Polyphosphoramidate gene carriers: effect of charge group on gene transfer efficiency

Cationic polymeric carriers have been widely used for gene delivery. However, the structure-function relationship, especially the effect of charge groups of cationic polymeric carriers on the transfection activity, is poorly understood. To examine this important parameter, a series of cationic polymers, polyphosphoramidates (PPAs) with an identical backbone, same side chain spacer, similar molecular weights but different charge groups containing primary to quaternary amino groups (PPA-EA, PPA-MEA, PPA-DMA and PPA-TMA, Figure 1) were synthesized. The DNA-binding affinity of these four PPAs increased in the order of PPA-EA<PPA-MEA<PPA-DMA approximately PPA-TMA. The cytotoxicity decreased in the order of PPA-EA>PPA-MEA>PPA-DMA>PPA-TMA. Particle size and zeta potential of four different types of PPA/DNA nanoparticles did not show significant correlation with PPA structure. These PPAs did not show significant buffering capacity within pH 5-7, even though transfection mediated by PPA-EA was the only one that seemed to be limited by endolysomal escape. Endocytosis of DNA mediated by PPAs was also similar (17-22%) for all four PPAs. However, the transfection efficiency of these PPAs varied significantly. In vitro transfection efficiency of PPAs decreased in the order of PPA-EA>PPA-MEA>PPA-DMA approximately PPA-TMA. Nanoparticles with PPA-EA containing primary amino groups gave the highest transfection efficiency in cell lines at the charge ratios from 6/1 to 20/1 (+/-). Matching the trend of transfection efficiency observed in vitro, PPA-EA mediated the highest transgene expression, comparable to that of polyethylenimine, in the spinal cord following intrathecal injection of the nanoparticles. These results establish that PPA gene carriers with primary amino group side chains are more potent than those with secondary, tertiary or quaternary amino groups in vitro and in the intrathecal gene delivery model.

CNS gene transfer mediated by a novel controlled release system based on DNA complexes of degradable polycation PPE-EA: a comparison with polyethylenimine/DNA complexes

Nonviral gene delivery systems based upon polycation/plasmid DNA complexes are quickly gaining recognition as an alternative to viral gene vectors for their potential in avoiding immunogenicity and toxicity problems inherent in viral systems. We investigated in this study the feasibility of using a controlled release system based on DNA complexed with a recently developed polymeric gene carrier, polyaminoethyl propylene phosphate (PPE-EA), to achieve gene transfer in the brain. A unique feature of this gene delivery system is the biodegradability of PPE-EA, which can provide a sustained release of DNA at different rates depending on the charge ratio of the polymer to DNA. PPE-EA/DNA complexes, naked DNA, and DNA complexed with polyethylenimine (PEI), a nondegradable cationic polymer known to be an effective gene carrier, were injected intracisternally into the mouse cerebrospinal fluid. Transgene expression mediated by naked DNA was mainly detected in the brain stem, a region close to the injection site. With either PPE-EA or PEI as a carrier, higher levels of gene expression could be detected in the cerebral cortex, basal ganglia, and diencephalons. Transgene expression in the brain mediated by PPE-EA/DNA complexes at an N/P ratio of 2 persisted for at least 4 weeks, with a significant higher level than that produced by either naked plasmid DNA or PEI/DNA at the 4-week time point. Furthermore, PPE-EA displayed much lower toxicity in cultured neural cells as compared to PEI and did not cause detectable pathological changes in the central nervous system (CNS). The results established the potential of PPE-EA as a new and biocompatible gene carrier to achieve sustained gene expression in the CNS.

Microbial fed-batch production of 1,3-propanediol by Klebsiella pneumoniae under micro-aerobic conditions

The microbial production of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae under micro-aerobic conditions was investigated in this study. The experimental results of batch fermentation showed that the final concentration and yield of 1,3-PD on glycerol under micro-aerobic conditions approached values achieved under anaerobic conditions. However, less ethanol was produced under microaerobic than anaerobic conditions at the end of fermentation. The batch micro-aerobic fermentation time was markedly shorter than that of anaerobic fermentation. This led to an increment of productivity of 1,3-PD. For instance, the concentration, molar yield, and productivity of 1,3-PD of batch micro-aerobic fermentation by K. pneumoniae DSM 2026 were 17.65 g/l, 56.13%, and 2.94 g l(-1) h(-1), respectively, with a fermentation time of 6 h and an initial glycerol concentration of 40 g/l. Compared with DSM 2026, the microbial growth of K. pneumoniae AS 1.1736 was slow and the concentration of 1,3-PD was low under the same conditions. Furthermore, the microbial growth in fed-batch fermentation by K. pneumoniae DSM 2026 was faster under micro-aerobic than anaerobic conditions. The concentration, molar yield, and productivity of 1,3-PD in fed-batch fermentation under micro-aerobic conditions were 59.50 g/l, 51.75%, and 1.57 g l(-1) h(-1), respectively. The volumetric productivity of 1,3-PD under microaerobic conditions was almost twice that of anaerobic fed-batch fermentation, at 1.57 and 0.80 g l(-1) h(-1), respectively.

Repeated intrathecal administration of plasmid DNA complexed with polyethylene glycol-grafted polyethylenimine led to prolonged transgene expression in the spinal cord

Gene delivery into the spinal cord provides a potential approach to the treatment of spinal cord traumatic injury, amyotrophic lateral sclerosis, and spinal muscular atrophy. These disorders progress over long periods of time, necessitating a stable expression of functional genes at therapeutic levels for months or years. We investigated in this study the feasibility of achieving prolonged transgene expression in the rat spinal cord through repeated intrathecal administration of plasmid DNA complexed with 25 kDa polyethylenimine (PEI) into the lumbar subarachnoid space. With a single injection, DNA/PEI complexes could provide transgene expression in the spinal cord 40-fold higher than naked plasmid DNA. The transgene expression at the initial level persisted for about 5 days, with a low-level expression being detectable for at least 8 weeks. When repeated dosing was tested, a 70% attenuation of gene expression was observed following reinjection at a 2-week interval. This attenuation was associated with apoptotic cell death and detected even using complexes containing a noncoding DNA that did not mediate any gene expression. When each component of the complexes, PEI polymer or naked DNA alone, were tested in the first dosing, no reduction was found. Using polyethylene glycol (PEG)-grafted PEI for DNA complexes, no attenuation of gene expression was detected after repeated intrathecal injections, even in those rats receiving three doses, administered 2 weeks apart. Lumbar puncture is a routine and relatively nontraumatic clinical procedure. Repeated administration of DNA complexed with PEG-grafted PEI through this less invasive route may prolong the time span of transgene expression when needed, providing a viable strategy for the gene therapy of spinal cord disorders.

Polyethylene glycol modified polyethylenimine for improved CNS gene transfer: effects of PEGylation extent

Poor solubility of polycation complexes with DNA is one drawback for their in vivo use as gene delivery systems. PEGylation often can improve the solubility of the complexes, minimize their aggregation and reduce their interaction with proteins in the physiological fluid. We investigated in vivo application of polyethylene glycol (PEG) modified polyethylenimine (PEI) for gene expression in the central nervous system. Varied numbers of linear PEG (2 kDa) were grafted to branched PEI (25 kDa) from the average number of PEG per one PEI macromolecule at 1-14.5. While higher degrees of PEG grafting did not improve gene expression, a PEI conjugate with one segment of PEG was able to mediate transgene expression in the spinal cord up to 11-fold higher than PEI homopolymer after intrathecal administration of its DNA complexes into the lumbar spinal cord subarachnoid space. Improved gene expression with this conjugate was observed as well in the brain after the lumbar injection. As assessed in in vitro studies, the PEI conjugate with a low degree of PEG grafting was able to reduce the size of polymer DNA complexes, prevent the aggregation of complexes, decrease the interactions of the complexes with serum proteins, counter the inhibition of serum to gene transfer, and enhance transfection efficiency, although not significant in affecting complex formation and reducing in vitro cell toxicity of PEI. The study provides the in vivo evidence that an appropriate degree of PEG modification is decisive in improving gene transfer mediated by PEGylated polymers.

Reverse transcription slippage over the mRNA secondary structure of the LIP1 gene

The secondary structures in mRNA often cause early termination during the synthesis of cDNA. In an attempt to determine the 5'-untranslated region (UTR) of the gene LIP1 using the RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE), we found that reverse transcriptases skipped over the LIP1 RNA secondary structures and continued the DNA synthesis through RNA adapter sequences without early termination. A fragment of only three nucleotides upstream of the LIP1 translation initiation codon was obtained from the initial RACE-PCR, which was much shorter than the 57-nucleotide fragment obtained from the cDNA library screening. Analysis of the 5' end sequence indicates the presence of high G+C content and stem-loop secondary structures. Therefore, optimizations of the reaction with high temperature (70 degrees C) and a thermostable reverse transcriptase were performed to synthesize the first-strand cDNA, which was determined to have 73 nucleotides in the 5'-UTR. These results suggest that, under cDNA synthesis conditions at 42 degrees C and 60 degrees C, the reverse transcriptases skipped over the stem-loop structures of LIP1 mRNA and continued the cDNA synthesis until they reached the RNA adapter sequences. Thisfinding draws attention to adopting optimized conditions for cDNA synthesis on G+C-rich RNA templates.

Seroprevalence of Kaposi's sarcoma-associated herpesvirus infection among blood donors from Texas

PURPOSE

Kaposi's sarcoma-associated herpesvirus (KSHV), a gammaherpesvirus recently discovered among AIDS patients with Kaposi's sarcoma, is a potential candidate for screening in blood and plasma donors. While a number of studies have assessed KSHV infection among U.S. blood donors, larger-scale population-based studies would be necessary to develop more refined estimates of the magnitude and variation of KSHV infection across different geographic regions of the U.S. blood supply. The goal of the present study, therefore, was to determine the seroprevalence of KSHV infection and to assess demographic correlates of KSHV infection among south Texas blood donors.

METHODS

KSHV infection was determined using specific serologic assays that measure antibodies to KSHV latent and lytic antigens.

RESULTS

The overall seroprevalence of KSHV in Texas blood donors (15.0%) is substantially higher than previously reported among blood donor and general population samples in the United States. This high rate of KSHV infection persisted across most of the sociodemographic subgroups under study but was particularly elevated among participants with less than a high school education. The infection rate also increased linearly with age.

CONCLUSIONS

The elevated infection rate reported in the present study suggests that screening methods to detect KSHV infection in blood donors should be considered. In view of the etiologic role of KSHV for several malignancies, it would be important for future studies to directly assess the risk of KSHV transmission via blood transfusion.

Transgene Expression in the Brain Stem Effected by Intramuscular Injection of Polyethylenimine/DNA Complexes

Gene delivery into the CNS without tissue destruction is challenging. As neurons are capable of taking up exogenous particulates from the muscles that they innervate, we investigated the feasibility of achieving gene transfer in CNS neurons by peripheral intramuscular injection of plasmid DNA complexed with the cationic polymer polyethylenimine (PEI) in the rat hypoglossal system. Using the luciferase reporter gene driven by a Rous sarcoma virus promoter, transgene expression of up to 4 x 10(6) RLU per brain stem at 20 microg of plasmid DNA was achieved after tongue injection. Using lacZ as a reporter gene, transgene expression in the brain stem was detected in hypoglossal motor neurons, a group of neurons that innervate tongue muscles. The plasmid DNA was detected by PCR analysis in the brain-stem samples, demonstrating that the PEI/DNA complexes had migrated by retrograde axonal transport to neuronal cell bodies in the brain stem after being internalized by nerve terminals in the tongue muscle. Using a therapeutic bcl-2 gene driven by a cytomegalovirus promoter and Western blotting, transgene expression was detectable in the brain stem as early as 18 h after tongue injection and lasted for at least 2 weeks. Two lipid transfection agents, GenePORTER and TransFast, mediated a weak gene expression in the hypoglossal system, but not two polymers, poly-l-lysine and chitosan. The nonviral neuronal gene delivery method established in this study bypasses the blood-brain barrier and suggests a possible therapeutic strategy for noninvasive CNS gene transfer.

Suppression of oncogenic viral interferon regulatory factor (vIRF) of Kaposi's sarcoma-associated herpesvirus by ribozyme-mediated cleavage

Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV8) has been etiologically associated with several malignancies including Kaposi's sarcoma and primary effusion lymphoma. Oncogenic viral interferon regulatory factor (vIRF) encoded by KSHV ORF-K9 is a homologue of cellular interferon regulatory factor (IRF), and has been demonstrated to inhibit type I/II interferon signal transduction and transform NIH3T3 cells through the interactions with IRF-1, IRF-3, and CBP/p300 proteins. To counteract vIRF's pathogenic role, we have developed five ribozymes targeting ORF-K9 mRNA to suppress vIRF expression. The vIRF RNA substrates were cleaved up to 80% in a substrate-specific manner in transcript cleavage assays in vitro. In a transient transfection assay, two of the ribozymes efficiently suppressed the expression of vIRF protein measured by dual-color immunofluorescence assay that simultaneously detects the expression of both vIRF protein and ribozyme. Flow cytometry analysis showed that these ribozymes reduced vIRF expression up to 76%. A mutant ribozyme had no cleavage activity in vitro, but exhibited antisense effect in vivo. These results suggest that the ribozymes may provide a new approach for functional knockout of vIRF gene, and are potential candidates of antiviral therapy for KSHV-related malignancies.

Characterization of the promoter region of the viral interferon regulatory factor encoded by Kaposi's sarcoma-associated herpesvirus

Viral interferon regulatory factor (vIRF) encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) inhibits the expression of interferon-responsive genes, causes cellular transformation and transactivates KSHV genes. In the present study, we characterized the mRNA expression pattern of the vIRF gene and its promoter. A vIRF transcript of 1.7 kb in size was detected in low level in uninduced KSHV-infected cells and its expression was inducible by 12-O-tetradecanoylphorbol-13-acetate (TPA), sensitive to cycloheximide and resistant to phosphonoacetic acid. The transcription start site was mapped to 79 nt upstream of the ATG initiation site by 5'-RACE. Mutagenesis analysis identified a region between -56 and the transcription start site (+1) as the minimal promoter region that contains a functional TATA box at -27. A region between -337 and -125 contains a repressor domain negated by sequence from -991 to -499 in BCBL-1 cells, a region which was also identified to be responsive to TPA induction. These results demonstrate vIRF as a KSHV early gene, identify its promoter and define the promoter regions that contain regulatory elements controlling vIRF transcription.

Distinct distribution of rare US genotypes of Kaposi's sarcoma-associated herpesvirus (KSHV) in South Texas: implications for KSHV epidemiology

Genotypes of Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) from patients with KS in South Texas were examined. Open-reading frame (ORF)-K1 and ORF-K15 DNA segments from 16 KSHV isolates were amplified by polymerase chain reaction, and KSHV subtypes were assigned on the basis of sequence variations. K1 genotyping showed that 75% exhibited C subtype and 25% exhibited A subtype. K15 genotyping showed that 56% exhibited M form, of which 89% exhibited C3 K1 subtype and 44% exhibited P form. A unique isolate was found and was classified as C6 clade. All of the M KSHV isolates had been obtained from human immunodeficiency virus-negative classic KS patients >50 years of age, of whom 78% were Hispanic. Conversely, all KS patients with AIDS were <36 years of age and exhibited P form KSHV. These findings indicate that C3/M KSHV genotypes are more prevalent in South Texas (50%) than in other US regions (3%) and that M form KSHV likely existed in this region long before the AIDS epidemic.

Evaluation of human herpesvirus type 8 infection in childhood langerhans cell histiocytosis

The etiology of Langerhans cell histiocytosis (LCH) is unknown. Viral causes, including human herpesvirus type 6 (HHV6), have been suggested but remain unproved. The recently discovered human herpesvirus type 8 (HHV8), the cause of Kaposi's sarcoma, infects dendritic cells in the bone marrow associated with multiple myeloma. Evidence for an association of HHV8 infection with LCH in children was studied by two approaches: indirectly by HHV8-specific serologic assays and directly by detection of HHV8 sequences using polymerase chain reaction in affected bone marrow samples. Using three different assays specific for HHV8 antibodies, 3 of 10 (30%) children with LCH had detectable HHV8 antibodies, which was not different from the prevalence of 5 of 30 (17%) in healthy controls of similar age (P = 0.65). Of bone marrow samples from three additional children with LCH, all had amplifiable DNA but were negative for HHV8 sequences. These studies of a small number of patients do not demonstrate an increased prevalence of HHV8 infection in children with LCH, and they do not suggest a causal role for HHV8 in the etiology of LCH.

Kaposi's sarcoma-associated herpesvirus gene sequences are detectable at low copy number in primary amyloidosis

Primary amyloidosis (AL), like multiple myeloma (MM), results from a clonal proliferation of plasma cells. Recent detection of Kaposi's sarcoma-associated herpesvirus (KSHV) gene sequences in MM patients, although controversial, suggested that KSHV may also be present in AL. In the present study, we assayed for KSHV gene sequences in patients with primary AL independently in 2 laboratories. Nested polymerase chain reaction (PCR) was performed on DNA isolated from 21 bone marrow (BM) core biopsy samples to amplify orf26 and orf72, 2 regions of the KSHV genome. Eighteen of 21 (86%) BM core biopsy samples were KSHV PCR positive. BM aspirates from 16 of these 21 AL patients were cultured for 4-6 weeks to generate long term bone marrow stromal cells (LT-BMSCs), and 13 of 16 (81%) LT-BMSCs were also KSHV PCR positive. Results in all but 1 sample were consistent in the 2 laboratories. Sequencing of the PCR products in the 2 laboratories confirmed 94-98% and 95-98% homology to the published orf 26 and orf 72 KSHV gene sequences respectively, with interpatient base pair differences. Despite the presence of KSHV gene sequences, only 4/18 (22%) KSHV PCR positive patients demonstrated KSHV lytic antibodies by immunoblot assay. A sensitive assay performed on the BCBL-1 cell line confirmed the presence of KSHV at a very low copy number in AL. PCR using patient specific light chain gene primers also amplified DNA isolated from 2 AL BM core biopsies and 3 AL LT-BMSCs which were KSHV PCR positive, suggesting the presence of clonotypic cells. Our results therefore demonstrate KSHV gene sequences albeit at a very low copy number in the majority of BM core biopsies and LT-BMSCs from AL patients, and serological responses in only a minority of cases. Ongoing studies to identify viral transcripts and gene products will determine the biological relevance of KSHV in AL disease pathogenesis.

Absence of herpesvirus DNA sequences in the 5T murine model of human multiple myeloma

Kaposi's sarcoma-associated herpesvirus (KSHV, also known as HHV-8) has been found in patients with multiple myeloma (MM) and postulated to be aetiologically associated with the development of this common plasma cell malignancy. A murine model of MM was previously established in which intravenous transfer of 5T myeloma cells into C57BL/KaLwRij mice resulted in characteristic features of human MM. In the present study, we sought to identify herpesvirus DNA sequences in this murine model of MM through polymerase chain reaction (PCR) analysis using primers specific for KSHV, murine herpesvirus 68 (MHV68) and murine cytomegalovirus (MCMV) as well as consensus primers designed from the highly conserved DNA polymerase genes of the Herpesviridae family. None of the DNA samples from whole bone marrow (n = 6) or dendritic cells enriched by long-term culture (n = 8) of 5T myeloma-bearing mice as well as the 5T myeloma cell lines (n = 3) maintained in long-term culture yielded specific amplification products in any of the PCR assays. Two KSHV-specific serological assays measuring antibodies to KSHV latent and lytic antigens also failed to detect the presence of anti-KSHV antibodies in mice that developed MM. These results suggest that the development of 5T murine MM is unlikely to be involved with KSHV or a KSHV-like murine herpesvirus.

Epidemiology of herpesvirus papio infection in a large captive baboon colony: similarities to Epstein-Barr virus infection in humans

The epidemiology of herpesvirus papio, a lymphocryptovirus similar to Epstein-Barr virus (EBV), was studied in a captive colony of >1900 baboons. Herpesvirus papio IgG antibody titers were measured by IFA. In total, 438 specimens from 296 baboons were assessed, including 116 serial specimens from 52 juveniles and 6 infants studied monthly for 1 year following birth and at age 18 months. Maternally derived antibody reached a nadir at 4 months of age. About 75% of animals at 12 months of age and >95% of animals after age 24 months demonstrated serologic evidence of herpesvirus papio infection. After age 3 years, the geometric mean titer was 1:60-75. The epidemiology of herpesvirus papio infection in baboons closely parallels that of EBV infection in humans. An animal model of lymphocryptovirus infection will facilitate investigations of human lymphocryptovirus biology.

Molecular polymorphism of Kaposi's sarcoma-associated herpesvirus (Human herpesvirus 8) latent nuclear antigen: evidence for a large repertoire of viral genotypes and dual infection with different viral genotypes

Molecular polymorphism was found in Kaposi's sarcoma-associated herpesvirus (KSHV) latent nuclear antigen (LNA), mapped to the internal repeat domain of the encoding orf73 gene, and used to develop a novel genotyping technique, KSHV LNA genotyping (KVNAtyping). KVNAtype was stable during latent and lytic viral replication in cell culture and in humans. Diverse KVNAtypes were identified in 43 specimens: 6 KSHV cell lines and 6 Kaposi's sarcoma (KS) and 4 primary effusion lymphoma (PEL) tumor samples from the United States, 15 KS tumor samples from Italy, and 12 KS tumor samples from Zambia. A single KVNAtype was detected in each of 41 specimens, and 2 KVNAtypes were detected in each of 2 KS specimens. Multifocal KS from 3 patients showed the same single KVNAtype at all sites in each patient. These results demonstrate a large repertoire of KSHV genotypes and suggest that the development of most KSs and PELs is associated with a single viral genotype.

Kaposi's sarcoma-associated herpesvirus: a sexually transmissible infection?

We examined sexual behavior as a risk factor for Kaposi's sarcoma-associated herpesvirus (KSHV) infection and examined the relation between KSHV seropositivity and development of KS in cross-sectional and cohort studies of 130 homosexual men diagnosed with AIDS in Sydney, Australia during the period from 1991 to 1993. KSHV serology was measured using antibody tests to latency-associated nuclear antigen (LANA) and lytically expressed open reading frame (ORF) 65.2. In the cross-sectional analysis, 52% (68) of study subjects were KSHV-seropositive by either assay. KSHV-seropositive men were significantly more likely to be seropositive to both herpes simplex type 2 (odds ratio [OR] 3.0; 95% confidence interval [CI], 1.2-7.5 for LANA and OR 2.8; 95% CI, 1.3-6.0 for ORF 65) and hepatitis A virus (OR 2.2; 95% CI, 1.1-4.5 for ORF 65). KSHV-seropositive men reported nonsignificantly more casual sexual partners and were nonsignificantly more likely to report insertive oroanal contact with casual partners. These data suggest that KSHV might be sexually transmitted among homosexual men. Men were observed until October 1996 for development of KS. Those seropositive to either KSHV assay at baseline were more likely than the seronegative to develop KS during follow-up (rate ratio [RR] 4.4; 95% CI, 1.9-10.2). Of those seropositive for KSHV, 53% developed KS.

Human herpesvirus-8 (HHV-8) associated with small non-cleaved cell lymphoma in a child with AIDS

The association of human herpesvirus-8 (HHV-8) with a small non-cleaved cell lymphoma is described in a child with the acquired immunodeficiency syndrome (AIDS) who developed a malignant pleural effusion and radiologic evidence of multiple solid tumors. HHV-8 DNA and Epstein-Barr virus DNA were identified in pleural fluid cells by polymerase chain reaction (PCR) amplification. The serum antibody titer against lytic HHV-8 proteins was 1:640; antibodies to latent HHV-8 proteins were not detected. Cytogenetic analysis of malignant cells revealed three abnormal karyotypes sharing the common finding of a t(8;14) translocation. Rearrangement of c-myc was demonstrated by PCR analysis. Oligoclonal JH immunoglobulin bands were found. Insufficient pleural fluid cells were available to permit localization of HHV-8 to malignant cells by in situ hybridization. This malignancy contrasts with HHV-8-associated lymphomas reported in adult patients with AIDS with respect to cell morphology, c-myc translocation, and oligoclonal immunoglobulin gene rearrangement. HHV-8 is associated with a wider spectrum of malignancies than recognized previously.

Antibodies to Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in patients with multiple myeloma

Kaposi's sarcoma-associated herpesvirus (KSHV) serologic assays were used to detect specific antibodies to KSHV lytic and latent antigens in 27 patients with multiple myeloma, 27 control patients with other cancers, and 50 random blood donors. Antibodies to KSHV recombinant minor capsid antigen orf65 were found in 81% of patients with multiple myeloma, 22% of control patients with other cancers, and 6% of the blood donors. Antibodies to KSHV latent nuclear antigens were found in 52% of patients with multiple myeloma, 26% of control patients with other cancers, and 2% of the blood donors. All of the 11 patients with progressive multiple myeloma were KSHV-seropositive. Antibodies to Epstein-Barr virus nuclear antigen 1 were present in 89% of patients with multiple myeloma, 93% of control patients with other cancers, and 88% of the blood donors. These data support the possible association of KSHV infection with multiple myeloma, particularly with progressive disease.

Artificial imitation of glutathione peroxidase with 6-selenium-bridged beta-cyclodextrin

On the basis of cyclodextrin, 6-selenium bridged beta-cyclodextrin (6-beta-CD-Se-Se-beta-CD, known as 6-SeCD) was synthesized by the selective tosylation of beta-cyclodextrin and nucleophilic displacement by sodium hydroselenide to imitate glutathione peroxidase (GPX). The GPX activity of diselenide 6-SeCD is 4.3 times that of PZ51. The structure of the mimic 6-SeCD was characterized by means of laser mass spectroscopy, elemental analysis, IR and 1H NMR. The selenium content and its valence in 6-SeCD were determined by means of X-ray photoelectron spectra. Kinetics of the mimic showed that its enzymatic behavior was similar to that of native GPX.

Establishing a KSHV+ cell line (BCP-1) from peripheral blood and characterizing its growth in Nod/SCID mice

Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) sequences are present in primary effusion lymphomas (PEL). KSHV+ cell lines have been established from such lymphomas. Here we report the first description of the establishment of a KSHV+, EBV- cell line (BCP-1) from the peripheral blood of a patient with PEL. Using this cell line and a KSHV+, EBV+ PEL cell line (HBL-6) previously established from ascitic fluid, we investigated whether in nonobese diabetic/severe combined immunodeficiency disease (Nod/SCID) mice tumors representing PEL can be established. When injected intravenously (IV) into Nod/SCID mice, BCP-1 and HBL-6 infiltrated organs, with only occasional macroscopic tumor formation. Intraperitoneal injections (ip) led to the development of ascites and diffuse infiltration of organs, without obviously solid lymphoma formation, resembling the diffuse nature of human PEL. To investigate a possible mechanism for the peculiar phenotype of PEL, we examine the presence of adhesion molecules and homing markers on PEL cells before and after growing in mice. Both BCP-1 and HBL-6 cells lack expression of important cytoadhesion molecules including CD11a and CD18 (LFA1 alpha and beta chains), CD29, CD31, CD44, CD54 (ICAM-1), and CD62L and E (L and E selectins).

KSHV ORF K9 (vIRF) is an oncogene which inhibits the interferon signaling pathway

Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus linked to the development of Kaposi's sarcoma and a rare B cell lymphoma, primary effusion lymphoma. The KSHV gene ORF K9 encodes vIRF which is a protein with low but significant homology to members of the interferon (IFN) regulatory factor (IRF) family responsible for regulating intracellular interferon signal transduction (Moore PS, Boshoff C, Weiss RA and Chang Y. (1996). Science, 274, 1739-1744). vIRF inhibits IFN-beta signal transduction as measured using an IFN-responsive ISG54 reporter construct co-transfected with ORF K9 into HeLa and 293 cells. vIRF also suppresses genes under IFN regulatory control as shown by inhibition of the IFN-beta inducibility of p21WAF1/CIP1, however, no direct DNA-binding or protein-protein interactions characteristic for IRF repressor proteins were identified. Stable transfectant NIH3T3 clones expressing vIRF grew in soft agar and at low serum concentrations, lost contact inhibition and formed tumors after injection into nude mice indicating that vIRF has the properties of a viral oncogene. Since vIRF is primarily expressed in KSHV-infected B cells, not KS spindle cells, this study suggests that vIRF is a transforming oncogene active in B cell neoplasias that may provide a unique immune escape mechanism for infected cells. This data is consistent with tumor suppressor pathways serving a dual function as host cell antiviral pathways.

Risk of Kaposi's sarcoma-associated herpes virus transmission from donor allografts among Italian posttransplant Kaposi's sarcoma patients

Kaposi's sarcoma-associated herpesvirus (KSHV) is a newly discovered herpes virus found in all forms of Kaposi's sarcoma (KS) including KS among immunosuppressed transplant patients. It is unknown whether this virus is transmitted by organ transplantation or is reactivated during immunosuppression among those patients infected before transplantation. To investigate the risk of KSHV transmission during organ transplantation, we conducted a case-control study of transplant recipients with and without KS matched to their respective donors. Sera were collected at time of transplantation and tested in a randomized and blinded fashion using four KSHV serologic assays testing for antibodies to both latent and lytic phase antigens. Ten (91%) of 11 organ recipients who developed KS were seropositive prior to transplantation by one or more of the assays compared with two (12%) of 17 control organ recipients (OR = 75, 95% CI = 4.7, 3500). KS cases were more likely to have been born in southern Italy where KS is endemic than the recipient controls or either donor group. Only four (36%) of 11 donors to case patients and three (18%) of 17 donors to control patients were seropositive (P = .38, two-tailed Fisher's exact test). KSHV transmission could not be ruled out for the single KS patient seronegative at transplantation and clear evidence for organ-related transmission was found for another KS patient outside of the case-control study. Antibodies to KSHV are detectable in the sera from most transplant recipients before initiation of immunosuppressive treatment suggesting that KS among immunosuppressed transplant patients is primarily due to virus reactivation. KSHV transmission, however, from an infected allograft can occur, and our study reports the first documented case of person-to-person transmission of KSHV.