Immunology
Abstract
During chronic HIV infection, immune cells become increasingly dysfunctional and exhausted. Little is known about how immune functions are restored after initiation of antiretroviral therapy (ART). In this study, we assessed cellular and metabolic activity and evaluated the effect of individual antiretrovirals on cellular subsets ex vivo in ART-treated and treatment-naive chronically HIV-infected individuals. We observed that cellular respiration was significantly decreased in most immune cells in chronic HIV infection. The respiration was correlated to immune activation and the inhibitory receptor programmed cell death 1 on CD8+ T cells. ART restored the metabolic phenotype, but the respiratory impairment persisted in CD4+ T cells. This was particularly the case for individuals receiving integrase strand transfer inhibitors. CD4+ T cells from these individuals showed a significant reduction in ex vivo proliferative capacity compared with individuals treated with protease inhibitors or nonnucleoside reverse transcriptase inhibitors. We noticed a significant decrease in respiration of cells treated with dolutegravir (DLG) or elvitegravir (EVG) and a switch from polyfunctional to TNF-α–dominated “stress” immune response. There was no effect on glycolysis, consistent with impaired mitochondrial function. We detected increased levels of mitochondrial ROS and mitochondrial mass. These findings indicate that EVG and DLG use is associated with slow proliferation and impaired respiration with underlying mitochondrial dysfunction, resulting in overall decreased cellular function in CD4+ T cells.
Authors
Marek Korencak, Morgan Byrne, Enrico Richter, Bruce T. Schultz, Patrick Juszczak, Julie A. Ake, Anuradha Ganesan, Jason F. Okulicz, Merlin L. Robb, Buena de los Reyes, Sandra Winning, Joachim Fandrey, Timothy H. Burgess, Stefan Esser, Nelson L. Michael, Brian K. Agan, Hendrik Streeck
Abstract
The activation and recruitment of NK cells to the site of viral infection are crucial for virus control. However, it remains largely unknown what controls the recruitment of the activated NK cells to the infection site. In a model of intraperitoneal infection with vaccinia virus (VV), we showed that poly(ADP-ribose) polymerase-1 (PARP-1), a sensor of DNA damage, is critical for NK cell recruitment to the site of infection and viral control in vivo. We further demonstrated that PARP-1 promotes the production of CCL2 and that the CCL2-CCR2 axis is essential for NK cell recruitment to the infection site. In addition, we demonstrated that peritoneal macrophages are the main producer of PARP-1–dependent CCL2 secretion. Mechanistically, PARP-1 functions as a regulator of NF-κB by promoting its nuclear translocation and binding to its response sequences in macrophages upon VV infection. Taken together, our results reveal a potentially previously unknown role for PARP-1–dependent CCL2 production in NK cell migration and viral control and may provide important insights into the design of effective NK cell–based therapies for viral infections and cancer.
Authors
Qiyang Shou, Huiying Fu, Xiaopei Huang, Yiping Yang
Abstract
Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by muscle weakness and caused by pathogenic autoantibodies that bind to membrane proteins at the neuromuscular junction. Most patients have autoantibodies against the acetylcholine receptor (AChR), but a subset of patients have autoantibodies against muscle-specific tyrosine kinase (MuSK) instead. MuSK is an essential component of the pathway responsible for synaptic differentiation, which is activated by nerve-released agrin. Through binding MuSK, serum-derived autoantibodies inhibit agrin-induced MuSK autophosphorylation, impair clustering of AChRs, and block neuromuscular transmission. We sought to establish individual MuSK autoantibody clones so that the autoimmune mechanisms could be better understood. We isolated MuSK autoantibody-expressing B cells from 6 MuSK MG patients using a fluorescently tagged MuSK antigen multimer, then generated a panel of human monoclonal autoantibodies (mAbs) from these cells. Here we focused on 3 highly specific mAbs that bound quantitatively to MuSK in solution, to MuSK-expressing HEK cells, and at mouse neuromuscular junctions, where they colocalized with AChRs. These 3 IgG isotype mAbs (2 IgG4 and 1 IgG3 subclass) recognized the Ig-like domain 2 of MuSK. The mAbs inhibited AChR clustering, but intriguingly, they enhanced rather than inhibited MuSK phosphorylation, which suggests an alternative mechanism for inhibiting AChR clustering.
Authors
Kazushiro Takata, Panos Stathopoulos, Michelangelo Cao, Marina Mané-Damas, Miriam L. Fichtner, Erik S. Benotti, Leslie Jacobson, Patrick Waters, Sarosh R. Irani, Pilar Martinez-Martinez, David Beeson, Mario Losen, Angela Vincent, Richard J. Nowak, Kevin C. O’Connor
Abstract
NK cell exhaustion (NCE) due to sustained proliferation results in impaired NK cell function with loss of cytokine production and lytic activity. Using murine models of chronic NK cell stimulation, we have identified a phenotypic signature of NCE characterized by up-regulation of the terminal differentiation marker KLRG1 and by down-regulation of eomesodermin and the activating receptor NKG2D. Chronic stimulation of mice lacking NKG2D resulted in minimized NCE compared to control mice, thus identifying NKG2D as a crucial mediator of NCE. NKG2D internalization and downregulations on NK cells has been previously observed in the presence of tumor cells with high expression of NKG2D ligands (NKG2DL) due to the activation of the DNA damage repair pathways. Interestingly, our study revealed that during NK cell activation there is an increase of MULT1, and NKG2DL, that correlates with an induction of DNA damage. Treatment with the ATM DNA damage repair pathway inhibitor KU55933 (KU) during activation reduced NCE by improving expression of activation markers and genes involved in cell survival, by sustaining NKG2D expression and by preserving cell functionality. Importantly, NK cells expanded ex vivo in the presence of KU displayed increased anti-tumor efficacy in both NKG2D-dependent and -independent mouse models. Collectively, these data demonstrate that NCE is caused by DNA damage and regulated, at least in part, by NKG2D. Further, the prevention of NCE is a promising strategy to improve NK cell-based immunotherapy.
Authors
Maite Alvarez, Federico Simonetta, Jeanette Baker, Antonio Pierini, Arielle S. Wenokur, Alyssa R. Morrison, William J. Murphy, Robert S. Negrin
Abstract
Immunotherapy holds promise for multiple myeloma (MM) patients but little is known about how MM-induced immunosuppression influences response to therapy. Here, we investigated the impact of disease progression on immunotherapy efficacy in the Vk*MYC mouse model. Treatment with agonistic anti-CD137 (4-1BB) mAbs efficiently protected mice when administered early but failed to contain MM growth when delayed more than three weeks after Vk*MYC tumor cell challenge. The quality of CD8+ T cell response to CD137 stimulation was not altered by the presence of MM, but CD8+ T cell numbers were profoundly reduced at the time of treatment. Our data suggest that an insufficient ratio of CD8+ T cells over MM cells (CD8/MM) accounts for the loss of anti-CD137 mAb efficacy. We established serum M-protein levels prior to therapy as a predictive factor of response. Moreover, we developed an in silico model to capture the dynamic interactions between CD8+ T cells and MM cells. Finally, we explored two methods to improve the CD8/MM ratio: anti-CD137 mAb immunotherapy combined with Treg-depletion or administered after chemotherapy treatment with cyclophosphamide or melphalan efficiently reduced MM burden and prolonged survival. Altogether, our data indicate that consolidation treatment with anti-CD137 mAbs might prevent MM relapse.
Authors
Camille Guillerey, Kyohei Nakamura, Andrea C. Pichler, Deborah Barkauskas, Sophie Krumeich, Kimberley Stannard, Kim Miles, Heidi Harjunpää, Yuan Yu, Mika Casey, Alina I. Doban, Mircea Lazar, Gunter Hartel, David Smith, Slavica Vuckovic, Michele W.L. Teng, P. Leif Bergsagel, Marta Chesi, Geoffrey R. Hill, Ludovic Martinet, Mark J. Smyth
Abstract
In the United States, poison ivy exposure is the most common naturally occurring allergen to cause allergic contact dermatitis (ACD). The immune and pruritic mechanisms associated with poison ivy ACD remain largely unexplored. Here, we compared skin whole transcriptomes and itch mediator levels in mouse ACD models induced by the poison ivy allergen, urushiol, and the synthetic allergen, oxazolone. The urushiol model produced a Th2-biased immune response and scratching behavior, resembling findings in poison ivy patients. Urushiol-challenged skin contained elevated levels of the cytokine thymic stromal lymphopoietin (TSLP), a T-cell regulator and itch mediator, and pruritogenic serotonin (5-HT) and endothelin (ET-1), but not substance P (SP) or histamine. The oxazolone model generated a mixed Th1/Th2 response associated with increased levels of substance P, 5-HT, ET-1, but not TSLP or histamine. Injections of a TSLP monoclonal neutralizing antibody, serotonergic or endothelin inhibitors, but not SP inhibitors or antihistamines, reduced scratching behaviors in urushiol-challenged mice. Our findings suggest that the mouse urushiol model may serve as a translational model of human poison ivy ACD study. Inhibiting signaling by TSLP and other cytokines may represent alternatives to the standard steroid/antihistamine regimen for steroid-resistant or -intolerant patients and in exaggerated systemic responses to poison ivy.
Authors
Boyi Liu, Yan Tai, Boyu Liu, Ana I. Caceres, Chengyu Yin, Sven-Eric Jordt
Abstract
Despite the accepted notion that granulocytes play a universally destructive role in organ and tissue grafts, it has been recently described that eosinophils can facilitate immunosuppression-mediated acceptance of murine lung allografts. The mechanism of eosinophil-mediated tolerance, or their role in regulating alloimmune responses in the absence of immunosuppression, remains unknown. Using lung transplants in a fully MHC-mismatched BALB/c (H2d) to C57BL/6 (H2b) strain combination, we demonstrate that eosinophils downregulate T cell–mediated immune responses and play a tolerogenic role even in the absence of immunosuppression. We further show that such downregulation depends on PD-L1/PD-1–mediated synapse formation between eosinophils and T cells. We also demonstrate that eosinophils suppress T lymphocyte responses through the inhibition of T cell receptor/CD3 (TCR/CD3) subunit association and signal transduction in an inducible NOS–dependent manner. Increasing local eosinophil concentration, through administration of intratracheal eotaxin and IL-5, can ameliorate alloimmune responses in the lung allograft. Thus, our data indicate that eosinophil mobilization may be utilized as a novel means of lung allograft–specific immunosuppression.
Authors
Oscar Okwudiri Onyema, Yizhan Guo, Bayan Mahgoub, Qing Wang, Amir Manafi, Zhongcheng Mei, Anirban Banerjee, Dongge Li, Mark H. Stoler, Melissa T. Zaidi, Adam G. Schrum, Daniel Kreisel, Andrew E. Gelman, Elizabeth A. Jacobsen, Alexander Sasha Krupnick
Abstract
Immune responses to therapeutic transgenes are a potential hurdle to treat monogenic muscle disorders. These responses result from the neutralizing activity of transgene-specific B cells and cytotoxic T cells recruited upon gene transfer. We explored here how dual muscle-liver expression of a foreign transgene allows muscle transgene engraftment after adenoassociated viral vector delivery. We found in particular that induction of transgene-specific tolerance is imposed by concurrent muscle and liver targeting, resulting in the absence of CD8+ T cell responses to the transgene. This tolerance can be temporally decoupled, because transgene engraftment can be achieved in muscle weeks after liver transduction. Importantly, transgene-specific CD8+ T cell tolerance can be established despite preexisting immunity to the transgene. Whenever preexisting, transgene-specific CD4+ and CD8+ memory T cell responses are present, dual muscle-liver transduction turns polyclonal, transgene-specific CD8+ T cells into typically exhausted T cells with high programmed cell death 1 (PD-1) expression and lack of IFN-γ production. Our results demonstrate that successful transduction of muscle tissue can be achieved through liver-mediated control of humoral and cytotoxic T cell responses, even in the presence of preexisting immunity to the muscle-associated transgene.
Authors
Laurent Bartolo, Stéphanie Li Chung Tong, Pascal Chappert, Dominique Urbain, Fanny Collaud, Pasqualina Colella, Isabelle Richard, Giuseppe Ronzitti, Jocelyne Demengeot, David A. Gross, Federico Mingozzi, Jean Davoust
Abstract
Tuberculosis patients and mice infected with live Mycobacterium tuberculosis (Mtb) accumulate high numbers of myeloid-derived suppressor cells (MDSCs). Here, we hypothesized that also dead Mtb vaccines may induce MDSCs that could impair the efficacy of vaccination. We found that repeated injections of Mtb vaccines (heat-killed Mtb in Incomplete Freund's Adjuvant, like Montanide) but not single or control vaccines without Mtb strongly expanded CD11b+ myeloid cells in the spleen, that suppressed T cell proliferation and killing ex vivo. Dead Mtb vaccination induced the generation of CD11b+ Ly-6Chigh CD115+ iNOS/Nos2+ monocytic MDSCs (M-MDSCs) upon application of inflammatory or microbial activation signals. In vivo these M-MDSCs positioned strategically in the spleen by infiltrating the splenic bridging channels and white pulp areas. Notably, within 6 to 24 hours in a Nos2-dependent fashion they produced NO to rapidly kill conventional and plasmacytoid dendritic cells (cDCs, pDCs) while, surprisingly, sparing T cells in vivo. Thus, we demonstrate that Mtb vaccine induced M-MDSCs to not directly suppress T cell in vivo but, instead, M-MDSCs directly target DC subpopulations thereby indirectly suppressing effector T cell responses. Collectively, we demonstrate that Mtb booster vaccines induce M-MDSCs in the spleen that can be activated to kill DCs cautioning to thoroughly investigate MDSC formation in individuals after Mtb vaccination in clinical trials.
Authors
Eliana Ribechini, Ina Eckert, Andreas Beilhack, Nelita Du Plessis, Gerhard Walzl, Ulrike Schleicher, Uwe Ritter, Manfred B. Lutz
Abstract
Sex-based differences influence incidence and outcome of infectious disease. Women have a significantly greater incidence of urinary tract infection (UTI) than men, yet, conversely, male UTI is more persistent with greater associated morbidity. Mechanisms underlying these sex-based differences are unknown, in part due to a lack of experimental models. We optimized a model to transurethrally infect male mice and directly compared UTI in both sexes. Although both sexes were initially equally colonized by uropathogenic E. coli, only male and testosterone-treated female mice remained chronically infected for up to 4 weeks. Female mice had more robust innate responses, including higher IL-17 expression, and increased γδ T cells and group 3 innate lymphoid cells in the bladder following infection. Accordingly, neutralizing IL-17 abolished resolution in female mice, identifying a cytokine pathway necessary for bacterial clearance. Our findings support the concept that sex-based responses to UTI contribute to impaired innate immunity in males and provide a rationale for non-antibiotic-based immune targeting to improve the response to UTI.
Authors
Anna Zychlinsky Scharff, Matthieu Rousseau, Livia Lacerda Mariano, Tracy Canton, Camila Rosat Consiglio, Matthew L. Albert, Magnus Fontes, Darragh Duffy, Molly A. Ingersoll
No posts were found with this tag.
