B Cell-Specific Expression of Ataxia-Telangiectasia Mutated Protein Kinase Promotes Chronic Gammaherpesvirus Infection

Abstract

Manipulation of host cellular pathways is a strategy employed by gammaherpesviruses, including mouse gammaherpesvirus 68 (MHV68), in order to negotiate a chronic infection. Ataxia-telangiectasia mutated (ATM) plays a unique yet incompletely understood role in gammaherpesvirus infection, as it has both proviral and antiviral effects. Chronic gammaherpesvirus infection is poorly controlled in a host with global ATM insufficiency, whether the host is a mouse or a human. In contrast, ATM facilitates replication, reactivation, and latency establishment of several gammaherpesviruses in vitro, suggesting that ATM is proviral in the context of infected cell cultures. The proviral role of ATM is also evident in vivo, as myeloidspecific ATM expression facilitates MHV68 reactivation during the establishment of viral latency. In order to better understand the complex relationship between host ATM and gammaherpesvirus infection, we depleted ATM specifically in B cells, a cell type critical for chronic gammaherpesvirus infection. B cell-specific ATM deficiency attenuated the establishment of viral latency due to compromised differentiation of ATM-deficient B cells. Further, we found that during long-term infection, peritoneal B-1b, but not related B-1a, B cells display the highest frequency of gammaherpesvirus infection. While ATM expression did not affect gammaherpesvirus tropism for B-1 B cells, B cell-specific ATM expression was necessary to support viral reactivation from peritoneal cells during long-term infection. Thus, our study reveals a role of ATM as a host factor that promotes chronic gammaherpesvirus infection of B cells.IMPORTANCE Gammaherpesviruses infect a majority of the human population and are associated with cancer, including B cell lymphomas. ATM is a unique host kinase that has both proviral and antiviral roles in the context of gammaherpesvirus infection. Further, there is insufficient understanding of the interplay of these roles in vivo during chronic infection. In this study, we show that ATM expression by splenic B cells is required for efficient establishment of gammaherpesvirus latency. We also show that ATM expression by peritoneal B cells is required to facilitate viral reactivation during long-term infection. Thus, our study defines a proviral role of B cellspecific ATM expression during chronic gammaherpesvirus infection.KEYWORDS ATM, gammaherpesvirus, B cell, T cell response, reactivation, chronic infection A taxia-telangiectasia (A-T) mutated (ATM) kinase is a multifunctional kinase, insufficiency of which in humans manifests as A-T (1, 2). The function of ATM was originally defined in the context of response to double-stranded DNA breaks. However,

B Cell-Intrinsic Expression of Interferon Regulatory Factor 1 Supports Chronic Murine Gammaherpesvirus 68 Infection

“…Enzyme-linked immunosorbent assay (ELISA). Total, MHV68-specific, LCMV-specific, and dsDNA immunoglobulin levels were determined as previously described (14,21,(47)(48)(49)(50). Briefly, Nunc MaxiSorp plates (Fisher Scientific, Pittsburgh, PA) were coated with either anti-mouse IgG antibodies (heavy plus light chain) or anti-mouse IgM antibodies (total IgG and IgM levels) (Jackson ImmunoResearch, West Grove, PA), UV-irradiated MHV68 virus stock-PBS (Stratalinker UV Crosslinker 1800; Agilent Technologies, Santa Clara, CA) (740,000 J/cm 2 ϫ 2), LCMV clone 13-infected BHK cell lysates, or dsDNA from Escherichia coli (12.5 g/ml; Sigma-Aldrich, St. Louis, MO) overnight at 4°C.…”

p53 Controls Murine Gammaherpesvirus Latency and Prevents Infection-AssociatedIgH/c-MycTranslocations

“…It is reasonable to suggest that MHV68 likewise triggers p53 through an ATM-mediated DDR, and we previously demonstrated that this is the case during lytic viral replication(39). Whether MHV68 causes ATM activation during latency establishment specifically in infected B cells has not been directly evaluated.However, the observation that B-cell-specific deletion of ATM correlates with a global defect in MHV68 latency(19), rather than the early enhancement in infection we observed in the absence of p53 during initial colonization of the host, suggests that ATM and p53 function independently in latently infected cells in vivo. Alternatively, it is possible that p53 induction occurs during MHV68 infection as a consequence of replication stress due to virus-driven cellular proliferation.…”

“…A role for ATM in restricting MHV68 infection in vivo recently was tested; however, ATM deficiency did not promote enhanced latent infection by MHV68 (17). Rather, ATM facilitates B cell latency (18,19).…”

γ-herpesvirus latency attenuates Mycobacterium tuberculosis infection in mice

“…Intranasal inoculation of 6–8 week old mice with 10 4 PFU of wild type murine gammaherpesvirus 68 (MHV68; WUMS strain) or 15 μl of phosphate buffered saline(PBS) was performed under light anesthesia, as previously reported [22]. MHV68-innoculated mice were housed separately from carrier-inoculated mice for the duration of the study.…”