SARS Coronavirus 3b Accessory Protein Modulates Transcriptional Activity of RUNX1b

BACKGROUND: The causative agent of severe acute respiratory syndrome, SARS coronavirus (SARS-CoV) genome encodes several unique group specific accessory proteins with unknown functions. Among them, accessory protein 3b (also known as ORF4) was lately identified as one of the viral interferon antagonist. Recently our lab uncovered a new role for 3b in upregulation of AP-1 transcriptional activity and its downstream genes. Thus, we believe that 3b might play an important role in SARS-CoV pathogenesis and therefore is of considerable interest. The current study aims at identifying novel host cellular interactors of the 3b protein. METHODOLOGY/PRINCIPAL FINDINGS: In this study, using yeast two-hybrid and co-immunoprecipitation techniques, we have identified a host transcription factor RUNX1b (Runt related transcription factor, isoform b) as a novel interacting partner for SARS-CoV 3b protein. Chromatin immunoprecipitaion (ChIP) and reporter gene assays in 3b expressing jurkat cells showed recruitment of 3b on the RUNX1 binding element that led to an increase in RUNX1b transactivation potential on the IL2 promoter. Kinase assay and pharmacological inhibitor treatment implied that 3b also affect RUNX1b transcriptional activity by regulating its ERK dependent phosphorylation levels. Additionally, mRNA levels of MIP-1α, a RUNX1b target gene upregulated in SARS-CoV infected monocyte-derived dendritic cells, were found to be elevated in 3b expressing U937 monocyte cells. CONCLUSIONS/SIGNIFICANCE: These results unveil a novel interaction of SARS-CoV 3b with the host factor, RUNX1b, and speculate its physiological relevance in upregulating cytokines and chemokine levels in state of SARS virus infection

Statement in Support of: "Virology under the Microscope-a Call for Rational Discourse".

Letter to the Editor OnlinePublPeter Speck ... Michael Beard ... et al

Seropositivity for CMV and IL-6 levels are associated with grip strength and muscle size in the elderly

BACKGROUND: Sarcopenia is an important cause of morbidity and mortality in older adults, with immunosenescence and inflammation being possible underlying mechanisms. We investigated the relationship between latent cytomegalovirus (CMV) infection, Interleukin 6 (IL-6) levels, muscle size and strength in a group of healthy older community-dwelling people. METHODS: Participants were healthy volunteers from the Lothian Birth Cohort 1936 study. Participants had IL-6 level and CMV antibody titre measured at age 70 years and grip strength and a volumetric T1-weighted MRI brain scan (allowing measurement of neck muscle cross-sectional area (CSA)) at age 73. Markers of childhood deprivation were adjusted for in the analysis due to correlations between childhood deprivation and latent CMV infection. RESULTS: 866 participants were studied; 448 men (mean age 72.48 years, sd 0.70) and 418 women (mean age 72.51 years, sd 0.72). In men, CMV seropositivity was associated with smaller neck muscle CSA (p = 0.03, partial eta squared = 0.01), even after adjustment for IL-6 levels. Neck muscle CSA was not associated with CMV seropositivity in women, or CMV antibody titre or IL-6 level in either sex. Grip strength associated negatively with IL-6 level (right grip strength p<0.00001, partial eta squared 0.032 and left grip strength p<0.00001, partial eta squared 0.027) with or without adjustment for CMV serostatus or antibody titre. CMV status and antibody titre were not significantly associated with grip strength in either hand. CONCLUSION: These findings support the hypothesis that there is a relationship between markers of immunosenescence (i.e. CMV serostatus and IL6 level) and low muscle mass and strength and longitudinal studies in older cohorts are now required to investigate these relationships further

IL-10 Suppression of NK/DC Crosstalk Leads to Poor Priming of MCMV-Specific CD4 T Cells and Prolonged MCMV Persistence

IL-10 is an anti-inflammatory cytokine that regulates the extent of host immunity to infection by exerting suppressive effects on different cell types. Herpes viruses induce IL-10 to modulate the virus-host balance towards their own benefit, resulting in prolonged virus persistence. To define the cellular and molecular players involved in IL-10 modulation of herpes virus-specific immunity, we studied mouse cytomegalovirus (MCMV) infection. Here we demonstrate that IL-10 specifically curtails the MCMV-specific CD4 T cell response by suppressing the bidirectional crosstalk between NK cells and myeloid dendritic cells (DCs). In absence of IL-10, NK cells licensed DCs to effectively prime MCMV-specific CD4 T cells and we defined the pro-inflammatory cytokines IL-12, IFN-γ and TNF-α as well as NK cell activating receptors NKG2D and NCR-1 to regulate this bidirectional NK/DC interplay. Consequently, markedly enhanced priming of MCMV-specific CD4 T cells in Il10-/-mice led to faster control of lytic viral replication, bu

Statement in Support of: "Virology under the Microscope-a Call for Rational Discourse"

Letter to the Editor. Published 25 April 2023Peter Speck, Jason Mackenzie, Rowena A. Bull, Barry Slobedman, Heidi Drummer, Johanna Fraser, Lara Herrero, Karla Helbig, Sarah Londrigan, Gregory Moseley, Natalie Prow, Grant Hansman, Robert Edwards, Chantelle Ahlenstiel, Allison Abendroth, David Tscharke, Jody Hobson-Peters, Robson Kriiger-Loterio, Rhys Parry, Glenn Marsh, Emma Harding, David A. Jacques, Matthew J. Gartner, Wen Shi Lee, Julie McAuley, Paola Vaz, Frank Sainsbury, Michelle D. Tate, Jane Sinclair, Allison Imrie, Stephen Rawlinson, Andrew Harman, Jillian M. Carr, Ebony A. Monson, Merilyn Hibma, Timothy J.Mahony, Thomas Tu, Robert J. Center, Lok Bahadur Shrestha, Robyn Hall, Morgyn Warner, Vernon Ward, Danielle E. Anderson, Nicholas S. Eyre, Natalie E. Netzler, Alison J. Peel, Peter Revill, Michael Beard, Alistair R. Legione, Alexandra J. Spencer, Adi Idris, Jade Forwood, Subir Sarker, Damian F. J. Purcell, Nathan Bartlett, Joshua M. Deerain, Bruce J. Brew, Sassan Asgari, Helen Farrell, Alexander Khromykh, Daniel Enosi Tuipulotu, David Anderson, Sevim Mese, Yaman Tayyar, Kathryn Edenborough, Jasim Muhammad Uddin, Abrar Hussain, Connor J. I. Daymond, Jacinta Agius, Karyn N. Johnson, Paniz Shirmast, Mahdi Abedinzadeshahri, Robin MacDiarmid, Caroline L. Ashley, Jay Laws, Lucy L. Furfaro, Thomas D. Burton, Stephen M. R. Johnson, Zahra Telikani, Mary Petrone, Justin A. Roby, Carolyn Samer, Andreas Suhrbier, April Van Der Kamp, Anthony Cunningham, Celeste Donato, Jackie Mahar, Wesley D. Black, Subhash Vasudevan, Roman Lenchine, Kirsten Spann, Daniel J. Rawle, Penny Rudd, Jessica Neil, Richard Kingston, Timothy P. Newsome, Ki Wook Kim, Johnson Mak, Kym Lowry, Nathan Bryant, Joanne Meers, Jason A. Roberts, Nigel McMillan, Larisa I. Labzin, Andrii Slonchak, Leon E. Hugo, Bennett Henzeler, Natalee D. Newton, Cassandra T. David, Patrick C. Reading, Camille Esneau, Tatiana Briody, Najla Nasr, Donna McNeale, Brian McSharry, Omid Fakhri, Bethany A. Horsburgh, Grant Logan, Paul Howley, Paul Youn

Host Immune Responses to a Viral Immune Modulating Protein: Immunogenicity of Viral Interleukin-10 in Rhesus Cytomegalovirus-Infected Rhesus Macaques

, consistent with a central role for rhcmvIL-10 during acute virus-host interactions. Since cmvIL-10 and rhcmvIL-10 are extremely divergent from the cIL-10 of their respective hosts, vaccine-mediated neutralization of their function could inhibit establishment of viral persistence without inhibition of cIL-10.As a prelude to evaluating cmvIL-10-based vaccines in humans, the rhesus macaque model of HCMV was used to interrogate peripheral and mucosal immune responses to rhcmvIL-10 in RhCMV-infected animals. ELISA were used to detect rhcmvIL-10-binding antibodies in plasma and saliva, and an IL-12-based bioassay was used to quantify plasma antibodies that neutralized rhcmvIL-10 function. rhcmvIL-10 is highly immunogenic during RhCMV infection, stimulating high avidity rhcmvIL-10-binding antibodies in the plasma of all infected animals. Most infected animals also exhibited plasma antibodies that partially neutralized rhcmvIL-10 function but did not cross-neutralize the function of rhesus cIL-10. Notably, minimally detectable rhcmvIL-10-binding antibodies were detected in saliva.This study demonstrates that rhcmvIL-10, as a surrogate for cmvIL-10, is a viable vaccine candidate because (1) it is highly immunogenic during natural RhCMV infection, and (2) neutralizing antibodies to rhcmvIL-10 do not cross-react with rhesus cIL-10. Exceedingly low rhcmvIL-10 antibodies in saliva further suggest that the oral mucosa, which is critical in RhCMV natural history, is associated with suboptimal anti-rhcmvIL-10 antibody responses