bluuebunny/crossref_metadata_2025_split huggingface dataset:
Primary Occult Hepadnavirus Infection Induces Virus-Specific T-Cell and Aberrant Cytokine Responses in the Absence of Antiviral Antibody Reactivity in the Woodchuck Model of Hepatitis B Virus Infection
Authors: Gujar Shashi A. , Michalak Tomasz I. 
Published: February 2009

ABSTRACTAlthough the virological features of serologically silent hepadnaviral primary occult infection (POI) have been relatively well recognized in the woodchuck model of hepatitis B virus infection, the characteristics of accompanying immune responses remain unknown. In this study, the kinetics of woodchuck hepatitis virus (WHV)-specific and generalized (mitogen-induced) T-cell proliferative responses and cytokine expression profiles in circulating lymphoid cells and the liver, along with WHV-specific antibody responses, were investigated during experimentally induced POI and subsequent challenge with a liver-pathogenic dose (>103virions) or liver-nonpathogenic dose (50 virions) of the same virus. The data revealed that POI, which does not prompt WHV surface antigenemia, antiviral antibody response, and hepatitis or protect from challenge with a liver-pathogenic virus dose, was accompanied by the appearance of a strong WHV-specific T-cell response directed against multiple viral epitopes that intermittently persisted at low levels for up to 10-months during follow-up. Furthermore, immediately after exposure to a liver-nonpathogenic dose of WHV, lymphocytes acquired a heightened capacity to proliferate in response to mitogenic stimuli and displayed augmented expression of alpha interferon, interleukin-12 (IL-12), and IL-2, but not tumor necrosis factor alpha. Overall, the kinetics of WHV-specific and mitogen-induced T-cell proliferative and cytokine responses in POI were closely comparable to those seen in infection induced by liver-pathogenic viral doses. The data demonstrated that virus-specific T-cell proliferative reactivity is a very sensitive indicator of exposure to hepadnavirus, even to small amounts inducing serologically mute infection. They also showed that hepadnaviral POI is not only a molecularly but also an immunologically identifiable and distinctive entity.
Novel Immunocompetent Murine Tumor Model for Evaluation of Conditionally Replication-Competent (Oncolytic) Murine Adenoviral Vectors
Authors: Robinson Michael , Li Betty , Ge Ying , Ko Derek , Yendluri Satya , Harding Thomas , VanRoey Melinda , Spindler Katherine R. , Jooss Karin 
Published: February 2009

ABSTRACT
Oncolytic adenoviral vectors that express immunostimulatory transgenes are currently being evaluated in clinic. Preclinical testing of these vectors has thus far been limited to immunodeficient xenograft tumor models since human adenoviruses do not replicate effectively in murine tumor cells. The effect of the immunostimulatory transgene on overall virus potency can therefore not be readily assessed in these models. Here, a model is described that allows the effective testing of mouse armed oncolytic adenovirus (MAV) vectors in immunocompetent syngeneic tumor models. These studies demonstrate that the MAV vectors have a high level of cytotoxicity in a wide range of murine tumor cells. The murine oncolytic viruses were successfully armed with murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) by a novel method which resulted in vectors with a high level of tumor-specific transgene expression. The mGM-CSF-armed MAV vectors showed an improved level of antitumor potency and induced a systemic antitumor immune response that was greater than that induced by unarmed parental vectors in immunocompetent syngeneic tumor models. Thus, the oncolytic MAV-1 system described here provides a murine homolog model for the testing of murine armed oncolytic adenovirus vectors in immunocompetent animals. The model allows evaluation of the impact of virus replication and the host immune response on overall virus potency and enables the generation of translational data that will be important for guiding the clinical development of these viruses.
The Intersection of Epstein-Barr Virus with the Germinal Center
Authors: Roughan Jill E. , Thorley-Lawson David A. 
Published: February 2009

ABSTRACT
The current model of Epstein-Barr virus (EBV) infection and persistence in vivo proposes that EBV uses the germinal center (the GC model) to establish a quiescent latent infection in otherwise-normal memory B cells. However, the evidence linking EBV-infected cells and the GC is only indirect and limited. Therefore, a key portion of the model, that EBV-infected cells physically reside and participate in GCs, has yet to be verified. Furthermore, recent experiments suggested that upon infection of GC cells the viral growth latency transcription program is dominant and GC functionality and phenotype are ablated, i.e., EBV infection is not consistent with GC function. In this study we show that in vivo, EBV-infected B cells in the tonsils retain expression of functional and phenotypic markers of GC cells, including bcl-6 and AID. Furthermore, these cells are physically located in the GC and express a restricted form of latency, the default latency program. Thus, the EBV default latency transcription program, unlike the growth latency program, is consistent with the retention of GC functionality in vivo. This work verifies key components of the GC model of EBV persistence and suggests that EBV and the GC can interact to produce the latently infected memory cells found in the periphery. Furthermore, it identifies latently infected GC B cells as a potential pathogenic nexus for the development of the EBV-positive, GC-associated lymphomas Hodgkin's disease and Burkitt's lymphoma.
MAVS Self-Association Mediates Antiviral Innate Immune Signaling
Authors: Tang Eric D. , Wang Cun-Yu 
Published: February 2009

ABSTRACT

The innate immune system recognizes nucleic acids during viral infection and stimulates cellular antiviral responses. Intracellular detection of RNA virus infection is mediated by the RNA helicases RIG-I (
r
etinoic acid
i
nducible
g
ene
I
) and MDA-5, which recognize viral RNA and signal through the adaptor molecule MAVS (
m
itochondrial
a
nti
v
iral
s
ignaling) to stimulate the phosphorylation and activation of the transcription factors IRF3 (
i
nterferon
r
egulatory
f
actor
3
) and IRF7. Once activated, IRF3 and IRF7 turn on the expression of type I interferons, such as beta interferon. Interestingly, unlike other signaling molecules identified in this pathway, MAVS contains a C-terminal transmembrane (TM) domain that is essential for both type I interferon induction and localization of MAVS to the mitochondrial outer membrane. However, the role the MAVS TM domain plays in signaling remains unclear. Here we report the identification of a function for the TM domain in mediating MAVS self-association. The activation of RIG-I/MDA-5 leads to the TM-dependent dimerization of the MAVS N-terminal caspase recruitment domain, thereby providing an interface for direct binding to and activation of the downstream effector TRAF3 (
t
umor necrosis factor
r
eceptor-
a
ssociated
f
actor
3
). Our results reveal a role for MAVS self-association in antiviral innate immunity signaling and provide a molecular mechanism for downstream signal transduction.
In Vivo gp41 Antibodies Targeting the 2F5 Monoclonal Antibody Epitope Mediate Human Immunodeficiency Virus Type 1 Neutralization Breadth
Authors: Shen Xiaoying , Parks Robert J. , Montefiori David C. , Kirchherr Jennifer L. , Keele Brandon F. , Decker Julie M. , Blattner William A. , Gao Feng , Weinhold Kent J. , Hicks Charles B. , Greenberg Michael L. , Hahn Beatrice H. , Shaw George M. , Haynes Barton F. , Tomaras Georgia D. 
Published: February 2009

ABSTRACT
The broadly neutralizing human monoclonal antibodies (MAbs) 2F5 and 4E10, both targeting the highly conserved human immunodeficiency virus type 1 (HIV-1) envelope membrane proximal external region (MPER), are among the MAbs with the broadest heterologous neutralizing activity and are of considerable interest for HIV-1 vaccine development. We have identified serum antibodies from an HIV-infected subject that both were broadly neutralizing and specifically targeted MPER epitopes that overlap the 2F5 epitope. These MPER-specific antibodies were made 15 to 20 months following transmission and concomitantly with the development of autoantibodies. Our findings suggest that multiple events (i.e., genetic predisposition and HIV-1 immune dysregulation) may be required for induction of broadly reactive gp41 MPER antibodies in natural infection.
Characterization of Pseudorabies Virus (PrV) Cleavage-Encapsidation Proteins and Functional Complementation of PrV pUL32 by the Homologous Protein of Herpes Simplex Virus Type 1
Authors: Fuchs Walter , Klupp Barbara G. , Granzow Harald , Leege Tobias , Mettenleiter Thomas C. 
Published: February 2009

ABSTRACT

Cleavage and encapsidation of newly replicated herpes simplex virus type 1 (HSV-1) DNA requires several essential viral gene products that are conserved in sequence within the
Herpesviridae
. However, conservation of function has not been analyzed in greater detail. For functional characterization of the UL6, UL15, UL28, UL32, and UL33 gene products of pseudorabies virus (PrV), the respective deletion mutants were generated by mutagenesis of the virus genome cloned as a bacterial artificial chromosome (BAC) in
Escherichia coli
and propagated in transgenic rabbit kidney cells lines expressing the deleted genes. Neither of the PrV mutants was able to produce plaques or infectious progeny in noncomplementing cells. DNA analyses revealed that the viral genomes were replicated but not cleaved into monomers. By electron microscopy, only scaffold-containing immature but not DNA-containing mature capsids were detected in the nuclei of noncomplementing cells infected with either of the mutants. Remarkably, primary envelopment of empty capsids at the nuclear membrane occasionally occurred, and enveloped tegument-containing light particles were formed in the cytoplasm and released into the extracellular space. Immunofluorescence analyses with monospecific antisera of cells transfected with the respective expression plasmids indicated that pUL6, pUL15, and pUL32 were able to enter the nucleus. In contrast, pUL28 and pUL33 were predominantly found in the cytoplasm. Only pUL6 could be unequivocally identified and localized in PrV-infected cells and in purified virions, whereas the low abundance or immunogenicity of the other proteins hampered similar studies. Yeast two-hybrid analyses revealed physical interactions between the PrV pUL15, pUL28, and pUL33 proteins, indicating that, as in HSV-1, a tripartite protein complex might catalyze cleavage and encapsidation of viral DNA. Whereas the pUL6 protein is supposed to form the portal for DNA entry into the capsid, the precise role of the UL32 gene product during this process remains to be elucidated. Interestingly, the defect of UL32-negative PrV could be completely corrected in
trans
by the homologous protein of HSV-1, demonstrating similar functions. However,
trans
-complementation of UL32-negative HSV-1 by the PrV protein was not observed.
A Short-term Rat Mammary Carcinogenesis Model for the Prevention of Hormonally Responsive and NonresponsiveIn situCarcinomas
Authors: Woditschka Stephan , Haag Jill D. , Sullivan Ruth , Gould Michael N. 
Published: February 2009

AbstractPreclinical models that accurately reproduce specific aspects of human disease etiology are invaluable for the initial development and evaluation of chemopreventive agents. We developed a novel, short-term prevention model, which is particularly useful for assessing the efficacy of a compound to prevent hormonally responsive and nonresponsive in situ carcinomas. In this model, carcinogenesis is induced by a high titer of neu-containing, replication-defective retrovirus. The multiplicity and size of the resulting in situ carcinomas are scored in whole-mounted, aluminum carmine–stained mammary glands at 15 days postinfusion. These in situ carcinomas represent a distinct biological time point in the development of neu-induced mammary cancer in the rat. They are characterized by high rates of proliferation (40.0%; P &lt; 0.0001) and apoptosis (2.8%; P &lt; 0.005) compared with mammary carcinomas. The majority of in situ carcinomas regress spontaneously after 20 days postinfusion. The in situ carcinomas at 15 days postinfusion exhibit hormonal responsiveness. The effects of the chemoprevention agents tamoxifen, celecoxib, and targretin on hormonally responsive and nonresponsive in situ carcinomas recapitulate those observed on mammary carcinomas at 12 and 18 weeks postinfusion for intact and ovariectomized rats, respectively. Neu-induced in situ carcinomas in the rat represent etiologically relevant intermediate time points of mammary carcinogenesis. Our prevention model represents a cost-efficient in vivo system to determine whether the preventive effects of a compound extend to hormonally nonresponsive mammary lesions, for which new chemoprevention approaches are needed.
Lack of Efficacy of the Statins Atorvastatin and Lovastatin in Rodent Mammary Carcinogenesis
Authors: Lubet Ronald A. , Boring Daniel , Steele Vernon E. , Ruppert J. Michael , Juliana M. Margaret , Grubbs Clinton J. 
Published: February 2009

AbstractThe statins are highly effective in lowering cholesterol by inhibiting 3-hydroxy-3-methylglutaryl CoA reductase. Recently, there has been conflicting epidemiologic data indicating that statins decrease the incidence of certain types of cancer, including breast cancer. Atorvastatin and lovastatin, statins with different lipophicilities, were administered in diet either as single agents or in combination with suboptimal doses of tamoxifen or the retinoid X receptor agonist bexarotene were evaluated for prevention of estrogen receptor–positive mammary cancers induced in the rat with methylnitrosourea. Atorvastatin (125 or 500 mg/kg diet) alone did not significantly alter cancer incidence or multiplicity. Suboptimal doses of tamoxifen (0.4 mg/kg diet) or bexarotene (80 mg/kg diet) reduced cancer multiplicity from 3.8 (control) to 2.9 and 0.9, respectively. Combining atorvastatin (500 mg/kg diet) with either of these effective agents minimally altered their efficacy. Although this dose of atorvastatin did not decrease serum triglyceride levels in control rats, it significantly decreased triglyceride levels that had been increased in bexarotene-treated rats. Experiments done with a second statin, lovastatin (100 and 400 mg/kg diet), yielded similar results: (a) limited activity when administered alone, (b) no obvious synergy with bexarotene, and (c) an ability to decrease bexarotene-induced increases in serum triglycerides. Thus, the statins had minimal activity in this model of mammary cancer in which approximately half of the cancers are mutated in the Ha Ras oncogene. Similarly, atorvastatin failed to alter the development of estrogen receptor–negative mammary carcinomas in a new animal model using bitransgenic mice (MMTV-Neu+/−/p53KO+/−), whereas bexarotene (250 mg/kg diet) was effective.
Racial and Ethnic Representation in Gifted Programs
Authors: So Yoon Yoon  , Gentry Marcia 
Published: February 2009

The Elementary and Secondary School Survey data and Civil Rights Data Collection of the Office for Civil Rights (OCR) were analyzed to describe the issue of overrepresentation of gifted Asian American students in gifted education programs in the United States. Nationally, Asian and Whites have been overrepresented in gifted education since 1978, whereas, students from other ethnic backgrounds, such as those from American Indian or Alaska Native, Hispanic, and African American groups, have been underrepresented with gradual increases in this underrepresentation since 1994. When the data were disaggregated by state for the period from 2002 to 2006, each racial and ethnic group displayed varied ranges of representation. Those varied distributions can be attributed to each state's unique demographic profile, varied definitions of giftedness, identification procedures, and identification policies. By focusing on Asian American students, this study addressed some difficulties that gifted Asian American students may face concerning the image of model minority and through the acculturation processes as immigrants or descendents of immigrants. Furthermore, this study suggests a need for disaggregated data collection and more research concerning gifted Asian American students from various ethnic Asian groups. Putting the Research to Use: Findings from this study highlight the need for carefully collected data in the field of gifted education concerning race and ethnicity of students in programs and provide the reader with a picture of both underrepresentation and overrepresentation of students by state and ethnic group. Attention needs to be paid to sub-groups within categories of race and ethnicity to understand representation. By considering the issue of Asian Americans and their overrepresentation, this research has raised awareness about factors, such as identification processes, acculturation, and academic motivation that might promote recognition of giftedness among some ethnic groups. Finally, this research offers readers with a new, multiple-year, current, analysis of the representation in gifted programs nationally and by state for racial/ethnic groups, an area of continued concern to those in the field of gifted education.
Potentiating effects of RAD001 (Everolimus) on vincristine therapy in childhood acute lymphoblastic leukemia
Authors: Crazzolara Roman , Cisterne Adam , Thien Marilyn , Hewson John , Baraz Rana , Bradstock Kenneth F. , Bendall Linda J. 
Published: February 2009

AbstractDespite advances in the treatment of acute lymphoblastic leukemia (ALL), the majority of children who relapse still die of ALL. Therefore, the development of more potent but less toxic drugs for the treatment of ALL is imperative. We investigated the effects of the mammalian target of rapamycin inhibitor, RAD001 (Everolimus), in a nonobese diabetic/severe combined immunodeficiency model of human childhood B-cell progenitor ALL. RAD001 treatment of established disease increased the median survival of mice from 21.3 days to 42.3 days (P < .02). RAD001 together with vincristine significantly increased survival compared with either treatment alone (P < .02). RAD001 induced a cell-cycle arrest in the G0/1 phase with associated dephosphorylation of the retinoblastoma protein, and reduced levels of cyclin-dependent kinases 4 and 6. Ultrastructure analysis demonstrated the presence of autophagy and limited apoptosis in cells of RAD001-treated animals. In contrast, cleaved poly(ADP-ribose) polymerase suggested apoptosis in cells from animals treated with vincristine or the combination of RAD001 and vincristine, but not in those receiving RAD001 alone. In conclusion, we have demonstrated activity of RAD001 in an in vivo leukemia model supporting further clinical development of target of rapamycin inhibitors for the treatment of patients with ALL.
Alternative pre-mRNA splicing switches modulate gene expression in late erythropoiesis
Authors: Yamamoto Miki L. , Clark Tyson A. , Gee Sherry L. , Kang Jeong-Ah , Schweitzer Anthony C. , Wickrema Amittha , Conboy John G. 
Published: February 2009

AbstractDifferentiating erythroid cells execute a unique gene expression program that insures synthesis of the appropriate proteome at each stage of maturation. Standard expression microarrays provide important insight into erythroid gene expression but cannot detect qualitative changes in transcript structure, mediated by RNA processing, that alter structure and function of encoded proteins. We analyzed stage-specific changes in the late erythroid transcriptome via use of high-resolution microarrays that detect altered expression of individual exons. Ten differentiation-associated changes in erythroblast splicing patterns were identified, including the previously known activation of protein 4.1R exon 16 splicing. Six new alternative splicing switches involving enhanced inclusion of internal cassette exons were discovered, as well as 3 changes in use of alternative first exons. All of these erythroid stage-specific splicing events represent activated inclusion of authentic annotated exons, suggesting they represent an active regulatory process rather than a general loss of splicing fidelity. The observation that 3 of the regulated transcripts encode RNA binding proteins (SNRP70, HNRPLL, MBNL2) may indicate significant changes in the RNA processing machinery of late erythroblasts. Together, these results support the existence of a regulated alternative pre-mRNA splicing program that is critical for late erythroid differentiation.
Urokinase-mediated recruitment of myeloid-derived suppressor cells and their suppressive mechanisms are blocked by MUC1/sec
Authors: Ilkovitch Dan , Lopez Diana M. 
Published: February 2009

AbstractThe transmembrane isoform of mucin 1 (MUC1/TM) is a well-recognized tumor antigen, contributing to tumorigenesis and immune evasion. Although MUC1/TM has been correlated with malignancy, we have previously reported on antitumor properties and prevention of tumor development by a secreted splice variant of MUC1 (MUC1/sec). Because myeloid-derived suppressor cells (MDSCs) play a critical role in tumor-induced immunosuppression, we investigated their recruitment by tumor cells expressing either MUC1/TM or MUC1/sec. DA-3 tumor cells expressing MUC1/sec recruit dramatically lower levels of MDSCs, relative to MUC1/TM-expressing DA-3 cells. Because MUC1/sec was previously shown to down-regulate tumor expression of urokinase plasminogen activator (uPA), a protease linked to tumor aggressiveness and metastasis, the potential role of uPA in MDSC recruitment was investigated. Tumor-derived uPA is capable of recruiting MDSCs, and correlates with tumor development. In addition to diminishing recruitment of MDSCs, the effect of MUC1/sec on MDSC-suppressive mechanisms was investigated. MUC1/sec, or its unique immunoenhancing peptide, is capable of blocking expression of arginase 1 and production of reactive oxygen species in MDSCs, implicated in the suppression of T cells. These findings demonstrate a new mechanism of MDSC recruitment, and provide evidence that MUC1/sec has antitumor properties affecting MDSCs.
Pivotal role of mast cells in pruritogenesis in patients with myeloproliferative disorders
Authors: Ishii Takefumi , Wang Jiapeng , Zhang Wei , Mascarenhas John , Hoffman Ronald , Dai Ying , Wisch Nathaniel , Xu Mingjiang 
Published: February 2009

AbstractPruritus is a common symptom in patients with Philadelphia chromosome–negative myeloproliferative disorders (MPDs). The pathophysiology of MPD-associated pruritus is unclear. We have demonstrated that MPD mast cells (MCs) are involved by the malignant process. In the present study, we explored the hypothesis that MCs play an important role in the development of pruritogenesis in MPDs. We found that MPD MCs released significantly greater amounts of pruritogenic factors, including histamine, leukotrienes, and interleukin-31 (IL-31) than normal MCs. Elevated levels of IL-31 were also observed in MPD CD3+ cell-conditioned media. MPD MCs exhibited increased migratory behavior in response to stem cell factor or interleukin-8, which was associated with increased filamentous-actin content. Furthermore, the presence of pruritus in MPDs was statistically correlated with a greater number of MCs being generated by CD34+ cells, a greater number of MC colonies being formed by CD34+ cells, decreased apoptosis and prostaglandin D2 release by cultured MCs, and higher plasma levels of IL-31. These data demonstrate that functional abnormalities of MPD MCs probably lead to pruritogenesis in patients with MPDs. These studies provide cellular and molecular targets for the development of antipruritus drugs for patients with MPDs.