Publications by authors named "Locke Bryan"

21 Publications

  • Page 1 of 1

Leukaemic relapse of anaplastic large cell lymphoma, ALK negative.

BMJ Case Rep 2021 Feb 22;14(2). Epub 2021 Feb 22.

Hematology Oncology, Augusta University, Augusta, Georgia, USA.

Anaplastic large cell lymphoma (ALCL), ALK negative (ALK-) is an aggressive lymphoproliferative disorder of mature T lymphocytes characterised by hallmark cells, CD30 positivity and lacking ALK protein expression. ALCL, ALK- has to be differentiated from peripheral T-cell lymphoma-not otherwise specified and classical Hodgkin's lymphoma. ALK- anaplastic large cell leukaemia should be considered in a patient with a history of ALCL, ALK- presenting with new leukaemia. We report a rare presentation of relapsed ALCL, ALK- with leukaemia after autologous stem cell transplantation in a 57-year-old male. Leukaemia, either as primary presentation or secondary transformation confers worse prognosis in ALCL, ALK- with very few cases reported so far. Emergency resuscitation with leukapheresis and treatment of tumour lysis syndrome along with supportive care should be followed by combination chemotherapy. Brentuximab vedotin and stem cell transplantation are the backbone of treatment for relapsed/refractory disease.
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http://dx.doi.org/10.1136/bcr-2020-239213DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7903072PMC
February 2021

The Monocytes That Repopulate in Mice After Cyclophosphamide Treatment Acquire a Neutrophil Precursor Gene Signature and Immunosuppressive Activity.

Front Immunol 2020 25;11:594540. Epub 2021 Jan 25.

Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.

Cyclophosphamide (CTX) is a major component of the chemotherapy conditioning regimens used in the clinic to prepare cancer patients for hematopoietic stem cell transplantation or adoptive T cell therapy. Previous studies have shown that CTX given at nonmyeloablative doses in mice and patients leads to expansion of myeloid cells within which the monocytic subset exhibits immunosuppressive activity. However, the ontogeny and gene expression signature of these CTX-induced monocytes are not well-defined. Here, we report that the expansion of myeloid cells is a default process intrinsic to hematopoietic recovery after chemotherapy. During this process, the monocytes repopulated in mice acquire immunosuppressive activity, which can persist long after cessation of chemotherapy. Moreover, monocytes acquire a gene signature characteristic of neutrophil precursors, marked by increased proliferative capability and elevated expressions of multiple primary and secondary granules. We provide evidence that CTX-induced myeloid cell expansion is regulated by DNA methyltransferase 1 (Dnmt1) and dependent on chemotherapy-induced microbial translocation. These findings help advance our understanding of the differentiation, heterogeneity, and function of myeloid cells repopulating after chemotherapy.
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http://dx.doi.org/10.3389/fimmu.2020.594540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7868404PMC
January 2021

Assessing the impact of adding acetazolamide to oral or intravenous sodium bicarbonate as compared with intravenous bicarbonate monotherapy as urinary alkalinization in adults receiving high-dose methotrexate.

Support Care Cancer 2021 Mar 28;29(3):1527-1534. Epub 2020 Jul 28.

Department of Medicine, Augusta University Medical Center, Augusta, GA, USA.

Purpose: High-dose methotrexate (HD-MTX) requires urine alkalinization to pH ≥ 7 for adequate excretion to prevent toxicity. Due to shortages of IV sodium bicarbonate (IV-NaHCO3), few reports have demonstrated utility of oral bicarbonate (PO-NaHCO3); however, the addition of acetazolamide (Acet) has not been well described. Our study compares outcomes between alkalinization methods of IV-NaHCO3 monotherapy versus IV-NaHCO2 + Acet and PO-NaHCO3 + Acet.

Methods: A single-center, IRB exempt, retrospective review was conducted from Jan 2016 to Sept 2019 of adults receiving HD-MTX ≥ 500 mg/m. The primary outcome was time from start of alkalinization to pH ≥ 7. Secondary outcomes included time from start of alkalinization to initiation of HD-MTX, time to MTX clearance, length of stay (LOS), percentage of urine pH assessments < 7, and incidence of MTX toxicity. Statistical analysis was performed using SAS9.4 with alpha 0.05.

Results: Overall demographics (n = 196 HD-MTX cycles for 55 patients) include a mean age 55 years, HD-MTX dose ~ 5400 mg/m, and 69% with a diagnosis of lymphoma. Adjusting for baseline demographic differences among groups, median time from first dose alkalinization to pH ≥ 7 and to start of HD-MTX was longer for those receiving IV-NaHCO3 (n = 41) vs either IV-NaHCO3 + Acet (n = 70) or PO-NaHCO3 + Acet (n = 76) (p = 0.0001). HD-MTX clearance to a level < 0.1 μmol/L was not improved with the addition of Acet. No difference existed among groups for pH results < 7, LOS, or incidence of MTX toxicity (p > 0.05).

Conclusions: Addition of Acet to NaHCO3 reduces time to pH ≥ 7 and initiation of HD-MTX but does not appear to improve LOS, MTX toxicities, or time to MTX clearance.
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http://dx.doi.org/10.1007/s00520-020-05646-zDOI Listing
March 2021

A 43-Year-Old Woman With Hoarseness of Voice and Chest Pressure.

Chest 2019 11;156(5):e107-e110

Division of Hematology and Oncology, Augusta University, Augusta, GA.

Case Presentation: A 43-year-old woman with a medical history of cervical cancer treated with curative hysterectomy 12 years earlier developed progressive dyspnea, chest discomfort, and hoarse voice over a 7-month period. The patient never smoked and had no exposure history. Imaging at an outside hospital showed a mediastinal mass with hilar adenopathy (Fig 1A), which was biopsied via endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) and revealed noncaseating granulomas with surrounding rims of lymphocytes (Fig 1B). The patient was given the diagnosis of sarcoidosis and started on prednisone 60 mg daily. She had no improvement in symptoms after 3 months of therapy and therefore presented for a second opinion.
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http://dx.doi.org/10.1016/j.chest.2019.06.025DOI Listing
November 2019

Tumefactive fibroinflammatory lesion successfully treated with Rituximab.

Intractable Rare Dis Res 2019 May;8(2):138-141

Department of Otolaryngology, Head and Neck Surgery, Medical College of Georgia at Augusta University, Augusta, GA, USA.

Skull base pseudotumors, or tumefactive fibroinflammatory lesions (TFIL), are tumors characterized by local destruction with benign histopathology. Treatment includes surgery and steroids with varying degrees of symptom relief. A 45-year-old female presented with right otorrhea and middle ear effusion, which progressed to CN V pain/numbness, trismus, headache, and autophony. MRI showed a diffuse infiltrating mass in the right infratemporal region involving the trigeminal ganglion. Biopsy revealed benign fibromuscular and adipose tissue with lymphoplasmacytic infiltrate, giving a diagnosis of TFIL. Resection would be very difficult given tumor location. Initial treatment included an extended course of steroids without response, and interval disease progression. Two courses of rituximab 375 mg/m weekly × 4 given 3 months apart were then completed with excellent tolerance. With sixteen months following induction, the patient reports minimal symptoms with radiographic findings confirming continued disease regression. Rituximab is a potential treatment option for patients with TFIL without response to steroids.
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http://dx.doi.org/10.5582/irdr.2019.01061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6557232PMC
May 2019

Spotlight on copanlisib and its potential in the treatment of relapsed/refractory follicular lymphoma: evidence to date.

Onco Targets Ther 2018 13;11:4817-4827. Epub 2018 Aug 13.

Division of Hematology/Oncology, Augusta University, Augusta, GA, USA,

The importance of the phosphatidylinositol-3-kinase (PI3K) pathway in cell survival and proliferation has made it an attractive target in cancer therapy. The development of small molecule inhibitors for the PI3K pathway continues to provide treatment alternatives across a range of malignancy types. Several agents, including idelalisib, copanlisib and duvelisib, not only inhibit the PI3K pathway, but also have effects on associated mechanisms including the ATK and mTOR pathways. The advent of PI3K-specific small molecular inhibitors has led to increased efficacy with avoidance of an excessive toxicity profile. Key enzymes of the PI3K pathway exhibit differing expression in tissue types and roles in tumor pathogenesis. Copanlisib (BAY 80-6946) is a pan-specific PI3K small molecule inhibitor for four key isoforms with increased activity against PI3Kα and PI3Kδ, both important in B-cell malignancies. Follicular lymphoma is one of the most common indolent B-cell non-Hodgkin lymphomas worldwide. Follicular lymphoma like other indolent B-cell non-Hodgkin lymphomas is beleaguered by high relapse rates and the need for subsequent therapy options. Based on efficacy and a limited toxicity profile, copanlisib received accelerated US Food and Drug Administration approval for the treatment of adult patients with relapsed follicular lymphoma following two lines of therapy. Here, we review the development of copanlisib and the role of this agent in the treatment of follicular lymphoma.
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http://dx.doi.org/10.2147/OTT.S142264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6097514PMC
August 2018

The impact of antibiotic usage on the efficacy of chemoimmunotherapy is contingent on the source of tumor-reactive T cells.

Oncotarget 2017 Dec 5;8(67):111931-111942. Epub 2017 Dec 5.

Georgia Cancer Center, Augusta University, Augusta, Georgia, USA.

In recent years the combined use of chemotherapy and immunotherapy, collectively termed chemoimmunotherapy, has emerged as a promising treatment option for patients with cancer. Antibiotics are commonly used to reduce infection-related complications in patients undergoing chemotherapy. Intriguingly, accumulating evidence has implicated gut microbiota as a critical determinant of host antitumor immune responses, raising the question as to whether the use of broad-spectrum antibiotics would invariably diminish tumor response to chemoimmunotherapies. We investigated the impact of antibiotics on the therapeutic outcomes of cyclophosphamide (CTX) chemotherapy and adoptive T-cell therapy (ACT) where CTX was used as the host-conditioning regimen in mice. We show that antibiotic prophylaxis dampened the endogenous T cell responses elicited by CTX, and reduced the efficacy of CTX against B-cell lymphoma. In the ACT setting, antibiotics administration impaired the therapeutic effects of adoptively transferred tumor-specific CD4+ T cells in mice with implanted colorectal tumors. In contrast, long-term antibiotic exposure did not affect the efficacy of ACT using CD19-targeting chimeric antigen receptor (CAR) T cells in mice with systemic B-cell lymphoma, although it correlated with prolonged CAR expression and sustained B-cell aplasia. Our study demonstrates that chemoimmunotherapies may have variable reliance on intestinal microbiota for T cell activation and function, and thus have different sensitivities to antibiotic prophylaxis. These findings may have implications for the judicial use of antibiotics in cancer patients receiving chemoimmunotherapies.
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http://dx.doi.org/10.18632/oncotarget.22953DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762370PMC
December 2017

Persistent indolent pancolonic marginal zone lymphoma of MALT-type with plasmacytic differentiation - A rare post-transplant lymphoma?

Hum Pathol (N Y) 2017 Nov 9;10:74-78. Epub 2017 Jul 9.

Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States.

Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is associated with chronic inflammatory disorders. We present an indolent pancolonic MALT lymphoma occurring in a 39-year-old female with history of autoimmune hepatitis requiring liver transplant in 1997 and ulcerative colitis diagnosed in 2004. Random biopsies from a grossly unremarkable surveillance colonoscopy in 2015 revealed a dense monomorphic plasmacytoid infiltrate causing expansion of lamina propria without significant crypt infiltration or destruction. These cells were positive for CD79a and CD138 and showed lambda restriction; however, CD20, CD43, CD56, HHV8, and EBER were negative. A similar pancolonic infiltrate was identified in all prior colorectal biopsies from 2010 and 2012 upon retrospective review. Subsequent computed tomography of the abdomen revealed no bowel wall thickening nor enlarged lymph nodes. Bone marrow revealed involvement consistent with stage IV disease. Biopsies from 2010 and 2015 demonstrated clonal immunoglobulin gene rearrangement. mutation was not detected. The overall features were indicative of MALT lymphoma. Although low-grade B-cell lymphomas are not considered part of the post-transplant lymphoproliferative disorder spectrum, such cases have been reported, and are typically EBV-negative. Patient underwent treatment with pentostatin for her MALT lymphoma reaching a sustained remission despite additional immunosuppression for resurgent hepatic dysfunction. To our knowledge, this is the first reported case of EBV-negative pancolonic MALT lymphoma with plasmacytic differentiation post liver transplant presenting in an indolent, asymptomatic fashion with persistence for greater than five years successfully managed without compromising the patient's liver transplant.
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http://dx.doi.org/10.1016/j.ehpc.2017.06.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019211PMC
November 2017

Adjuvant IL-7 potentiates adoptive T cell therapy by amplifying and sustaining polyfunctional antitumor CD4+ T cells.

Sci Rep 2017 09 22;7(1):12168. Epub 2017 Sep 22.

Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.

Increased availability of homeostatic cytokines is considered a major mechanism by which lymphodepletion enhances the efficacy of adoptive T cell therapy (ACT). IL-7 is one such cytokine capable of augmenting the function of tumor-reactive CD8+ T cells. However, whether host-derived IL-7 plays a role in driving the proper function of CD4+ T cells in an ACT setting remains unclear. Here we report that lymphodepleting chemotherapy by cyclophosphamide (CTX) does not lead to increased availability of the endogenous IL-7 in mice. Despite of a paucity of IL-7 in the immune milieu, CTX preconditioning allowed adoptively transferred naïve tumor-specific CD4+ T cells to undergo effector differentiation and regain IL-7Rα expression, giving rise to IL-7-responsive polyfunctional CD4+ effector cells. Correspondingly, supplementation of exogenous recombinant IL-7 markedly amplified and sustained polyfunctional CD4+ effector cells, resulting in improved therapeutic outcome in a mouse lymphoma model. We further demonstrated that the immune-enhancing effects of IL-7 were also applicable to donor CD4+ T cells pre-activated under Th1 polarizing condition. These findings suggest caution in relying on the endogenous IL-7 to enhance donor T cell expansion and persistence after lymphodepleting chemotherapy, and highlight the usefulness of recombinant IL-7 as an adjuvant for adoptive immunotherapy.
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http://dx.doi.org/10.1038/s41598-017-12488-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610351PMC
September 2017

Releasing the Brake on the Immune System: The PD-1 Strategy for Hematologic Malignancies.

Oncology (Williston Park) 2015 Jun;29(6):431-9

Manipulation of the immune system as a viable cancer treatment strategy has re-emerged. The programmed death 1 (PD-1) pathway is an important, physiologic immune checkpoint necessary to limit autoimmune processes but co-opted by tumors to suppress the antitumor response and allow tumor escape. Blockade of the PD-1 pathway through the use of PD-1 or PD ligand 1(PD-L1) antibodies releases this brake on the immune response. The anti-PD-1 antibodies have produced encouraging results across a broad range of malignancies. Many hematologic malignancies have usurped the PD-1 pathway. Recent investigations have explored the use of anti-PD-1 therapy in hematologic malignancies, with encouraging results. Incorporation of PD-1 blockade into the treatment algorithms for hematologic malignancies is currently being pursued in multiple active clinical trials. Here we review the data on anti-PD-1 monoclonal antibodies to date and discuss ongoing and future clinical trials.
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June 2015

Factors predicting survival in peripheral T-cell lymphoma in the USA: a population-based analysis of 8802 patients in the modern era.

Br J Haematol 2015 Mar 7;168(5):708-18. Epub 2014 Nov 7.

Division of Hematology/Oncology, Northwestern University, Chicago, IL, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA.

Current prognostic models for peripheral T-cell lymphoma (PTCL) have multiple limitations, and questions exist regarding applicability to current patients. We utilized the Surveillance Epidemiology and End Results (SEER)-18 database to evaluate factors affecting overall survival (OS) of PTCL in the modern era and identified 8802 patients between 2000-2010. Most subtypes of PTCL increased in incidence during the study period. In univariate analyses, age >55 years, black race, advanced stage, absence of extra-nodal disease, omission of radiation therapy (RT) and high-risk histology each predicted inferior OS (P < 0·0001). Multivariate analysis (MVA) demonstrated that hepatosplenic, enteropathy-associated and extra-nodal Natural Killer/T cell histologies, each had hazard ratios >1·5 (P ≤ 0·0001) for death. Further, age ≥55 years, black race and advanced stage maintained their significance in the MVA (P < 0·0001 each). Based on the significant factors, a prognostic model was constructed and subsequently validated in an independent cohort. The new model incorporated age, stage, histology and race, with an OS ranging from 9 months (highest risk group) to 120 months (lowest risk group). In summary, this is the largest study of PTCL patients in the modern era that provides risk stratification utilizing a new prognostic model that can be incorporated into future prospective clinical trials.
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http://dx.doi.org/10.1111/bjh.13202DOI Listing
March 2015

Blocking tumor escape in hematologic malignancies: the anti-PD-1 strategy.

Blood Rev 2015 Jan 16;29(1):25-32. Epub 2014 Sep 16.

Division of Hematology/Oncology, Robert H. Lurie Comprehensive Cancer Center, 676 N St Clair, Suite 850, Chicago, IL 60611, USA. Electronic address:

Immunotherapy remains an important tool for treatment of hematologic malignancies. The Programmed Death-1 (PD-1) immune checkpoint pathway has emerged as a mechanism of tumor evasion from the anti-tumor immune response. The recent development of anti-PD-1 monoclonal antibodies has offered a targeted approach to cancer therapy. Several agents are in various stages of development and have shown clinical responses across a broad spectrum of both solid and hematologic malignancies. The use of anti-PD-1 therapy in hematologic malignancies is limited but has demonstrated clinical responses in relapsed/refractory disease following multiple lines of therapy. PD-1 blockade may reduce relapse rates for patients who fail to obtain a complete remission prior to autologous hematopoietic cell transplant. The role of the PD-1 pathway for tumor escape is reviewed. We explore the use of anti-PD-1 therapy in hematologic malignancies. The proposed mechanism of PD-1 blockade as a modulator of the innate and acquired immune response is considered. Finally, the challenges of anti-PD-1 therapy and the future direction of investigation in this area are reviewed.
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http://dx.doi.org/10.1016/j.blre.2014.09.004DOI Listing
January 2015

Pidilizumab in the treatment of diffuse large B-cell lymphoma.

Expert Opin Biol Ther 2014 Sep 24;14(9):1361-8. Epub 2014 Jul 24.

Northwestern University, Division of Hematology/Oncology , 676 N St Clair Ste 850, Chicago, IL 60611 , USA

Introduction: The programmed death-1 (PD-1) immune checkpoint pathway is an emerging target in the treatment of hematologic malignancies. Pidilizumab is an mAb that binds to PD-1 and is a safe and well-tolerated therapy. Recent data have shown clinical activity utilizing this strategy in diffuse large B-cell lymphoma (DLBCL).

Areas Covered: The role of PD-1 expression in hematologic malignancies is explored. Recent clinical trials including the results of a Phase I trial in hematologic malignancies and a Phase II trial of pidilizumab following autologous hematopoietic stem-cell transplant (AHSCT) are reviewed.

Expert Opinion: We review data that suggest that PD-1 is a promising target in the treatment and management of DLBCL. Changes in immune subsets following administration of pidilizumab are felt to represent on-target responses. The improvement in progression-free survival (PFS) following AHSCT supports a response to therapy. Importantly, the improvement in PFS for patients with positive FDG-PET/CT following AHSCT indicating residual disease further supports direct activity of pidilizumab in DLBCL.
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http://dx.doi.org/10.1517/14712598.2014.942637DOI Listing
September 2014

Higher soluble P-selectin is associated with chronic venous insufficiency: the San Diego Population Study.

Thromb Res 2012 Nov 12;130(5):716-9. Epub 2012 Aug 12.

University of Vermont, Department of Medicine, Colchester, VT 05446, USA.

Introduction: P-selectin is a cell adhesion molecule shown to play a role in venous thromboembolism. We evaluated whether higher P-selectin is associated with chronic venous insufficiency (CVI).

Materials And Methods: In a cohort of 2408 participants, the San Diego Population Study, peripheral venous disease was established by symptoms, clinical examination, and ultrasound. We measured P-selectin in a subsample of 352 CVI cases frequency matched to controls. Cases included four hierarchical groups of increasing severity of CVI.

Results: The association of P-selectin with CVI considering all cases was weak, with an age, race and sex-adjusted odds ratio (OR) of 1.3 (95% CI 1.0-2.2) for values in the 3rd versus 1st tertile. The OR for cases in the two most severe groups was 2.3 (95% CI 1.2-4.2). Addition of body mass index to the model reduced this OR to 1.9 (95% CI 1.0-3.6).

Conclusions: Higher circulating P-selectin was associated with more severe CVI, but not CVI overall. Results support that platelet and endothelial cell activation may be involved in the pathogenesis of CVI.
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http://dx.doi.org/10.1016/j.thromres.2012.07.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3474873PMC
November 2012

Why is my patient anemic?

Hematol Oncol Clin North Am 2012 Apr;26(2):205-30, vii

University of Vermont College of Medicine, 111 Colchester Avenue, Smith Room 244, Burlington, VT 05401, USA.

Anemia is a decreased number of circulating red blood cells and is a common medical condition faced in clinical practice. Anemia is caused by loss of red blood cells, destruction of red blood cells, decreased production of red blood cells, or a combination of these processes. Through a clinical history, physical examination, and laboratory evaluation the provider must identify the process by which the patient is anemic. Often the cause of anemia is straightforward; however, the cause can be challenging, requiring a thorough knowledge of both hematology and general medicine.
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http://dx.doi.org/10.1016/j.hoc.2012.02.008DOI Listing
April 2012

Rana catesbeiana virus Z (RCV-Z): a novel pathogenic ranavirus.

Dis Aquat Organ 2006 Nov;73(1):1-11

Department of Microbiology, University of Mississippi Medical Center, Jackson, Mississipi 39216, USA.

A virus, designated Rana catesbeiana virus Z (RCV-Z), was isolated from the visceral tissue of moribund tadpoles of the North American bullfrog Rana catesbeiana. SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) analysis of viral proteins and sequence analysis of the amino terminal end of the major capsid protein showed that RCV-Z was similar to frog virus 3 (FV3) and other ranaviruses isolated from anurans and fish. However, analysis of restriction fragment profiles following digestion of viral genomic DNA with XbaI and BamHI indicated that RCV-Z was markedly different from FV3. Moreover, in contrast to FV3, RCV-Z contained a full-length copy of the viral homolog of eukaryotic initiation factor 2 alpha (eIF-2alpha). Experimental infection of bullfrog tadpoles with FV3 and RCV-Z demonstrated that RCV-Z was much more pathogenic than FV3, and that prior infection with FV3 protected them from subsequent RCV-Z induced mortality. Collectively, these results suggest that RCV-Z may represent a novel species of ranavirus capable of infecting frogs and that possession of a viral eIF-2alpha homolog (vIF-2alpha) correlates with enhanced virulence.
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http://dx.doi.org/10.3354/dao073001DOI Listing
November 2006

Inhibition of iridovirus protein synthesis and virus replication by antisense morpholino oligonucleotides targeted to the major capsid protein, the 18 kDa immediate-early protein, and a viral homolog of RNA polymerase II.

Virology 2007 Feb 3;358(2):311-20. Epub 2006 Oct 3.

Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, USA.

Frog virus 3 (FV3) is a large DNA virus that encodes approximately 100 proteins. Although the general features of FV3 replication are known, the specific roles that most viral proteins play in the virus life cycle have not yet been elucidated. To address the question of viral gene function, antisense morpholino oligonucleotides (asMOs) were used to transiently knock-down expression of specific viral genes and thus infer their role in virus replication. We designed asMOs directed against the major capsid protein (MCP), an 18 kDa immediate-early protein (18K) that was thought to be a viral regulatory protein, and the viral homologue of the largest subunit of RNA polymerase II (vPol-IIalpha). All three asMOs successfully inhibited translation of the targeted protein, and two of the three asMOs resulted in marked phenotypic changes. Knock-down of the MCP resulted in a marked reduction in viral titer without a corresponding drop in the synthesis of other late viral proteins. Transmission electron microscopy (TEM) showed that in cells treated with the anti-MCP MO assembly sites were devoid of viral particles and contained numerous aberrant structures. In contrast, inhibition of 18K synthesis did not block virion formation, suggesting that the 18K protein was not essential for replication of FV3 in fathead minnow (FHM) cells. Finally, consistent with the view that late viral gene expression is catalyzed by a virus-encoded or virus-modified Pol-II-like protein, knock-down of vPol-IIalpha triggered a global decline in late gene expression and virus yields without affecting the synthesis of early viral genes. Collectively, these results demonstrate the utility of using asMOs to elucidate the function of FV3 proteins.
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http://dx.doi.org/10.1016/j.virol.2006.07.009DOI Listing
February 2007

Identification of a cDNA encoding channel catfish interferon.

Dev Comp Immunol 2004 Feb;28(2):97-111

Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, USA.

Despite considerable advances in our understanding of teleost immunity, relatively few cytokine genes, including those for interferon (IFN), have been identified at the molecular level. In contrast, numerous studies have shown that following virus infection or exposure to double-stranded RNA, fish or fish cells produce a soluble factor that is functionally similar to mammalian IFN. A putative catfish (CF) IFN cDNA was identified by BLASTX screening of a catfish EST library generated from a mixed lymphocyte culture enriched for NK-like cells. Consistent with its designation as a putative cytokine cDNA, the 3' non-translated region contained multiple copies of an RNA instability motif. Analysis of the deduced amino acid sequence of CF IFN showed low levels of identity/similarity to a panel of mammalian and avian IFN proteins, and markedly higher similarity to a recently identified zebrafish IFN. To determine if the identified cDNA encoded CF IFN, expression was monitored following infection of channel catfish ovary (CCO) cells with UV-inactivated catfish reovirus or exposure to double-stranded RNA, treatments which induce IFN or IFN-like activity in catfish and other species. In both cases, upregulation of putative CF IFN mRNA was detected. Moreover, upregulation of CF IFN mRNA was accompanied by the appearance of an antiviral factor in the culture medium. To confirm these results, recombinant CF IFN was synthesized in COS-7 cells and shown to have antiviral activity in CCO cells. Collectively, these results argue strongly that the identified catfish cDNA is an IFN homolog.
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http://dx.doi.org/10.1016/s0145-305x(03)00122-8DOI Listing
February 2004

Induction of apoptosis in frog virus 3-infected cells.

Virology 2003 Feb;306(2):303-12

Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, USA.

The ability of frog virus 3 (FV3), the type species of the family Iridoviridae, to induce apoptosis was examined by monitoring DNA cleavage, chromatin condensation, and cell-surface expression of phosphotidylserine (PS) in fathead minnow (FHM) and baby hamster kidney (BHK) cells. In productively infected FHM cells, DNA fragmentation was first noted at 6-7 h postinfection and was clearly seen by 17 h postinfection, while chromatin condensation was detected at 8.5 h postinfection. As with some other viruses, FV3-induced apoptosis did not require de novo viral gene expression as both heat-inactivated and UV-inactivated virus readily triggered DNA fragmentation in FHM cells. Moreover, FV3-induced apoptosis was blocked in FHM cells by the pan-caspase inhibitor Z-VAD-FMK, suggesting that virus infection triggers programmed cell death through activation of the caspase cascade. FV3 infection also triggered apoptosis in BHK cells as monitored by TUNEL and annexin V binding assays. To determine whether FV3, similar to other large DNA viruses, encoded proteins that block or delay apoptosis, mock- and FV3-infected FHM cells were osmotically shocked and assayed for DNA fragmentation 3 hours later. DNA fragmentation was clearly seen whether or not shocked cells were previously infected with FV3, indicating that infection with FV3 did not block apoptosis induced by osmotic shock in FHM cells. The above results demonstrate that iridoviruses triggered apoptosis and that the induction of programmed cell death did not require viral gene expression. However, it remains to be determined if virion attachment to target cells is sufficient to induce cell death, or if apoptosis is triggered directly or indirectly by one or more virion-associated proteins.
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http://dx.doi.org/10.1016/s0042-6822(02)00039-9DOI Listing
February 2003