scholarly journals CD4+ T cells cause multinucleated giant cells to form around Cryptococcus neoformans and confine the yeast within the primary site of infection in the respiratory tract.

1992 ◽  
Vol 175 (6) ◽  
pp. 1685-1695 ◽  
Author(s):  
J O Hill

The possible mechanisms by which CD4+ T cells prevent the dissemination of Cryptococcus neoformans from the primary site of infection in the respiratory tract were examined. It was found that even before fungicidal mechanisms are fully induced in the lungs, the host generates a CD4+ T cell-dependent inflammatory response that sequesters yeast within the pulmonary alveoli. This confinement is evident histopathologically and demonstrable objectively as a rapid decline in the ability to dislodge yeast from the lungs by bronchopulmonary lavage. One striking component of this response is the enclosure of cryptococci within multinucleated giant cells in granulomas. Studies in severe combined immunodeficient mice that were engrafted with selected lymphocyte subpopulations show that B cells, and hence anti-Cryptococcus antibodies, are not necessary for the CD4+ T cell-dependent responses that isolate and subsequently destroy this opportunistic pathogen in the lung parenchyma.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2337-2337
Author(s):  
Robert Chiesa ◽  
Prashant Hiwarkar ◽  
Kanchan Rao ◽  
Waseem Qasim ◽  
Kimberly Gilmour ◽  
...  

Abstract Abstract 2337 Viral infections remain a significant problem following haematopoietic cell transplantation (HCT). Recovery of CD4+ T-cells only occurs with return of thymopoiesis 6–12 months after HCT. In an attempt to improve immune reconstitution and reduce viral infections following unrelated cord blood transplantation (CBT), serotherapy was omitted from conditioning. 26 children, median age 19 months (range 1–147) underwent unrelated CBT for immunodeficiency (13) or high risk/relapsed leukemia (13). Pre-transplant co-morbidities included lung aspergillosis (2), adenoviraemia (1), Paraflu3 respiratory tract infection (3). Conditioning was myeloablative in 25 patients. HLA matching was 6/6, 5/6 and 4/6 in 13, 14 and 3 cases respectively (4 double cords). GvHD prophylaxis was mostly cyclosporine/mycophenolate mofetil (24). The median number of nucleated, CD34+ and CD3+ cells infused was 8.12 × 107/kg (range, 4.7–17.72), 3.5 × 105/kg (range, 1.23–11.95) and 5.63 × 106/kg (range, 1.9–24.45). Median time to myeloid and platelet engraftment was 22 (range, 13–38) and 39 (range, 21–110) days. One patient died from conditioning related toxicity and 3 patients died after leukaemia relapse. 22 patients are alive and in remission with a median follow up of 12 months (range 3–66). 18 patients have full donor engraftment while 4 patients are mixed chimeras. Acute GvHD > grade I occurred in 16 patients (grade II n=11; grade III-IV n=5) but in general this responded to steroids and only 1 child developed cGvHD. There was no infection-related mortality, despite early adenoviraemia (4), CMV viraemia (4), HHV6 encephalitis (1) and RSV/Paraflu3 respiratory tract infections (3). The most striking finding was a rapid and sustained CD4+ T-cell expansion with conversion from naive to memory/effector phenotype. The median CD3+, CD4+ and CD8+ counts at 2 months post CBT was 0.85 ×109cells/L (range, 0.44–2.44), 0.55 ×109cells/L (range, 0.06–1.89), and 0.21 ×109cells/L (range, 0.01–1.21) respectively. As a comparison, the median CD4+ T-cell count at 2 months post a HCT from a matched sibling donor was 0.24 ×109cells/L in 23 children evaluated in our institution. In 3 patients who developed adenoviral/CMV reactivation virus-specific T cells were detected by ELISPOT/IFN-g assays as early as 45 days post transplant, and viral infections resolved rapidly. Unrelated CBT without serotherapy results in rapid “peripheral” expansion of naive/memory CD4+ T-cells, and restores cell-mediated immunity in children faster than any other HCT donor source. Disclosures: No relevant conflicts of interest to declare.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Stephanie M. Dillon ◽  
Tezha A. Thompson ◽  
Allison J. Christians ◽  
Martin D. McCarter ◽  
Cara C. Wilson

Abstract Background The etiology of the low-level chronic inflammatory state associated with aging is likely multifactorial, but a number of animal and human studies have implicated a functional decline of the gastrointestinal immune system as a potential driver. Gut tissue-resident memory T cells play critical roles in mediating protective immunity and in maintaining gut homeostasis, yet few studies have investigated the effect of aging on human gut T cell immunity. To determine if aging impacted CD4 T cell immunity in the human large intestine, we utilized multi-color flow cytometry to measure colonic lamina propria (LP) CD4 T cell frequencies and immune-modulatory marker expression in younger (mean ± SEM: 38 ± 1.5 yrs) and older (77 ± 1.6 yrs) adults. To determine cellular specificity, we evaluated colon LP CD8 T cell frequency and phenotype in the same donors. To probe tissue specificity, we evaluated the same panel of markers in peripheral blood (PB) CD4 T cells in a separate cohort of similarly aged persons. Results Frequencies of colonic CD4 T cells as a fraction of total LP mononuclear cells were higher in older persons whereas absolute numbers of colonic LP CD4 T cells per gram of tissue were similar in both age groups. LP CD4 T cells from older versus younger persons exhibited reduced CTLA-4, PD-1 and Ki67 expression. Levels of Bcl-2, CD57, CD25 and percentages of activated CD38+HLA-DR+ CD4 T cells were similar in both age groups. In memory PB CD4 T cells, older age was only associated with increased CD57 expression. Significant age effects for LP CD8 T cells were only observed for CTLA-4 expression, with lower levels of expression observed on cells from older adults. Conclusions Greater age was associated with reduced expression of the co-inhibitory receptors CTLA-4 and PD-1 on LP CD4 T cells. Colonic LP CD8 T cells from older persons also displayed reduced CTLA-4 expression. These age-associated profiles were not observed in older PB memory CD4 T cells. The decline in co-inhibitory receptor expression on colonic LP T cells may contribute to local and systemic inflammation via a reduced ability to limit ongoing T cell responses to enteric microbial challenge.


Immuno ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 119-131
Author(s):  
Jana Palmowski ◽  
Kristina Gebhardt ◽  
Thomas Reichel ◽  
Torsten Frech ◽  
Robert Ringseis ◽  
...  

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.


2009 ◽  
Vol 83 (13) ◽  
pp. 6566-6577 ◽  
Author(s):  
Katherine A. Richards ◽  
Francisco A. Chaves ◽  
Andrea J. Sant

ABSTRACT The specificity of the CD4 T-cell immune response to influenza virus is influenced by the genetic complexity of the virus and periodic encounters with variant subtypes and strains. In order to understand what controls CD4 T-cell reactivity to influenza virus proteins and how the influenza virus-specific memory compartment is shaped over time, it is first necessary to understand the diversity of the primary CD4 T-cell response. In the study reported here, we have used an unbiased approach to evaluate the peptide specificity of CD4 T cells elicited after live influenza virus infection. We have focused on four viral proteins that have distinct intracellular distributions in infected cells, hemagglutinin (HA), neuraminidase (NA), nucleoprotein, and the NS1 protein, which is expressed in infected cells but excluded from virion particles. Our studies revealed an extensive diversity of influenza virus-specific CD4 T cells that includes T cells for each viral protein and for the unexpected immunogenicity of the NS1 protein. Due to the recent concern about pandemic avian influenza virus and because CD4 T cells specific for HA and NA may be particularly useful for promoting the production of neutralizing antibody to influenza virus, we have also evaluated the ability of HA- and NA-specific CD4 T cells elicited by a circulating H1N1 strain to cross-react with related sequences found in an avian H5N1 virus and find substantial cross-reactivity, suggesting that seasonal vaccines may help promote protection against avian influenza virus.


Author(s):  
Njabulo Ngwenyama ◽  
Annet Kirabo ◽  
Mark Aronovitz ◽  
Francisco Velázquez ◽  
Francisco Carrillo-Salinas ◽  
...  

Background: Despite the well-established association between T cell-mediated inflammation and non-ischemic heart failure (HF), the specific mechanisms triggering T cell activation during the progression of HF and the antigens involved are poorly understood. We hypothesized that myocardial oxidative stress induces the formation of isolevuglandin (IsoLG)-modified proteins that function as cardiac neoantigens to elicit CD4+ T cell receptor (TCR) activation and promote HF. Methods: We used transverse aortic constriction (TAC) in mice to trigger myocardial oxidative stress and T cell infiltration. We profiled the TCR repertoire by mRNA sequencing of intramyocardial activated CD4+ T cells in Nur77 GFP reporter mice, which transiently express GFP upon TCR engagement. We assessed the role of antigen presentation and TCR specificity in the development of cardiac dysfunction using antigen presentation-deficient MhcII -/- mice, and TCR transgenic OTII mice that lack specificity for endogenous antigens. We detected IsoLG-protein adducts in failing human hearts. We also evaluated the role of reactive oxygen species (ROS) and IsoLGs in eliciting T cell immune responses in vivo by treating mice with the antioxidant TEMPOL, and the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) during TAC, and ex-vivo in mechanistic studies of CD4+ T cell proliferation in response to IsoLG-modified cardiac proteins. Results: We discovered that TCR antigen recognition increases in the left ventricle (LV) as cardiac dysfunction progresses, and identified a limited repertoire of activated CD4+ T cell clonotypes in the LV. Antigen presentation of endogenous antigens was required to develop cardiac dysfunction since MhcII -/- mice reconstituted with CD4+ T cells, and OTII mice immunized with their cognate antigen were protected from TAC-induced cardiac dysfunction despite the presence of LV-infiltrated CD4+ T cells. Scavenging IsoLGs with 2-HOBA reduced TCR activation and prevented cardiac dysfunction. Mechanistically, cardiac pressure overload resulted in ROS dependent dendritic cell accumulation of IsoLG-protein adducts which induced robust CD4+ T cell proliferation. Conclusions: Collectively, our study demonstrates an important role of ROS-induced formation of IsoLG-modified cardiac neoantigens that lead to TCR-dependent CD4+ T cell activation within the heart.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A770-A770
Author(s):  
Michael Brown ◽  
Zachary McKay ◽  
Yuanfan Yang ◽  
Darell Bigner ◽  
Smita Nair ◽  
...  

BackgroundPVSRIPO, a recombinant poliovirus derived from the live-attenuated Sabin oral polio vaccine strain, is being tested in multi-institutional phase II clinical trials for recurrent glioblastoma (NCT04479241) and unresectable, PD-1 refractory melanoma (NCT04577807) in combination with PD1 blockade. PVSRIPO capsid is identical to the Sabin vaccine strain and >99% identical to the inactivated Polio vaccine (IPOL, Salk), against which public health mandated childhood vaccination is near universal. In non-vaccinated mice, PVSRIPO mediates antitumor efficacy in a replication-dependent manner via engaging innate inflammation and antitumor T cells. Accordingly, it is anticipated that pre-existing immunity to PVSRIPO impedes antitumor therapy. However, recent evidence indicates that immunological 'recall', or reactivation of memory T cells, may mediate anti-tumor effects.MethodsThe impact of prior polio vs control (KLH) vaccination on intratumor viral replication, tumor inflammation, and overall tumor growth after intratumor PVSRIPO therapy was assessed in murine tumor models. The role of polio capsid and tetanus recall antigens in mediating intratumor inflammation and antitumor efficacy was similarly studied in mice non-permissive to PVSRIPO infection. To mechanistically define antitumor effects of polio recall, B cell and CD8 T cell knockout mice were used, in addition to adoptive transfer of CD4+ T cells from vaccinated mice. Intratumor polio or tetanus recall antigen therapy was performed after OT-I transfer (OVA-specific T cells) in the B16-OVA melanoma model to gauge antitumor T cell activity. Lastly, the inflammatory effects of polio and tetanus antigens was tested in human peripheral blood mononuclear cells (PBMCs).ResultsDespite curtailing intratumor viral replication, prior polio vaccination in mice potentiated subsequent antitumor efficacy of PVSRIPO. Intratumor recall responses induced by polio and tetanus antigens also delayed tumor growth. Recall antigen therapy was associated with marked intratumor influx of eosinophils, conventional CD4+ T cells, and increased expression of IFN-g, TNF, and Granzyme B in tumor infiltrating T cells. The antitumor efficacy of polio recall antigen was mediated by CD4+ T cells, partially depended upon CD8+ T cells, and was impaired by B cells. Both polio and tetanus recall antigen therapy bolstered the antitumor function of tumor-specific OT-I CD8+ T cells. Polio and tetanus antigens induced CXCL10 and type I/II/III IFNs in PBMCs in vitro.ConclusionsChildhood vaccine-specific CD4+ T cells hold cancer immunotherapy potential. In the context of PVSRIPO therapy, antitumor and inflammatory effects of polio vaccine-specific CD4+ T cell recall supersedes inhibitory effects of attenuated intratumor viral replication, and represents a novel mechanism of action.Ethics ApprovalThe animal work described in this study was approved by the Duke University IACUC.


Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2053-2061 ◽  
Author(s):  
Laura Crompton ◽  
Naeem Khan ◽  
Rajiv Khanna ◽  
Laxman Nayak ◽  
Paul A. H. Moss

Antigen-specific CD8+ cytotoxic T cells often demonstrate extreme conservation of T-cell receptor (TCR) usage between different individuals, but similar characteristics have not been documented for CD4+ T cells. CD4+ T cells predominantly have a helper immune role, but a cytotoxic CD4+ T-cell subset has been characterized, and we have studied the cytotoxic CD4+ T-cell response to a peptide from human cytomegalovirus glycoprotein B presented through HLA-DRB*0701. We show that this peptide elicits a cytotoxic CD4+ T-cell response that averages 3.6% of the total CD4+ T-cell repertoire of cytomegalovirus-seropositive donors. Moreover, CD4+ cytotoxic T-cell clones isolated from different individuals exhibit extensive conservation of TCR usage, which indicates strong T-cell clonal selection for peptide recognition. Remarkably, this TCR sequence was recently reported in more than 50% of cases of CD4+ T-cell large granular lymphocytosis. Immunodominance of cytotoxic CD4+ T cells thus parallels that of CD8+ subsets and suggests that cytotoxic effector function is critical to the development of T-cell clonal selection, possibly from immune competition secondary to lysis of antigen-presenting cells. In addition, these TCR sequences are highly homologous to those observed in HLA-DR7+ patients with CD4+ T-cell large granular lymphocytosis and implicate cytomegalovirus as a likely antigenic stimulus for this disorder.


2021 ◽  
Vol 118 (37) ◽  
pp. e2103444118
Author(s):  
Felipe Valença-Pereira ◽  
Qian Fang ◽  
Isabelle J. Marié ◽  
Emily L. Giddings ◽  
Karen A. Fortner ◽  
...  

Interleukin 6 (IL-6) is known to regulate the CD4 T cell function by inducing gene expression of a number of cytokines through activation of Stat3 transcription factor. Here, we reveal that IL-6 strengthens the mechanics of CD4 T cells. The presence of IL-6 during activation of mouse and human CD4 T cells enhances their motility (random walk and exploratory spread), resulting in an increase in travel distance and higher velocity. This is an intrinsic effect of IL-6 on CD4 T-cell fitness that involves an increase in mitochondrial Ca2+. Although Stat3 transcriptional activity is dispensable for this process, IL-6 uses mitochondrial Stat3 to enhance mitochondrial Ca2+-mediated motility of CD4 T cells. Thus, through a noncanonical pathway, IL-6 can improve competitive fitness of CD4 T cells by facilitating cell motility. These results could lead to alternative therapeutic strategies for inflammatory diseases in which IL-6 plays a pathogenic role.


Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1047
Author(s):  
Chiu-Li Yeh ◽  
Sharon Angela Tanuseputero ◽  
Jin-Ming Wu ◽  
Yi-Ru Tseng ◽  
Po-Jen Yang ◽  
...  

This study investigated the effects of a single dose of arginine (Arg) administration at the beginning of sepsis on CD4+ T-cell regulation and liver inflammation in C57BL/6J mice. Mice were divided into normal control (NC), sham (SH), sepsis saline (SS), and sepsis Arg (SA) groups. An inducible nitric oxide (NO) synthase (iNOS) inhibitor was administered to additional sepsis groups to evaluate the role of NO during sepsis. Sepsis was induced using cecal ligation and puncture (CLP). The SS and SA groups received saline or Arg (300 mg/kg body weight) via tail vein 1 h after CLP. Mice were euthanized at 12 and 24 h post-CLP. Blood, para-aortic lymph nodes, and liver tissues were collected for further measurement. The findings showed that sepsis resulted in decreases in blood and para-aortic lymph node CD4+ T-cell percentages, whereas percentages of interleukin (IL)-4- and IL-17-expressing CD4+ T cells were upregulated. Compared to the SS group, Arg administration resulted in maintained circulating and para-aortic lymph node CD4+ T cells, an increased Th1/Th2 ratio, and a reduced Th17/Treg ratio post-CLP. In addition, levels of plasma liver injury markers and expression of inflammatory genes in liver decreased. These results suggest that a single dose of Arg administered after CLP increased Arg availability, sustained CD4+ T-cell populations, elicited more-balanced Th1/Th2/Th17/Treg polarization in the circulation and the para-aortic lymph nodes, and attenuated liver inflammation in sepsis. The favorable effects of Arg were abrogated when an iNOS inhibitor was administered, which indicated that NO may be participated in regulating the homeostasis of Th/Treg cells and subsequent liver inflammation during sepsis.


2019 ◽  
Vol 11 (2) ◽  
pp. 108-123
Author(s):  
Dan Tong ◽  
Li Zhang ◽  
Fei Ning ◽  
Ying Xu ◽  
Xiaoyu Hu ◽  
...  

Abstract Common γ chain cytokines are important for immune memory formation. Among them, the role of IL-2 remains to be fully explored. It has been suggested that this cytokine is critically needed in the late phase of primary CD4 T cell activation. Lack of IL-2 at this stage sets for a diminished recall response in subsequent challenges. However, as IL-2 peak production is over at this point, the source and the exact mechanism that promotes its production remain elusive. We report here that resting, previously antigen-stimulated CD4 T cells maintain a minimalist response to dendritic cells after their peak activation in vitro. This subtle activation event may be induced by DCs without overt presence of antigen and appears to be stronger if IL-2 comes from the same dendritic cells. This encounter reactivates a miniature IL-2 production and leads a gene expression profile change in these previously activated CD4 T cells. The CD4 T cells so experienced show enhanced reactivation intensity upon secondary challenges later on. Although mostly relying on in vitro evidence, our work may implicate a subtle programing for CD4 T cell survival after primary activation in vivo.


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