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Leary JJ, Wittrock R, Sarisky RT, Weinberg A, Levin MJ. Susceptibilities of herpes simplex viruses to penciclovir and acyclovir in eight cell lines. Antimicrob Agents Chemother 2002; 46:762-8. [PMID: 11850259 PMCID: PMC127472 DOI: 10.1128/aac.46.3.762-768.2002] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The commonly used antiviral drugs acyclovir (ACV) and penciclovir (PCV) possess similarly potent antiviral activities in vivo against herpes simplex virus (HSV). Assay methods for sensitivity to ACV are not necessarily transferable to PCV, even though the two drugs have similar in vivo potencies and mechanisms of action. We determined by plaque reduction assay the relative activities of ACV and PCV against five laboratory-adapted strains of HSV types 1 and 2 (including sensitive and resistant strains) in seven human cell lines and one nonhuman primate cell line. Seven characteristics were used to evaluate the cell lines. All cell lines were similar in their plating efficiencies and abilities to discriminate between sensitive and resistant HSV isolates. Vero and MRC-5 cells yielded the most discordant 50% inhibitory concentrations (IC50s) for the two HSV types, while Vero and WI-38 VA-13 cells yielded large differences in the IC50s of ACV and PCV. The limited life spans and poor plaque morphologies of the fibroblast lines were undesirable characteristics. Among the transformed cell lines producing well-defined plaques, A549 cells provided the best concordance between IC50s for the two HSV types and two antiherpes drugs. Comparison experiments with a yield reduction format indicated that the use of assays of this type might allow some of the cell-specific properties observed in plaque reduction assays to be avoided.
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177
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López Bergami P, Scaglione J, Levin MJ. Antibodies against the carboxyl-terminal end of the Trypanosoma cruzi ribosomal P proteins are pathogenic. FASEB J 2001; 15:2602-12. [PMID: 11726536 DOI: 10.1096/fj.01-0132com] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sera from patients with chronic Chagas heart disease recognize the carboxyl-terminal regions of the Trypanosoma cruzi ribosomal P proteins defined by B cell epitopes P013 (EDDDDDFGMGALF) and R13 (EEEDDDMGFGLFD) corresponding to the T. cruzi ribosomal P0 (TcP0) and P2beta (TcP2beta) proteins, respectively. It has been hypothesized that both epitopes may induce antibodies that cross-react and stimulate the beta1-adrenoreceptor. However, no proof as to their pathogenicity has been obtained. We investigated the consequences of immunizing mice with either TcP0 or TcP2beta proteins. Of 24 immunized animals, 16 generated antibodies against the carboxyl-terminal end of the corresponding protein, 13 of which showed an altered ECG (P<0.001, 81%). Immunization with TcP0 induced anti-P013 antibodies that bind to and stimulate cardiac G-protein-coupled receptors and are linked to the induction of supraventricular arrhythmia, repolarization, and conduction abnormalities as monitored by serial electrocardiographic analysis. In contrast, immunization with TcP2beta generated anti-R13 antibodies with an exclusive beta1-adrenergic-stimulating activity whose appearance strictly correlated with the recording of supraventricular tachycardia and death. These findings demonstrate that anti-P antibodies are arrhythmogenic in the setting of a normal heart, since no inflammatory lesions or fibrosis were evident to light microscopic examination.
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Levin MJ, Weinberg A, Leary JJ, Sarisky RT. Development of acyclovir-resistant herpes simplex virus early during the treatment of herpes neonatorum. Pediatr Infect Dis J 2001; 20:1094-7. [PMID: 11734722 DOI: 10.1097/00006454-200111000-00021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Genotypic analysis of herpes simplex virus (HSV) DNA extracted from clinical specimens from a case of fatal disseminated neonatal HSV demonstrated that an infant developed an acyclovir-resistant HSV containing a mutation in the HSV thymidine kinase gene during the first seven days of acyclovir therapy.
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Gómez EB, Medina G, Ballesta JP, Levin MJ, Téllez-Iñón MT. Acidic ribosomal P proteins are phosphorylated in Trypanosoma cruzi. Int J Parasitol 2001; 31:1032-9. [PMID: 11429166 DOI: 10.1016/s0020-7519(01)00219-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Trypanosoma cruzi ribosomes from epimastigote forms were purified as determined by electron microscopy and isoelectrofocusing was used to analyse this purified ribosome fraction. Silver stained gels revealed that acidic proteins are present in at least 10 different isoforms, in accord with previous cloning studies. To detect phosphorylation, in vitro phosphorylation assays using the recombinant protein TcP2beta-mbp were carried out. The results showed that T. cruzi cytosolic fraction possesses protein kinase activity able to phosphorylate the recombinant protein. Purified ribosomes contain protein kinases that could also phosphorylate the recombinant protein TcP2beta-mbp. Labelling parasites with [(32)Pi] in a phosphate free medium demonstrated that ribosome proteins, recognised with a specific mouse antiserum against recombinant TcP2beta proteins, are phosphorylated in vivo. All these results suggest that in vivo phosphorylation of ribosome TcP2beta proteins are mediated by protein kinase(s) not yet identified.
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180
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Levin MJ, Gershon AA, Weinberg A, Blanchard S, Nowak B, Palumbo P, Chan CY. Immunization of HIV-infected children with varicella vaccine. J Pediatr 2001; 139:305-10. [PMID: 11487761 DOI: 10.1067/mpd.2001.115972] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To determine the safety and immunogenicity of varicella vaccine in children with human immunodeficiency virus (HIV) infection. Children (n = 41) who were mildly affected by HIV (Centers for Disease Control and Prevention stage N1 or A1) and had no history or serum antibody indicative of prior varicella infection were immunized with two doses of live attenuated varicella vaccine. RESULTS A minority of the vaccine recipients had mild local or systemic reactions. Vaccination had no effect on the clinical stage of HIV or the HIV RNA plasma load. CD4 cell percentage and CD4 cell count were marginally decreased at week 4 after the first vaccination; this effect was no longer present at week 8 after vaccination. Two months after the second dose of vaccine, 60% of vaccine recipients had anti-varicella antibody in their serum, and 83% had a positive lymphocyte proliferation assay response to varicella antigen. CONCLUSION On the basis of its safety and immunogenicity, varicella vaccine should be considered in the childhood vaccines given to mildly affected HIV-infected children.
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181
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Mahler E, Sepulveda P, Jeannequin O, Liegeard P, Gounon P, Wallukat G, Eftekhari P, Levin MJ, Hoebeke J, Hontebeyrie M. A monoclonal antibody against the immunodominant epitope of the ribosomal P2beta protein of Trypanosoma cruzi interacts with the human beta 1-adrenergic receptor. Eur J Immunol 2001; 31:2210-6. [PMID: 11449375 DOI: 10.1002/1521-4141(200107)31:7<2210::aid-immu2210>3.0.co;2-j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Monoclonal antibodies were raised against a recombinant ribosomal P2beta protein of Trypanosoma cruzi. One of these reacted with the C terminus of this protein (peptide R13, EEEDDDMGFGLFD) and epitope mapping confirmed that this epitope was the same as the one defined by the serum of immunized mice, and similar to the previously described chronic Chagas' heart disease (cChHD) anti-P epitope. Western blotting showed that the monoclonal antibody recognized the parasite ribosomal P proteins, as well as the human ribosomal P proteins. Electron microscopy showed that it stained different structures in parasite and human cells. Interestingly, surface plasmon resonance measurements indicated that the affinity for the parasite ribosomal P protein epitope (R13) was five times higher than for its human counterpart (peptide H13, EESDDDMGFGLFD). Since the human epitope contained an acidic region (EESDD) similar to the AESDE peptide recognized by cChHD patients in the second extra-cellular loop of the human beta1-adrenergic receptor, the biological activity of the antibody was assessed on neonatal rat cardiomyocytes in culture. The monoclonal antibody had an agonist-like effect. These results, together with the fact that the monoclonal reacted in Western blots with the different isoforms of the heart beta1-adrenergic receptor, confirm the possible pathogenic role of antibodies against the parasite ribosomal P protein based on their cross-reaction with the human beta1-adrenergic receptor.
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182
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Juri Ayub M, Levin MJ, Aguilar CF. Overexpression and refolding of the hydrophobic ribosomal P0 protein from Trypanosoma cruzi: a component of the P1/P2/P0 complex. Protein Expr Purif 2001; 22:225-33. [PMID: 11437598 DOI: 10.1006/prep.2001.1427] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The P0 protein is part of the ribosomal eukaryotic stalk, which is an elongated lateral protuberance of the large ribosomal subunit involved in the translocation step of protein synthesis. P0 is the minimal portion of the stalk that is able to support accurate protein synthesis. The P0 C-terminal peptide is highly antigenic and a major target of the antibody response in patients with systemic lupus erythematosus and patients suffering chronic heart disease produced by the Trypanosoma cruzi parasite. The T. cruzi P0 (TcP0) protein was cloned into the pRSET A vector and expressed in Escherichia coli fused to a His-tag. The identity of the protein was confirmed by immunoblotting. Due to the formation of inclusion bodies the protein was purified using the following steps: (i) differential centrifugation to separate the inclusion bodies from soluble proteins and (ii) affinity chromatography under denaturing conditions. TcP0 showed high tendency to aggregation during refolding assays. However, TcP0 could be efficiently folded in the presence of a low concentration of SDS. The folding of the protein was confirmed using urea gradient electrophoresis, limited proteolysis, circular dichroism, and tryptophan fluorescence. Native electrophoresis showed that the folded TcP0 (and not a folding intermediate) was the cause of aggregation in the absence of SDS. The protocol described here permitted us to obtain large amounts (up to 30 mg per culture liter) of pure and folded TcP0, a very hydrophobic protein with a high tendency to aggregation.
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183
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Ponnuraj EM, John TJ, Levin MJ, Simoes EAF. Sabin attenuated LSc/2ab strain of poliovirus spreads to the spinal cord from a peripheral nerve in bonnet monkeys (Macaca radiata). J Gen Virol 2001; 82:1329-1338. [PMID: 11369876 DOI: 10.1099/0022-1317-82-6-1329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vaccine-associated paralytic poliomyelitis is a serious concern while using the live attenuated oral polio vaccine for the eradication of poliomyelitis. The bonnet monkey model of poliovirus central nervous system (CNS) infection following experimental inoculation into the ulnar nerve allows the comparative study of wild-type and attenuated poliovirus invasiveness. Dosages >/=10(4) TCID(50) of Mahoney strain of poliovirus type 1 [PV1(M)] result in paralysis. In contrast, even with 10(7) TCID(50) of Sabin attenuated strain of poliovirus type 1 (LSc/2ab), no paralysis occurs, but virus spreads into the CNS where viral RNA is found in spinal cord neurons. While wild-type PV1(M) viral RNA replicates in neurons (and possibly in glial cells) and in cells around vessel walls, which may be mononuclear or endothelial cells, attenuated viral RNA is detected only in neurons. Systemic viraemia and gastrointestinal virus shedding occurs only in PV1(M)-infected animals. While a systemic serologic response is detected in both groups of animals, cerebrospinal fluid antibodies are detected only in animals infected with PV1(M). Both the PV1(M) and LSc/2ab strains spread to the cervical spinal cord and then to the lumbar spinal cord following ulnar nerve inoculation. Neuronophagia and neuronal loss are only seen in PV1(M)-infected monkeys in whom clinical paralysis is observed. Infection with LSc/2ab does not result in neuronophagia, neuronal loss or clinical paralysis. Spread of attenuated poliovirus in spinal cord neurons without causing paralysis following inoculation into the ulnar nerve is an important finding.
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184
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Levin MJ. Use of varicella vaccines to prevent herpes zoster in older individuals. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 2001:151-60. [PMID: 11339544 DOI: 10.1007/978-3-7091-6259-0_16] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is likely that the frequency and severity of herpes zoster in older people is the result of an age-related decline in varicella-zoster virus-specific T-cell mediated immunity. Numerous trials of vaccines to boost these responses have demonstrated their safety and immunogenicity. Both live attenuated and inactivated vaccines have been studied. Persistence of booster responses is dose-related, and the half-life of some boosted measures of T-cell mediated immunity exceeds 5 years. Although these trials have been hampered by uncertainty about the critical immune responses to evaluate, the stage is set for a double-blind, placebo-controlled trial of sufficient size to determine efficacy. Such a trial is now underway.
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185
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Chiale PA, Ferrari I, Mahler E, Vallazza MA, Elizari MV, Rosenbaum MB, Levin MJ. Differential profile and biochemical effects of antiautonomic membrane receptor antibodies in ventricular arrhythmias and sinus node dysfunction. Circulation 2001; 103:1765-71. [PMID: 11282908 DOI: 10.1161/01.cir.103.13.1765] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The relationship between anti-beta-adrenergic (anti-betaR) and anti-M(2)-cholinergic (anti-M2R) receptor antibodies (Abs) and cardiac arrhythmias and their biochemical effects have not been systematically investigated. METHODS AND RESULTS We studied 41 patients, 28 with ventricular arrhythmias (primary or due to Chagas' heart disease or idiopathic dilated cardiomyopathy; group I), 13 with sinus node dysfunction (primary or caused by Chagas' heart disease; group II), and 10 healthy controls (group III). The chronotropic effects of the IgG and immunopurified anti-beta(1)RAbs or anti-M2RAbs were assessed on cultured cardiomyocytes before and after exposure to atropine and propranolol. The biochemical effects of the IgG from 9 patients from group I, 6 from group II, and 6 controls were evaluated on COS7 cells transfected with genes encoding for beta(1),beta(2)-adrenergic receptors (cAMP increment) or M(2)-cholinergic receptors (phosphatidylinositol increment). The IgG from group I patients exerted a positive chronotropic action, with a high prevalence of anti-betaRAbs (75%) and low prevalence of anti-M2RAbs (10.7%) and induced a clear-cut and long-lasting increment in cAMP. The IgG from group II patients depressed chronotropism, with a high prevalence of anti-M2RAbs (76.9%) and low prevalence of anti-betaRAbs (15.4%) and evoked a marked augmentation of phosphatidylinositol. CONCLUSIONS Our results demonstrate a strong correlation between anti-betaRAbs and ventricular arrhythmias and anti-M2RAbs and sinus node dysfunction. Anti-betaRAbs increase and anti-M2RAbs inhibit cAMP production. These findings offer new insight into the etiology and pathophysiology of cardiac arrhythmias, with therapeutic implications.
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MESH Headings
- Adult
- Aged
- Amino Acid Sequence
- Animals
- Arrhythmia, Sinus/complications
- Arrhythmia, Sinus/immunology
- Arrhythmias, Cardiac/complications
- Arrhythmias, Cardiac/immunology
- Atropine/pharmacology
- Autoantibodies/analysis
- Autoantibodies/immunology
- COS Cells
- Cardiomyopathy, Dilated/complications
- Cardiomyopathy, Dilated/immunology
- Chagas Cardiomyopathy/complications
- Chagas Cardiomyopathy/immunology
- Cyclic AMP/metabolism
- Electrocardiography
- Female
- Heart Rate/drug effects
- Humans
- Immunoglobulin G/analysis
- Immunoglobulin G/immunology
- Male
- Middle Aged
- Molecular Sequence Data
- Phosphatidylinositols/metabolism
- Propranolol/pharmacology
- Receptors, Adrenergic, beta/chemistry
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/immunology
- Receptors, Cholinergic/chemistry
- Receptors, Cholinergic/genetics
- Receptors, Cholinergic/immunology
- Second Messenger Systems/drug effects
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186
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Shin YK, Cai GY, Weinberg A, Leary JJ, Levin MJ. Frequency of acyclovir-resistant herpes simplex virus in clinical specimens and laboratory isolates. J Clin Microbiol 2001; 39:913-7. [PMID: 11230403 PMCID: PMC87849 DOI: 10.1128/jcm.39.3.913-917.2001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The proportion of acyclovir (ACV)-resistant herpes simplex virus (HSV) isolates in clinical specimens and laboratory isolates was determined. HSV isolates in clinical specimens and laboratory isolates were cultured in the absence or presence of 5 microg of ACV per ml. The frequency of ACV-resistant HSV was calculated as (average virus titer in the wells with ACV)/(average virus titer in the wells without ACV). The mutation frequency of HSV type 1 isolates in clinical samples (directly from patient lesions) was 7.5 x 10(-4) +/- 2.5 x 10(-4) (mean +/- standard error), and that of HSV type 2 isolates was 15.0 x 10(-4) +/- 4.6 x 10(-4). The mutation frequencies of isolates derived in the laboratory from these clinical samples were very similar. Similarly, the 50% inhibitory concentrations for isolates in clinical samples and laboratory isolates were identical. The frequencies of ACV-resistant HSV types 1 and 2 were in a narrow range of 7.5 x 10(-4) to 15.0 x 10(-4) among isolates in clinical specimens and did not change for laboratory-derived pools of viral isolates.
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187
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Dankner WM, Lindsey JC, Levin MJ. Correlates of opportunistic infections in children infected with the human immunodeficiency virus managed before highly active antiretroviral therapy. Pediatr Infect Dis J 2001; 20:40-8. [PMID: 11176565 DOI: 10.1097/00006454-200101000-00008] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Opportunistic infections (OIs) are an important cause of morbidity and mortality in children infected with HIV. However, few data are available regarding the overall prevalence, incidence and immunologic correlates associated with these diseases in the pediatric HIV population. The Pediatric AIDS Clinical Trials Group (PACTG) has conducted multicenter studies in HIV-infected children since 1988 and through these studies has collected prospective data on the immunologic and virologic status of study participants and recorded complications, including infectious diseases, related to HIV infection and its treatments. Therefore data were analyzed from across 13 PACTG studies, performed before treatment with highly active antiretroviral therapy was given, to determine the rates of various infectious complications and the immunologic correlates, specifically CD4 cell counts, associated with these diseases. RESULTS OIs were tabulated from 3331 HIV-infected children who participated in 13 clinic trials undertaken before highly effective antiretroviral therapy was available. Five OIs occurred at event rates of >1.0 per 100 patient years (person years): serious bacterial infections, 15.1; herpes zoster, 2.9; disseminated Mycobacterium avium complex (DMAC), 1.8; Pneumocystis carinii pneumonia, 1.3; and tracheobronchial and esophageal candidiasis, 1.2. Six other OIs evaluated, cytomegalovirus (CMV) disease, cryptosporidiosis, tuberculosis, systemic fungal infections, toxoplasmosis and progressive multifocal leukoencephalopathy, occurred at event rates of <1.0 per 100 person years. Pneumonia (11.1 per 100 person years) and bacteremia (3.3 per 100 person years) were the most common bacterial infections. An AIDS-defining OI before entry was a risk factor for the development of a new OI during a trial. Bacterial infections, herpes zoster and tuberculosis occurred frequently at all stages of HIV infection; whereas DMAC, P. carinii pneumonia, CMV and other OIs occurred primarily in children with severe immunosuppression. CONCLUSIONS The frequency of OIs in HIV-infected children in the pre-highly active antiretroviral therapy era varies with age, pathogen, prior OI and immunologic status. Analysis of CD4 counts at the time of DMAC, CMV and PCP provide validation for current prophylaxis guidelines in children > or =2 years old. This information on infectious complications of pediatric HIV will be especially valuable for contemporary management of HIV infection that is poorly responsive to highly active antiretroviral therapy.
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Schijman AG, Vigliano C, Burgos J, Favaloro R, Perrone S, Laguens R, Levin MJ. Early diagnosis of recurrence of Trypanosoma cruzi infection by polymerase chain reaction after heart transplantation of a chronic Chagas' heart disease patient. J Heart Lung Transplant 2000; 19:1114-7. [PMID: 11077230 DOI: 10.1016/s1053-2498(00)00168-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heart transplantation is contraindicated as an effective treatment for end-stage Chagas' heart disease because of post-operative recurrence of Trypanosoma cruzi infection and reactivation of disease after immunosupression. In a follow-up study of a heart transplanted patient with Chagas' disease, we prospectively evaluated the usefulness of the polymerase chain reaction (PCR) for early diagnosis of reactivation. We monitored post-operative recurrence of Trypanosoma cruzi infection with microscopic observation of the parasite in peripheral blood (Strout's method), endomyocardial biopsies (EMBs), skin lesions, and 2 PCR assays, based on the amplification of specific T cruzi kinetoplastid and nuclear DNA sequences. During follow-up, parasite DNA was amplified in blood samples and EMB sections 41 days before we observed patent parasitemia and cutaneous manifestations of reactivation, proving that PCR is much more sensitive than direct microscopic observation for early diagnosis of disease reactivation in heart-transplanted Chagas' disease patients.
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189
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Lorenzi HA, Vázquez MP, Levin MJ. The genes for a DEAH RNA helicase, a NifU like protein and the translation factor eIF6 constitute the SZ5 locus of Trypanosoma cruzi. Mol Biochem Parasitol 2000; 111:207-11. [PMID: 11087930 DOI: 10.1016/s0166-6851(00)00297-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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190
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Sepulveda P, Liegeard P, Wallukat G, Levin MJ, Hontebeyrie M. Modulation of cardiocyte functional activity by antibodies against trypanosoma cruzi ribosomal P2 protein C terminus. Infect Immun 2000; 68:5114-9. [PMID: 10948133 PMCID: PMC101752 DOI: 10.1128/iai.68.9.5114-5119.2000] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibodies against the Trypanosoma cruzi ribosomal P2beta protein (TcP2beta) have been associated with the chronic cardiac pathology of Chagas' disease in humans. Using synthetic peptides spanning the entire TcP2beta molecule, we investigated their epitope recognition by antibodies from mice chronically infected with T. cruzi and from mice immunized with two recombinant TcP2betas. We found clear differences in epitope recognition between antibodies from T. cruzi-infected mice and mice immunized with two different recombinant TcP2betas associated with different schedules of immunization. Major epitopes recognized by antibodies from mice immunized with recombinant glutathione S-transferase (GST) or histidine (Hist) fusion TcP2beta (GST-TcP2beta or Hist-TcP2beta) are located in the central and hinge regions of the molecule. Nevertheless, mice immunized with Hist-TcP2beta were also able to elicit antibodies against the TcP2beta C terminus, a region which is highly conserved in both T. cruzi and mammal ribosomal P proteins. Strikingly, antibodies from infected animals recognized only the TcP2beta C terminus. By using these antisera with distinct profiles of epitope recognition, it could be shown that only C terminus-specific antibodies were able to increase the beating frequency of cardiomyocytes from neonatal rats in vitro by selective stimulation of the beta1-adrenergic receptor. Thus, antibodies against the TcP2beta C terminus elicited in the absence of infection are able to modulate a functional activity of host cells through a molecular mimicry mechanism.
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191
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Levin MJ. [Contribution of the Trypanosoma cruzi Genome Project to the understanding of the pathogenesis of Chagas disease]. Medicina (B Aires) 2000; 59 Suppl 2:18-24. [PMID: 10668239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The Trypanosoma cruzi Genome Project (TcGP) is developed by a consortium of laboratories brought together by two international agencies, WHO/TDR and CYTED. The TcGP is an important tool for the study of Chagas disease. It provides researchers and clinicians with information about expressed parasite genes (see TcGP database, http:@gene.dbbm.fiocruz.br) and with an important number of genomic libraries and probes (ESTs). We show with four examples how the TcGP contributes to the understanding of the pathogenesis of this infection. 1) We demonstrate how to derive antigens from ESTs, an important feature regarding the generation of anti-cardiac receptor antibodies in chagasic patients. 2) We introduce concepts such as proteome vaccinome and pathonome that include all techniques needed to analyze quickly the growing amount of genomic information. 3) We show that the genomic regions that have been already sequenced give clues as to the plastic nature of the parasite nuclear genome. Finally, 4) we show how the genome sequences can be used to study the parasite DNA that is associated to the cardiac lesions.
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Vazquez M, Ben-Dov C, Lorenzi H, Moore T, Schijman A, Levin MJ. The short interspersed repetitive element of Trypanosoma cruzi, SIRE, is part of VIPER, an unusual retroelement related to long terminal repeat retrotransposons. Proc Natl Acad Sci U S A 2000; 97:2128-33. [PMID: 10688909 PMCID: PMC15765 DOI: 10.1073/pnas.050578397] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The short interspersed repetitive element (SIRE) of Trypanosoma cruzi was first detected when comparing the sequences of loci that encode the TcP2beta genes. It is present in about 1,500-3,000 copies per genome, depending on the strain, and it is distributed in all chromosomes. An initial analysis of SIRE sequences from 21 genomic fragments allowed us to derive a consensus nucleotide sequence and structure for the element, consisting of three regions (I, II, and III) each harboring distinctive features. Analysis of 158 transcribed SIREs demonstrates that the consensus is highly conserved. The sequences of 51 cDNAs show that SIRE is included in the 3' end of several mRNAs, always transcribed from the sense strand, contributing the polyadenylation site in 63% of the cases. This study led to the characterization of VIPER (vestigial interposed retroelement), a 2,326-bp-long unusual retroelement. VIPER's 5' end is formed by the first 182 bp of SIRE, whereas its 3' end is formed by the last 220 bp of the element. Both SIRE moieties are connected by a 1,924-bp-long fragment that carries a unique ORF encoding a complete reverse transcriptase-RNase H gene whose 15 C-terminal amino acids derive from codons specified by SIRE's region II. The amino acid sequence of VIPER's reverse transcriptase-RNase H shares significant homology to that of long terminal repeat retrotransposons. The fact that SIRE and VIPER sequences are found only in the T. cruzi genome may be of relevance for studies concerning the evolution and the genome flexibility of this protozoan parasite.
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Santos MR, Lorenzi H, Porcile P, Carmo MS, Schijman A, Brandão A, Araya JE, Gomes HB, Chiurillo MA, Ramirez JL, Degrave WM, Levin MJ, da Silveira JF. Physical mapping of a 670-kb region of chromosomes XVI and XVII from the human protozoan parasite Trypanosoma cruzi encompassing the genes for two immunodominant antigens. Genome Res 1999; 9:1268-76. [PMID: 10613849 PMCID: PMC311010 DOI: 10.1101/gr.9.12.1268] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
As part of the Trypanosoma cruzi Genome Initiative, we have mapped a large portion of the chromosomal bands XVI (2.3 Mb) and XVII (2.6 Mb) containing the highly repetitive and immunodominant antigenic gene families h49 and jl8. Restriction mapping of the isolated chromosomal bands and hybridization with chromosome specific gene probes showed that genes h49 and jl8 are located in a pair of size-polymorphic homologous chromosomes. To construct the integrated map of the chromosomes harboring the h49 and jl8 loci, we used YAC, cosmid, and lambda phage overlapping clones, and long range restriction analysis using a variety of probes (i.e., known gene sequences, ESTs, polymorphic repetitive sequences, anonymous sequences, STSs generated from the YAC ends). The total length covered by the YAC contig was approximately 670 kb, and its map agreed and was complementary to the one obtained by long-range restriction fragment analysis. Average genetic marker spacing in a 105 kb region around h49 and jl8 genes was estimated to be 6.2 kb/marker. We have detected some polymorphism in the H49/JL8 antigens-encoding chromosomes, affecting also the coding regions. The physical map of this region, together with the isolation of specific chromosome markers, will contribute in the global effort to sequence the nuclear genome of this parasite.
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Vázquez M, Lorenzi H, Schijman AG, Ben-Dov C, Levin MJ. Analysis of the distribution of SIRE in the nuclear genome of Trypanosoma cruzi. Gene 1999; 239:207-16. [PMID: 10548721 DOI: 10.1016/s0378-1119(99)00387-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The short interspersed repetitive element (SIRE) of the nuclear genome of Trypanosoma cruzi was first detected when comparing the sequences of loci that encode the TcP2beta genes. The present study was designed to assess its distribution and organization in the nuclear genome of the parasite. Southern blots of genomic DNA from different strains demonstrated that each one possesses a defined and characteristic pattern of SIRE distribution. The conservation of the SIRE sequence in T. cruzi strains allowed the development of a rapid inter-SIRE PCR reaction that yields strain-specific amplicon profiles. In the T. cruzi CL Brener clone, we found 1500 copies of the element distributed in all chromosomes. 16 genomic fragments containing SIRE (SZs) were isolated and characterized. In fragments SZ10, SZ12 and SZ31, SIRE was linked to TcRel, a novel repeated sequence that constitutes the 3' end of vp85 genes. SIRE was also linked to an unknown open reading frame in fragments SZ14 and SZ23 which might be related to the subtelomeric regions of T. cruzi chromosomes. Further sequencing of SZ fragments revealed that SIRE was also linked to protein coding genes that have not yet been described in kinetoplastids such as the one coding for PRP22 helicase and a thimet oligopeptidase. To allow the rapid-generation genetic markers associated with SIRE, we developed a SIRE-bubble PCR reaction that provided several such markers for the construction of the physical map of chromosome XVI. The results herein demonstrate that SIRE-associated sites (SAS) may be of great help in physical mapping and interpretation of T. cruzi genomic sequence data.
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Vazquez MP, Levin MJ. Functional analysis of the intergenic regions of TcP2beta gene loci allowed the construction of an improved Trypanosoma cruzi expression vector. Gene 1999; 239:217-25. [PMID: 10548722 DOI: 10.1016/s0378-1119(99)00386-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
TcP2beta ribosomal protein genes in Trypanosoma cruzi are encoded by four different loci, H6.4, H1.8, H1.5 and H1.3. All loci have a similar organization, except for H1.8 that harbors two TcP2beta genes arranged in tandem and separated by a short repetitive sequence, named SIRE (short interspersed repetitive element), which is also found upstream of the first gene of the tandem and downstream of the second. In this locus the trans-splicing signal of TcP2beta is located within the SIRE element, while in the other loci it is positioned within the first 50bases upstream of the AUG with an AG acceptor site at position -12 respective to the initiation codon. Transient transfection experiments were used to evaluate the efficiency of these two different trans-splicing regions to drive CAT activity. The region named HX1 located upstream the TcP2beta H1. 8 gene was clearly more efficient than the SIRE sequence contained in the region named HX2. Therefore, we decided to use the HX1 region to ameliorate the performance of the cryptic trans-splicing signal present in the T. cruzi expression vector pRIBOTEX (Martinez-Calvillo, S., López, I., Hernandez, H., 1997. pRIBOTEX expression vector: a pTEX derivative for a rapid selection of Trypanosoma cruzi transfectants. Gene 199, 71-76). By insertion of the region HX1 downstream of the ribosomal promoter of pRIBOTEX, we constructed pRHX1CAT40 that, in stable transfected cells, was able to drive CAT activity 2760 times more efficiently than the control plasmids. Based on this, a novel plasmid vector was conceived, named pTREX-n, which retains the neo gene of pRIBOTEX as a positive selectable marker and replaces the CAT-SV40 cassette in pRHX1CAT40 by a multiple cloning site.
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196
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Levin MJ, Pfeiffer CJ. Photoreceptor ultrastructure of the amphipod, Cyamus ceti (Linné, 1758), an ectoparasite of bowhead, right and gray whales. JOURNAL OF SUBMICROSCOPIC CYTOLOGY AND PATHOLOGY 1999; 31:397-405. [PMID: 10626006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Light and electron microscopic findings are presented for the first time on a species of amphipod whale louse, Cyamus ceti, with reference to the paired photoreceptor structures of the head. Whale lice are crustacean ectoparasites of large, slow moving whales. Twenty-two known species parasitize mainly baleens but also toothed whales. Samples were collected from Alaskan bowhead whales during an Eskimo hunt. The photoreceptors, or compound eyes, were sessile and located on the dorsal cephalon. Each photoreceptor contained approximately 50 visual ommatidial units. The general organization was similar to other amphipod crustacean compound eyes. The single ommatidial unit consisted of 1) an overlying cuticle, 2) crystalline cone secreted by cone cells, 3) a fusiform layered rhabdom, 4) surrounding pigmented retinular cells, and 5) basal lamina and axon. The cuticle over each eye was translucent, convex, and thinner than the rest of the cranial cuticle. The photosensitive rhabdom contained a central core of alternating microvillous projections, and the rhabdomere unit was formed by five or six retinular cells. There were numerous electron-dense and electron-lucent granules within the cytoplasm of the retinular cells, corresponding to visual pigment or reflecting granules. The eyes most likely play a role in detecting light direction, duration and/or intensity, which may direct molting, reproduction, or other functions of this cetacean ectoparasite.
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197
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Umezawa ES, Bastos SF, Camargo ME, Yamauchi LM, Santos MR, Gonzalez A, Zingales B, Levin MJ, Sousa O, Rangel-Aldao R, da Silveira JF. Evaluation of recombinant antigens for serodiagnosis of Chagas' disease in South and Central America. J Clin Microbiol 1999; 37:1554-60. [PMID: 10203520 PMCID: PMC84826 DOI: 10.1128/jcm.37.5.1554-1560.1999] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The commercially available diagnostic tests for Chagas' disease employ whole extracts or semipurified fractions of Trypanosoma cruzi epimastigotes. Considerable variation in the reproducibility and reliability of these tests has been reported by different research laboratories, mainly due to cross-reactivity with other pathogens and standardization of the reagents. The use of recombinant antigens for the serodiagnosis of Chagas' disease is recommended to increase the sensitivity and specificity of serological tests. Expressed in Escherichia coli, as fusion products with glutathione S-transferase, six T. cruzi recombinant antigens (H49, JL7, A13, B13, JL8, and 1F8) were evaluated in an enzyme-linked immunosorbent assay for Chagas' disease. The study was carried out with a panel of 541 serum samples of chagasic and nonchagasic patients from nine countries of Latin America (Argentina, Bolivia, Brazil, Chile, Colombia, El Salvador, Guatemala, Honduras, and Venezuela). The optimal concentration of each recombinant antigen for coating of plates was determined with the help of 125I-labelled recombinant proteins. While the specificity of the epimastigote antigen was 84% because of false positives from leishmaniasis cases, for the recombinant antigens it varied from 96.2 to 99.6%. Recombinant antigens reacted with 79 to 100% of serum samples from chronic chagasic patients. In this way, it is proposed that a mixture of a few T. cruzi recombinant antigens should be employed in a diagnostic kit to minimize individual variation and promote high sensitivity in the diagnosis of Chagas' disease.
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198
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Chan KH, Winslow CP, Levin MJ, Abzug MJ, Shira JE, Liu AH, Simoes EA, Strain JD, Stool SE. Clinical practice guidelines for the management of chronic sinusitis in children. Otolaryngol Head Neck Surg 1999; 120:328-34. [PMID: 10064633 DOI: 10.1016/s0194-5998(99)70270-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Chronic sinusitis in children is a common and vexing disease for clinicians and the public. There are insufficient data in the literature to develop an evidence-based clinical guideline. Experience in managing pediatric chronic sinusitis has been gained through a multidisciplinary clinic at our institution during the past 3 years. A panel of experts was formed, and with the guidance of a guideline methodologist, the development of a rigorous outcome-based guideline was undertaken. Symptom-improvement and recurrence estimates for a variety of medical and surgical treatments were assessed. Wide probability estimates were made by the panelists in most cases. Although we refrained from making specific recommendations, we developed a ranked series of practical treatment options taking into account side effects and costs.
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199
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Kaplan D, Baldi C, Chiaramonte MG, Fernandez MM, Levin MJ, Malchiodi E, Baldi A. Expression of a recombinant Fab antibody fragment against cruzipain, the major cysteine proteinase of Trypanosoma cruzi. Biochem Biophys Res Commun 1998; 253:53-8. [PMID: 9875219 DOI: 10.1006/bbrc.1998.9654] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cruzipain, the major proteinase of Trypanosoma cruzi, plays an important role in the biology of this parasite. This study reports the development of a recombinant Fab antibody, using RNA isolated from the anti-Ag163B6 hybridoma against cruzipain. This procedure involves the use of cDNAs obtained with the aid of a specific set of primers complementary to the complete light kappa chain (L kappa) and the first two domains of the IgG1 heavy chain (VH/CH1). These products were subsequently cloned in the pComb3 system, from which the gIII gene had been removed, and expressed in Escherichia coli cells. The recombinant Fab molecule recognized cruzipain by ELISA, in a fashion similar to the original mAb anti-Ag163B6. Nucleotide sequence analysis of the recombinant molecule, together with its immunological recognition by specific anti-mouse IgG (Fab)2, indicated the immunoglobulin nature of the recombinant product. Moreover, both the mAb anti-Ag163B6 and the soluble Fab fragment described here react similarly with the intact parasite surface, as observed in an indirect immunofluorescence assay. In conclusion, our recombinant Fab anti-Ag 163B6 allows the possible use of this molecule for diagnosis, antigen purification, and eventually treatment of Chagas-afflicted individuals.
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Irwin M, Costlow C, Williams H, Artin KH, Chan CY, Stinson DL, Levin MJ, Hayward AR, Oxman MN. Cellular immunity to varicella-zoster virus in patients with major depression. J Infect Dis 1998; 178 Suppl 1:S104-8. [PMID: 9852986 DOI: 10.1086/514272] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The incidence of herpes zoster increases markedly with advancing age, and this appears to be causally related to an age-dependent decline in varicella-zoster virus (VZV)-specific cellular immunity. Psychologic stress has also been linked to the occurrence of herpes zoster, but the mechanism involved has not been investigated. This study examined the relationship between major depression and VZV-specific cellular immunity by comparing VZV-specific responder cell frequency (RCF) in adults with major depression (n = 11) to that in age- and sex-matched nondepressed controls (n = 11) and in a larger group of nondepressed adults who were > or = 60 years old. VZV-specific RCF in depressed patients was markedly reduced compared with the RCF in matched controls (t = 2.7, P < .02). In fact, the levels of VZV-specific RCF in the depressed patients were comparable in magnitude to the low levels found in adults > or = 60 years of age. These data indicate that major depression is associated with a marked decline in VZV-specific cellular immunity.
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