more advanced liver fibrosis and treatment failure. Iron deposits in liver specimens were not accompanied by exacerbation of necro-inflammatory activity and advanced fibrosis. Elevated biochemical values of iron metabolism parameters and presence of hepatic iron deposits correlated positively with C282Y mutations. The lack of sustained viral response after treatment with pegylated interferon and ribavirin was observed more frequently in carriers of HFE mutations. CONCLUSIONS Iron overload was frequently detected in patients with CHC, and was associated only with C282Y alleles. Biochemical markers of iron overload and HFE gene mutations were negative prognostic factors of antiviral treatment.
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HFE genotypes in patients with chronic pancreatitis and pancreatic adenocarcinoma.
Hucl, T, Kylanpää-Bäck, ML, Witt, H, Künzli, B, Lempinen, M, Schneider, A, Kemppainen, E, Löhr, M, Friess, H, Ockenga, J, et al
Genetics in medicine : official journal of the American College of Medical Genetics. 2007;(7):479-83
Abstract
PURPOSE The homozygous p.C282Y variant of the HFE gene is a major risk factor for hereditary hemochromatosis, a disorder of iron metabolism resulting in progressive iron accumulation in a variety of organs including the pancreas. Heterozygosity of p.C282Y and p.H63D may increase susceptibility to chronic liver and pancreatic disease. This study determines the frequencies of p.C282Y and p.H63D alterations in patients with chronic pancreatitis and pancreatic adenocarcinoma. METHODS In total, 958 patients (349 with alcoholic pancreatitis, 343 with idiopathic pancreatitis, 64 with familial chronic pancreatitis, 34 with acute pancreatitis, and 168 with pancreatic adenocarcinoma) were enrolled and compared with 681 healthy and 100 alcoholic controls. Furthermore, 45 parent-offspring trios were included for segregation analysis. Genotyping of p.C282Y and p.H63D was performed by restriction fragment length polymorphism or melting curve analyses. RESULTS No significant differences were found in heterozygosity for p.C282Y and p.H63D when patients with alcoholic (8.0/21.5%), idiopathic (7.3/24.5%), or familial (9.8/23.0%) pancreatitis, or pancreatic adenocarcinoma (5.4/28.6%) were compared with healthy (6.2/24.8%) and alcoholic (7.0/25.0%) controls. Neither genotype was associated with the presence of secondary diabetes mellitus in patients with chronic pancreatitis. CONCLUSION Although hemochromatosis is associated with pancreatic pathology, the p.C282Y and p.H63D variants do not play a significant role in the pathogenesis of chronic pancreatitis or pancreatic adenocarcinoma.
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Roles of iron and HFE mutations on severity and response to therapy during retreatment of advanced chronic hepatitis C.
Bonkovsky, HL, Naishadham, D, Lambrecht, RW, Chung, RT, Hoefs, JC, Nash, SR, Rogers, TE, Banner, BF, Sterling, RK, Donovan, JA, et al
Gastroenterology. 2006;(5):1440-51
Abstract
BACKGROUND & AIMS Iron overload may cause or contribute to hepatic injury and fibrosis. Mutations in the HFE gene may influence development or progression of chronic liver disease by increasing iron stores or modulating immune responses. The aim of this work was to assess the influence of HFE mutations and serum and hepatic measures of iron status on baseline features and response to lead-in therapy in subjects with advanced chronic hepatitis C enrolled in the Hepatitis C Anti-viral Long-term Treatment to prevent Cirrhosis (HALT-C) Trial. METHODS Entry criteria included an Ishak fibrosis score >2 and lack of iron overload (Scheuer iron grade <3+) according to local study pathologists. All baseline biopsy specimens were rescored by consensus of study pathologists, and detailed assessment of stainable iron was performed. Hepatic iron concentrations were measured on portions of 144 liver biopsy specimens. A total of 1051 out of 1145 subjects agreed to HFE mutational testing (C282Y, H63D, S65C). RESULTS Thirty-five percent carried at least one HFE gene mutation. There were no significant differences in the prevalence of HFE gene mutations among subjects with fibrosis (35.5%) versus cirrhosis (32.9%). Thirty-three percent of subjects had end-of-treatment and 16% sustained virologic responses. Presence of HFE mutations, in particular the H63D variation, was associated with increased end-of-treatment (40% vs 29%, P = .0078) and sustained virologic responses (20% with HFE mutation vs 14% sustained virologic response without HFE mutation; P = .009). CONCLUSIONS Although HFE mutations (especially the most frequent H63D mutation) are associated with increased iron loading, they are also associated with increased sustained virologic responses in US patients with advanced chronic hepatitis C.
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Comparison of the unsaturated iron-binding capacity with transferrin saturation as a screening test to detect C282Y homozygotes for hemochromatosis in 101,168 participants in the hemochromatosis and iron overload screening (HEIRS) study.
Adams, PC, Reboussin, DM, Leiendecker-Foster, C, Moses, GC, McLaren, GD, McLaren, CE, Dawkins, FW, Kasvosve, I, Acton, RT, Barton, JC, et al
Clinical chemistry. 2005;(6):1048-52
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T cell responses in HIV type 1-infected adolescent minorities share similar epitope specificities with whites despite significant differences in HLA class I alleles.
Bansal, A, Sabbaj, S, Edwards, BH, Ritter, D, Perkins, C, Tang, J, Szinger, JJ, Weiss, H, Goepfert, PA, Korber, B, et al
AIDS research and human retroviruses. 2003;(11):1017-26
Abstract
African-Americans (AFAM) and Hispanics (HIS) represent only 13% and 12% of the U.S. population but 54% and 19%, respectively, of annually incident HIV-1 infections in the United States. The 88 patients in the current study were from U.S. racial or ethnic minority groups (72% African-American, 17% Hispanic), female (85%), and adolescent (mean age 20 years). Their HLA allele distributions were distinct from patterns in U.S. whites. Overall, HIV-1-specific T cell responses were observed in 91% of participants: 75% recognized peptides in Gag, 67% Pol, 57% Nef, and 41% Env. The patients recognized 87 (36%) of 244 Gag, Pol, Env, or Nef peptides tested. Similar to what has been seen in white cohorts, epitope-rich peptide clusters were identified within conserved functional domains in Gag matrix, Gag capsid, Pol reverse transcriptase, and Nef. Peptides representing variable regions from within the B subtype or with more changes from the B subtype consensus sequence were less likely to stimulate a positive T cell response. A small percentage (17%) of unique T cell responses was found in this cohort that displayed no previously known T cell epitopes. Dominant responses generally overlapped with epitope-rich regions in HIV-1 described previously for whites, although many of these peptides were likely restricted by HLA class I alleles not previously associated with these epitopes. Hence host genetic variation among different racial groups may have less impact on the utility of candidate HIV-1 vaccines than previously suspected.