Infectious disease
Abstract
Clostridioides difficile infection (CDI) recurs in one of five patients. Monoclonal antibodies targeting the virulence factor TcdB reduce disease recurrence, suggesting that an inadequate anti-TcdB response to CDI leads to recurrence. In patients with CDI, we discovered that IL33 measured at diagnosis predicts future recurrence, leading us to test the role of IL33 signaling in the induction of humoral immunity during CDI. Using a mouse recurrence model, IL33 was demonstrated to be integral for anti-TcdB antibody production. IL33 acted via ST2+ ILC2 cells, facilitating germinal center T follicular helper (GC-Tfh) cell generation of antibodies. IL33 protection from reinfection was antibody-dependent, as mMT KO mice and mice treated with anti-CD20 mAb were not protected. These findings demonstrate the critical role of IL33 in generating humoral immunity to prevent recurrent CDI.
Authors
Farha Naz, Md Jashim Uddin, Nicholas M. Hagspiel, Mary K. Young, David Tyus, Rachel Boone, Audrey C. Brown, Girija Ramakrishnan, Isaura Rigo, Claire Fleming, Gregory R. Madden, William A. Petri Jr.
Abstract
BACKGROUND.Pneumocystis jirovecii pneumonia (PCP) is a leading cause of fungal pneumonia, but its diagnosis primarily relies on invasive bronchoalveolar lavage (BAL) specimens that are difficult to obtain. Oropharyngeal swabs and serum could improve the PCP diagnostic workflow, and we hypothesized that CRISPR could enhance assay sensitivity to allow robust P. jirovecii diagnosis using swabs and serum. Herein we describe the development of an ultrasensitive RT-PCR-coupled CRISPR assay with high active-infection specificity in infant swabs and adult BAL and serum. METHODS. Mouse analyses employed an RT-PCR CRISPR assay to analyze P. murina transcripts in wild-type and Rag2–/– mouse lung RNA, BAL, and serum at 2-, 4-, and 6-weeks post-infection. Human studies used an optimized RT-PCR CRISPR assay to detect P. jirovecii transcripts in infant oropharyngeal swab samples, adult serum, and adult BAL specimens from P. jirovecii-infected and P. jirovecii-non-infected patients. RESULTS. The P. murina assays sensitively detected Pneumocystis RNA in the serum of infected mice throughout infection. Oropharyngeal swab CRISPR assay results identified infants infected with P. jirovecii with greater sensitivity (96.3% vs. 66.7%) and specificity (100% vs. 90.6%) than RT-qPCR compared to mtLSU standard marker, and CRISPR results achieved higher sensitivity than RT-qPCR results (93.3% vs. 26.7%) in adult serum specimens. CONCLUSION. Since swabs are routinely collected in pediatric pneumonia patients and serum is easier to obtain than BAL, this assay approach could improve the accuracy and timing of pediatric and adult Pneumocystis diagnosis by achieving specificity for active infection and potentially avoiding the requirement for BAL specimens.
Authors
Brady M. Youngquist, Ayanda Trevor Mnguni, Dora Pungan, Rachel P.J. Lai, Guixiang Dai, Chun Fai Ng, Amy Samson, Yasmean Abdelgaliel, Christopher J. Lyon, Bo Ning, Shahid Husain, Sean Wasserman, Jay K. Kolls, Tony Y. Hu
Abstract
The cornerstone of functional cure for chronic hepatitis B (CHB) is hepatitis B surface antigen (HBsAg) loss from blood. HBsAg is encoded by covalently closed circular DNA (cccDNA) and HBV DNA integrated into the host genome (iDNA). Nucleos(t)ide analogues (NUCs), the mainstay of CHB treatment, rarely lead to HBsAg loss, which we hypothesized was due to continued iDNA transcription despite decreased cccDNA transcription. To test this, we applied a novel multiplex droplet digital PCR that identifies the dominant source of HBsAg mRNAs to 3436 single cells from paired liver biopsies from ten people with CHB and HIV receiving NUCs. With increased NUC duration, cells producing HBsAg mRNAs shifted from chiefly cccDNA to chiefly iDNA. This shift was due to both a reduction in the number of cccDNA-containing cells and diminished cccDNA-derived transcription per cell; furthermore, it correlated with reduced detection of proteins deriving from cccDNA but not iDNA. Despite this shift in the primary source of HBsAg, rare cells remained with detectable cccDNA-derived transcription, suggesting a source for maintaining the replication cycle. Functional cure must address both iDNA and residual cccDNA transcription. Further research is required to understand the significance of HBsAg when chiefly derived from iDNA.
Authors
Maraake Taddese, Tanner Grudda, Giulia Belluccini, Mark Anderson, Gavin Cloherty, Hyon S. Hwang, Monika Mani, Che-Min Lo, Naomi Esrig, Mark S. Sulkowski, Richard K. Sterling, Yang Zhang, Ruy M. Ribeiro, David L. Thomas, Chloe L. Thio, Ashwin Balagopal
Abstract
Natural resistance to Mycobacterium tuberculosis (Mtb) infection in some people with HIV (PWH) is unexplained. We performed single cell RNA-sequencing of bronchoalveolar lavage cells, unstimulated or ex vivo stimulated with Mtb, for 7 PWH who were TST & IGRA positive (called LTBI) and 6 who were persistently TST & IGRA negative (called resisters). Alveolar macrophages (AM) from resisters displayed a baseline M1 macrophage phenotype while AM from LTBI did not. Resisters displayed alveolar lymphocytosis, with enrichment of all T cell subpopulations including IFNG-expressing cells. In both groups, mycobactericidal granulysin was expressed almost exclusively by a T cell subtype that co-expressed granzyme B, perforin and NK cell receptors. These poly-cytotoxic T lymphocytes (CTL) over-expressed activating NK cell receptors and were increased in resister BAL. Following challenge with Mtb, only Intraepithelial Lymphocytes-like cells from LTBI participants responded with increased transcription of IFNG. AM from resisters responded with a stronger TNF signature at 6h post-infection while at 24h post-infection AM from LTBI displayed a stronger IFN-γ signature. Conversely, at 24h post-infection only AM from resisters displayed a significant upregulation of MICA transcripts which encode an activating ligand for poly-CTL. These results suggest that poly-CTL and AM mediate the resister phenotype in PWH.
Authors
Monica Dallmann-Sauer, Vinicius M. Fava, Stephanus T. Malherbe, Candice E. MacDonald, Marianna Orlova, Elouise E. Kroon, Aurélie Cobat, Stéphanie Boisson-Dupuis, Eileen G. Hoal, Laurent Abel, Marlo Möller, Jean-Laurent Casanova, Gerhard Walzl, Nelita Du Plessis, Erwin Schurr
Abstract
Neutrophils, particularly low-density neutrophils (LDNs), are believed to contribute to acute COVID-19 severity. Here, we showed that neutrophilia can be detected acutely and even months after SARS-CoV-2 infection in patients and mice, while neutrophil depletion reduced disease severity in mice. A key factor in neutrophilia and severe disease in infected mice was traced to the chemokine CXCL12 secreted by bone marrow cells and unexpectedly, endothelial cells. CXCL12 levels were negatively correlated with LDN numbers in longitudinal analyses of patient blood samples. CXCL12 blockade in SARS-CoV-2-infected mice increased blood/lung neutrophil numbers thereby accelerating disease progression without changing lung virus titers. The exaggerated mortality caused by CXCL12 blockade can be reversed by neutrophil depletion. In addition, blocking interactions between SARS-CoV-2 and Angiotensin-Converting Enzyme 2 (ACE2) reduced CXCL12 levels, suggesting a signal transduction from virus-mediated ACE2 ligation to increased CXCL12 secretion. Collectively, these results demonstrate a previously unappreciated role of CXCL12 in diminishing neutrophilia, including low density neutrophilia, and its deleterious effects in SARS-CoV-2 infections. The results also support the involvement of SARS-CoV-2-endothelial cell interactions in viral pathogenesis.
Authors
Jian Zheng, Hima Dhakal, Enya Qing, Rejeena Shrestha, Anne E. Geller, Samantha M. Morrissey, Divyasha Saxena, Xiaoling Hu, Hong Li, Haiyan Li, Kevin Wilhelmsen, Linder H. Wendt, Klaus Klumpp, Patrick S. Hume, William J. Janssen, Rachel Brody, Kenneth E. Palmer, Silvia M. Uriarte, Patrick P. Ten Eyck, David K. Meyerholz, Michael L. Merchant, Kenneth McLeish, Tom Gallagher, Jiapeng Huang, Jun Yan, Stanley Perlman
Abstract
The risk of severe outcomes of influenza increases during pregnancy. Whether vaccine-induced T cell memory–primed prepregnancy retains the ability to mediate protection during pregnancy, when systemic levels of several hormones with putative immunomodulatory functions are increased, is unknown. Here, using murine adoptive transfer systems and a translationally relevant model of cold-adapted live-attenuated influenza A virus vaccination, we show that preexisting virus-specific memory T cell responses are largely unaltered and highly protective against heterotypic viral challenges during pregnancy. Expression of the transcription factor T-bet, which is upregulated in antiviral T cells responding in pregnant mice, is critical in preventing hormone-associated gain of detrimental T helper type 2 (TH2) attributes reported in other settings. Beyond antiviral effects, preexisting vaccine-primed T cell immunity prevents metabolic dysfunction in gravid dams and adverse neonatal outcomes often associated with maternal influenza infection. These results demonstrate robust protection of the maternal-fetal unit from severe consequences of respiratory virus infection by preexisting T cell immunity.
Authors
Valeria Flores Malavet, Kunal Dhume, Ali Satchmei, Andrea C. Arvelo, Aaron J. Beaird, Siva N. Annamalai, Lauren A. Kimball, K. Kai McKinstry, Tara M. Strutt
Abstract
Mycobacterium tuberculosis causes human tuberculosis. As mycobacteria are protected by thick lipid cell wall, humans have developed immune responses against diverse mycobacterial lipids. Most of these immunostimulatory lipids are known as adjuvants acting through innate immune receptors, such as C-type lectin receptors. Although a few mycobacterial lipid antigens activate unconventional T cells, antigenicity of most adjuvantic lipids are unknown. Here, we identified that trehalose monomycolate (TMM), an abundant mycobacterial adjuvant, activates human T cells bearing a unique ɑβTCR. This recognition was restricted by CD1b, a monomorphic antigen-presenting molecule conserved in primates but not mice. Single-cell TCR-RNA sequencing using newly established CD1b-TMM tetramers revealed that TMM-specific T cells are present as CD4+ effector memory T cells in the periphery of uninfected donors, but express IFNγ, TNF and anti-mycobacterial effectors upon TMM stimulation. TMM-specific T cells are detected in cord blood and PBMCs of non-BCG-vaccinated donors, but are expanded in active tuberculosis patients. A cryo-electron microscopy study of CD1b-TMM-TCR complexes revealed unique antigen recognition by conserved features of TCRs, positively-charged CDR3ɑ and long CDR3β regions. These results indicate that humans have a commonly-shared and pre-formed CD4+ T cell subset recognizing a typical mycobacterial adjuvant as an antigen. Furthermore, the dual role of TMM justifies reconsideration of the mechanism of action of adjuvants.
Authors
Yuki Sakai, Minori Asa, Mika Hirose, Wakana Kusuhara, Nagatoshi Fujiwara, Hiroto Tamashima, Takahiro Ikazaki, Shiori Oka, Kota Kuraba, Kentaro Tanaka, Takashi Yoshiyama, Masamichi Nagae, Yoshihiko Hoshino, Daisuke Motooka, Ildiko Van Rhijn, Xiuyuan Lu, Eri Ishikawa, D. Branch Moody, Takayuki Kato, Shinsuke Inuki, Go Hirai, Sho Yamasaki
Abstract
Authors
Tasha Tsao, Amanda M. Buck, Lilian Grimbert, Brian H. LaFranchi, Belen Altamirano Poblano, Emily A. Fehrman, Thomas Dalhuisen, Priscilla Y. Hsue, J. Daniel Kelly, Jeffrey N. Martin, Steven G. Deeks, Peter W. Hunt, Michael J. Peluso, Oscar A. Aguilar, Timothy J. Henrich
Abstract
The pathobiont Staphylococcus aureus (Sa) induces nonprotective antibody imprints that underlie ineffective staphylococcal vaccination. However, the mechanism by which Sa modifies antibody activity is not clear. Herein, we demonstrate that IL-10 is the decisive factor that abrogates antibody protection in mice. Sa-induced B10 cells drive antigen-specific vaccine suppression that affects both recalled and de novo developed B cells. Released IL-10 promotes STAT3 binding upstream of the gene encoding sialyltransferase ST3gal4 and increases its expression by B cells, leading to hyper-α2,3sialylation of antibodies and loss of protective activity. IL-10 enhances α2,3sialylation on cell-wall–associated IsdB, IsdA, and MntC antibodies along with suppression of the respective Sa vaccines. Consistent with mouse findings, human anti-Sa antibodies as well as anti-pseudomonal antibodies from cystic fibrosis subjects (high IL-10) are hypersialylated, compared with anti–Streptococcus pyogenes and pseudomonal antibodies from normal individuals. Overall, we demonstrate a pathobiont-centric mechanism that modulates antibody glycosylation through IL-10, leading to loss of staphylococcal vaccine efficacy.
Authors
Chih-Ming Tsai, Irshad A. Hajam, J.R. Caldera, Austin W.T. Chiang, Cesia Gonzalez, Xin Du, Biswa Choudhruy, Haining Li, Emi Suzuki, Fatemeh Askarian, Ty’Tianna Clark, Brian Lin, Igor H. Wierzbicki, Angelica M. Riestra, Douglas J. Conrad, David J. Gonzalez, Victor Nizet, Nathan E. Lewis, George Y. Liu
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ISSN: 0021-9738 (print), 1558-8238 (online)