Immunology
Abstract
Novel prime-boost immunization strategies are required to control the global Tuberculosis (TB) pandemic, which claims approximately 3 lives every minute. Here, we have generated an immunogenic complex against Mycobacterium tuberculosis (M.tb), consisting of promiscuous T cell epitopes (M.tb peptides) and TLR ligands assembled in liposomes. Interestingly, this complex (PTLs; peptide-TLR agonist-liposomes) induced significant activation of CD4+ T cells and IFNγ production in the PBMCs derived from PPD+ healthy individuals as compared to PPD- controls. Furthermore, intranasal delivery of PTLs significantly reduced the bacterial burden in the infected mice by inducing M.tb specific polyfunctional (IFNγ+IL17+TNFα+IL2+) immune responses and long-lasting central memory responses thereby reducing the risk of TB recurrence in DOTS treated infected animals. The transcriptome analysis of peptide-stimulated immune cells unveiled the molecular basis of enhanced protection. Furthermore, PTLs immunization significantly boosted the BCG-primed immune responses against TB. The greatly enhanced efficacy of BCG-PTLs vaccine model in controlling pulmonary TB projects PTLs as an adjunct vaccine against TB.
Authors
Santosh Kumar, Ashima Bhaskar, Gautam Patnaik, Chetan Sharma, Dhiraj K. Singh, Sandeep Kaushik, Shivam Chaturvedi, Gobardhan Das, Ved Prakash Dwivedi
Abstract
Background: Mitochondrial DNA (MT-DNA) are intrinsically inflammatory nucleic acids released by damaged solid organs. Whether circulating cell-free MT-DNA quantitation could be used to predict the risk of poor COVID-19 outcomes remains undetermined. Methods: We measured circulating MT-DNA levels in prospectively collected, cell-free plasma samples from 97 subjects with COVID-19 at hospital presentation. Our primary outcome was mortality. ICU admission, intubation, vasopressor and renal replacement therapy requirements were secondary outcomes. Multivariate regression analysis determined whether MT-DNA levels were independent of other reported COVID-19 risk factors. Receiver operating characteristics and area under-the-curve assessment were used to compare MT-DNA levels to established and emerging inflammatory markers of COVID-19. Results: Circulating MT-DNA levels were highly elevated in patients who eventually died, required ICU admission, intubation, vasopressor use or renal replacement therapy. Multivariate regression revealed that high circulating MT-DNA is an independent risk factor for these outcomes after adjusting for age, sex, and comorbidities. We also found that circulating MT-DNA levels have a similar or superior area-under-the curve when compared against clinically-established measures of inflammation and emerging markers currently of interest as investigational targets for COVID-19 therapy. Conclusions: These results show that high circulating MT-DNA levels are a potential early indicator for poor COVID-19 outcomes. Funding: This project was supported by Washington University Institute of Clinical Translational Sciences COVID-19 Research Program. Sample procurement and patient outcome data collection was supported by the Washington University ICTS NIH grant UL1TR002345.
Authors
Davide Scozzi, Marlene Cano, Lina Ma, Dequan Zhou, Ji Hong Zhu, Jane A. O’Halloran, Charles W. Goss, Adriana M. Rauseo, Zhiyi Liu, Sanjaya Kumar Sahu, Valentina Peritore, Monica Rocco, Alberto Ricci, Rachele Amodeo, Laura Aimati, Mohsen Ibrahim, Ramsey R. Hachem, Daniel Kreisel, Philip A. Mudd, Hrishikesh S. Kulkarni, Andrew E. Gelman
Abstract
The CNS is regarded as an immunoprivileged organ, evading routine immune surveillance; however, the coordinated development of immune responses profoundly influences outcomes after brain injury. Innate lymphoid cells (ILCs) are cytokine-producing cells that are critical for the initiation, modulation, and resolution of inflammation, but the functional relevance and mechanistic regulation of ILCs are unexplored after acute brain injury. We demonstrate increased proliferation of all ILC subtypes within the meninges for up to 1 year after experimental traumatic brain injury (TBI) while ILCs were present within resected dura and elevated within cerebrospinal fluid (CSF) of moderate-to-severe TBI patients. In line with energetic derangements after TBI, inhibition of the metabolic regulator, AMPK, increased meningeal ILC expansion, whereas AMPK activation suppressed proinflammatory ILC1/ILC3 and increased the frequency of IL-10–expressing ILC2 after TBI. Moreover, intracisternal administration of IL-33 activated AMPK, expanded ILC2, and suppressed ILC1 and ILC3 within the meninges of WT and Rag1–/– mice, but not Rag1–/– IL2rg–/– mice. Taken together, we identify AMPK as a brake on the expansion of proinflammatory, CNS-resident ILCs after brain injury. These findings establish a mechanistic framework whereby immunometabolic modulation of ILCs may direct the specificity, timing, and magnitude of cerebral immunity.
Authors
Babak Baban, Molly Braun, Hesam Khodadadi, Ayobami Ward, Katelyn Alverson, Aneeq Malik, Khoi Nguyen, Skon Nazarian, David C. Hess, Scott Forseen, Alexander F. Post, Fernando L. Vale, John R. Vender, Md. Nasrul Hoda, Omid Akbari, Kumar Vaibhav, Krishnan M. Dhandapani
Abstract
The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), coupled with a lack of therapeutics, has paralyzed the globe. Although significant effort has been invested in identifying antibodies that block infection, the ability of antibodies to target infected cells through Fc interactions may be vital to eliminate the virus. To explore the role of Fc activity in SARS-CoV-2 immunity, the functional potential of a cross–SARS-reactive antibody, CR3022, was assessed. CR3022 was able to broadly drive antibody effector functions, providing critical immune clearance at entry and upon egress. Using selectively engineered Fc variants, no protection was observed after administration of WT IgG1 in mice or hamsters. Conversely, the functionally enhanced Fc variant resulted in increased pathology in both the mouse and hamster models, causing weight loss in mice and enhanced viral replication and weight loss in the more susceptible hamster model, highlighting the pathological functions of Fc-enhancing mutations. These data point to the critical need for strategic Fc engineering for the treatment of SARS-CoV-2 infection.
Authors
Caroline Atyeo, Matthew D. Slein, Stephanie Fischinger, John Burke, Alexandra Schäfer, Sarah R. Leist, Natalia A. Kuzmina, Chad Mire, Anna Honko, Rebecca Johnson, Nadia Storm, Matthew Bernett, Pei Tong, Teng Zuo, Junrui Lin, Adam Zuiani, Caitlyn Linde, Todd Suscovich, Duane R. Wesemann, Anthony Griffiths, John R. Desjarlais, Boris D. Juelg, Jaap Goudsmit, Alexander Bukreyev, Ralph Baric, Galit Alter
Abstract
2'3'-cGAMP is known as a non-classical 2nd messenger and small immune modulator that possesses potent anti-tumor and antiviral activities through stimulating STING-mediated signaling pathway. However, its function in regulating type 2 immune responses remains unknown. We sought to determine a role of STING activation by 2'3'-cGAMP in type 2 inflammatory reactions in multiple mouse models of eosinophilic asthma. We discovered that 2'3'-cGAMP administration strongly attenuated type 2 lung immunopathology and airway hyperresponsiveness (AHR) induced by IL-33 and a fungal allergen, A. flavus. Mechanistically, upon the respiratory delivery, 2'3'-cGAMP was mainly internalized by alveolar macrophages, in which it activated the STING-IRF3-IFN-I signaling axis to induce the production of inhibitory factors containing IFNα, which blocked the IL-33-mediated activation of group 2 innate lymphoid cells (ILC2) in vivo. We further demonstrated that 2'3'-cGAMP directly suppressed the proliferation and function of both human and mouse ILC2 in vitro. Taken together, our findings suggest that STING activation by 2'3'-cGAMP in alveolar macrophages and ILC2 cells can negatively regulate type 2 immune responses, implying that the respiratory delivery of 2'3'-cGAMP might be further developed as an alternative strategy for treating type 2 immunopathologic diseases such as eosinophilic asthma.
Authors
Li She, Gema D. Barrera, Liping Yan, Hamad Hazzaa Alanazi, Edward G. Brooks, Peter H. Dube, Yilun Sun, Hong Zan, Daniel P. Chupp, Nu Zhang, Xin Zhang, Yong Liu, Xiao-Dong Li
Abstract
Antiretroviral therapies (ART) abrogate HIV replication; however, infection persists as long-lived reservoirs of infected cells with integrated proviruses, which re-seed replication if ART is interrupted. A central tenet of our current understanding of this persistence is that infected cells are shielded from immune recognition and elimination through a lack of antigen expression from proviruses. Efforts to cure HIV infection have therefore focused on reactivating latent proviruses to enable immune-mediated clearance, but these have yet to succeed in reducing viral reservoirs. Here, we revisited the question of whether HIV reservoirs are predominately immunologically silent from a new angle: by querying the dynamics of HIV-specific T-cell responses over long-term ART for evidence of ongoing recognition of HIV-infected cells. In longitudinal assessments, we show that the rates of change in persisting HIV Nef-specific responses, but not responses to other HIV gene products, were associated with residual frequencies of infected cells. These Nef-specific responses were highly stable over time, and disproportionately exhibited a cytotoxic, effector functional profile, indicative of recent in vivo recognition of HIV antigens. These results indicate substantial visibility of the HIV-infected cells to T-cells on stable ART, presenting both opportunities and challenges for the development of therapeutic approaches to curing infection.
Authors
Eva M. Stevenson, Adam R. Ward, Ronald Truong, Allison S. Thomas, Szu-Han Huang, Thomas R. Dilling, Sandra Terry, John K. Bui, Talia M. Mota, Ali Danesh, Guinevere Q. Lee, Andrea Gramatica, Pragya Khadka, Winiffer D. Conce Alberto, Rajesh T. Gandhi, Deborah K. McMahon, Christina M. Lalama, Ronald J. Bosch, Bernard J. Macatangay, Joshua C. Cyktor, Joseph J. Eron, John W. Mellors, R. Brad Jones
Abstract
Hepatitis B virus (HBV)-specific CD8+ T cells fail to acquire effector functions after priming in the liver, but the molecular basis for the dysfunctionality is poorly understood. By comparing the gene expression profile of intrahepatically primed, dysfunctional HBV-specific CD8+ T cells with that of systemically primed, functional effector counterparts, we found that the expression of interferon-stimulated genes (ISGs) is selectively suppressed in the dysfunctional CD8+ T cells. The ISG suppression was associated with impaired phosphorylation of STAT1 in response to IFNα treatment. Importantly, a strong induction of type interferons (IFN-Is) in the liver facilitated the functional differentiation of intrahepatically primed HBV-specific CD8+ T cells in association with the restoration of ISGs expression in the T cells. These results suggest that intrahepatic priming suppresses IFN-I signaling in CD8+ T cells, which may contribute to the dysfunctionality. The data also suggest a therapeutic value of the robust induction of intrahepatic IFN-Is for the treatment of chronic HBV infection.
Authors
Keigo Kawashima, Masanori Isogawa, Masaya Onishi, Ian Baudi, Satoru Saito, Atsushi Nakajima, Takashi Fujita, Yasuhito Tanaka
Abstract
Interleukin-10 (IL-10) is a critical cytokine used by immune cells to suppress inflammation. Paradoxically, immune cell-derived IL-10 can drive insulin resistance in obesity by suppressing adipocyte energy expenditure and thermogenesis. However, the source of IL-10 necessary for the suppression of adipocyte thermogenesis is unknown. We show here that CD4+ Foxp3+ regulatory T cells (Tregs) are a significant source of IL-10, and that Treg-derived IL-10 can suppress adipocyte beiging. Unexpectedly, Treg-specific loss of IL-10 resulted in increased insulin sensitivity and reduced obesity in high fat diet (HFD)-fed male mice. Mechanistically, we determined that Treg-specific loss of the transcription factor Blimp-1, a driver of IL-10 expression by Tregs, phenocopied the Treg-specific IL-10-deficient mice. Loss of Blimp-1 expression in Tregs resulted in reduced ST2+, KLRG1+, IL-10-secreting Tregs, particularly in the white adipose tissue. Blimp-1-deficient mice were protected from glucose intolerance, insulin resistance and diet-induced obesity (DIO), through increased white adipose tissue browning. Taken together, our data show that Blimp-1-regulated IL-10 secretion by Tregs represses white adipose tissue beiging to maintain adipose tissue homeostasis.
Authors
Lisa Y. Beppu, Raja Mooli, Xiaoyao Qu, Giovanni J. Marrero, Christopher A. Finley, Allen N. Fooks, Zackary P. Mullen, Adolfo B. Frias Jr., Ian J. Sipula, Bingxian Xie, Katherine E. Helfrich, Simon C. Watkins, Amanda C. Poholek, Sadeesh K. Ramakrishnan, Michael J. Jurczak, Louise M. D'Cruz
Abstract
Although many HIV cure strategies seek to expand HIV-specific CD8+ T cells to control the virus, all are likely to fail if cellular exhaustion is not prevented. A loss in stem-like memory properties (i.e., the ability to proliferate and generate secondary effector cells) is a key feature of exhaustion; little is known, however, about how these properties are regulated in human virus-specific CD8+ T cells. We found that virus-specific CD8+ T cells from humans and non-human primates naturally controlling HIV/SIV infection express more of the transcription factor, TCF-1, than non-controllers. HIV-specific CD8+ T cell TCF-1 expression correlated with memory marker expression and expansion capacity and declined with antigenic stimulation. CRISPR-Cas9 editing of TCF-1 in human primary T cells demonstrated a direct role in regulating expansion capacity. Collectively, these data suggest that TCF-1 contributes to the regulation of the stem-like memory property of secondary expansion capacity of HIV-specific CD8+ T cells, and they provide a rationale for exploring the enhancement of this pathway in T cell-based therapeutic strategies for HIV.
Authors
Rachel L. Rutishauser, Christian Deo T. Deguit, Joseph Hiatt, Franziska Blaeschke, Theodore L. Roth, Lynn Wang, Kyle A. Raymond, Carly E. Starke, Joseph C. Mudd, Wenxuan Chen, Carolyn P. Smullin, Rodrigo Matus-Nicodemos, Rebecca Hoh, Melissa R. Krone, Frederick M. Hecht, Christopher D. Pilcher, Jeffrey N. Martin, Richard A. Koup, Daniel C. Douek, Jason M. Brenchley, Rafick-Pierre Sékaly, Satish K. Pillai, Alexander Marson, Steven G. Deeks, Joseph M. McCune, Peter W. Hunt
Abstract
Clinical trials of biologic therapies in type 1 diabetes (T1D) aim to mitigate autoimmune destruction of pancreatic beta cells through immune perturbation and serve as resources to elucidate immunological mechanisms in health and disease. In the T1DAL trial of alefacept (LFA3-Ig) in recent onset T1D, endogenous insulin production was preserved in 30% of subjects for two years post-therapy. Given our previous findings linking exhausted CD8 T cells to beneficial response in T1D trials, we applied unbiased analyses to sorted CD8 T cells to evaluate their potential role in T1DAL. Using RNA-seq, we found that greater insulin C-peptide preservation was associated with a module of activation- and exhaustion-associated genes. This signature was dissected into two distinct CD8 memory populations through correlation with clustered cytometry data. Both populations were hypo-proliferative, shared expanded TCR junctions, and expressed exhaustion-associated markers including TIGIT and KLRG1. The populations were distinguished by reciprocal expression of CD8 T and NK cell markers (GZMB, CD57 and inhibitory KIR genes), versus T cell activation and differentiation markers (PD1 and CD28). These findings support previous evidence linking exhausted CD8 T cells to successful immune interventions for T1D, while suggesting multiple inhibitory mechanisms can promote this beneficial cell state.
Authors
Kirsten E. Diggins, Elisavet Serti, Virginia S. Muir, Mario G. Rosasco, TingTing Lu, Elisa Balmas, Gerald T. Nepom, S. Alice Long, Peter S. Linsley
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