Chronic viral infections are often established by the exploitation of immune regulatory mechanisms that result in non-functional T cell responses. Viruses that establish persistent infections remain a serious threat to human health. Sphingosine kinase (SphK) 2 generates sphingosine 1-phosphate, which is a molecule known to regulate multiple cellular processes. However, little is known about SphK2’s role during the host immune responses to viral infection. Here, we demonstrate that SphK2 functions during lymphocytic choriomeningitis virus Cl 13 (LCMV Cl 13) infection to limit T cell immune pathology, which subsequently aids in the establishment of virus-induced immunosuppression and the resultant viral persistence. The infection of Sphk2-deficient (Sphk2-/-) mice with LCMV Cl 13 led to the development of nephropathy and mortality via T cell-mediated immunopathology. Following LCMV infection, Sphk2-/- CD4+ T cells displayed increased activity and proliferation, and these cells promoted overactive LCMV Cl 13-specific CD8+ T cell responses. Notably, oral instillation of an SphK2-selective inhibitor promoted protective T cell responses and accelerated the termination of LCMV Cl 13 persistence in mice. Thus, SphK2 is indicated as an immunotherapeutic target for the control of persistent viral infections.
Caleb J. Studstill, Curtis J. Pritzl, Young-Jin Seo, Dae Young Kim, Chuan Xia, Jennifer J. Wolf, Ravi Nistala, Madhuvanthi Vijayan, Yong-Bin Cho, Kyung Won Kang, Sang-Myeong Lee, Bumsuk Hahm
The development of broadly neutralizing antibodies (BNAbs) in HIV infection is a result of long-term co-evolutionary interaction between viruses and antibodies. Understanding how this interaction promotes the increase of neutralization breadth during infection will improve the way in which we design AIDS vaccine strategies. In this paper, we used SIV-infected rhesus macaques as a model to study the development of neutralization breadth by infecting rhesus macaques with longitudinal NAb escape variants and evaluating the kinetics of NAb response and viral evolution. We found that the infected macaques developed a stepwise NAb response against escape variants and increased neutralization breadth during the course of infection. Furthermore, the increase of neutralization breadth correlated with the duration of infection but was independent of properties of the inoculum, viral loads or viral diversity during infection. These results imply that the duration of infection was the main factor driving the development of BNabs. These data suggest the importance of novel immunization strategies to induce effective NAb response against HIV infection by mimicking long-term infection.
Fan Wu, Ilnour Ourmanov, Andrea Kirmaier, Sivan Leviyang, Celia LaBranche, Jinghe Huang, Sonya Whitted, Kenta Matsuda, David Montefiori, Vanessa M. Hirsch
The SARS-CoV-2 is the causative agent for COVID-19 pneumonia. Little is known about the kinetics, tissue distribution, cross-reactivity and neutralization antibody response in COVID-19 patients. Two groups of RT-PCR confirmed COVID-19 patients were enrolled in this study, including 12 severe patients in ICUs who needed mechanical ventilation and 11 mild patients in isolation wards. Serial clinical samples were collected for laboratory detection. Results showed that most of the severe patients had viral shedding in a variety of tissues for 20~40 days post onset of disease (8/12, 66.7%); while the majority of mild patients had viral shedding restricted to the respiratory tract and had no detectable virus RNA after 10 days post-onset (9/11, 81.8%). Mild patients showed significantly lower IgM response compared with that of the severe group. IgG responses were detected in most patients in both severe and mild groups at 9 days post onset and remained high level throughout the study. Antibodies cross-reactive to SARS-CoV and SARS-CoV-2 were detected in COVID-19 patients but not in MERS patients. High-levels of neutralizing antibodies were induced after about 10 days post onset in both severe and mild patients which were higher in the severe group. SARS-CoV-2 pseudotype neutralization test and focus reduction neutralization test with authentic virus showed consistent results. Sera from COVID-19 patients, but not convalescent SARS and MERS patients inhibited SARS-CoV-2 entry. Anti-SARS-CoV-2 S and N IgG level exhibited moderate correlation with neutralization titers in patients’ plasma. This study improves our understanding of immune response in human after SARS-CoV-2 infection.
Yanqun Wang, Lu Zhang, Ling Sang, Feng Ye, Shicong Ruan, Bei Zhong, Tie Song, Abeer N. Alshukairi, Rongchang Chen, Zhaoyong Zhang, Mian Gan, Airu Zhu, Yongbo Huang, Ling Luo, Chris KP Mok, Manal M. Al Gethamy, Haitao Tan, Zhengtu Li, Xiaofang Huang, Fang Li, Jing Sun, Yanjun Zhang, Liyan Wen, Yuming Li, Zhao Chen, Zhen Zhuang, Jianfen Zhuo, Chunke Chen, Lijun Kuang, Junxiang Wang, Huibin Lv, Yongliang Jiang, Min Li, Yimin Lin, Ying Deng, Lan Tang, Jieling Liang, Jicheng Huang, Stanley Perlman, Nanshan Zhong, Jingxian Zhao, J.S. Malik Peiris, Yimin Li, Jincun Zhao
In patients with HBV and HCV coinfection, HBV reactivation leading to severe hepatitis has been reported with the use of direct-acting antivirals (DAAs) to treat HCV infection. Here we study the molecular mechanisms behind this viral interaction. In coinfected cell culture and humanized mice, HBV replication was suppressed by HCV coinfection. In vitro, HBV suppression was attenuated when interferon signaling was blocked. In vivo, HBV viremia, after initial suppression by HCV super-infection, rebounded following HCV clearance by DAA treatment that was accompanied by a reduced hepatic interferon response. Using blood samples of coinfected patients, interferon-stimulated gene products including C-X-C motif chemokine 10 (CXCL10) and C-C motif chemokine ligand 5 (CCL5), and alanine aminotransferase (ALT) were identified to have predictive value for HBV reactivation after HCV clearance. Taken together, our data suggest that HBV reactivation is a result of diminished hepatic interferon response following HCV clearance and identifies serologic markers that can predict HBV reactivation in DAA-treated HBV-HCV coinfected persons.
Xiaoming Cheng, Takuro Uchida, Yuchen Xia, Regina Umarova, Chun-Jen Liu, Pei-Jer Chen, Anuj Gaggar, Vithika Suri, Marcus Maximilian Mücke, Johannes Vermehren, Stefan Zeuzem, Yuji Teraoka, Mitsutaka Osawa, Hiroshi Aikata, Keiji Tsuji, Nami Mori, Shuhei Hige, Yoshiyasu Karino, Michio Imamura, Kazuaki Chayama, T. Jake Liang
The mechanisms underlying rapid elimination of herpes simplex virus-2 (HSV-2) in the human genital tract despite low tissue-resident CD8+ and CD4+ T-cell density (TRM) are unknown. We analyzed shedding episodes during chronic HSV-2 infection: viral clearance always predominated within 24 hours of detection even if viral load exceeded 107 HSV DNA copies; surges in granzyme B and interferon-γ occurred within the early hours after reactivation and correlated with local viral load. We next developed an agent-based mathematical model of an HSV-2 genital ulcer to integrate mechanistic observations of TRM in situ proliferation, trafficking, cytolytic effects and cytokine alarm signaling from murine studies with viral kinetics, histopathology and lesion size data from humans. A sufficiently high density of HSV-2 specific TRM predicted rapid elimination of infected cells, but our data suggest that such TRM densities are relatively uncommon in infected tissues. At lower, more commonly observed TRM densities, TRM must initiate a rapidly diffusing, polyfunctional cytokine response with activation of bystander T cells in order to eliminate a majority of infected cells and eradicate briskly spreading HSV-2 infection.
Pavitra Roychoudhury, David A. Swan, Elizabeth R. Duke, Lawrence Corey, Jia Zhu, Veronica A. Davé, Laura E. Richert-Spuhler, Jennifer M. Lund, Martin Prlic, Joshua T. Schiffer
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever caused by a tick-borne banyangvirus and is associated with high fatality. Despite increasing incidence of SFTS and serious public health concerns in East Asia, the pathogenesis of lethal SFTS virus (SFTSV) infection in humans is not fully understood. Numbers of postmortem examinations to determine target cells of the viral infection have so far been limited. Here we showed that B cells differentiating into plasmablasts and macrophages in secondary lymphoid organs were targets for SFTSV at the end stage of lethal infection, and the majority of SFTSV-infected cells were B cell–lineage lymphocytes. In affected individuals, B cell–lineage lymphocytes with SFTSV infection were widely distributed in both lymphoid and nonlymphoid organs, and infiltration of these cells into the capillaries of the organs could be observed occasionally. Moreover, a human plasmablastic lymphoma cell line, PBL-1, was susceptible to SFTSV propagation, and had a similar immunophenotype to that of target cells of SFTSV in fatal SFTS. PBL-1 can therefore provide a potential in vitro model for human SFTSV infection. These results extend our understanding of the pathogenesis of human lethal SFTSV infection, and can facilitate the development of SFTSV countermeasures.
Tadaki Suzuki, Yuko Sato, Kaori Sano, Takeshi Arashiro, Harutaka Katano, Noriko Nakajima, Masayuki Shimojima, Michiyo Kataoka, Kenta Takahashi, Yuji Wada, Shigeru Morikawa, Shuetsu Fukushi, Tomoki Yoshikawa, Masayuki Saijo, Hideki Hasegawa
Chikungunya virus (CHIKV) is an arbovirus capable of causing a severe and often debilitating rheumatic syndrome in humans. CHIKV replicates in a wide variety of cell types in mammals, which has made attributing pathologic outcomes to replication at specific sites difficult. To assess the contribution of CHIKV replication in skeletal muscle cells to pathogenesis, we engineered a CHIKV strain exhibiting restricted replication in these cells via incorporation of target sequences for skeletal muscle cell-specific miR-206. This virus, which we term SKE, displayed diminished replication in skeletal muscle cells in a mouse model of CHIKV disease. Mice infected with SKE developed less severe disease signs, including diminished swelling in the inoculated foot and less necrosis and inflammation in the interosseous muscles. SKE infection was associated with diminished infiltration of T cells into the interosseous muscle as well as decreased production of IL-1b, IL-6, IP-10, and TNFa. Importantly, blockade of the IL-6 receptor led to diminished swelling of a control CHIKV strain capable of replication in skeletal muscle, reducing swelling to levels observed in mice infected with SKE. These data implicate replication in skeletal muscle cells and release of IL-6 as important mediators of CHIKV disease.
Anthony J. Lentscher, Mary K. McCarthy, Nicholas A. May, Bennett J. Davenport, Stephanie A. Montgomery, Krishnan Raghunathan, Nicole McAllister, Laurie A. Silva, Thomas E. Morrison, Terence S. Dermody
Recent occurrences of filoviruses and the arenavirus Lassa virus (LASV) in overlapping endemic areas of Africa highlight the need for a prophylactic vaccine that would confer protection against all of these viruses that cause lethal hemorrhagic fever (HF). We developed a quadrivalent formulation of Vesiculovax that contains recombinant vesicular stomatitis virus (rVSV) vectors expressing filovirus glycoproteins and also contains a rVSV vector expressing the glycoprotein of a lineage IV strain of LASV. Cynomolgus macaques were vaccinated twice with the quadrivalent formulation, followed by challenge 28 days after the boost vaccination with each of the three corresponding filoviruses (Ebola, Sudan, Marburg) or a heterologous contemporary lineage II strain of LASV. Serum IgG and neutralizing antibody responses specific for all four glycoproteins were detected in all vaccinated animals. A modest and balanced cell-mediated immune response specific for the glycoproteins was also detected in most of the vaccinated macaques. Regardless of the levels of total glycoprotein-specific immune response detected after vaccination, all immunized animals were protected from disease and death following lethal challenges. These findings indicate that vaccination with attenuated rVSV vectors each expressing a single HF virus glycoprotein may provide protection against those filoviruses and LASV most commonly responsible for outbreaks of severe HF in Africa.
Robert W. Cross, Rong Xu, Demetrius Matassov, Stefan Hamm, Theresa E. Latham, Cheryl S. Gerardi, Rebecca M. Nowak, Joan B. Geisbert, Ayuko Ota-Setlik, Krystle N. Agans, Amara Luckay, Susan E. Witko, Lena Soukieh, Daniel J. Deer, Chad E. Mire, Heinz Feldmann, Christian Happi, Karla A. Fenton, John H. Eldridge, Thomas W. Geisbert
A vaccine for hepatitis C virus (HCV) is urgently needed. Development of broadly-neutralizing plasma antibodies during acute infection is associated with HCV clearance, but the viral epitopes of these plasma antibodies are unknown. Identification of these epitopes could define the specificity and function of neutralizing antibodies (NAbs) that should be induced by a vaccine. Here, we present development and application of a high-throughput method that deconvolutes polyclonal anti-HCV NAbs in plasma, delineating the epitope specificities of anti-HCV NAbs in acute infection plasma of forty-four humans with subsequent clearance or persistence of HCV. Remarkably, we identified multiple broadly neutralizing antibody (bNAb) combinations that were associated with greater plasma neutralizing breadth and with HCV clearance. These studies have potential to inform new strategies for vaccine development by identifying bNAb combinations in plasma associated with natural clearance of HCV, while also providing a high-throughput assay that could identify these responses after vaccination trials.
Valerie J. Kinchen, Guido Massaccesi, Andrew I. Flyak, Madeleine C. Mankowski, Michelle D. Colbert, William O. Osburn, Stuart C. Ray, Andrea L. Cox, James E. Crowe Jr., Justin R. Bailey
We previously generated 32 rotavirus-specific (RV-specific) recombinant monoclonal antibodies (mAbs) derived from B cells isolated from human intestinal resections. Twenty-four of these mAbs were specific for the VP8* fragment of RV VP4, and most (20 of 24) were non-neutralizing when tested in the conventional MA104 cell–based assay. We reexamined the ability of these mAbs to neutralize RVs in human intestinal epithelial cells including ileal enteroids and HT-29 cells. Most (18 of 20) of the “non-neutralizing” VP8* mAbs efficiently neutralized human RV in HT-29 cells or enteroids. Serum RV neutralization titers in adults and infants were significantly higher in HT-29 than MA104 cells and adsorption of these sera with recombinant VP8* lowered the neutralization titers in HT-29 but not MA104 cells. VP8* mAbs also protected suckling mice from diarrhea in an in vivo challenge model. X-ray crystallographic analysis of one VP8* mAb (mAb9) in complex with human RV VP8* revealed that the mAb interaction site was distinct from the human histo-blood group antigen binding site. Since MA104 cells are the most commonly used cell line to detect anti-RV neutralization activity, these findings suggest that prior vaccine and other studies of human RV neutralization responses may have underestimated the contribution of VP8* antibodies to the overall neutralization titer.
Ningguo Feng, Liya Hu, Siyuan Ding, Mrinmoy Sanyal, Boyang Zhao, Banumathi Sankaran, Sasirekha Ramani, Monica McNeal, Linda L. Yasukawa, Yanhua Song, B.V. Venkatar Prasad, Harry B. Greenberg
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