scholarly journals Immune Sensing of Candida albicans

2021 ◽  
Vol 7 (2) ◽  
pp. 119 ◽  
Author(s):  
Ebrima Bojang ◽  
Harlene Ghuman ◽  
Pizga Kumwenda ◽  
Rebecca A. Hall
Keyword(s):  
Candida Albicans ◽  
Immune Responses ◽  
Immune Cells ◽  
Oral Candidiasis ◽  
Innate Immune ◽  
Vaginal Mucosa ◽  
Innate Immune Cells ◽  
Innate Immune Responses ◽  
Immune Sensing ◽  
Infection Types

Candida albicans infections range from superficial to systemic and are one of the leading causes of fungus-associated nosocomial infections. The innate immune responses during these various infection types differ, suggesting that the host environment plays a key role in modulating the host–pathogen interaction. In addition, C. albicans is able to remodel its cell wall in response to environmental conditions to evade host clearance mechanisms and establish infection in niches, such as the oral and vaginal mucosa. Phagocytes play a key role in clearing C. albicans, which is primarily mediated by Pathogen Associated Molecular Pattern (PAMP)–Pattern Recognition Receptor (PRR) interactions. PRRs such as Dectin-1, DC-SIGN, and TLR2 and TLR4 interact with PAMPs such as β-glucans, N-mannan and O-mannan, respectively, to trigger the activation of innate immune cells. Innate immune cells exhibit distinct yet overlapping repertoires of PAMPs, resulting in the preferential recognition of particular Candida morphotypes by them. The role of phagocytes in the context of individual infection types also differs, with neutrophils playing a prominent role in kidney infections, and dendritic cells playing a prominent role in skin infections. In this review, we provide an overview of the key receptors involved in the detection of C. albicans and discuss the differential innate immune responses to C. albicans seen in different infection types such as vulvovaginal candidiasis (VVC) and oral candidiasis.

scholarly journals Toll-Like Receptors in Natural Killer Cells and Their Application for Immunotherapy

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Ji-Yoon Noh ◽  
Suk Ran Yoon ◽  
Tae-Don Kim ◽  
Inpyo Choi ◽  
Haiyoung Jung
Keyword(s):  
Immune Responses ◽  
Nk Cells ◽  
Immune Cells ◽  
Viral Infections ◽  
Nk Cell ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Innate Immune Responses ◽  
Toll Like Receptors ◽  
Microbial Infection

Innate immunity represents the first barrier for host defense against microbial infection. Toll-like receptors (TLRs) are the most well-defined PRRs with respect to PAMP recognition and induction of innate immune responses. They recognize pathogen-associated molecular patterns (PAMPs) and trigger innate immune responses by inducing inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory molecules. TLRs are expressed either on the cell surface or within endosomes of innate immune cells. NK cells are one of the innate immune cells and also express TLRs to recognize or respond to PAMPs. TLRs in NK cells induce the innate immune responses against bacterial and viral infections via inducing NK cytotoxicity and cytokine production. In this review, we will discuss the expression and cellular function of TLRs in NK cells and also introduce some therapeutic applications of TLR agonists for NK cell-mediated immunotherapy.

scholarly journals Natural Killer Dendritic Cells Enhance Immune Responses Elicited byα-Galactosylceramide-Stimulated Natural Killer T Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Sung Won Lee ◽  
Hyun Jung Park ◽  
Nayoung Kim ◽  
Seokmann Hong
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Immune Responses ◽  
Natural Killer ◽  
Immune Cells ◽  
Tumor Antigens ◽  
Nkt Cells ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Natural Killer T

Natural killer dendritic cells (NKDCs) possess potent anti-tumor activity, but the cellular effect of NKDC interactions with other innate immune cells is unclear. In this study, we demonstrate that the interaction of NKDCs and natural killer T (NKT) cells is required for the anti-tumor immune responses that are elicited byα-galactosylceramide (α-GC) in mice. The rapid and strong expression of interferon-γby NKDCs afterα-GC stimulation was dependent on NKT cells. Various NK and DC molecular markers and cytotoxic molecules were up-regulated followingα-GC administration. This up-regulation could improve NKDC presentation of tumor antigens and increase cytotoxicity against tumor cells. NKDCs were required for the stimulation of DCs, NK cells, and NKT cells. The strong anti-tumor immune responses elicited byα-GC may be due to the down-regulation of regulatory T cells. Furthermore, the depletion of NKDCs dampened the tumor clearance mediated byα-GC-stimulated NKT cellsin vivo. Taken together, these results indicate that complex interactions of innate immune cells might be required to achieve optimal anti-tumor immune responses during the early stages of tumorigenesis.

scholarly journals Remasking of Candida albicans β-Glucan in Response to Environmental pH Is Regulated by Quorum Sensing

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Fabien Cottier ◽  
Sarah Sherrington ◽  
Sarah Cockerill ◽  
Valentina del Olmo Toledo ◽  
Stephen Kissane ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Quorum Sensing ◽  
Immune Responses ◽  
Female Reproductive Tract ◽  
Innate Immune ◽  
Immune Recognition ◽  
Innate Immune Responses ◽  
Content Type ◽  
Cell Wall Remodeling

ABSTRACT Candida albicans is a commensal yeast of the human gut which is tolerated by the immune system but has the potential to become an opportunistic pathogen. One way in which C. albicans achieves this duality is through concealing or exposing cell wall pathogen-associated molecular patterns (PAMPs) in response to host-derived environment cues (pH, hypoxia, and lactate). This cell wall remodeling allows C. albicans to evade or hyperactivate the host’s innate immune responses, leading to disease. Previously, we showed that adaptation of C. albicans to acidic environments, conditions encountered during colonization of the female reproductive tract, induces significant cell wall remodeling resulting in the exposure of two key fungal PAMPs (β-glucan and chitin). Here, we report that this pH-dependent cell wall remodeling is time dependent, with the initial change in pH driving cell wall unmasking, which is then remasked at later time points. Remasking of β-glucan was mediated via the cell density-dependent fungal quorum sensing molecule farnesol, while chitin remasking was mediated via a small, heat-stable, nonproteinaceous secreted molecule(s). Transcript profiling identified a core set of 42 genes significantly regulated by pH over time and identified the transcription factor Efg1 as a regulator of chitin exposure through regulation of CHT2. This dynamic cell wall remodeling influenced innate immune recognition of C. albicans, suggesting that during infection, C. albicans can manipulate the host innate immune responses. IMPORTANCE Candida albicans is part of the microbiota of the skin and gastrointestinal and reproductive tracts of humans and has coevolved with us for millennia. During that period, C. albicans has developed strategies to modulate the host’s innate immune responses, by regulating the exposure of key epitopes on the fungal cell surface. Here, we report that exposing C. albicans to an acidic environment, similar to the one of the stomach or vagina, increases the detection of the yeast by macrophages. However, this effect is transitory, as C. albicans is able to remask these epitopes (glucan and chitin). We found that glucan remasking is controlled by the production of farnesol, a molecule secreted by C. albicans in response to high cell densities. However, chitin-remasking mechanisms remain to be identified. By understanding the relationship between environmental sensing and modulation of the host-pathogen interaction, new opportunities for the development of innovative antifungal strategies are possible.

scholarly journals Glycosylation of Candida albicans Cell Wall Proteins Is Critical for Induction of Innate Immune Responses and Apoptosis of Epithelial Cells

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e50518 ◽  
Author(s):  
Jeanette Wagener ◽  
Günther Weindl ◽  
Piet W. J. de Groot ◽  
Albert D. de Boer ◽  
Susanne Kaesler ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Epithelial Cells ◽  
Immune Responses ◽  
Innate Immune ◽  
Cell Wall Proteins ◽  
Innate Immune Responses

scholarly journals An Interspecies Regulatory Network Inferred from Simultaneous RNA-seq of Candida albicans Invading Innate Immune Cells

2012 ◽  
Vol 3 ◽  
Author(s):  
Lanay Tierney ◽  
Jörg Linde ◽  
Sebastian Müller ◽  
Sascha Brunke ◽  
Juan Camilo Molina ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Immune Cells ◽  
Regulatory Network ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Rna Seq

scholarly journals Pregnancy alters innate immune responses to Zika virus infection in the genital tract

2019 ◽  
Author(s):  
Kelsey E. Lesteberg ◽  
Dana S. Fader ◽  
J. David Beckham
Keyword(s):  
Virus Infection ◽  
Immune Responses ◽  
Zika Virus ◽  
Immune Cell ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Innate Immune Responses ◽  
Zikv Infection ◽  
Zika Virus Infection ◽  
Pregnant Mice

AbstractRecent outbreaks of Zika virus (ZIKV) have been associated with birth defects, including microcephaly and neurological impairment. However, the mechanisms which confer increased susceptibility to ZIKV during pregnancy remain unclear. We hypothesized that poor outcomes from ZIKV infection during pregnancy are due in part to pregnancy-induced alteration of innate immune cell frequencies and cytokine expression. To examine the impact of pregnancy on innate immune responses, we inoculated pregnant and non-pregnant female C57BL/6 mice with 5×105 FFU of ZIKV intravaginally. Innate immune cell frequencies and cytokine expression were measured by flow cytometry at day 3 post infection. Compared to non-pregnant mice, pregnant mice exhibited higher frequencies of uterine macrophages (CD68+) and tolerogenic dendritic cells (CD11c+ CD103+ and CD11c+ CD11b+). Additionally, ZIKV-infected pregnant mice had lower frequencies of CD45+ IL-12+ and CD11b+ IL-12+ cells in the uterus and spleen. These data show that pregnancy results in an altered innate immune response to ZIKV infection in the genital tract of mice and that pregnancy-associated immune modulation may play an important role in the severity of acute ZIKV infection.ImportancePregnant females longer duration that viremia following infection with Zika virus but the mechanism of this is not established. Innate immune cellular responses are important for controlling virus infection and are important for development and maintenance of pregnancy. Thus, the acute immune response to Zika virus during pregnancy may be altered so that the pregnancy can be maintained. To examine this interaction, we utilized a mouse model of Zika virus infection during pregnancy using intravaginal inoculation. We found that following Zika virus infection, pregnant mice exhibited increased expression of tolerant or non-inflammatory dendritic cells. Additionally, we found that pregnant mice have significantly depressed ability to secrete the cytokine IL-12 from innate immune cells in the uterus and the spleen while maintaining MHCII expression. These findings show that pregnancy-induced changes in the innate immune cells are biased towards tolerance and can result in decreased antigen-dependent stimulation of immune responses.

scholarly journals The Life Cycle Stages of Pneumocystis murina Have Opposing Effects on the Immune Response to This Opportunistic Fungal Pathogen

2016 ◽  
Vol 84 (11) ◽  
pp. 3195-3205 ◽  
Author(s):  
Heather M. Evans ◽  
Grady L. Bryant ◽  
Beth A. Garvy
Keyword(s):  
Cell Wall ◽  
Life Cycle ◽  
Immune Responses ◽  
Immune Cells ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Content Type ◽  
Life Cycle Stages ◽  
Ifn Γ

The cell wall β-glucans of Pneumocystis cysts have been shown to stimulate immune responses in lung epithelial cells, dendritic cells, and alveolar macrophages. Little is known about how the trophic life forms, which do not have a fungal cell wall, interact with these innate immune cells. Here we report differences in the responses of both neonatal and adult mice to the trophic and cystic life cycle stages of Pneumocystis murina . The adult and neonatal immune responses to infection with Pneumocystis murina trophic forms were less robust than the responses to infection with a physiologically normal mixture of cysts and trophic forms. Cysts promoted the recruitment of nonresident innate immune cells and T and B cells into the lungs. Cysts, but not trophic forms, stimulated increased concentrations of the cytokine gamma interferon (IFN-γ) in the alveolar spaces and an increase in the percentage of CD4 + T cells that produce IFN-γ. In vitro , bone marrow-derived dendritic cells (BMDCs) stimulated with cysts produced the proinflammatory cytokines interleukin 1β (IL-1β) and IL-6. In contrast, trophic forms suppressed antigen presentation to CD4 + T cells, as well as the β-glucan-, lipoteichoic acid (LTA)-, and lipopolysaccharide (LPS)-induced production of interleukin 1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) by BMDCs. The negative effects of trophic forms were not due to ligation of mannose receptor. Our results indicate that optimal innate and adaptive immune responses to Pneumocystis species are dependent on stimulation with the cyst life cycle stage. Conversely, trophic forms suppress β-glucan-induced proinflammatory responses in vitro , suggesting that the trophic forms dampen cyst-induced inflammation in vivo .

scholarly journals Reprogramming Interferon Regulatory Factor Signaling in Cardiometabolic Diseases

Physiology ◽  
2017 ◽  
Vol 32 (3) ◽  
pp. 210-223 ◽  
Author(s):  
Yaxing Zhang ◽  
Hongliang Li
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Immune Cells ◽  
Interferon Regulatory Factor ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Regulatory Factor ◽  
Cardiometabolic Diseases ◽  
Evolutionarily Conserved

Interferon regulatory factors (IRFs) are evolutionarily conserved proteins expressed not only in immune cells but also in other tissues and organs outside the immune system. In this review, we discuss mechanisms responsible for IRF-mediated innate immune responses and the function and mechanism of IRFs in cardiometabolic diseases. We focus on the role of IRFs in innate immunity and cardiometabolic homeostasis, and highlight reprogrammed IRF signaling.

scholarly journals IL-17A in Human Respiratory Diseases: Innate or Adaptive Immunity? Clinical Implications

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Dominique M. A. Bullens ◽  
Ann Decraene ◽  
Sven Seys ◽  
Lieven J. Dupont
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Respiratory Diseases ◽  
Inflammatory Diseases ◽  
Cell Lineage ◽  
Innate Immune ◽  
Clinical Implications ◽  
Innate Immune Cells ◽  
Innate Immune Responses

Since the discovery of IL-17 in 1995 as a T-cell cytokine, inducing IL-6 and IL-8 production by fibroblasts, and the report of a separate T-cell lineage producing IL-17(A), called Th17 cells, in 2005, the role of IL-17 has been studied in several inflammatory diseases. By inducing IL-8 production and subsequent neutrophil attraction towards the site of inflammation, IL-17A can link adaptive and innate immune responses. More specifically, its role in respiratory diseases has intensively been investigated. We here review its role in human respiratory diseases and try to unravel the question whether IL-17A only provides a link between the adaptive and innate respiratory immunity or whether this cytokine might also be locally produced by innate immune cells. We furthermore briefly discuss the possibility to reduce local IL-17A production as a treatment option for respiratory diseases.

scholarly journals Determinants of Innate Immunity in Visceral Leishmaniasis and Their Implication in Vaccine Development

2021 ◽  
Vol 12 ◽  
Author(s):  
Greta Volpedo ◽  
Thalia Pacheco-Fernandez ◽  
Parna Bhattacharya ◽  
Timur Oljuskin ◽  
Ranadhir Dey ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Immune Cells ◽  
Metabolic Pathways ◽  
Vaccine Development ◽  
Innate Immune ◽  
Epigenetic Reprogramming ◽  
Sand Fly ◽  
Innate Immune Cells ◽  
Innate Immune Responses ◽  
Inflammatory Monocytes

Leishmaniasis is endemic to the tropical and subtropical regions of the world and is transmitted by the bite of an infected sand fly. The multifaceted interactions between Leishmania, the host innate immune cells, and the adaptive immunity determine the severity of pathogenesis and disease development. Leishmania parasites establish a chronic infection by subversion and attenuation of the microbicidal functions of phagocytic innate immune cells such as neutrophils, macrophages and dendritic cells (DCs). Other innate cells such as inflammatory monocytes, mast cells and NK cells, also contribute to resistance and/or susceptibility to Leishmania infection. In addition to the cytokine/chemokine signals from the innate immune cells, recent studies identified the subtle shifts in the metabolic pathways of the innate cells that activate distinct immune signal cascades. The nexus between metabolic pathways, epigenetic reprogramming and the immune signaling cascades that drive the divergent innate immune responses, remains to be fully understood in Leishmania pathogenesis. Further, development of safe and efficacious vaccines against Leishmaniasis requires a broader understanding of the early interactions between the parasites and innate immune cells. In this review we focus on the current understanding of the specific role of innate immune cells, the metabolomic and epigenetic reprogramming and immune regulation that occurs during visceral leishmaniasis, and the strategies used by the parasite to evade and modulate host immunity. We highlight how such pathways could be exploited in the development of safe and efficacious Leishmania vaccines.

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