bluuebunny/crossref_metadata_2025_split huggingface dataset:
“Natural” antibodies against bacterial lipopolysaccharide and lipoteichoic acid in juvenile chickens (44.36)
Authors: Koppenheffer Thomas L. 
Published: January 2023

Abstract
Naturally occurring Abs are thought to provide protection from microbial pathogens. Chickens are susceptible to, and are potential carriers of, a number of pathogenic bacteria, yet sera of adult birds contain Abs against bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA). This apparent anomaly led to undertaking a study of the production of these Abs during post-hatching development, the pattern of which may provide insight into understanding the factors that are involved in resistance to infection. Using Salmonella minnesota LPS and Staphylococcus aureus LTA as sentinel antigens in ELISA tests, relatively large amounts of LPS- and LTA-specific IgY were found in yolk of embryonated eggs and in serum of hatchlings. Thereafter, serum IgY levels declined rapidly over several weeks, but by 5–6 weeks of age some birds began to produce specific IgM and IgA Abs. Subsequently, the levels of LPS- and LTA-specific Abs of all isotypes gradually increased, approaching adult levels by 12 weeks of age. Thus, if resistance to infection is related to the levels of these Abs, chicks of about one month of age would be most susceptible to bacterial pathogens. Further, the concomitant appearance of specific Abs of all isotypes during the later phase of post-hatching development suggests that the birds in this study were sensitized through environmental exposure to bacterial cell wall antigens.
Supported in part by the Ralph and Louise Bricker Memorial Endowed Fund
Dissecting complement regulatory sites of the smallpox inhibitor of complement and abrogating function with a monoclonal antibody (44.37)
Authors: Liszewski M. Kathryn , Leung Marilyn K. , Bertram Paula , Atkinson John P. 
Published: January 2023

Abstract
Public health concerns have emerged regarding use of smallpox as a bioterrorist weapon and the possibility of natural emerging infection with monkeypox. Stockpiles of variola in rogue nations and the outbreak of monkeypox in the US in 2003 underpin these concerns. Poxviruses express virulence factors that down-modulate the host’s innate immune system. We previously constructed the smallpox inhibitor of complement enzymes, SPICE, from its homolog in vaccinia, VCP. Additionally, we cloned and functionally characterized MOPICE, the highly homologous monkeypox inhibitor. SPICE had enhanced activity over both poxviral inhibitors (PICES).
The goals of our current study were
to dissect the complement regulatory sites of SPICE andto characterize a monoclonal antibody that binds to and abrogates function of the PICES.
We created SPICE-VCP chimeras and SPICE point mutations. Generally, function increased for human C3b and C4b as more SPICE amino acids were present. We also identified SPICE residues that were critical for ligand binding and cofactor activities. Additionally, we characterized a mAb that binds SPICE, MOPICE and VCP. This mAb served as a capture reagent for ELISA to quantify PICES and as a detection mAb in Western blots. Importantly, the mAb blocked cofactor and decay accelerating activities, suggesting its possible use as a therapeutic. Thus, our studies add novel data relative to the complement inhibitory profile of SPICE. Further, a cocktail of such mAbs that inhibit virulence factors could serve in both diagnostic and therapeutic applications for poxviruses.
Proteasome activator and antigen-processing aminopeptidases are regulated by virus-induced type I interferon in the hepatitis C virus-infected liver (44.39)
Authors: Shin Eui-Cheol , Seifert Ulrike , Urban Sabrina , Truong Kim-Thuy , Feinstone Stephen M , Rice Charles M , Kloetzel Peter -M , Rehermann Barbara 
Published: January 2023

Abstract
Many components of the class I-antigen-processing pathway are thought to be regulated solely by IFN-γ. Recently, however, we reported type I IFN-mediated induction of immunoproteasomes in a viral infection of the liver (J Clin Invest 2006, 116:3006). In the present study, we extended this analysis to additional components of the MHC class I antigen-processing machinery. Specifically, we investigated type I IFN-mediated induction of the proteasome activator 28 (PA28) subunits α and β, the ER aminopeptidases-1 (ERAP1), -2 (ERAP2) and leucine aminopeptidase (LAP) in vitro and in vivo in a model of HCV infection. This mechanism was initiated by either synthetic or hepatitis C virus (HCV) RNA and abrogated by blocking of type I IFN. In the liver of chimpanzees with acute HCV infection, increased mRNA levels of PA28 subunits and all aminopeptidases occurred prior to IFN-γ responses and instead, coincided with type I IFN responses. Taken together, viral RNA-induced type I IFN regulates the antigen-processing machinery early during infection. Thus, viral RNA-induced type I IFN does not only exert direct antiviral functions but also enhances antigen processing in virus-infected cells to facilitate recognition by effector CD8+ T cells.
The Role of Toll-Like Receptor 7 (TLR7) in Neuroinflammatory Responses to Retrovirus Infection in Mice (44.41)
Authors: Peterson Karin E , Lewis Stephanie , Pourciau Susan , Du Min , Khaleduzzaman Mohammed 
Published: January 2023

Abstract
Retrovirus infection in the central nervous system of infants is often associated with strong innate immune responses including production of cytokines and chemokines, activation of astrocytes and microglia and recruitment of macrophages. Understanding how retrovirus infection leads to the induction of these innate immune responses in the CNS is important in determining mechanisms of pathogenesis. Several studies have demonstrated that single-stranded RNA viruses can stimulate macrophages and dendritic cells through toll-like receptor 7 (TLR7). In the current study, we analyzed whether TLR7 was expressed in the neonatal brain and whether TLR7 contributed to retroviral-induced innate immune response. TLR7 was expressed primarily by ependymal and endothelial cells in the brain as detected by immunohistochemistry. Deficiency in TLR7 did not alter interferon beta responses to neurovirulent murine retrovirus infection, virus replication in the brain or virus-mediated neurological disease. However, retrovirus-induced activation of astrocytes and the production of multiple chemokines were suppressed in TLR7 deficient mice compared to wildtype controls. Thus, TLR7 signaling appears to play a significant role in the activation of the innate immune response to retrovirus infection in the neonatal brain.
This study was supported by NIH IP20RR020159-01.
TLR2/1-induced IL-15 triggers a vitamin D3-dependent antimicrobial activity against Mycobacterium tuberculosis in human macrophages (44.5)
Authors: Krutzik Stephan Richard , Robles Juan Antonio , Hewison Martin , Corcoran Kellie , Montoya Dennis , Liu Philip T , Adams John , Modlin Robert L 
Published: January 2023

Abstract
Toll-like receptors (TLRs) are an integral component of the innate host defense, triggering macrophage differentiation by secretion of IL-15 and antimicrobial activity against intracellular M. tuberculosis through a vitamin D-dependent pathway. Here we investigate the mechanism by which TLR2/1 activates this antimicrobial pathway. We found that the TLR2/1-mediated induction of Cyp27B1 and VDR in human monocytes was dependent on secretion of IL-15. The direct activity of IL-15 to induce this pathway was examined in comparison to IL-4, since both induce monocytes to differentiate into CD209+ macrophages but with unique FcR expression. We found that IL-15 but not IL-4 was sufficient to induce Cyp27B1 and the VDR. The IL-15-derived macrophages upregulated Cyp27B1 activity as demonstrated by their ability to convert the vitamin D prohormone 25D3 to 1,25D3. Finally, in IL-15-derived macrophages, 25D3 triggered induction of the antimicrobial peptide cathelicidin and an antimicrobial activity against intracellular M. tuberculosis. Together, our data suggest that the TLR2/1 induction of the vitamin D-dependent antimicrobial pathway is dependent on the production and direct actions of IL-15.
Trafficking of dendritic cell subsets to the lung controls viral replication and pathology in human paramyxovirus infections (44.6)
Authors: Guerrero-Plata Antonieta , Casola Antonella , Garofalo Roberto P. 
Published: January 2023

Abstract
Three subsets of pulmonary dendritic cells (DC) have been described in mice: conventional DC (cDC, CD11c+MHCII+), plasmacytoid DC (pDC, CD11cintB220+Ly6C+), and the recently characterized IFN-producing killer cells (IKDC, CD11cintB220+CD49b+). Here, we examined the recruitment of DC to the lung in the context of two human paramyxovirus infections: respiratory syncytial virus (RSV) and human metapneumovirus (hMPV). Recruitment of DC to the lung in infected mice was determined by flow cytometry. Both infections induced a peak of cDC recruitment (&gt;3×106) by day 8 for RSV and by day 10 for hMPV. cDC remained elevated throughout the inflammatory and the resolution phases of infection (1×106) compared to control (1×105). RSV induced a peak of 8×105 pDC recruited by day 3, while hMPV induced similar numbers but at day 8. pDC returned to basal levels (1×105) by day 6 (RSV) and by day 12 (hMPV). IKDC mirrored the pattern of migration of pDC but overall numbers of IKDC were smaller: peak for RSV was 5×105 IKDC and &lt;4×105 IKDC for hMPV. Furthermore, depletion of pDC with anti-mPDCA1 antibody resulted in significant increases in peak titers and pulmonary inflammation in RSV and hMPV infected mice. In conclusion, this study demonstrates that all three subsets of DC are attracted to the site of infection in the course of paramyxovirus infections and pDC play a critical role in viral replication and pathogenesis.
NIH/NIAID P01 AI062885
NADPH Oxidase but not Myeloperoxidase Protects Lymphopenic Mice from Spontaneous Multi-Organ Infections (44.9)
Authors: Ostanin Dmitry V. , Barlow Shayne , Shukla Deepti , Grisham Matthew B. 
Published: January 2023

Abstract
The objective of this study was to define the role that NADPH oxidase or myeloperoxidase (MPO) plays in host defense in lymphopenic mice. To do this we crossed gp91 phox deficient (gp91 ko) or MPO ko mice with mice deficient in recombinase activating gene-1 (RAG ko) to generate lymphopenic offspring deficient in either NADPH oxidase or MPO. We found that neither gp91 ko, MPO ko mice nor RAG ko mice developed spontaneous infections when raised under specific pathogen free (SPF) conditions and all animals lived normal life spans. In contrast, gp91/RAG double deficient (gp91/RAG DKO) but not MPO/RAG DKO mice developed spontaneous multi-organ bacterial and fungal infections early in life and lived only a few months. Addition of antibiotics to the drinking water attenuated some of the infections and increased modestly the survival of these mice. The enhanced mortality of the gp91/RAG DKO mice was not due to defects in inflammatory cell recruitment or NO synthase (iNOS) activity as the number of elicited PMNs and macrophages as well as PMN and macrophage-derived production of nitric oxide in these mice were similar to wt, gp91 ko or RAG ko mice. Taken together, our data suggest that that NADPH oxidase but not MPO (or iNOS) is required for host defense in lymphopenic mice and that lymphocytes and NADPH oxidase may compensate for each others deficiency in providing resistance to spontaneous infections
(Supported by DK64023).
Intrahepatic expression of HCV core impairs CD4+ T cell response in vivo (45.10)
Authors: Lassen Matthew G. , Hahn Young S. 
Published: January 2023

Abstract
Hepatitis C virus (HCV) is remarkably efficient in establishing a persistent infection, with &gt;70% of acutely infected individuals developing chronic HCV. Resolution of HCV infection requires a strong, broad Th1 response, including robust IFN-γ and IL-2 production. Patients that develop chronic infection display lower proliferative capacity, a narrow clonal repertoire, and decreased IFN-γ and IL-2 production within the CD4+ T cell compartment, compared to patients who resolve infection. We sought to determine if the expression of the HCV core protein (core) within the liver compartment dysregulates intrahepatic CD4+ T cells in vivo during an inflammatory response. We preferentially targeted the expression of core protein to liver cells by injecting Balb/c mice intravenously with a replication deficient adenovirus that expresses core under the CMV promoter (Ad-core). Compared to control mice infected with β-galactosidase expressing adenovirus, intrahepatic CD4+ T cells from Ad-core infected mice expressed lower levels of CD25 on days 1 and 8 post-infection (p.i.), as well as lower IFN-γ production at day 15 p.i. In contrast, CD25 expression and IFN-γ levels on splenic CD4+ T cells were similar between Ad-core infected and control mice. These results suggest that expression of core within the liver leads to an impaired CD4+ T cell response.
The Vif Accessory Protein Alters the Cell Cycle of Human Immunodeficiency Virus Type 1 Infected Cells (45.15)
Authors: Wang Jiangfang , Shackelford Jason M. , Casella Carolyn R. , Shivers Debra K. , Rapaport Eric L. , Liu Bindong , Yu Xiao-Fang , Finkel Terri H. 
Published: January 2023

Abstract
The viral infectivity factor gene (vif) of HIV-1 increases the infectivity of viral particles by inactivation of cellular anti-viral factors, and supports productive viral replication in primary human CD4 T-cells and in certain non-permissive T cell lines. Here, we demonstrate that Vif also contributes to the arrest of HIV-1 infected cells in the G2 phase of the cell cycle. Viruses deleted in Vif or Vpr induce less cell cycle arrest than wild-type virus, while cells infected with HIV-1 deleted in both Vif and Vpr have a cell cycle profile equivalent to that of uninfected cells. Furthermore, expression of Vif alone induces accumulation of cells in the G2 phase of the cell cycle. These data demonstrate a novel role for Vif in cell cycle regulation and suggest that Vif and Vpr independently drive G2 arrest in HIV-1 infected cells. Our results may have implications for the actions and interactions of key HIV-1 accessory proteins in AIDS pathogenesis.
Loss of Antibody Neutralization Activity in Mice During Persistent γ-herpesvirus Infection (45.16)
Authors: Yager Eric J , Kim In-Jeong , Burkum Claire , Rochford Rosemary , Blackman Marcia A 
Published: January 2023

Abstract
Murine γ-herpesvirus-68 (γHV68), like the human γ-herpesviruses EBV and KSHV, initiates an acute, readily controlled lytic infection in mice, which is followed by the establishment of a persistent latent infection. Although T cells are important for control of both lytic and latent γHV68 infection, specific antibody alone is sufficient to prevent viral recrudescence during latency. Although chronic viral infections can affect the generation and maintenance of T cell immunity, it is unclear whether B cell immunity is also affected. Titers of γHV68-specific IgG remained relatively stable in latently infected mice up to 20 months postinfection. However, neutralization titers were found to wane in most latently infected mice, with declines observed as early as 10 months postinfection. Corresponding to a loss in neutralization activity, the transfer of immune sera taken from long-term (&gt;18 months) γHV68-infected mice afforded naïve mice less protection against acute γHV68 infection when compared to immune sera taken from recently infected mice. No direct correlation between reduced neutralization activity and sera isotype profile, or overall affinity for viral antigen, was found. As serum levels of specific antibody are maintained by long-lived plasma cells, ongoing studies are examining whether γHV68 persistence adversely affects CD4+ T helper cell function and/or the survival of long-lived plasma cells. In summary, these observations support the novel idea that persistent viruses can adversely influence the maintenance of protective humoral immune responses.
This work was supported by NIH institutional training grant AI49823 and NIH grant AG021600.
Anti-TNF-α treatment activates Borrelia burgdorferi infection in ceftriaxone treated C3H/He mice (45.17)
Authors: Yrjänäinen Heta , Hytönen Jukka , Song Xiao-yu R. , Oksi Jarmo , Hartiala Kaija , Viljanen Matti K. 
Published: January 2023

Abstract
The effect of anti-TNF-α treatment in B. burgdorferi infected C3H/He mice treated with ceftriaxone was evaluated in this study. Mice were infected with B. garinii Å218 or B. burgdorferi sensu stricto N40. At two weeks of infection, a group of ten mice was treated with ceftriaxone for five days, while another group received anti-TNF-α simultaneously with ceftriaxone. A third group received anti-TNF-α four weeks after the ceftriaxone treatment and a fourth group received only anti-TNF-α. Ceftriaxone improved joint swelling and decreased B. burgdorferi specific IgG antibody responses. At 14 weeks of infection, B. burgdorferi could not be detected by cultivation or by PCR from tissue samples of any of the animals treated only with ceftriaxone. However, spirochetes grew from the tissue samples of one third of the mice treated with both anti-TNF-α and ceftriaxone, regardless of whether the treatments were received simultaneously or four weeks apart. No loss of plasmids, decreased ceftriaxone sensitivity or virulence rate was found when the activated spirochetes were compared to the bacteria used to infect the mice. All infected control mice and the mice that only received anti-TNF-α were culture positive. These results show that a number of B. burgdorferi infected mice still have live spirochetes which are activated by the anti-TNF-α treatment in their body after treatment with ceftriaxone.
Viral immune evasion protein mK3 targets MHC I proteins for rapid degradation by specifically ubiquitinating serine or lysine residues in the cytoplasmic tail of the heavy chain (45.9)
Authors: Herr Roger Alan , Lybarger Lonnie , Wiertz Emmanuel J. H. J. , Wang Xiaoli , Hansen Ted H. 
Published: January 2023

Abstract
The immune evasion protein mK3 is a viral RING type E3 ubiquitin ligase encoded by murine gamma herpesvirus68. mK3 specifically targets nascent MHC I heavy chain (HC) for rapid degradation in a ubiquitination-proteasome dependent manner, thus blocking detection of virally infected cells by CD8 T cells. To address the question of how HC is retrotranslocated from the ER and what role mK3 plays, we investigated ubiquitin conjugation sites in HC using mutagenesis and biochemistry approaches. Surprisingly, we found that a totally K-less HC had a similar polyubiquitination pattern and rapid degradation as wt HC in mK3 expressing cells. In addition, we found that polyubiquitinated HCs became undetectable after removal of their cytoplasmic tails by proteinase K digestion or thrombin cleavage at an engineered site. HCs with tail substitutions to remove all K,C,S & T residues abolished mK3-mediated polyubiquitination and ERAD, whereas adding backing K or S residues restored polyubiquitination and ERAD. This demonstration that S residues can function as ubiquitination sites is novel. Furthermore, the fact that mK3 specifically ubiquitinates the tail of HC suggests that it is dislocated via its C-terminus.
Supported by NIH grants AI019687 and T32AI007163-30
Functionally impaired T cell-dependent immunopathology in FK506-treated mice with LCMV infection (46.10)
Authors: Araki Koichi , Gangappa Shivaprakash , Rouse Barry T , Larsen Christian P , Ahmed Rafi 
Published: January 2023

Abstract
Lymphocytic choriomeningitis virus (LCMV) was recently shown to contaminate transplanted organs with lethal consequences in transplant recipients. The diagnosis of LCMV as a cause of death under circumstances of immunosuppression is somewhat paradoxical since LCMV is a non-cytolytic virus and is the classic example of immune-mediated disease. To understand how treatment with immunosuppressive drugs given to transplant recipients results in LCMV disease, we have initiated studies using the calcineurin inhibitor FK506. Surprisingly, FK506-treated LCMV-infected mice showed high lethality. The drug treatment resulted in a failure of infection control and interestingly induced functionally impaired virus-specific T cells. Lesions and death appeared to be the consequence of overproduction of cytokines, such as TNF-alpha. This response was dependent on the presence of T cells but these cells themselves appeared not to be the source of the disease-producing cytokines. Our results suggest that functionally impaired T cells in drug treated animals signal cells in LCMV infected tissues to overproduce the cytokines responsible for lesions.
Differential Dysfunction of Dendritic Cells and B-cells During Chronic HCV Infection (46.11)
Authors: Ayers Chris L , Averill Lynn , Pillai Vinodh , Firan Mihail , Wang CK , Lee William M , Karandikar Nitin J 
Published: January 2023

Abstract
Chronic hepatitis C virus (HCV) infection is characterized by attenuated antiviral T cell responses. We hypothesized that HCV-associated dysfunction of antigen presenting cells (APC) may be responsible, in part, for such attenuation. We evaluated the function and phenotype of dendritic cells (myeloid vs. plasmacytoid), B cells, and monocytes, finding distinct functional differences among the APC subsets. Myeloid DC (MDC) from chronic HCV patients showed slightly lower APC capacity with lower HLA-DR and CD86 expression. HCV-MDC also had a tendency to secrete more IL-10, when compared to healthy MDC. On the other hand, HCV-plasmacytoid DC (PDC) showed a significantly reduced ability to make IFN-α. B cells from HCV patients had a hyperactivated phenotype and a marked enhanced APC capacity. Interestingly, the enhanced B cell APC function correlated with detection of virus in these cells. Finally, increased APC functionality was paradoxically associated with the generation of a higher proportion of induced regulatory T-cells, providing a plausible explanation for T-cell attenuation. In conclusion, our studies underscore the necessity to dissect APC subsets for functional perturbations and provide evidence for their role in the immune attenuation accompanying chronic HCV infection.
Differential responses of DCs from susceptible and resistant mice to Theiler’s virus infection (46.18)
Authors: HOU Wanqiu , SO Eui Young , KIM Byung S 
Published: January 2023

Abstract
Although persistent viral infection-associated diseases are a major health issue, the underlying cellular mechanisms of differential susceptibility to such persistent infections among individuals are unknown. Theiler’s virus (TMEV), a natural mouse pathogen, induces a chronic demyelinating disease similar to multiple sclerosis in susceptible mice. Resistant mice completely clear the virus and do not develop chronic demyelinating disease. Here, we compared interactions between TMEV and dendritic cells (DCs) in these mice. Our results indicate that immature DCs from susceptible mice are significantly more permissive to viral infection and infection-induced DC maturation arrest than those from resistant mice, despite the production of higher levels of anti-viral cytokines, including type I/II IFNs. Further studies showed that the timing of DC exposure to type I/II IFNs is critical in controlling viral infection. Moreover, a greater level of type I/II IFNs, which are induced in DCs from susceptible mice by TMEV infection, resulted in severe inhibition of DC cytokine production in response to LPS. Thus, differential interactions between DCs and TMEV, leading to a preferential deficiency in DC maturation and activation of DCs from susceptible mice, may be a mechanism through which TMEV establishes persistent infection and chronic demyelinating disease.
(Supported by NS23349, NS28752 and NS33008)