Bone Marrow–Allograft Rejection by T Lymphocytes Recognizing a Single Amino Acid Difference in HLA-B44

1990 ◽  
Vol 323 (26) ◽  
pp. 1818-1822 ◽  
Author(s):  
Katharina Fleischhauer ◽  
Nancy A. Kernan ◽  
Richard J. O'Reilly ◽  
Bo Dupont ◽  
Soo Young Yang
Keyword(s):  
Bone Marrow ◽  
Amino Acid ◽  
T Lymphocytes ◽  
Allograft Rejection ◽  
Single Amino Acid ◽  
Amino Acid Difference

scholarly journals Monoclonal Antibodies Detect a Single Amino Acid Difference Between the Coat Proteins of Soilborne Wheat Mosaic Virus Isolates: Implications for Virus Structure

1997 ◽  
Vol 87 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Jianping Chen ◽  
Lesley Torrance ◽  
Graham H. Cowan ◽  
Stuart A. MacFarlane ◽  
Gerald Stubbs ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Mosaic Virus ◽  
Single Amino Acid ◽  
Computer Assisted ◽  
Amino Acid Difference ◽  
Coat Proteins ◽  
C Terminus ◽  
Readthrough Protein

Four monoclonal antibodies (MAbs) were prepared against an isolate of soilborne wheat mosaic furovirus from Oklahoma (SBWMV Okl-7). Three MAbs had different reactivities in tests on SBWMV isolates from Nebraska (Lab1), France, and Japan. One MAb (SCR 133) also reacted with oat golden stripe furovirus. None of the MAbs cross-reacted with other rod-shaped viruses including beet necrotic yellow vein furovirus, potato mop-top furovirus, and tobacco rattle tobravirus. Sequence analysis of nucleotides between 334 and 1,000 of RNA 2, the region that encodes the coat protein (CP) and the first 44 amino acids of a readthrough protein, of the four SBWMV isolates revealed up to 27 base changes from the published sequence of a Nebraska field isolate of SBWMV. Most changes were translationally silent, but some caused differences of one to three amino acids in residues located near either the N- or C-terminus of the CPs of the different isolates. Two further single amino acid changes were found at the beginning of the readthrough domain of the CP-readthrough protein. Some of these amino acid changes could be discriminated by MAbs SCR 132, SCR 133, and SCR 134. Peptide scanning (Pepscan) analysis indicated that the epitope recognized by SCR 134 is located near the N-terminus of the CP. SCR 132 was deduced to react with a discontinuous CP epitope near the C-terminus, and SCR 133 reacted with a surface-located continuous epitope also near the C-terminus. Predictions of CP structure from computer-assisted three-dimensional model building, by comparison with the X-ray fiber diffraction structure of tobacco mosaic virus, suggested that the three CP amino acids found to differ between isolates of SBWMV were located near the viral surface and were in regions predicted to be antigenic.

Direct Alloreactivity by Human Cytotoxic T Lymphocytes Can Be Inhibited by Altered Peptide Ligand Antagonism

Blood ◽  
1999 ◽  
Vol 93 (3) ◽  
pp. 1020-1024 ◽  
Author(s):  
Scott R. Burrows ◽  
Rajiv Khanna ◽  
Denis J. Moss
Keyword(s):  
Cytochrome P450 ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Allograft Rejection ◽  
Single Amino Acid ◽  
Peptide Ligand ◽  
Target Cells ◽  
Altered Peptide Ligand ◽  
Altered Peptide Ligands ◽  
Mhc Molecules

Abstract Alloreactive T lymphocytes that respond directly to foreign major histocompatibility complex (MHC) molecules and bound peptide are known to be central mediators of graft-versus-host disease (GVHD) and allograft rejection. We have recently identified a peptide from the human protein, cytochrome P450 (isotypes IIC9, 10, or 18), that is recognized in association with human leukocyte antigen (HLA) B*3501 by alloreactive cytotoxic T lymphocytes (CTLs). These CTLs with this specificity were isolated from several unrelated individuals and were found to express a common T-cell receptor (TCR). Synthetic analogs of the cytochrome P450 peptide were generated by introducing single amino acid substitutions at putative TCR contact positions. Four altered peptide ligands were powerful competitive antagonists of these CTL clones, reducing lysis levels of target cells expressing the alloantigen HLA B*3501 by over 80%. This first demonstration that it is possible to suppress CTL alloreactivity with structural variants of allodeterminants raises the prospect that such TCR antagonists could be exploited within the clinical arena to specifically modulate GVHD and allograft rejection.

Recapitulation of the Fetal Pattern of Expression of the Iγ and Vγ-Globin Genes in Cultured Baboon CD34+ Bone Marrow Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1590-1590
Author(s):  
Donald Lavelle ◽  
Kestis Vaitkus ◽  
Mahipal Singh ◽  
Maria Hankewych ◽  
Joseph DeSimone
Keyword(s):  
Bone Marrow ◽  
Amino Acid ◽  
Bone Marrow Cells ◽  
Globin Gene ◽  
Single Amino Acid ◽  
Globin Genes ◽  
Globin Chain ◽  
Hemoglobin Switching ◽  
Globin Chains

Abstract The human Gγ-globin and Aγ-globin genes differ by the presence of a single amino acid, either glycine or alanine, at position 136. The ratio of Gγ/Aγ-globin expression is approximately 7/3 at birth and changes to 2/3 in the adult. The mechanism responsible for this developmental switch is unknown. In the baboon, the duplicated γ-globin genes differ by the presence of a single amino acid at position 75. The Iγ-globin gene contains isoleucine at position 75, while the Vγ-globin gene contains valine at this position. The ratio of expression of the Iγ and Vγ-globin chains also differs in the fetal and adult stages. The Iγ/Vγ ratio is 3/2 in the fetus and 2/3 in the adult. Thus the pattern of expression of the baboon Iγ-globin gene is analogous to the human Gγ-globin gene, and that of the Vγ-globin gene is analogous to the human Aγ-globin gene. During stress erythropoiesis, moderately increased HbF levels are observed (5–10% HbF) and the Iγ/Vγ-globin chains are expressed in the characteristic adult ratio. Decitabine treatment reactivates HbF expression to high levels (50–70% HbF) and Iγ/Vγ ratios of approximately 1:1 have been observed following decitabine treatment. Thus decitabine treatment alters the Iγ/Vγ ratio but does not cause a complete reversion to the fetal pattern of expression. HbF is also reactivated to high levels in cultured baboon BFUe. In this investigation the pattern of expression of the Iγ- and Vγ-globin genes in cultured baboon CD34+ bone marrow (BM) cells was analyzed to determine whether reactivation of HbF in culture was associated with a change in the pattern of expression of the Iγ-and Vγ-globin genes. CD34+ cells were enriched from baboon BM using the 12.8 monoclonal antibody in combination with immunomagnetic microbead columns (Miltenyi) and cultured in Iscove’s media supplemented with 30% fetal bovine serum, stem cell factor (SCF; 200ng/ml), erythropoietin (EPO; 2U/ml), and dexamethasone (Dex; 1μM). The pattern of globin chain expression in d12 cultures, cord blood (CB) of a 58d fetus, and peripheral blood (PB) of adult baboons following phlebotomy and decitabine treatment was compared by HPLC analysis of hemolysates. The baboon 58d CB contained >90% HbF and the ratio of Iγ/Vγ was 1.85. In the adult (phlebotomized) PB the level of HbF was 8.1% and the Iγ/Vγ ratio was 0.75 thus confirming that the ratio of the baboon Iγ and Vγ-globin chains differs in the fetal and adult stages of development in a manner similar to that of the human Gγ and Aγ-globin chains. Following decitabine treatment (PA 7002) an HbF level of 55% was attained with an Iγ/Vγ ratio of 1.1. Hemolysates prepared from d12 cultures of CD34+ baboon (PA 7002) BM cells grown in the presence of SCF, EPO, and Dex contained 57.6% HbF, nearly the same level observed following decitabine treatment in vivo. The Iγ/Vγ ratio was 1.94, markedly different from that observed in this same baboon following decitabine in vivo and, moreover, nearly identical to the fetal ratio. Thus HbF reactivation in cultured adult baboon CD34+ BM cells was associated with a change in the ratio of expression of the two baboon γ-globin genes to that characteristic of the fetal stage. Recapitulation of the fetal pattern of γ-globin chain expression in cultured baboon CD34+ progenitors demonstrates yet another advantage of the baboon model for investigations of hemoglobin switching.

scholarly journals A Single Amino Acid Difference Distinguishes Resistant and Susceptible Alleles of the Rice Blast Resistance Gene Pi-ta

2000 ◽  
Vol 12 (11) ◽  
pp. 2033-2045 ◽  
Author(s):  
Gregory T. Bryan ◽  
Kun-Sheng Wu ◽  
Leonard Farrall ◽  
Yulin Jia ◽  
Howard P. Hershey ◽  
...  
Keyword(s):  
Amino Acid ◽  
Resistance Gene ◽  
Rice Blast ◽  
Blast Resistance ◽  
Single Amino Acid ◽  
Amino Acid Difference ◽  
Rice Blast Resistance ◽  
Blast Resistance Gene

scholarly journals Antagonism of BST-2/Tetherin Is a Conserved Function of the Env Glycoprotein of Primary HIV-2 Isolates

2016 ◽  
Vol 90 (24) ◽  
pp. 11062-11074 ◽  
Author(s):  
Chia-Yen Chen ◽  
Masashi Shingai ◽  
Sarah Welbourn ◽  
Malcolm A. Martin ◽  
Pedro Borrego ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Change ◽  
Mixed Population ◽  
Single Amino Acid ◽  
Amino Acid Difference ◽  
Virus Release ◽  
Host Restriction ◽  
Single Amino Acid Change ◽  
Hiv 1 ◽  
Env Glycoprotein

ABSTRACTAlthough HIV-2 does not encode avpugene, the ability to antagonize bone marrow stromal antigen 2 (BST-2) is conserved in some HIV-2 isolates, where it is controlled by the Env glycoprotein. We previously reported that a single-amino-acid difference between the laboratory-adapted ROD10 and ROD14 Envs controlled the enhancement of virus release (referred to here as Vpu-like) activity. Here, we investigated how conserved the Vpu-like activity is in primary HIV-2 isolates. We found that half of the 34 tested primary HIV-2 Env isolates obtained from 7 different patients enhanced virus release. Interestingly, most HIV-2 patients harbored a mixed population of viruses containing or lacking Vpu-like activity. Vpu-like activity and Envelope functionality varied significantly among Env isolates; however, there was no direct correlation between these two functions, suggesting they evolved independently. In comparing the Env sequences from one HIV-2 patient, we found that similar to the ROD10/ROD14 Envs, a single-amino-acid change (T568I) in the ectodomain of the TM subunit was sufficient to confer Vpu-like activity to an inactive Env variant. Surprisingly, however, absence of Vpu-like activity was not correlated with absence of BST-2 interaction. Taken together, our data suggest that maintaining the ability to antagonize BST-2 is of functional relevance not only to HIV-1 but also to HIV-2 as well. Our data show that as with Vpu, binding of HIV-2 Env to BST-2 is important but not sufficient for antagonism. Finally, as observed previously, the Vpu-like activity in HIV-2 Env can be controlled by single-residue changes in the TM subunit.IMPORTANCELentiviruses such as HIV-1 and HIV-2 encode accessory proteins whose function is to overcome host restriction mechanisms. Vpu is a well-studied HIV-1 accessory protein that enhances virus release by antagonizing the host restriction factor BST-2. HIV-2 does not encode avpugene. Instead, the HIV-2 Env glycoprotein was found to antagonize BST-2 in some isolates. Here, we cloned multiple Env sequences from 7 HIV-2-infected patients and found that about half were able to antagonize BST-2. Importantly, most HIV-2 patients harbored a mixed population of viruses containing or lacking the ability to antagonize BST-2. In fact, in comparing Env sequences from one patient combined with site-directed mutagenesis, we were able to restore BST-2 antagonism to an inactive Env protein by a single-amino-acid change. Our data suggest that targeting BST-2 by HIV-2 Env is a dynamic process that can be regulated by simple changes in the Env sequence.

Pre-Donor Evaluation of an HLA Matched Sibling Identifies a Novel Inherited RUNX1 Mutation Encoding a Missense Mutation Found Outside of the RUNT Domain in Familial Platelet Disorder

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2709-2709 ◽  
Author(s):  
Jacqueline S Garcia ◽  
Jozef Madzo ◽  
Devin Cooper ◽  
Sarah A Jackson ◽  
Kenan Onel ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Amino Acid ◽  
Dna Binding ◽  
Amino Acid Change ◽  
Single Amino Acid ◽  
Wild Type ◽  
Single Amino Acid Change ◽  
Platelet Disorder ◽  
Familial Platelet Disorder ◽  
Runx1 Mutation

Abstract Abstract 2709 Introduction: RUNX1 is a critical transcription factor in the regulation of normal hematopoiesis. Inherited RUNX1 mutations have been identified as the culprit genetic lesion in Familial Platelet Disorder (FPD; OMIM 601399), a rare autosomal dominant condition with a propensity to myeloid malignancy. The spectrum of RUNX1 mutations causing the FPD/acute myeloid leukemia (AML) syndrome includes frameshift and termination mutations detected throughout the gene, and missense mutations clustered within the highly conserved RUNT homology domain (RHD), which is responsible for both DNA binding and heterodimerization with CBFβ/PEBP2β, the non-DNA binding regulatory subunit. We present a new FPD/AML pedigree with a novel missense mutation leading to a single amino acid change, L56S. This L56S mutation is the first reported point mutation in this syndrome to be found outside of the RHD. Patients and Methods: Our new pedigree involves a 41-year-old man (proband) diagnosed with myelodysplastic syndrome (MDS, specifically refractory anemia with excess blasts type-2) with a normal karyotype. He was initiated on azacitidine, which was administered on a seven-day treatment schedule every four weeks. Bone marrow biopsy analysis after six monthly cycles of azacitidine showed persistent MDS, with similar findings after a total of ten monthly cycles. Given his lack of a clinical response, his young age and good performance status, he was referred to The University of Chicago for allogeneic hematopoietic stem cell transplantation (HCT). Routine pre-transplant evaluation revealed mild thrombocytopenia (platelets = 123,000 K/μl) in his HLA-matched brother. In addition, his father was reported to have thrombocytopenia. Clinical concern for an inherited condition initiated the investigation for a RUNX1 mutation in the family. Results: We sequenced full-length cDNA synthesized from leukocyte-derived RNA collected from the proband's sibling with thrombocytopenia, and detected a novel missense germline mutation in exon 4 at nucleotide position 371, causing a T to C mutation leading to a single amino acid change in the RUNX1 protein, L56S. This amino acid substitution is located N-terminal to the RHD (aa 76–209). RUNX1 sequencing of the proband with MDS demonstrated the same mutation. The RUNX1 RHD and the transactivation domain remain intact in this mutant. Initial transactivation assays using a luciferase reporter assay performed in triplicate demonstrated similar levels of activation as wild-type RUNX1. Corresponding Western blot analysis showed similar levels of protein expression of both wild-type RUNX1 and mutant RUNX1 transfected cell lines using an anti-RUNX1-antibody. Current studies include determination of the transactivation ability of mutant RUNX1 with its heterodimerization partner, CBFβ/PEBP2β, testing the DNA binding ability of this RUNX1 mutant by electrophoretic mobility shift assay, and analysis of the RUNX1 cDNA for an acquired biallelic mutation in leukocytes collected from the proband's bone marrow aspirate at the time of diagnosis of bone marrow malignancy. Conclusions: FPD/AML is likely an underreported condition. Clinical suspicion for this inherited syndrome may be raised by the presence of mild to moderate thrombocytopenia in healthy siblings, and should lead to prompt screening for germline RUNX1 mutations to confirm an inherited predisposition and to prevent siblings carrying RUNX1 mutations from being selected as HCT donors. In vitro studies of identified RUNX1 mutations may elucidate potential mechanisms involved in the pathogenesis of the FPD/AML syndrome. Disclosures: No relevant conflicts of interest to declare.

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