Immunology
Abstract
Authors
Aysefa Doganci, Tatjana Eigenbrod, Norbert Krug, George T. De Sanctis, Michael Hausding, Veit J. Erpenbeck, El-Bdaoui Haddad, Edgar Schmitt, Tobias Bopp, Karl-J. Kallen, Udo Herz, Steffen Schmitt, Cornelia Luft, Olaf Hecht, Jens M. Hohlfeld, Hiroaki Ito, Norihiro Nishimoto, Kazuyuki Yoshizaki, Tadamitsu Kishimoto, Stefan Rose-John, Harald Renz, Markus F. Neurath, Peter R. Galle, Susetta Finotto
Abstract
X-linked lymphoproliferative disease (XLP) is an often-fatal immunodeficiency characterized by hypogammaglobulinemia, fulminant infectious mononucleosis, and/or lymphoma. The genetic lesion in XLP, SH2D1A, encodes the adaptor protein SAP (signaling lymphocytic activation molecule–associated [SLAM-associated] protein); however, the mechanism(s) by which mutations in SH2D1A causes hypogammaglobulinemia is unknown. Our analysis of 14 XLP patients revealed normal B cell development but a marked reduction in the number of memory B cells. The few memory cells detected were IgM+, revealing deficient isotype switching in vivo. However, XLP B cells underwent proliferation and differentiation in vitro as efficiently as control B cells, which indicates that the block in differentiation in vivo is B cell extrinsic. This possibility is supported by the finding that XLP CD4+ T cells did not efficiently differentiate into IL-10+ effector cells or provide optimal B cell help in vitro. Importantly, the B cell help provided by SAP-deficient CD4+ T cells was improved by provision of exogenous IL-10 or ectopic expression of SAP, which resulted in increased IL-10 production by T cells. XLP CD4+ T cells also failed to efficiently upregulate expression of inducible costimulator (ICOS), a potent inducer of IL-10 production by CD4+ T cells. Thus, insufficient IL-10 production may contribute to hypogammaglobulinemia in XLP. This finding suggests new strategies for treating this immunodeficiency.
Authors
Cindy S. Ma, Nathan J. Hare, Kim E. Nichols, Loic Dupré, Grazia Andolfi, Maria-Grazia Roncarolo, Stephen Adelstein, Philip D. Hodgkin, Stuart G. Tangye
Abstract
Authors
Gaël Ménasché, Chen Hsuan Ho, Ozden Sanal, Jérôme Feldmann, Ilhan Tezcan, Fügen Ersoy, Anne Houdusse, Alain Fischer, Geneviève de Saint Basile
Abstract
Authors
Kyoko Katakura, Jongdae Lee, Daniel Rachmilewitz, Gloria Li, Lars Eckmann, Eyal Raz
Abstract
Experimental colitis is mediated by inflammatory or dysregulated immune responses to microbial factors of the gastrointestinal tract. In this study we observed that administration of Toll-like receptor 9 (TLR9) agonists suppressed the severity of experimental colitis in RAG1–/– but not in SCID mice. This differential responsiveness between phenotypically similar but genetically distinct animals was related to a partial blockade in TLR9 signaling and defective production of type I IFN (i.e., IFN-α/β) in SCID mice upon TLR9 stimulation. The addition of neutralization antibodies against type I IFN abolished the antiinflammatory effects induced by TLR9 agonists, whereas the administration of recombinant IFN-β mimicked the antiinflammatory effects induced by TLR9 agonists in this model. Furthermore, mice deficient in the IFN-α/β receptor exhibited more severe colitis than wild-type mice did upon induction of experimental colitis. These results indicate that TLR9-triggered type I IFN has antiinflammatory functions in colitis. They also underscore the important protective role of type I IFN in intestinal homeostasis and suggest that strategies to modulate innate immunity may be of therapeutic value for the treatment of intestinal inflammatory conditions.
Authors
Kyoko Katakura, Jongdae Lee, Daniel Rachmilewitz, Gloria Li, Lars Eckmann, Eyal Raz
Abstract
Omenn syndrome is a severe primary immunodeficiency with putative autoimmune manifestations of the skin and gastrointestinal tract. The disease is caused by hypomorphic mutations in recombination-activating genes that impair but do not abolish the process of VDJ recombination, leading to the generation of autoreactive T cells with a highly restricted receptor repertoire. Loss of central tolerance in genetically determined autoimmune diseases, e.g., autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, is associated with defective expression by medullary thymic epithelial cells of AIRE, the transcription activator that induces thymic expression of tissue-specific antigens. Analysis of AIRE expression in the thymi of 2 Omenn syndrome patients and 1 SCID patient, by real-time RT-PCR and immunohistochemistry, demonstrated a profound reduction in the levels of AIRE mRNA and protein in patients as compared with a normal control subject. Lack of AIRE was associated with normal or even increased levels of keratin and lymphotoxin-β receptor mRNAs, while mRNAs of the self-antigens insulin, cytochrome P450 1a2, and fatty acid–binding protein were undetectable in thymi from immunodeficiency patients. These results demonstrate that deficiency of AIRE expression is observed in severe immunodeficiencies characterized by abnormal T cell development and suggest that in Omenn syndrome, the few residual T cell clones that develop may escape negative selection and thereafter expand in the periphery, causing massive autoimmune reactions.
Authors
Patrizia Cavadini, William Vermi, Fabio Facchetti, Stefania Fontana, Seiho Nagafuchi, Evelina Mazzolari, Anna Sediva, Veronica Marrella, Anna Villa, Alain Fischer, Luigi D. Notarangelo, Raffaele Badolato
Abstract
The induction of potent CD8+ T cell responses by vaccines to fight microbes or tumors remains a major challenge, as many candidates for human vaccines have proved to be poorly immunogenic. Deoxycytidyl-deoxyguanosin oligodeoxynucleotides (CpG ODNs) trigger Toll-like receptor 9, resulting in dendritic cell maturation that can enhance immunogenicity of peptide-based vaccines in mice. We tested whether a synthetic ODN, CpG 7909, could improve human tumor antigen–specific CD8+ T cell responses. Eight HLA-A2+ melanoma patients received 4 monthly vaccinations of low-dose CpG 7909 mixed with melanoma antigen A (Melan-A; identical to MART-1) analog peptide and incomplete Freund’s adjuvant. All patients exhibited rapid and strong antigen-specific T cell responses: the frequency of Melan-A–specific T cells reached over 3% of circulating CD8+ T cells. This was one order of magnitude higher than the frequency seen in 8 control patients treated similarly but without CpG and 1–3 orders of magnitude higher than that seen in previous studies with synthetic vaccines. The enhanced T cell populations consisted primarily of effector memory cells, which in part secreted IFN-γ and expressed granzyme B and perforin ex vivo. In vitro, T cell clones recognized and killed melanoma cells in an antigen-specific manner. Thus, CpG 7909 is an efficient vaccine adjuvant that promotes strong antigen-specific CD8+ T cell responses in humans.
Authors
Daniel E. Speiser, Danielle Liénard, Nathalie Rufer, Verena Rubio-Godoy, Donata Rimoldi, Ferdy Lejeune, Arthur M. Krieg, Jean-Charles Cerottini, Pedro Romero
Abstract
Genetic factors are known to strongly influence susceptibility to allergic inflammation. The Th2 cytokine IL-13 is a central mediator of allergy and asthma, and common single-nucleotide polymorphisms in IL13 are associated with allergic phenotypes in several ethnically diverse populations. In particular, IL13+2044G→A is expected to result in the nonconservative replacement of arginine 130 (R130) with glutamine (Q). We examined the impact of IL13+2044G→A on the functional properties of IL-13 by directly comparing the activity of WT IL-13 and IL-13 R130Q on primary human cells involved in the effector mechanisms of allergic inflammation. Our results show that IL-13 R130Q was significantly more active than WT IL-13 in inducing STAT6 phosphorylation and CD23 expression in monocytes and hydrocortisone-dependent IgE switching in B cells. Notably, IL-13 R130Q was neutralized less effectively than WT IL-13 by an IL-13Rα2 decoy. Decreased neutralization of the minor variant could contribute to its enhanced in vivo activity. Neither IL-13 variant was able to engage T cells, which suggests that increased allergic inflammation in carriers of IL13+2044A depends on enhanced IL-13–mediated Th2 effector functions rather than increased Th2 differentiation. Collectively, our data indicate that natural variation in the coding region of IL13 may be an important genetic determinant of susceptibility to allergy.
Authors
Frank D. Vladich, Susan M. Brazille, Debra Stern, Michael L. Peck, Raffaella Ghittoni, Donata Vercelli
Abstract
We show in these studies that Qa-1–dependent CD8+ T cells are involved in the establishment and maintenance of peripheral self tolerance as well as facilitating affinity maturation of CD4+ T cells responding to foreign antigen. We provide experimental evidence that the strategy used by the Qa-1–dependent CD8+ T cells to accomplish both these tasks in vivo is to selectively downregulate T cell clones that respond to both self and foreign antigens with intermediate, not high or low, affinity/avidity. Thus, the immune system evolved to regulate peripheral immunity using a unified mechanism that efficiently and effectively permits the system to safeguard peripheral self tolerance yet promote the capacity to deal with foreign invaders.
Authors
Hong Jiang, Yilun Wu, Bitao Liang, Zongyu Zheng, Guomei Tang, Jean Kanellopoulos, Mark Soloski, Robert Winchester, Itamar Goldstein, Leonard Chess
Abstract
The cytokine IL-6 acts via a specific receptor complex that consists of the membrane-bound IL-6 receptor (mIL-6R) or the soluble IL-6 receptor (sIL-6R) and glycoprotein 130 (gp130). In this study, we investigated the role of IL-6R components in asthma. We observed increased levels of sIL-6R in the airways of patients with allergic asthma as compared to those in controls. In addition, local blockade of the sIL-6R in a murine model of late-phase asthma after OVA sensitization by gp130–fraction constant led to suppression of Th2 cells in the lung. By contrast, blockade of mIL-6R induced local expansion of Foxp3-positive CD4+CD25+ Tregs with increased immunosuppressive capacities. CD4+CD25+ but not CD4+CD25– lung T cells selectively expressed the IL-6R α chain and showed IL-6–dependent STAT-3 phosphorylation. Finally, in an in vivo transfer model of asthma in immunodeficient Rag1 mice, CD4+CD25+ T cells isolated from anti–IL-6R antibody–treated mice exhibited marked immunosuppressive and antiinflammatory functions. IL-6 signaling therefore controls the balance between effector cells and Tregs in the lung by means of different receptor components. Furthermore, inhibition of IL-6 signaling emerges as a novel molecular approach for the treatment of allergic asthma.
Authors
Aysefa Doganci, Tatjana Eigenbrod, Norbert Krug, George T. De Sanctis, Michael Hausding, Veit J. Erpenbeck, El-Bdaoui Haddad, Edgar Schmitt, Tobias Bopp, Karl-J. Kallen, Udo Herz, Steffen Schmitt, Cornelia Luft, Olaf Hecht, Jens M. Hohlfeld, Hiroaki Ito, Norihiro Nishimoto, Kazuyuki Yoshizaki, Tadamitsu Kishimoto, Stefan Rose-John, Harald Renz, Markus F. Neurath, Peter R. Galle, Susetta Finotto
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)