B. Gewurz - Academia.edu (original) (raw)

Papers by B. Gewurz

Digestive Diseases and Sciences

A 24-year-old man with stricturing, ileocolonic Crohn’s disease with recent partial small bowel o... more A 24-year-old man with stricturing, ileocolonic Crohn’s disease with recent partial small bowel obstruction (SBO) due to terminal ileal stenosis, was evaluated 1 day prior to previously scheduled elective ileocecal resection with complaints of fevers, myalgias, and fatigue. His Crohn’s diagnosis occurred at age 13 (2006) when he was first evaluated with complaints of diarrhea and weight loss for the prior month. The initial diagnostic colonoscopy demonstrated inflammatory changes characterized by superficial and deep ulcerations with luminal narrowing in the terminal ileum and ascending colon. Initiation of infliximab in 2007 led to clinical remission until 2011 when response to the treatments waned. A switch to certolizumab in 2011 recaptured clinical remission until 2017 when he began to experience breakthrough symptoms. He was ultimately switched to adalimumab in 2017, which required titration from every other week to every 10-day dosing in order to achieve clinical response.

Oncogene, Jan 2, 2015

The REL gene, encoding the NF-κB subunit c-Rel, is frequently amplified in B-cell lymphoma and fu... more The REL gene, encoding the NF-κB subunit c-Rel, is frequently amplified in B-cell lymphoma and functions as a tumour-promoting transcription factor. Here we report the surprising result that c-rel-/- mice display significantly earlier lymphomagenesis in the c-Myc driven, Eμ-Myc model of B-cell lymphoma. c-Rel loss also led to earlier onset of disease in a separate TCL1-Tg-driven lymphoma model. Tumour reimplantation experiments indicated that this is an effect intrinsic to the Eμ-Myc lymphoma cells but, counterintuitively, c-rel-/- Eμ-Myc lymphoma cells were more sensitive to apoptotic stimuli. To learn more about why loss of c-Rel led to earlier onset of disease, microarray gene expression analysis was performed on B cells from 4-week-old, wild-type and c-rel-/- Eμ-Myc mice. Extensive changes in gene expression were not seen at this age, but among those transcripts significantly downregulated by the loss of c-Rel was the B-cell tumour suppressor BTB and CNC homology 2 (Bach2). Quan...

Immunology, 1992

Limulus polyphemus C-reactive protein (CRP) (limulin) has approximately 30% amino acid sequence h... more Limulus polyphemus C-reactive protein (CRP) (limulin) has approximately 30% amino acid sequence homology and shares at least one idiotypic determinant associated with ligand-binding activity with human CRP (hCRP); limulin also shares amino acid sequence homology and lectin activity with human serum amyloid P component (hSAP). In the present study panels of 14 anti-hCRP monoclonal antibodies (mAb) directed to distinct hCRP epitopes and 11 anti-hSAP mAb directed to distinct epitopes of hSAP were tested for reactivity with limulin and pentraxins of other species including rabbit CRP (raCRP), rat CRP and hamster female protein (FP) by ELISA and Western blot analyses. None of the anti-human pentraxin mAb showed strong cross-reactivity with limulin; only five mAb reacted with limulin at all, and cross-reactivities of these mAb with the other pentraxins, when present, also were weak. Cross-reactivity of limulin with hCRP and hSAP was similar, and in light of comparable amino acid sequence ...

Molecular Microbiology, 1996

ABSTRACT

Journal of Virology, 2000

Antibody and cytotoxic T-lymphocyte (CTL) responses have critical roles in eliminating many viral... more Antibody and cytotoxic T-lymphocyte (CTL) responses have critical roles in eliminating many viral infections. In addition to stimulation of the T-cell receptor, T cells require costimulatory signals to respond optimally. We evaluated the role of B7 costimulatory molecules (B7-1 and B7-2) in the immune response to viral infection using vesicular stomatitis virus (VSV) and mice lacking either B7-1 or B7-2 or both molecules. Mice lacking both B7-1 and B7-2 had essentially no anti-VSV immunoglobulin G1 (IgG1) response, decreased IgG2a responses, and normal IgM responses, while mice lacking either B7-1 or B7-2 had unaltered anti-VSV antibody responses compared to wild-type mice. Depletion of CD4+ cells further reduced the IgG2a response in mice lacking both B7 molecules, suggesting that CD4−cells may supply help for IgG2a in the absence of B7 costimulation. The absence of both B7 molecules profoundly reduced generation of both primary and secondary VSV-specific class I major histocompati...

Proceedings of The National Academy of Sciences, 2008

Proceedings of The National Academy of Sciences - PNAS, 2010

Epstein Barr virus latent membrane protein 1 (LMP1) induces NF-κB activation through transformati... more Epstein Barr virus latent membrane protein 1 (LMP1) induces NF-κB activation through transformation effector sites (TES) 1 and 2, both of which are critical for B-lymphocyte transformation. TES2 principally activates canonical NF-κB, which we confirm is NF-κB essential modifier (NEMO)-dependent and requires an intact ubiquitin binding in A20 binding inhibitor of NF-κB and NEMO (UBAN) domain. LMP1 TES2 activated NF-κB in Jurkat cell lines harboring NEMO truncated at 372 (A45) or NEMO with an in-frame deletion of 133-224 (2C), whereas TNFα, 12-O-Tetradecanoylphorbol-13-acetate, human T-cell leukemia virus 1 Tax, and CD40 did not. In both A45 and 2C Jurkat cell lines, LMP1 TES2-mediated NF-κB activation was blocked by siRNAs to TNFα receptor-associated factor 6 and NEMO, by IκB kinase inhibitors, and by the IκBα superrepressor, indicating that the NEMO mutants function to support canonical NF-κB activation. Expression of A45 or 2C mutants in NEMO-deficient murine embryonic fibroblasts reproduced the Jurkat phenotypes: LMP1 TES2 activated NF-κB in fibroblasts lacking NEMO amino acids 133-224 or 373-419, but TNFα and Tax did not. Further analysis indicated that TES2 did not activate NF-κB in cells expressing the double deletion mutant Δ133-224/Δ372-419. These data provide further evidence of the essential role for NEMO in LMP1 TES2 NF-κB activation and highlight the importance of unique domains within NEMO for sensing distinct NF-κB stimuli. IκB kinase γ | tumor necrosis factor alpha | human T-cell leukemia virus 1 Tax | CD40 E pstein-Barr virus (EBV) transforms resting B lymphocytes into

The Journal of …, 2000

B7-1 and B7-2 are important costimulatory molecules in the activation of T cell immunity. We have... more B7-1 and B7-2 are important costimulatory molecules in the activation of T cell immunity. We have used mice made genetically deficient in either or both B7 molecules to determine the role of B7 molecules in activation of primary alloreactive CTL. The absence of either B7-1 or B7-2 did not alter generation of CTL from unfractionated lymphocytes, but the absence of B7-2 greatly decreased CTL generation from purified CD8 ؉ responder cells. However, if B7-1 was induced on the stimulating cells then CTL generation was restored to wild-type levels. Absence of both B7-1 and B7-2 from MLR using whole splenocytes resulted in a profound reduction in generation of CTL. This could completely be reversed by the addition of IL-2. B7 molecules could directly costimulate CD8 ؉ cells, as purified CD8 ؉ cells developed into mature CTL when stimulated with wild-type APC, but not with B7-deficient APC. Again, IL-2 could drive CTL generation from purified CD8 ؉ cells, even in the absence of B7 molecules. Taken together, these results demonstrate an important role for B7 costimulation in CTL generation.

Immunological Investigations, 2000

MHC class I antigen presentation is a tightly regulated process that begins in the cell cytoplasm... more MHC class I antigen presentation is a tightly regulated process that begins in the cell cytoplasm with the generation of peptide ligands by the proteasome (1, 2). Peptides are translocated from the cytosol into the endoplasmic reticulum (ER) lumen through the MHC-encoded TAP complex. These peptides are loaded onto the class I heterodimer that is comprised of a 43 kDa type I membrane glycoprotein heavy chain and a 12 kDa soluble light chain (p2m). Shortly after synthesis of the class I heavy chain and &m, the complex is properly folded with assistance from ER resident chaperones such as calnexin, calreticulin and the thiol-reductase, ERp57(3). Tapasin, an ER-resident protein that associates with TAP, can interact with peptide-free class I heterodimerkhaperone complex and guide it to the TAP, where it is subsequently loaded with peptide. The generation of the trimeric class I complex allows its exit out of the ER and through the Golgi to the cell surface. The major histocompatibility complex (MHC) class I molecules present peptides derived from microbial and cellular proteins on the cell surface (4). The interaction of the MHC class I molecules with cytotoxic CD8'T lymphocytes (CTL) can activate an immune response and target the host cell for lysis, thereby eliminating the infected or abnormal cell. Several viruses and tumor cells can down-regulate the surface expression of class I molecuies at the transcriptional and post-translational levels(5, 6). The prevention of class I surface expression allows these cells to escape CTL detection. The mechanism by which tumors down-regulate class I molecules is not clearly understood. However, viral proteins have been identified which interfere with class I antigen presentation and may provide insight into how class I down-regulation is achieved in tumor cells as well.

Journal of Virology, 2001

The human cytomegalovirus-encoded US2 glycoprotein targets endoplasmic reticulum-resident major h... more The human cytomegalovirus-encoded US2 glycoprotein targets endoplasmic reticulum-resident major histocompatibility complex (MHC) class I heavy chains for rapid degradation by the proteasome. We demonstrate that the endoplasmic reticulum-lumenal domain of US2 allows tight interaction with class I molecules encoded by the HLA-A locus. Recombinant soluble US2 binds properly folded, peptide-containing recombinant HLA-A2 molecules in a peptide sequence-independent manner, consistent with US2's ability to broadly downregulate class I molecules. The physicochemical properties of the US2/MHC class I complex suggest a 1:1 stoichiometry. These results demonstrate that US2 does not require additional cellular proteins to specifically interact with soluble class I molecules. Binding of US2 does not significantly alter the conformation of class I molecules, as a soluble T-cell receptor can simultaneously recognize class I molecules associated with US2. The lumenal domain of US2 can differentiate between the products of distinct class I loci, as US2 binds several HLA-A locus products while being unable to bind recombinant HLA-B7, HLA-B27, HLA-Cw4, or HLA-E. We did not observe interaction between soluble US2 and either recombinant HLA-DR1 or recombinant HLA-DM. The substrate specificity of US2 may help explain the presence in human cytomegalovirus of multiple strategies for downregulation of MHC class I molecules.

Clinical infectious …, 2008

Background. Human babesiosis is a tickborne malaria-like illness that generally resolves without ... more Background. Human babesiosis is a tickborne malaria-like illness that generally resolves without complication after administration of atovaquone and azithromycin or clindamycin and quinine. Although patients experiencing babesiosis that is unresponsive to standard antimicrobial therapy have been described, the pathogenesis, clinical course, and optimal treatment regimen of such cases remain uncertain. Methods. We compared the immunologic status, clinical course, and treatment of 14 case patients who experienced morbidity or death after persistence of Babesia microti infection, despite repeated courses of antibabesial treatment, with those of 46 control subjects whose infection resolved after a single course of standard therapy. This retrospective case-control study was performed in southern New England, New York, and Wisconsin. Results. All case patients were immunosuppressed at the time of acute babesiosis, compared with !10% of the control subjects. Most case patients experienced B cell lymphoma and were asplenic or had received rituximab before babesial illness. The case patients were more likely than control subjects to experience complications, and 3 died. Resolution of persistent infection occurred in 11 patients after 2-10 courses of therapy, including administration of a final antimicrobial regimen for at least 2 weeks after babesia were no longer seen on blood smear. Conclusions. Immunocompromised people who are infected by B. microti are at risk of persistent relapsing illness. Such patients generally require antibabesial treatment for у6 weeks to achieve cure, including 2 weeks after parasites are no longer detected on blood smear. Human babesiosis is a zoonotic malaria-like illness that usually resolves 1-2 weeks after administration of a single course of atovaquone and azithromycin or clindamycin and quinine [1, 2]. Babesiosis is caused by

Over the past year, we have witnessed the discovery of further virus immuno-evasins--proteins tha... more Over the past year, we have witnessed the discovery of further virus immuno-evasins--proteins that alter the host immune response. Although many of these factors have been described over the past decade, the structural basis underlying their biology has lagged behind. Structural data have now been obtained for several such proteins. Major advances of the past year include the structures of a viral chemokine-binding protein, of an intact viral regulator of complement activation and of an immuno-evasin with its cellular target.

Many persistent viruses have evolved the ability to subvert MHC class I antigen presentation. Ind... more Many persistent viruses have evolved the ability to subvert MHC class I antigen presentation. Indeed, human cytomegalovirus (HCMV) encodes at least four proteins that down-regulate cellsurface expression of class I. The HCMV unique short (US)2 glycoprotein binds newly synthesized class I molecules within the endoplasmic reticulum (ER) and subsequently targets them for proteasomal degradation. We report the crystal structure of US2 bound to the HLA-A2͞Tax peptide complex. US2 associates with HLA-A2 at the junction of the peptide-binding region and the ␣3 domain, a novel binding surface on class I that allows US2 to bind independently of peptide sequence. Mutation of class I heavy chains confirms the importance of this binding site in vivo. Available data on class I-ER chaperone interactions indicate that chaperones would not impede US2 binding. Unexpectedly, the US2 ER-luminal domain forms an Ig-like fold. A US2 structure-based sequence alignment reveals that seven HCMV proteins, at least three of which function in immune evasion, share the same fold as US2. The structure allows design of further experiments to determine how US2 targets class I molecules for degradation.

Journal of Biological Chemistry, 2002

¶ Charles A. King Trust (Boston, MA) Research Fellow. 1 The abbreviations used are: ER, endoplasm... more ¶ Charles A. King Trust (Boston, MA) Research Fellow. 1 The abbreviations used are: ER, endoplasmic reticulum; HCMV, human cytomegalovirus; EndoH, endoglycosidase H; HC, class I heavy chain; FGF, fibroblast growth factor; aa, amino acid(s); ␤ 2 m, ␤ 2-microglobulin.

Annual Review of …, 2000

Given their short generation times, a proper host defense against viral pathogens is essential an... more Given their short generation times, a proper host defense against viral pathogens is essential and is aimed at several levels. Mechanical protection afforded by skin and epithelia can keep out many intruders, but viruses often possess specialized mechanisms to breach ...

Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) transforms rodent fibroblasts and is ex... more Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) transforms rodent fibroblasts and is expressed in most EBV-associated malignancies. LMP1 (transformation effector site 2 [TES2]/C-terminal activation region 2 [CTAR2]) activates NF-B, p38, Jun N-terminal protein kinase (JNK), extracellular signalregulated kinase (ERK), and interferon regulatory factor 7 (IRF7) pathways. We have investigated LMP1 TES2 genome-wide RNA effects at 4 time points after LMP1 TES2 expression in HEK-293 cells. By using a false discovery rate (FDR) of <0.001 after correction for multiple hypotheses, LMP1 TES2 caused >2-fold changes in 1,916 mRNAs; 1,479 RNAs were upregulated and 437 were downregulated. In contrast to tumor necrosis factor alpha (TNF-␣) stimulation, which transiently upregulates many target genes, LMP1 TES2 maintained most RNA effects through the time course, despite robust and sustained induction of negative feedback regulators, such as IB␣ and A20. LMP1 TES2-regulated RNAs encode many NF-B signaling proteins and secondary interacting proteins. Consequently, many LMP1 TES2-regulated RNAs encode proteins that form an extensive interactome. Gene set enrichment analyses found LMP1 TES2-upregulated genes to be significantly enriched for pathways in cancer, Band T-cell receptor signaling, and Toll-like receptor signaling. Surprisingly, LMP1 TES2 and IB␣ superrepressor coexpression decreased LMP1 TES2 RNA effects to only 5 RNAs, with FDRs of <0.001-fold and >2-fold changes. Thus, canonical NF-B activation is critical for almost all LMP1 TES2 RNA effects in HEK-293 cells and a more significant therapeutic target than previously appreciated. Although Epstein-Barr virus (EBV) infects most humans without causing significant disease, EBV is causally associated with Hodgkin's disease (HD) and other lymphoproliferative diseases (LPDs) in healthy and immune-compromised hosts (48, 49). EBV is also a causal agent of nasopharyngeal carcinoma (NPC) in southern Chinese, North Africans, and native Alaskans (67). In most EBV-associated malignancies and during replicative infection, EBV expresses latent infection membrane protein 1 (LMP1). LMP1 transforms rodent fibroblasts, as indicated by cell growth in lower serum concentrations, loss of contact inhibition, and anchorage independence (1, 44, 65). LMP1 is also essential for EBV conversion of human B lymphocytes to lymphoblastoid cell lines (LCLs) (32, 34). LMP1 is a 62-kDa, self-aggregating, integral membrane protein that constitutively activates NF-B, p38, Jun N-terminal protein kinase (JNK), exracellular signaling kinase (ERK), and interferon regulatory factor 7 (IRF7) signaling (19, 35, 66). LMP1 has a 24-amino-acid (aa) cytoplasmic N terminus, six highly hydrophobic transmembrane domains separated by

EBV nuclear antigen 3C (EBNA3C) is an essential transcription factor for EBV transformed lymphobl... more EBV nuclear antigen 3C (EBNA3C) is an essential transcription factor for EBV transformed lymphoblast cell line (LCL) growth. To identify EBNA3C-regulated genes in LCLs, microarrays were used to measure RNA abundances in each of three different LCLs that conditionally express EBNA3C fused to a 4-OH-Tamoxifen-dependent estrogen receptor hormone binding domain (EBNA3CHT). At least three RNAs were assayed for each EBNA3CHT LCL under nonpermissive conditions, permissive conditions, and nonpermissive conditions with wild-type EBNA3C transcomplementation. Using a two-way ANOVA model of EBNA3C levels, we identified 550 regulated genes that were at least 1.5-fold up-or down-regulated with false discovery rates < 0.01. EBNA3C-regulated genes overlapped significantly with genes regulated by EBNA2 and EBNA3A consistent with coordinated effects on cell gene transcription. Of the 550 EBNA3C-regulated genes, 106 could be placed in protein networks. A seeded Bayesian network analysis of the 80 most significant EBNA3C-regulated genes suggests that RAC1, LYN, and TNF are upstream of other EBNA3Cregulated genes. Gene set enrichment analysis found enrichment for MAP kinase signaling, cytokine-cytokine receptor interactions, JAK-STAT signaling, and cell adhesion molecules, implicating these pathways in EBNA3C effects on LCL growth or survival. EBNA3C significantly up-regulated the CXCL12 ligand and its CXCR4 receptor and increased LCL migration. CXCL12 up-regulation depended on EBNA3C's interaction with the cell transcription factor, RBPJ, which is essential for LCL growth. EBNA3C also up-regulated MYC 1.3-fold and down-regulated CDKN2A exons 2 and 3, shared by p16 and p14, 1.4-fold, with false discovery rates < 5 × 10 −4 .

mBio, Jan 19, 2014

Intestinal colonization by Vibrio parahaemolyticus-the most common cause of seafood-borne bacteri... more Intestinal colonization by Vibrio parahaemolyticus-the most common cause of seafood-borne bacterial enteritis worldwide-induces extensive disruption of intestinal microvilli. In orogastrically infected infant rabbits, reorganization of the apical brush border membrane includes effacement of some microvilli and marked elongation of others. All diarrhea, inflammation, and intestinal pathology associated with V. parahaemolyticus infection are dependent upon one of its type 3 secretion systems (T3SS2); however, translocated effectors that directly mediate brush border restructuring and bacterial adhesion are not known. Here, we demonstrate that the effector VopV is essential for V. parahaemolyticus intestinal colonization and therefore its pathogenicity, that it induces effacement of brush border microvilli, and that this effacement is required for adhesion of V. parahaemolyticus to enterocytes. VopV contains multiple functionally independent and mechanistically distinct domains through...

Molecular Immunology, 1992

We recently described 17 anti-CRP mAb, seven to native- (or conformational) and 10 to neo- (or se... more We recently described 17 anti-CRP mAb, seven to native- (or conformational) and 10 to neo- (or sequence-determined) epitopes, including several anti-neo-CRP mAb specific for CRP peptide 199-206. In the present study, four new anti-native- and four new anti-neo-CRP mAb were generated and characterized by ELISA reactivity with native and modified human and rabbit CRP, as well as binding to pronase fragments of human CRP in Western blots. Assays with 17 synthetic CRP peptides identified anti-neo-CRP mAb specific for peptides 1-16, 14-24 and 137-152, respectively. The anti-neo-CRP mAb were reacted with fragments obtained by digesting CRP with multiple additional enzymes, including Staphylococcal V8 protease, trypsin, elastase, plasmin, thrombin and alpha-chymotrypsin. Native CRP was remarkably resistant to enzymic digestion, particularly in the presence of calcium, but was readily cleavable upon denaturation. Twenty-three informative fragments served to further distinguish mAb reactivity with at least four additional neo-CRP epitopes, which presumptively included residues in the regions of amino acids 22-45, 41-61, 114-121 and 130-138, respectively. The eight epitopes identified corresponded well with predicted regions of CRP antigenicity. In addition, at least six distinct native or conformation-determined epitopes were delineated. Reactivity of the anti-neo-CRP mAb with fragments of CRP generated by PMN enzymes indicated that regions sensitive to cleavage by neutrophil enzymes are located at approximately 3, 10 and 16 kD from the amino terminus of the CRP subunit. We expect that the anti-CRP mAb described and mapped herein will be useful tools for the elucidation of CRP structure and function.