Human dendritic cells are less potent at killing Candida albicans than both monocytes and macrophages

ArticleinMicrobes and Infection 6(11):985-9 · October 2004with7 Reads
DOI: 10.1016/j.micinf.2004.05.013 · Source: PubMed
Abstract
Dendritic cells (DC) function as professional phagocytes to kill Candida albicans and subsequently present it to the adaptive immune system. Monocytes, macrophages and DC were generated from five individual donors and their Candida-killing capacity and cytokine release were assessed. Compared to monocytes and macrophages, DC from healthy volunteers were significantly less effective in C. albicans--stimulated cytokine release, killing of C. albicans blastoconidia and damaging of C. albicans hyphae. In conclusion, while important as antigen-presenting cells and initiators of the adaptive immune system, DC are poor in both intracellular killing and damaging of C. albicans hyphae. Effective handling of large numbers of C. albicans is the prime task of the innate immune system consisting of large numbers of neutrophils and monocytes.
    • "Invasive infections caused by this microorganism can become a serious clinical complication, since they frequently involve vital organs such as brain, liver and kidneys [11,12]. The host's defense against candidiasis comprises the intake and disposal of fungal structures by cells in the innate immune system, mainly neutrophils and macrophages [13] . These phagocytic cells are the key aspect in the antimicrobial response, which is the generation of oxygen and nitrogen reactive species [14,15]. "
    [Show abstract] [Hide abstract] ABSTRACT: Experimental maternal nutrition restriction models are used to investigate short or long-term consequences of nutritional deficiency on puppies' growth. By assuming that the immune function is directly related to host's nutritional status, the current study aims to investigate the effects of neonatal malnutrition on oxidative stress and on the cell death of the alveolar macrophage after in vitro infection by Candida albicans. Wistar rats were suckled by mothers fed on diets containing 17% protein (Nourished group) or 8% protein (Malnourished group) in the current assay. Both groups received the standard diet used in the vivarium until adulthood, after weaning. The results showed that the offspring from mothers fed on low-protein diet presented lower body weight from 5 days of life on. Their low weight remained until adulthood when it was compared to that of rats in the nourished group. Superoxide and nitric oxide production was lower in malnourished animals and it was accompanied by low inducible nitric oxide synthase gene expression levels in systems in which the alveolar macrophages were challenged by immunogenic stimulus. No significant differences were observed in comparisons performed between the nourished and malnourished groups in any of the analyzed cell viability (apoptosis/necrosis) parameters. The fungal inoculum-stimulated system induced higher oxidative stress and cell death by necrosis. The current study demonstrated that dietary restriction during lactation alters the oxidant function of alveolar macrophages in puppies; It happens from the gene transcription step to the release of mediators, thus compromising the host's defenses against Candida albicans. It raises the possibility that Candida albicans may cease to be a commensal fungus to become a pathogen in offspring that have suffered nutritional deficiency during critical developmental periods, due to impaired immune responses.
    Article · Mar 2016
    • "While neutrophils are crucial to eliminate the fungi via phagocytosis, macrophages/monocytes are key cells in the development of adaptive cellular response, mainly via cytokine production3233343536373839. Although neutrophils are key players in the phagocytosis of Candida spp.,Netea et al.showed that macrophages/monocytes are also able to kill yeasts and damage C. albicans hyphae in a similar manner among them, and more efficiently than dendritic cells[40]. Another study reported the ability of monocytes to kill hyphae, but less efficiently than phagocytized yeasts[41]. However, the candidacidal function of monocytes can be modulated by some cytokines[42,43]. "
    [Show abstract] [Hide abstract] ABSTRACT: Candida-associated denture stomatitis (DS) is the most frequent lesion among denture wearers, especially the elderly. DS is strongly associated with Candida albicans, as well as local and systemic factors, such as impaired immune response. Monocytes are important in the protective immune response against the fungus by the production of cytokines that recruit and activate leukocytes. There are functional changes in these cells with age, and individual alterations involving monocyte response may predispose the host to developing infections by Candida spp. In this study, our aim was to evaluate the production of TNF-α, IL-6, CXCL8, IL-1β, MCP-1 and IL-10 by monocytes from elderly denture wearers with/without DS and elderly or young non-denture wearers. We detected that monocytes from elderly denture wearers with Candida-related denture stomatitis produced lower levels of CXCL-8, IL-6 and MCP-1. This imbalance in cytokine levels was observed in spontaneous or LPS-stimulated production. Therefore, our data suggested that inherent aspects of the host, such as changes in cytokine production by monocytes, might be associated with the development and the persistence of DS irrespective of aging.
    Full-text · Article · Jan 2016
    • "These microorganisms represent a major problem for the elderly, who are more frequently subjected to transplantation , chemotherapy and the use of immunosuppressive drugs for the treatment of non-malignant diseases, thereby increasing the risk for conditions of candidemia [23, 24]. Given the important role of DCs in antigen presentation and activation of appropriate adaptive responses against the fungus, in addition to the ability of DCs to participate directly in this immune protection by eliminating the fungus252627, it is evident that the elderly could develop impairment, if changes in phagocytosis were to occur with aging. However, the evidence that phagocytosis of this fungus by DCs is not impaired with aging brings us to the question of which are the mechanisms truly associated with the prevalence of certain diseases in the elderly. "
    [Show abstract] [Hide abstract] ABSTRACT: Dendritic cells (DCs) are the most potent antigen-presenting cells, playing a key role in induction of both innate and adaptive immunity. Immunosenescence refers to age-associated changes in the immune system, which may be associated with susceptibility to infections and their clinical complications. The precise effects of aging on DCs in immunity to infections are not well understood. Among the common pathogenic microorganisms, the fungus Candida albicans is an important pathogen for the development of invasive infections, especially in immunocompromised individuals, as well as during aging. To make a comparative in vitro evaluation of the immunomodulatory function of DCs challenged with C. albicans, by phagocytosis of the fungal cells, and determine the involvement of TLR2 and TLR4 receptors. For this purpose, DCs were generated with the use of peripheral blood monocytes from healthy young and aged subjects. The phagocytosis of C. albicans is developed by DCs in TLR2- and TLR4-dependent way. This mechanism is not affected by aging. Given the important role of the DCs in responses against the fungus, it is evident that if changes in phagocytosis occurred with aging, impairment in the elderly could develop. However, the evidence that phagocytosis of this fungus by DCs is not impaired with aging, brings us to the question of which are the mechanisms truly associated with the prevalence of certain diseases in the elderly.
    Full-text · Article · Mar 2015
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