1
|
Becerra-Álvarez P, Escandón P, Lizarazo J, Quirós-Gómez Ó, Firacative C. Cryptococcus neoformans- and Cryptococcus gattii-specific IgG, IgA and IgM differ among children and adults with and without cryptococcosis from Colombia. Med Mycol 2022; 60:6692868. [PMID: 36066645 DOI: 10.1093/mmy/myac067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/22/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg) cause cryptococcosis, a life-threatening systemic mycosis of global distribution affecting mainly immunocompromised adults. Although a humoral response occurs during cryptococcosis, the role of antibody production against this mycosis is not fully understood. We aimed to determine total and specific antibodies against cryptococcal protein antigens in sera from people with and without diagnosis of cryptococcosis from Colombia. Using ELISA, total and specific levels of immunoglobulin (Ig)G, IgA and IgM were determined in sera from children and adults with (n = 109) and without (n = 119) cryptococcosis. Specific antibodies were those binding Cn- and Cg-protein antigens. In general, the mean of the total IgG production was higher in cryptococcosis patients than in controls (13 942.32 vs. 6459.91 µg/ml), while levels of IgA (488.13 vs. 1564.53 µg/ml) and IgM (775.69 vs. 1014.72 µg/ml) were higher in controls than in cryptococcosis patients (p ≤ 0.05). In patients with cryptococcosis, total IgG, IgA and IgM levels were higher in HIV + compared with HIV- (p ≤ 0.05). Specific antibodies tended to be higher in cryptococcosis patients than in controls and in adults than in children, with a positive correlation between antibody reactivity and age. All immunoglobulins were more reactive against Cn-proteins than Cg-proteins. Overall, a positive weak correlation between total and specific antibodies was found, although not always statistically significant. In patients with cryptococcosis from Colombia, the levels of immunoglobulins, total and specific, differ with respect to people without cryptococcosis. Variations in antibody production among adults and children with cryptococcosis and between Cn- and Cg-protein antigens were as well established. Our findings encourage further studies to determine the role of humoral immunity for host defence against cryptococcosis.
Collapse
Affiliation(s)
- Paola Becerra-Álvarez
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| | - Patricia Escandón
- Group of Microbiology, National Institute of Health, Bogota, Colombia
| | - Jairo Lizarazo
- Internal Medicine Department, Hospital Universitario Erasmo Meoz, Universidad de Pamplona, Cúcuta, Colombia
| | - Óscar Quirós-Gómez
- Group of Epidemiology and Biostatistics, Universidad CES, Medellin, Colombia
| | - Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| |
Collapse
|
2
|
Mo Z, Li C, Liang Z, Cui J, Yu L, Chen L. Clinical analysis of non-AIDS patients with pulmonary cryptococcosis and the change in their clinical features over 30 years in a tertiary hospital in Beijing, China. Jpn J Infect Dis 2022; 75:476-483. [PMID: 35491232 DOI: 10.7883/yoken.jjid.2022.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - Chunsun Li
- Department of Pulmonary and Critical Care Medicine, the Eighth Medical Centre, Chinese PLA General Hospital, China
| | - Zhixin Liang
- Department of Pulmonary and Critical Care Medicine, the Eighth Medical Centre, Chinese PLA General Hospital, China
| | - Jiewei Cui
- Department of Pulmonary and Critical Care Medicine, the Eighth Medical Centre, Chinese PLA General Hospital, China
| | - Ling Yu
- Department of Pulmonary and Critical Care Medicine, the Eighth Medical Centre, Chinese PLA General Hospital, China
| | - Liangan Chen
- Department of Pulmonary and Critical Care Medicine, the Eighth Medical Centre, Chinese PLA General Hospital, China
| |
Collapse
|
3
|
Rathore SS, Sathiyamoorthy J, Lalitha C, Ramakrishnan J. A holistic review on Cryptococcus neoformans. Microb Pathog 2022; 166:105521. [DOI: 10.1016/j.micpath.2022.105521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 12/21/2022]
|
4
|
Abstract
Systemic cryptococcosis is fatal without treatment. Globally, this disease kills 180,000 of the 225,000 infected people each year, even with the use of antifungal therapies. Currently, there is no vaccine to prevent cryptococcosis. Previously, we discovered that Znf2, a morphogenesis regulator that directs Cryptococcus yeast-to-hyphal transition, profoundly affects cryptococcal interaction with the host-overexpression of ZNF2 drives filamentous growth, attenuates cryptococcal virulence, and elicits protective host immune responses. Importantly, immunization with cryptococcal cells overexpressing ZNF2, either in live or heat-inactivated form, offers significant protection to the host from a subsequent challenge by the otherwise lethal wild-type H99 strain. We hypothesize that cellular components enriched in ZNF2oe cells are immunoprotective. Here, we discovered that serum from protected animals vaccinated with inactivated ZNF2oe cells recognizes cryptococcal antigens that reside within the capsule. Consistently, capsule is required for immunoprotection offered by ZNF2oe cells. Interestingly, the serum from protective animals recognizes antigens in both wild-type yeast cells and ZNF2oe cells, with higher abundance in the latter. Consequently, even the heat-inactivated wild-type cells become immunoprotective with an increased vaccination dose. We also found that disruption of a chromatin remodeling factor Brf1, which is important for initiation of filamentation by Znf2, reduces the antigen level in ZNF2oe cells. Deletion of BRF1 drastically reduces the protective effect of ZNF2oe cells in both live and heat-killed forms even though the ZNF2oebrf1Δ strain itself is avirulent. Collectively, our findings underscore the importance of identifying the subset of cryptococcal surface factors that are beneficial in host protection. IMPORTANCE Cryptococcosis claims close to 200,000 lives annually. There is no vaccine clinically available for this fungal disease. Many avirulent mutant strains do not provide protection against cryptococcosis. We previously discovered that hyphal ZNF2oe strains elicit protective host immune responses both in the live and heat-inactivated forms. Here we seek to understand the mechanism underlying the host protection provided by ZNF2oe cells. We discovered increased accumulation of antigens located within the caspusle of ZNF2oe cells and consequently the requirement of the capsule for ZNF2oe strain-elicited host protection. Furthermore, genetically blocking the ability of ZNF2oe cells to grow in the hyphal form significantly reduces antigen accumulation and impairs the ability of ZNF2oe strain to provide host protection. Our findings highlight the importance of identifying the Znf2-regulated capsular surface factors that are fundamental in host protection.
Collapse
|
5
|
Gressler AE, Volke D, Firacative C, Schnabel CL, Müller U, Krizsan A, Schulze-Richter B, Brock M, Brombacher F, Escandón P, Hoffmann R, Alber G. Identification of Disease-Associated Cryptococcal Proteins Reactive With Serum IgG From Cryptococcal Meningitis Patients. Front Immunol 2021; 12:709695. [PMID: 34367172 PMCID: PMC8342929 DOI: 10.3389/fimmu.2021.709695] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/21/2021] [Indexed: 01/16/2023] Open
Abstract
Cryptococcus neoformans, an opportunistic fungal pathogen ubiquitously present in the environment, causes cryptococcal meningitis (CM) mainly in immunocompromised patients, such as AIDS patients. We aimed to identify disease-associated cryptococcal protein antigens targeted by the human humoral immune response. Therefore, we used sera from Colombian CM patients, with or without HIV infection, and from healthy individuals living in the same region. Serological analysis revealed increased titers of anti-cryptococcal IgG in HIV-negative CM patients, but not HIV-positive CM patients, compared to healthy controls. In contrast, titers of anti-cryptococcal IgM were not affected by CM. Furthermore, we detected pre-existing IgG and IgM antibodies even in sera from healthy individuals. The observed induction of anti-cryptococcal IgG but not IgM during CM was supported by analysis of sera from C. neoformans-infected mice. Stronger increase in IgG was found in wild type mice with high lung fungal burden compared to IL-4Rα-deficient mice showing low lung fungal burden. To identify the proteins targeted by human anti-cryptococcal IgG antibodies, we applied a quantitative 2D immunoproteome approach identifying cryptococcal protein spots preferentially recognized by sera from CM patients or healthy individuals followed by mass spectrometry analysis. Twenty-three cryptococcal proteins were recombinantly expressed and confirmed to be immunoreactive with human sera. Fourteen of them were newly described as immunoreactive proteins. Twelve proteins were classified as disease-associated antigens, based on significantly stronger immunoreactivity with sera from CM patients compared to healthy individuals. The proteins identified in our screen significantly expand the pool of cryptococcal proteins with potential for (i) development of novel anti-cryptococcal agents based on implications in cryptococcal virulence or survival, or (ii) development of an anti-cryptococcal vaccine, as several candidates lack homology to human proteins and are localized extracellularly. Furthermore, this study defines pre-existing anti-cryptococcal immunoreactivity in healthy individuals at a molecular level, identifying target antigens recognized by sera from healthy control persons.
Collapse
Affiliation(s)
- A Elisabeth Gressler
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Daniela Volke
- Institute of Bioanalytical Chemistry, Leipzig University, Leipzig, Germany
| | - Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| | - Christiane L Schnabel
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Uwe Müller
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Andor Krizsan
- Institute of Bioanalytical Chemistry, Leipzig University, Leipzig, Germany
| | - Bianca Schulze-Richter
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Matthias Brock
- Fungal Genetics and Biology Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Frank Brombacher
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
| | | | - Ralf Hoffmann
- Institute of Bioanalytical Chemistry, Leipzig University, Leipzig, Germany
| | - Gottfried Alber
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| |
Collapse
|
6
|
Midiri A, Mancuso G, Lentini G, Famà A, Galbo R, Zummo S, Giardina M, De Gaetano GV, Teti G, Beninati C, Biondo C. Characterization of an immunogenic cellulase secreted by Cryptococcus pathogens. Med Mycol 2021; 58:1138-1148. [PMID: 32246714 DOI: 10.1093/mmy/myaa012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 01/25/2023] Open
Abstract
Members of the C. neoformans/C. gattiii species complex are an important cause of serious humans infections, including meningoencephalitis. We describe here a 45 kDa extracellular cellulase purified from culture supernatants of C. neoformans var. neoformans. The N-terminal sequence obtained from the purified protein was used to isolate a clone containing the full-length coding sequence from a C. neoformans var. neoformans (strain B-3501A) cDNA library. Bioinformatics analysis indicated that this gene is present, with variable homology, in all sequenced genomes of the C. neoformans/C. gattii species complex. The cDNA clone was used to produce a recombinant 45 kDa protein in E. coli that displayed the ability to convert carboxymethyl cellulose and was therefore designated as NG-Case (standing for Neoformans Gattii Cellulase). To explore its potential use as a vaccine candidate, the recombinant protein was used to immunize mice and was found capable of inducing T helper type 1 responses and delayed-type hypersensitivity reactions, but not immune protection against a highly virulent C. neoformans var grubii strain. These data may be useful to better understand the mechanisms underlying the ability C. neoformans/C. gattii to colonize plant habitats and to interact with the human host during infection.
Collapse
Affiliation(s)
- Angelina Midiri
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Giuseppe Mancuso
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Germana Lentini
- Department of Human Pathology, University of Messina, Messina, Italy
| | | | - Roberta Galbo
- Department of Chemical, Biological and Pharmaceutical Sciences, University of Messina, Messina, Italy
| | - Sebastiana Zummo
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Miriam Giardina
- Department of Human Pathology, University of Messina, Messina, Italy
| | | | | | - Concetta Beninati
- Department of Human Pathology, University of Messina, Messina, Italy.,Scylla Biotech Srl, Messina, Italy
| | - Carmelo Biondo
- Department of Human Pathology, University of Messina, Messina, Italy
| |
Collapse
|
7
|
Hembach L, Bonin M, Gorzelanny C, Moerschbacher BM. Unique subsite specificity and potential natural function of a chitosan deacetylase from the human pathogen Cryptococcus neoformans. Proc Natl Acad Sci U S A 2020; 117:3551-3559. [PMID: 32015121 PMCID: PMC7035615 DOI: 10.1073/pnas.1915798117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that infects ∼280,000 people every year, causing >180,000 deaths. The human immune system recognizes chitin as one of the major cell-wall components of invading fungi, but C. neoformans can circumvent this immunosurveillance mechanism by instead exposing chitosan, the partly or fully deacetylated form of chitin. The natural production of chitosans involves the sequential action of chitin synthases (CHSs) and chitin deacetylases (CDAs). C. neoformans expresses four putative CDAs, three of which have been confirmed as functional enzymes that act on chitin in the cell wall. The fourth (CnCda4/Fpd1) is a secreted enzyme with exceptional specificity for d-glucosamine at its -1 subsite, thus preferring chitosan over chitin as a substrate. We used site-specific mutagenesis to reduce the subsite specificity of CnCda4 by converting an atypical isoleucine residue in a flexible loop region to the bulkier or charged residues tyrosine, histidine, and glutamic acid. We also investigated the effect of CnCda4 deacetylation products on human peripheral blood-derived macrophages, leading to a model explaining the function of CnCda4 during infection. We propose that CnCda4 is used for the further deacetylation of chitosans already exposed on the C. neoformans cell wall (originally produced by CnChs3 and CnCda1 to 3) or released from the cell wall as elicitors by human chitinases, thus making the fungus less susceptible to host immunosurveillance. The absence of CnCda4 during infection could therefore promote the faster recognition and elimination of this pathogen.
Collapse
Affiliation(s)
- Lea Hembach
- Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany
| | - Martin Bonin
- Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany
| | - Christian Gorzelanny
- Experimental Dermatology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Bruno M Moerschbacher
- Institute for Biology and Biotechnology of Plants, University of Münster, 48143 Münster, Germany;
| |
Collapse
|
8
|
Guess TE, Rosen J, Castro-Lopez N, Wormley FL, McClelland EE. An inherent T cell deficit in healthy males to C. neoformans infection may begin to explain the sex susceptibility in incidence of cryptococcosis. Biol Sex Differ 2019; 10:44. [PMID: 31477151 PMCID: PMC6720413 DOI: 10.1186/s13293-019-0258-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/16/2019] [Indexed: 02/07/2023] Open
Abstract
Background Cryptococcus neoformans, the causative agent of cryptococcosis, causes ~ 181,000 deaths annually, with males having a higher incidence of disease than females (7M:3F). The reason for this sex bias remains unclear. We hypothesized that this disparity was due to biological differences between the male and female immune response. Methods Peripheral blood mononuclear cells (PBMCs) from healthy donors were isolated and infected with C. neoformans ± exogenous testosterone or 17-β-estradiol. C. neoformans, B, T, and NK cell proliferation was quantified by flow cytometry. Cytokine analysis was conducted via protein array or ELISA. Serological testing was conducted to determine previous exposure to C. neoformans. Results C. neoformans proliferated more in male PBMCs. T cell percentages in both sexes were lower in infected versus uninfected cells. Male PBMCs had lower CD3+, CD4+, and CD8+ T cells percentages during infection compared to females. Cytokine profiles showed differences in uninfected male and female PBMCs, which subsided during infection. Only one donor was sero-negative for prior C. neoformans exposure. There was an effect of estrogen in one dataset. Conclusions These results suggest that males show an inherent deficit in T cell response during infection, which may contribute to the increased incidence of disease in males. Electronic supplementary material The online version of this article (10.1186/s13293-019-0258-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Tiffany E Guess
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Joseph Rosen
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Natalia Castro-Lopez
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA.,South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Floyd L Wormley
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA.,South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Erin E McClelland
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA.
| |
Collapse
|
9
|
Coelho C, Camacho E, Salas A, Alanio A, Casadevall A. Intranasal Inoculation of Cryptococcus neoformans in Mice Produces Nasal Infection with Rapid Brain Dissemination. mSphere 2019; 4:e00483-19. [PMID: 31391283 PMCID: PMC6686232 DOI: 10.1128/msphere.00483-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022] Open
Abstract
Cryptococcus neoformans is an important fungal pathogen, causing life-threatening pneumonia and meningoencephalitis. Brain dissemination of C. neoformans is thought to be a consequence of an active infection in the lung which then extravasates to other sites. Brain invasion results from dissemination via either transport by free yeast cells in the bloodstream or Trojan horse transport within mononuclear phagocytes. We assessed brain dissemination in three mouse models of infection: intravenous, intratracheal, and intranasal models. All three modes of infection resulted in dissemination of C. neoformans to the brain in less than 3 h. Further, C. neoformans was detected in the entirety of the upper respiratory tract and the ear canals of mice. In recent years, intranasal infection has become a popular mechanism to induce pulmonary infection because it avoids surgery, but our findings show that instillation of C. neoformans produces cryptococcal nasal infection. These findings imply that immunological studies using intranasal infection should assume that the initial sites of infection of infection are brain, lung, and upper respiratory tract, including the nasal airways.IMPORTANCECryptococcus neoformans causes an estimated 181, 000 deaths each year, mostly associated with untreated HIV/AIDS. C. neoformans has a ubiquitous worldwide distribution. Humans become infected from exposure to environmental sources, after which the fungus lays dormant within the human body. Upon AIDS-induced immunosuppression or therapy-induced immunosuppression (required for organ transplant recipients or those suffering from autoimmune disorders), cryptococcal disease reactivates and causes life-threatening meningitis and pneumonia. This study showed that upon contact with the host, C. neoformans can quickly (a few hours) reach the host brain and also colonizes the nose of infected animals. Therefore, this work paves the way to better knowledge of how C. neoformans travels through the host body. Understanding how C. neoformans infects, disseminates, and survives within the host is critically required so that we can prevent infections and the disease caused by this deadly fungus.
Collapse
Affiliation(s)
- Carolina Coelho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
- Medical Research Council Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Emma Camacho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Antonio Salas
- Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Alexandre Alanio
- Institut Pasteur, Molecular Mycology Unit, CNRS UMR2000, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| |
Collapse
|
10
|
Abstract
Cryptococcus is among the most common invasive fungal pathogens globally and is one of the leading causes of acquired immunodeficiency virus-related deaths. Cryptococcus neoformans and Cryptococcus gattii are the most clinically relevant species and account for most cryptococcal disease. Pulmonary manifestations can range from mild symptoms to life-threatening infection. Treatment is tailored based on the severity of pulmonary infection, the presence of disseminated or central nervous system disease, and patient immune status. Amphotericin B and flucytosine followed by fluconazole remain the standard agents for the treatment of severe cryptococcal infection.
Collapse
Affiliation(s)
- Kate Skolnik
- Division of Respirology, Department of Internal Medicine, Rockyview General Hospital, University of Calgary, Respirology Offices, 7007 14th Street Southwest, Calgary, Alberta T2V 1P9, Canada
| | - Shaunna Huston
- Department of Physiology and Pharmacology, Health Research Innovation Centre, University of Calgary, Room 4AA08, 3330 Hospital Drive Northwest, Calgary, Alberta T2N 4N1, Canada
| | - Christopher H Mody
- Department of Microbiology and Infectious Diseases, Health Research Innovation Centre, University of Calgary, Room 4AA14, 3330 Hospital Drive Northwest, Calgary, Alberta T2N 4N1, Canada; Department of Internal Medicine, Health Research Innovation Centre, University of Calgary, Room 4AA14, 3330 Hospital Drive Northwest, Calgary, Alberta T2N 4N1, Canada.
| |
Collapse
|
11
|
Abstract
The Cryptococcus neoformans/Cryptococcus gattii species complex is a group of fungal pathogens with different phenotypic and genotypic diversity that cause disease in immunocompromised patients as well as in healthy individuals. The immune response resulting from the interaction between Cryptococcus and the host immune system is a key determinant of the disease outcome. The species C. neoformans causes the majority of human infections, and therefore almost all immunological studies focused on C. neoformans infections. Thus, this review presents current understanding on the role of adaptive immunity during C. neoformans infections both in humans and in animal models of disease.
Collapse
|
12
|
Grahnert A, Müller U, von Buttlar H, Treudler R, Alber G. Analysis of asthma patients for cryptococcal seroreactivity in an urban German area. Med Mycol 2015; 53:576-86. [PMID: 26026172 DOI: 10.1093/mmy/myv024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 01/15/2023] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes lung inflammation and meningoencephalitis in immunocompromised patients but is also able to asymptomatically infect immunocompetent individuals. C. neoformans is found ubiquitously especially in urban areas where it is spread by pigeons, and fungal exposure may predispose for asthma development already at an early age, as soon as confronted with pigeon droppings. In the study presented here, we investigated the presence of specific immunoglobulin G (IgG) against C. neoformans in sera from patients suffering from asthma in comparison to a healthy control cohort, accrued from the Leipzig Research Centre for Civilization Diseases (LIFE). For serological analysis we developed a flow cytometry (FACS) based assay specific for an acapsular strain of C. neoformans to comprehensively analyze different cryptococcal serotypes. Compared with the non-asthmatic cohort, asthmatics exhibited, as expected, an elevated level of total serum immunoglobulin E (IgE), whereas the IgG seroreactivity against C. neoformans was not significantly different among the two groups (P = .118). Nevertheless, there was a trend toward increased Cryptococcus-specific IgG antibodies in the serum of asthmatics. Additionally, in male asthmatics an increased IgG-mediated seroreactivity compared to female asthmatics was found. This points to a higher prevalence of subclinical C. neoformans infection in male asthmatics and may support the hypothesis of C. neoformans as a risk factor for the development of asthma in urban areas.
Collapse
Affiliation(s)
- Andreas Grahnert
- Institute of Immunology/Molecular Pathogenesis, Center for Biotechnology and Biomedicine, College of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Uwe Müller
- Institute of Immunology/Molecular Pathogenesis, Center for Biotechnology and Biomedicine, College of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Heiner von Buttlar
- Institute of Immunology/Molecular Pathogenesis, Center for Biotechnology and Biomedicine, College of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Regina Treudler
- Department of Dermatology, Venerology & Allergology, University of Leipzig, Leipzig, Germany LIFE-Leipzig Research Center for Civilization Diseases, Universität Leipzig, Germany
| | - Gottfried Alber
- Institute of Immunology/Molecular Pathogenesis, Center for Biotechnology and Biomedicine, College of Veterinary Medicine, University of Leipzig, Leipzig, Germany LIFE-Leipzig Research Center for Civilization Diseases, Universität Leipzig, Germany
| |
Collapse
|
13
|
Gibson JF, Johnston SA. Immunity to Cryptococcus neoformans and C. gattii during cryptococcosis. Fungal Genet Biol 2014; 78:76-86. [PMID: 25498576 PMCID: PMC4503824 DOI: 10.1016/j.fgb.2014.11.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 11/25/2014] [Accepted: 11/29/2014] [Indexed: 10/25/2022]
Abstract
The vast majority of infection with cryptococcal species occurs with Cryptococcus neoformans in the severely immunocompromised. A significant exception to this is the infections of those with apparently normal immune systems by Cryptococcus gattii. Susceptibility to cryptococcosis can be broadly categorised as a defect in adaptive immune responses, especially in T cell immunity. However, innate immune cells such as macrophages play a key role and are likely the primary effector cell in the killing and ultimate clearance of cryptococcal infection. In this review we discuss the current state of our understanding of how the immune system responds to cryptococcal infection in health and disease, with reference to the work communicated at the 9th International Conference on Cryptococcus and Cryptococcosis (ICCC9). We have focussed on cell mediated responses, particularly early in infection, but with the aim of presenting a broad overview of our understanding of immunity to cryptococcal infection, highlighting some recent advances and offering some perspectives on future directions.
Collapse
Affiliation(s)
- Josie F Gibson
- Department of Infection and Immunity, Medical School, University of Sheffield, S10 2RX, UK; Bateson Centre, Department of Biomedical Sciences, University of Sheffield, S10 2TN, UK
| | - Simon A Johnston
- Department of Infection and Immunity, Medical School, University of Sheffield, S10 2RX, UK; Bateson Centre, Department of Biomedical Sciences, University of Sheffield, S10 2TN, UK.
| |
Collapse
|
14
|
Datta K, Subramaniam KS. Host Defense Against Cryptococcal Disease: Is There a Role for B Cells and Antibody-Mediated Immunity? CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-014-0208-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
15
|
Barragan NC, Sorvillo F, Kuo T. Cryptococcosis-related deaths and associated medical conditions in the United States, 2000-2010. Mycoses 2014; 57:741-6. [PMID: 25135153 DOI: 10.1111/myc.12238] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/27/2014] [Accepted: 07/28/2014] [Indexed: 11/29/2022]
Abstract
Cryptococcosis is an invasive mycotic infection primarily affecting immunocompromised individuals. The objective of this study was to describe cryptococcosis mortality and associated medical conditions in the US for the period 2000-2010. Cryptococcosis-related deaths were identified from the national multiple-cause-of-death dataset. Mortality trends and comparison analyses were performed on overall cases of cryptococcosis and by subset [i.e. clinical manifestations of disease and human immunodeficiency virus (HIV) status]. A matched case-control analysis was also conducted to describe the associations between this disease and comorbid medical conditions. A total of 3210 cryptococcosis-related deaths were identified. Cerebral cryptococcosis was the most commonly reported clinical manifestation of the disease. Approximately one-fifth of the decedents (n = 616) had a co-diagnosis of HIV. Mortality rates were highest among men, blacks, Hispanics, Native Americans and older adults. Poisson regression analysis indicated a 6.52% annual decrease in mortality rates for the study period. HIV (MOR = 35.55, 95% CI 27.95-45.22) and leukaemia (MOR = 16.10, 95% CI 11.24-23.06) were highly associated with cryptococcosis-related deaths. Cryptococcosis mortality declined significantly during 2000-2010. However, the disease continues to cause appreciable mortality in the US. With the majority of decedents having no HIV co-diagnosis, there is still much to be learned about the epidemiology of this mycosis.
Collapse
Affiliation(s)
- Noel C Barragan
- Division of Chronic Disease and Injury Prevention, Los Angeles County Department of Public Health, Los Angeles, CA, USA
| | | | | |
Collapse
|
16
|
Microevolution during serial mouse passage demonstrates FRE3 as a virulence adaptation gene in Cryptococcus neoformans. mBio 2014; 5:e00941-14. [PMID: 24692633 PMCID: PMC3977352 DOI: 10.1128/mbio.00941-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Passage in mice of opportunistic pathogens such as Cryptococcus neoformans is known to increase virulence, but little is known about the molecular mechanisms involved in virulence adaptation. Serial mouse passage of nine environmental strains of serotype A C. neoformans identified two highly adapted virulent strains that showed a 4-fold reduction in time to death after four passages. Transcriptome sequencing expression studies demonstrated increased expression of a FRE3-encoded iron reductase in the two strains but not in a control strain that did not demonstrate increased virulence during mouse passage. FRE3 was shown to express an iron reductase activity and to play a role in iron-dependent growth of C. neoformans. Overexpression of FRE3 in the two original environmental strains increased growth in the macrophage cell line J774.16 and increased virulence. These data demonstrate a role for FRE3 in the virulence of C. neoformans and demonstrate how the increased expression of such a "virulence acquisition gene" during the environment-to-mammal transition, can optimize the virulence of environmental strains in mammalian hosts. IMPORTANCE Cryptococcus neoformans is a significant global fungal pathogen that also resides in the environment. Recent studies have suggested that the organism may undergo microevolution in the host. However, little is known about the permitted genetic changes facilitating the adaptation of environmental strains to mammalian hosts. The present studies subjected environmental strains isolated from several metropolitan areas of the United States to serial passages in mice. Transcriptome sequencing expression studies identified the increased expression of an iron reductase gene, FRE3, in two strains that adapted in mice to become highly virulent, and overexpression of FRE3 recapitulated the increased virulence after mouse passage. Iron reductase in yeast is important to iron uptake in a large number of microbial pathogens. These studies demonstrate the capacity of C. neoformans to show reproducible changes in the expression levels of small numbers of genes termed "virulence adaptation genes" to effectively increase pathogenicity during the environment-to-mammal transition.
Collapse
|
17
|
Interleukin-17A enhances host defense against cryptococcal lung infection through effects mediated by leukocyte recruitment, activation, and gamma interferon production. Infect Immun 2013; 82:937-48. [PMID: 24324191 DOI: 10.1128/iai.01477-13] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Infection of C57BL/6 mice with the moderately virulent Cryptococcus neoformans strain 52D models the complex adaptive immune response observed in HIV-negative patients with persistent fungal lung infections. In this model, Th1 and Th2 responses evolve over time, yet the contribution of interleukin-17A (IL-17A) to antifungal host defense is unknown. In this study, we show that fungal lung infection promoted an increase in Th17 T cells that persisted to 8 weeks postinfection. Our comparison of fungal lung infection in wild-type mice and IL-17A-deficient mice (IL-17A(-/-) mice; C57BL/6 genetic background) demonstrated that late fungal clearance was impaired in the absence of IL-17A. This finding was associated with reduced intracellular containment of the organism within lung macrophages and deficits in the accumulation of total lung leukocytes, including specific reductions in CD11c+ CD11b+ myeloid cells (dendritic cells and exudate macrophages), B cells, and CD8+ T cells, and a nonsignificant trend in the reduction of lung neutrophils. Although IL-17A did not alter the total number of CD4 T cells, decreases in the total number of CD4 T cells and CD8 T cells expressing gamma interferon (IFN-γ) were observed in IL-17A(-/-) mice. Lastly, expression of major histocompatibility complex class II (MHC-II) and the costimulatory molecules CD80 and CD86 on CD11c+ CD11b+ myeloid cells was diminished in IL-17A(-/-) mice. Collectively, these data indicate that IL-17A enhances host defenses against a moderately virulent strain of C. neoformans through effects on leukocyte recruitment, IFN-γ production by CD4 and CD8 T cells, and the activation of lung myeloid cells.
Collapse
|
18
|
Ishii K, Kawakami K. [Pattern recognition and host defense response to Cryptococcus neoformans]. Med Mycol J 2013; 53:247-54. [PMID: 23257725 DOI: 10.3314/mmj.53.247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes fatal meningoencephalitis in immunocompromised hosts such as patients with AIDS and hematological malignancy. Host defense to C. neoformans infection is mediated by Th1-type cellular immunity, which is triggered by host cell recognition of the pathogen-associated molecular patterns via the pattern recognition receptors. Recently, our study revealed that TLR9-dependent sensing of cryptococcal DNA was a pivotal step in initiating the host defense to this infection and raised a possibility that this process may be triggered in a distinct manner by bacterial DNA with a canonical CpG motif. In addition, we found that mice deficient in CARD9, a critical adapter molecule for signaling via C-type lectin receptors (CLRs), was highly susceptible to cryptococcal infection with impaired immune responses, suggesting a possible involvement of some CLRs. In this article, we review advances in understanding the pattern recognition and host defense response to C. neoformans, with a particular focus on our recent results.
Collapse
Affiliation(s)
- Keiko Ishii
- Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine, Japan
| | | |
Collapse
|
19
|
Coelho C, Bocca AL, Casadevall A. The intracellular life of Cryptococcus neoformans. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2013; 9:219-38. [PMID: 24050625 DOI: 10.1146/annurev-pathol-012513-104653] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cryptococcus neoformans is a fungal pathogen with worldwide distribution. Serological studies of human populations show a high prevalence of human infection, which rarely progresses to disease in immunocompetent hosts. However, decreased host immunity places individuals at high risk for cryptococcal disease. The disease can result from acute infection or reactivation of latent infection, in which yeasts within granulomas and host macrophages emerge to cause disease. In this review, we summarize what is known about the cellular recognition, ingestion, and killing of C. neoformans and discuss the unique and remarkable features of its intracellular life, including the proposed mechanisms for fungal persistence and killing in phagocytic cells.
Collapse
Affiliation(s)
- Carolina Coelho
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461;
| | | | | |
Collapse
|
20
|
Abstract
Cryptococcus neoformans is one of the most common causes of fungal disease in HIV-infected persons, but not all of those who are infected develop cryptococcal disease (CD). Although CD4+ T cell deficiency is a risk factor for HIV-associated CD, polymorphisms of phagocytic Fc gamma receptors (FCGRs) have been linked to CD risk in HIV-uninfected persons. To investigate associations between FCGR2A 131 H/R and FCGR3A 158 F/V polymorphisms and CD risk in HIV-infected persons, we performed PCR-based genotyping on banked samples from 164 men enrolled in the Multicenter AIDS Cohort Study (MACS): 55 who were HIV infected and developed CD and a matched control group of 54 who were HIV infected and 55 who were HIV uninfected. Using additive and allelic statistical models for analysis, the high-affinity FCGR3A 158V allele was significantly associated with CD status after adjusting for race/ethnicity (odds ratio [OR], 2.1; P = 0.005), as was the FCGR3A 158 VV homozygous genotype after adjusting for race/ethnicity, rate of CD4+ T cell decline, and nadir CD4+ T cell count (OR, 21; P = 0.005). No associations between CD and FCGR2A 131 H/R polymorphism were identified. In binding studies, human IgG (hIgG)-C. neoformans complexes exhibited more binding to CHO-K1 cells expressing FCGR3A 158V than to those expressing FCGR3A 158F, and in cytotoxicity assays, natural killer (NK) cells expressing FCGR3A 158V induced more C. neoformans-infected monocyte cytotoxicity than those expressing FCGR3A 158F. Together, these results show an association between the FCGR3A 158V allele and risk for HIV-associated CD and suggest that this polymorphism could promote C. neoformans pathogenesis via increased binding of C. neoformans immune complexes, resulting in increased phagocyte cargo and/or immune activation. HIV-associated CD4+ T cell deficiency is a sine qua non for HIV-associated cryptococcal disease (CD), but not all patients with CD4+ T cell deficiency develop CD despite serological evidence of previous infection. At present, there are no biomarkers that predict HIV-associated CD risk. The goal of our study was to understand whether Fc gamma receptor (FCGR) polymorphisms that have been shown to portend CD risk in HIV-uninfected people are associated with CD risk in HIV-infected people. Such biomarkers could identify those who would benefit most from targeted prophylaxis and/or earlier treatment, particularly in sub-Saharan Africa, where there are nearly a million cases of HIV-associated CD annually. A biomarker of risk could also identify potential candidates for immunization, should there be a vaccine for Cryptococcus neoformans.
Collapse
|
21
|
Springer DJ, Saini D, Byrnes EJ, Heitman J, Frothingham R. Development of an aerosol model of Cryptococcus reveals humidity as an important factor affecting the viability of Cryptococcus during aerosolization. PLoS One 2013; 8:e69804. [PMID: 23894542 PMCID: PMC3720958 DOI: 10.1371/journal.pone.0069804] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 06/12/2013] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus is an emerging global health threat that is annually responsible for over 1,000,000 infections and one third of all AIDS patient deaths. There is an ongoing outbreak of cryptococcosis in the western United States and Canada. Cryptococcosis is a disease resulting from the inhalation of the infectious propagules from the environment. The current and most frequently used animal infection models initiate infection via liquid suspension through intranasal instillation or intravenous injection. These models do not replicate the typically dry nature of aerosol exposure and may hinder our ability to decipher the initial events that lead to clearance or the establishment of infection. We have established a standardized aerosol model of murine infection for the human fungal pathogen Cryptococcus. Aerosolized cells were generated utilizing a Collison nebulizer in a whole-body Madison Chamber at different humidity conditions. The aerosols inside the chamber were sampled using a BioSampler to determine viable aerosol concentration and spray factor (ratio of viable aerosol concentration to total inoculum concentration). We have effectively delivered yeast and yeast-spore mixtures to the lungs of mice and observed the establishment of disease. We observed that growth conditions prior to exposure and humidity within the Madison Chamber during exposure can alter Cryptococcus survival and dose retained in mice.
Collapse
Affiliation(s)
- Deborah J Springer
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA.
| | | | | | | | | |
Collapse
|
22
|
Kabir MA, Hussain MA, Ahmad Z. Candida albicans: A Model Organism for Studying Fungal Pathogens. ISRN MICROBIOLOGY 2012; 2012:538694. [PMID: 23762753 PMCID: PMC3671685 DOI: 10.5402/2012/538694] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 08/30/2012] [Indexed: 01/12/2023]
Abstract
Candida albicans is an opportunistic human fungal pathogen that causes candidiasis. As healthcare has been improved worldwide, the number of immunocompromised patients has been increased to a greater extent and they are highly susceptible to various pathogenic microbes and C. albicans has been prominent among the fungal pathogens. The complete genome sequence of this pathogen is now available and has been extremely useful for the identification of repertoire of genes present in this pathogen. The major challenge is now to assign the functions to these genes of which 13% are specific to C. albicans. Due to its close relationship with yeast Saccharomyces cerevisiae, an edge over other fungal pathogens because most of the technologies can be directly transferred to C. albicans from S. cerevisiae and it is amenable to mutation, gene disruption, and transformation. The last two decades have witnessed enormous amount of research activities on this pathogen that leads to the understanding of host-parasite interaction, infections, and disease propagation. Clearly, C. albicans has emerged as a model organism for studying fungal pathogens along with other two fungi Aspergillus fumigatus and Cryptococcus neoformans. Understanding its complete life style of C. albicans will undoubtedly be useful for developing potential antifungal drugs and tackling Candida infections. This will also shed light on the functioning of other fungal pathogens.
Collapse
Affiliation(s)
- M Anaul Kabir
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut 673601, Kerala, India
| | | | | |
Collapse
|
23
|
Helbig S, Achkar JM, Jain N, Wang X, Gialanella P, Levi M, Fries BC. Diagnosis and inflammatory response of patients with candiduria. Mycoses 2012; 56:61-9. [PMID: 22574854 DOI: 10.1111/j.1439-0507.2012.02201.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Candiduria is common in hospitalised patients, but the clinical relevance is still unclear. This study was done to further our knowledge on detection of and host responses to candiduria. Urines and clinical data from 136 patients in whom presence of yeast was diagnosed by microscopic urinalysis were collected. Diagnosis by standard urine culture methods on blood and MacConkey agar as well as on fungal culture medium (Sabouraud dextrose agar) was compared. Inflammatory parameters (IL-6 and IL-17, Ig) were quantified in the urine and compared with levels in control patients without candiduria. Standard urine culture methods detected only 37% of Candida spp. in urine. Sensitivity was especially low (23%) for C. glabrata and was independent of fungal burden. Candida specific IgG but not IgA was significantly elevated when compared with control patients (P < 0.0001 and 0.07 respectively). In addition, urine levels of IL-6 and IL-17 were significantly higher in candiduric patients when compared with control patients (P < 0.001). Multivariate analysis documented an independent association between an increased IgG (odds ratio (OR) 136.0, 95% confidence interval (CI) 25.7-719.2; P < 0.0001), an increased IL-17 (OR 17.4, 95% CI 5.3-57.0; P < 0.0001) and an increased IL-6 level (OR 4.9, 95% CI 1.9-12.4; P = 0.001) and candiduria. In summary, our data indicate that clinical studies on candiduria should include fungal urine culture and that inflammatory parameters may be helpful to identify patients with clinically relevant candiduria.
Collapse
Affiliation(s)
- S Helbig
- Jacobi Medical Center HHC, Bronx, NY, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
Fungal meningitis is a serious disease caused by a fungal infection of the central nervous system (CNS) mostly in individuals with immune system deficiencies. Fungal meningitis is often fatal without proper treatment, and the mortality rate remains unacceptably high even with antifungal drug interventions. Currently, cryptococcal meningitis is the most common fungal meningitis in HIV-1/AIDS, and its disease mechanism has been extensively studied. The key steps for fungi to infect brain and cause meningitis after establishment of local infection are the dissemination of fungal cells to the bloodstream and invasion through the blood brain barrier to reach the CNS. In this review, we use cryptococcal CNS infection as an example to describe the current molecular understanding of fungal meningitis, including the establishment of the infection, dissemination, and brain invasion. Host and microbial factors that contribute to these infection steps are also discussed.
Collapse
Affiliation(s)
- Tong-Bao Liu
- The Public Health Research Institute, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | | | | |
Collapse
|
25
|
Analyses of pediatric isolates of Cryptococcus neoformans from South Africa. J Clin Microbiol 2010; 49:307-14. [PMID: 20980574 DOI: 10.1128/jcm.01277-10] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Compared to the incidence in adults, cryptococcosis is inexplicably rare among children, even in sub-Saharan Africa, which has the highest prevalence of coinfection with HIV and Cryptococcus neoformans. To explore any mycological basis for this age-related difference in the incidence of cryptococcosis, we investigated isolates of C. neoformans recovered from pediatric and adult patients during a 2-year period in South Africa. From reports to the Group for Enteric, Respiratory, and Meningeal Disease Surveillance in South Africa (GERMS-SA), we reviewed all cases of cryptococcosis in 2005 and 2006. We analyzed one isolate of C. neoformans from each of 82 pediatric patients (<15 years of age) and determined the multilocus sequence type (ST), mating type, ploidy, and allelic profile. This sample included isolates of all three molecular types of serotype A or C. neoformans var. grubii (molecular types VNI, VNII, and VNB) and one AD hybrid. Seventy-seven (94%) of the strains possessed the MATα mating type allele, and five were MATa. Seventy-five (91%) were haploid, and seven were diploid. A total of 24 different STs were identified. The ratios of each mating type and the proportion of haploids were comparable to those for the isolates that were obtained from 86 adult patients during the same period. Notably, the most prevalent pediatric ST was significantly associated with male patients. Overall, these pediatric isolates exhibited high genotypic diversity. They included a relatively large percentage of diploids and the rarely reported MATa mating type.
Collapse
|
26
|
Chun CD, Madhani HD. Applying genetics and molecular biology to the study of the human pathogen Cryptococcus neoformans. Methods Enzymol 2010; 470:797-831. [PMID: 20946836 DOI: 10.1016/s0076-6879(10)70033-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The basidiomycete yeast Crytococcus neoformans is a prominent human pathogen. It primarily infects immunocompromised individuals producing a meningoencephalitis that is lethal if untreated. Recent advances in its genetics and molecular biology have made it a model system for understanding both the Basidiomycota phylum and mechanisms of fungal pathogenesis. The relative ease of experimental manipulation coupled with the development of murine models for human disease allow for powerful studies in the mechanisms of virulence and host responses. This chapter introduces the organism and its life cycle and then provides detailed step-by-step protocols for culture, manipulation of the genome, analysis of nucleic acids and proteins, and assessment of virulence and expression of virulence factors.
Collapse
Affiliation(s)
- Cheryl D Chun
- University of California, San Francisco, California, USA
| | | |
Collapse
|
27
|
Chai HC, Tay ST. Detection of IgM and IgG antibodies to Cryptococcus neoformans proteins in blood donors and HIV patients with active cryptococcosis. Mycoses 2008; 52:166-70. [PMID: 18643920 DOI: 10.1111/j.1439-0507.2008.01549.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The serological responses to Cryptococcus neoformans proteins of blood donors and HIV patients with active cryptococcosis from a tropical region were investigated in this study. Exposure to C. neoformans, an organism ubiquitous in the environment, contributes to the antibody responses observed in the blood donors. IgG responses to cryptococcal proteins were stronger than IgM responses in most sera tested in this study. A 53-kDa cryptococcal protein fragment was identified as the most immunoreactive protein on the IgM immunoblots of both blood donors and patients. Overall, there was no obvious difference in IgG responses of patients when compared with blood donors. Some immunogenic protein fragments (27.5, 76, 78 and 91.5 kDa) were detected at least two times more frequently on IgM immunoblots of patients compared with those of blood donors. It is yet to be investigated whether the proteins identified in this study may have any potential to be used as biomarker for cryptococcosis.
Collapse
Affiliation(s)
- H C Chai
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | |
Collapse
|
28
|
Saha DC, Xess I, Zeng WY, Goldman DL. Antibody responses to Cryptococcus neoformans in Indian patients with cryptococcosis. Med Mycol 2008; 46:457-63. [PMID: 18608912 DOI: 10.1080/13693780801961345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
An important element of the host response to cryptococcosis is humoral immunity. Specific antibody responses in patients with cryptococcosis however, have not been extensively studied. We analyzed the antibody responses of 22 Indian patients with cryptococcosis, including both HIV+ and HIV- individuals. Sera from 10 Indian patients with AIDS and without cryptococcosis were studied as controls. Antibody responses to cryptococcal proteins were detected by immunoblot, while antibodies to glucuronoxylomannan (GXM), the main component of the cryptococcal capsular polysaccharide were measured by ELISA. Our results indicate that cryptococcosis elicits antibodies to a specific pattern of cytoplasmic proteins. Further, we find that antibody responses to both cytoplasmic proteins and GXM are less robust in HIV+ patients when compared with HIV- patients.
Collapse
|
29
|
Diversidad del complejo de especies Cryptococcus neoformans-Cryptococcus gattii. Rev Iberoam Micol 2008; 25:S4-12. [DOI: 10.1016/s1130-1406(08)70019-6] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
|
30
|
Saha DC, Goldman DL, Shao X, Casadevall A, Husain S, Limaye AP, Lyon M, Somani J, Pursell K, Pruett TL, Singh N. Serologic evidence for reactivation of cryptococcosis in solid-organ transplant recipients. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:1550-4. [PMID: 17959819 PMCID: PMC2168388 DOI: 10.1128/cvi.00242-07] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 09/19/2007] [Accepted: 10/15/2007] [Indexed: 11/20/2022]
Abstract
Cryptococcosis is a significant infection with a high mortality in solid-organ transplant recipients. Nonetheless, the pathogenesis of this disease is poorly understood. It has been hypothesized that cryptococcosis may result from either primary infection or reactivation of a latent infection. Sera were obtained from transplant recipients prior to transplantation and at the time they developed cryptococcosis. Control sera were obtained before and after transplant from patients who did not develop cryptococcosis. Sera were tested for antibodies against Cryptococcus neoformans by using an immunoblot assay. Antibody responses were also compared with those observed in sera from rats with experimental pulmonary cryptococcosis. In all, 52% of the transplant recipients who developed cryptococcosis exhibited serologic evidence of cryptococcal infection before transplantation. These patients developed cryptococcosis significantly earlier after transplant than patients without preexisting reactivity did (5.6 +/- 3.4 months compared to 40.6 +/- 63.8 months, respectively [P = 0.0011]). The results from our study suggest that a substantial proportion of transplant-associated cryptococcosis cases result from the reactivation of a latent infection. These findings also highlight the potential utility of serologic studies in identifying patients at risk for the development of cryptococcosis after transplantation.
Collapse
Affiliation(s)
- D C Saha
- Infectious Diseases Section, VA Medical Center, University Drive C, Pittsburgh, PA 15240, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Martins MA, Pappalardo MCSM, Melhem MSC, Pereira-Chioccola VL. Molecular diversity of serial Cryptococcus neoformans isolates from AIDS patients in the city of São Paulo, Brazil. Mem Inst Oswaldo Cruz 2007; 102:777-84. [DOI: 10.1590/s0074-02762007000700001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 10/25/2007] [Indexed: 11/22/2022] Open
|
32
|
Davis J, Zheng WY, Glatman-Freedman A, Ng JAN, Pagcatipunan MR, Lessin H, Casadevall A, Goldman DL. Serologic evidence for regional differences in pediatric cryptococcal infection. Pediatr Infect Dis J 2007; 26:549-51. [PMID: 17529880 DOI: 10.1097/inf.0b013e318047e073] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cryptococcus neoformans is present in areas contaminated with pigeon droppings. Unrecognized infections are hypothesized to occur commonly among immunocompetent individuals. We used serology to estimate prevalence of cryptococcal infection in immunocompetent children from 3 regions. Our results indicate unrecognized cryptococcal infections are extremely common in Bronx children, but uncommon in children from Dutchess County, NY and the Philippines.
Collapse
Affiliation(s)
- Jennifer Davis
- Department of Pediatrics, Childrens Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Lindell DM, Ballinger MN, McDonald RA, Toews GB, Huffnagle GB. Immunologic homeostasis during infection: coexistence of strong pulmonary cell-mediated immunity to secondary Cryptococcus neoformans infection while the primary infection still persists at low levels in the lungs. THE JOURNAL OF IMMUNOLOGY 2006; 177:4652-61. [PMID: 16982904 DOI: 10.4049/jimmunol.177.7.4652] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maintenance of immunity to persistent pathogens is poorly understood. In this study, we used a murine model of persistent pulmonary fungal infection to study the ongoing cell-mediated immune response. CBA/J mice with low-level persistent Cryptococcus neoformans infection had CD4+ T cells of effector memory phenotype present in their lungs. Although unable to eliminate the primary infection to sterility, these mice displayed hallmarks of immunologic memory in response to rechallenge with C. neoformans: 1) the secondary cryptococcal challenge was controlled much more rapidly, 2) the inflammatory response developed and resolved more rapidly, 3) CD4+ T and CD8+ T cell responses were higher in magnitude, and 4) effector cytokine production by T cells was greatly enhanced. Depletion of CD4+ T cells at the time of secondary challenge adversely affected clearance of C. neoformans from the lungs. These results demonstrate that persistent low-level infection with C. neoformans does not impair the cell-mediated response to the fungus. Although they are relatively free of overt disease, these mice can respond with a rapid secondary immune response if the burden of C. neoformans increases. These data support the concept that immunologically healthy individuals can maintain low numbers of cryptococci that can become a nidus for re-activation disease during immunodeficient states such as AIDS.
Collapse
Affiliation(s)
- Dennis M Lindell
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | | |
Collapse
|
34
|
Abstract
In the past 2 decades, Cryptococcus has emerged in its clinical significance and as a model yeast for understanding molecular pathogenesis. C neoformans and C gattii are currently considered major primary and secondary pathogens in a wide array of hosts that are known to be immunocompromised or apparently immunocompetent. A recent outbreak of C gattii infections further underscores the clinical importance of the yeast through its epidemiology and pathogenicity features. With an enlarging immunosuppressed population caused by HIV infection, solid organ transplantation, and clinical use of potent immunosuppressives, such as cancer chemotherapy, monoclonal antibodies, and corticosteroids, this fungus has become a well-established infectious complication of modern medicine. This article examines current issues in cryptococcal infections, including new classification, epidemiology, pathogenesis, and specific clinical aspects.
Collapse
Affiliation(s)
- Methee Chayakulkeeree
- Department of Medicine, Division of Infectious Diseases and International Health, Duke University Medical Center, P.O. Box 3353, Durham, NC 27710, USA
| | | |
Collapse
|
35
|
Discontinuation of highly active antiretroviral therapy leads to cryptococcal meningitis/choroiditis in an AIDS patient. ACTA ACUST UNITED AC 2006; 77:438-45. [DOI: 10.1016/j.optm.2006.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2006] [Indexed: 11/22/2022]
|
36
|
Wozniak KL, Vyas JM, Levitz SM. In vivo role of dendritic cells in a murine model of pulmonary cryptococcosis. Infect Immun 2006; 74:3817-24. [PMID: 16790753 PMCID: PMC1489690 DOI: 10.1128/iai.00317-06] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dendritic cells (DC) have been shown to phagocytose and kill Cryptococcus neoformans in vitro and are believed to be important for inducing protective immunity against this organism. Exposure to C. neoformans occurs mainly by inhalation, and in this study we examined the in vivo interactions of C. neoformans with DC in the lung. Fluorescently labeled live C. neoformans and heat-killed C. neoformans were administered intranasally to C57BL/6 mice. At specific times postinoculation, mice were sacrificed, and lungs were removed. Single-cell suspensions of lung cells were prepared, stained, and analyzed by microscopy and flow cytometry. Within 2 h postinoculation, fluorescently labeled C. neoformans had been internalized by DC, macrophages, and neutrophils in the mouse lung. Additionally, lung DC from mice infected for 7 days showed increased expression of the maturation markers CD80, CD86, and major histocompatibility complex class II. Finally, ex vivo incubation of lung DC from infected mice with Cryptococcus-specific T cells resulted in increased interleukin-2 production compared to the production by DC from naïve mice, suggesting that there was antigen-specific T-cell activation. This study demonstrated that DC in the lung are capable of phagocytosing Cryptococcus in vivo and presenting antigen to C. neoformans-specific T cells ex vivo, suggesting that these cells have roles in innate and adaptive pulmonary defenses against cryptococcosis.
Collapse
Affiliation(s)
- Karen L Wozniak
- Section of Infectious Diseases, Boston University Medical Center, 650 Albany St., Boston, MA 02118, USA
| | | | | |
Collapse
|
37
|
Abstract
In the Damage-response framework of microbial pathogenesis, infectious diseases are one outcome of a host-microorganism interaction in a susceptible host. In cryptococcal disease, damage to the host is caused by Cryptococcus neoformans virulence determinants, the nature of the host response, or both. Further, the disease may be acute or reactivated from a latent state. Hence, a vaccine for C. neoformans would need to prevent disease resulting from either acute or reactivated infection. The evidence to support the development of a vaccine for C. neoformans that induces antibody-mediated immunity is discussed herein.
Collapse
Affiliation(s)
- Kausik Datta
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | |
Collapse
|
38
|
Abstract
Cryptococcosis is a relatively common fungal disease caused by Cryptococcus neoformans that has high morbidity and mortality. Numerous studies have established the feasibility of enhancing host immunity to C neoformans in naive immunocompetent animal models by vaccination. Several antigens have been identified that appear to be suitable vaccine candidates. Induced immune responses can mediate protection through both humoral and cellular immunity. Hence, a vaccine against cryptococcosis in humans is probably feasible but there are significant obstacles to vaccine development that range from uncertainties about the pathogenesis of infection to economic considerations.
Collapse
Affiliation(s)
- Arturo Casadevall
- Division of Infectious Diseases of the Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
| | | |
Collapse
|
39
|
Biondo C, Messina L, Bombaci M, Mancuso G, Midiri A, Beninati C, Cusumano V, Gerace E, Papasergi S, Teti G. Characterization of two novel cryptococcal mannoproteins recognized by immune sera. Infect Immun 2005; 73:7348-55. [PMID: 16239533 PMCID: PMC1273869 DOI: 10.1128/iai.73.11.7348-7355.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Host defenses against the encapsulated yeast Cryptococcus neoformans involve both humoral and cell-mediated immunity. Mannoproteins (MPs) are a heterogeneous class of immunodominant glycoproteins which have been only incompletely characterized. In this study, we report on the molecular features of two novel MPs that are recognized by serum antibodies during cryptococcosis. After fractionation of extracellular cryptococcal products, MPs reacted more strongly than other components with sera from C. neoformans-infected AIDS patients. Further fractionation and Western blot analysis of MPs evidenced the presence of highly reactive bands with molecular masses of 250, 125, 115, and 84 kDa. The 115- and 84-kDa bands contained significant amounts of N-linked oligosaccharides, as shown by decreased molecular mass after peptide-N-glycosidase F treatment. N-terminal amino acid sequences of the two bands were used to search C. neoformans nucleotide databases. Homologous genomic sequences were used to synthesize DNA probes and isolate cDNA clones containing the full-length genes, which were designated MP84 and MP115. Both genes showed the presence of a serine/threonine-rich region, a potential site for heavy glycosylation. MP84 and MP115 showed homology with, respectively, polysaccharide deacetylases and carboxylesterases from other organisms. Recombinant, deglycosylated proteins expressed in Escherichia coli still reacted with sera from patients, albeit more weakly than natural MPs, indicating that at least some of the reactive epitopes were retained in the recombinant forms. In conclusion, we identified two novel MPs that are important targets of antibody responses during cryptococcosis. These data may be useful to devise alternative immunity-based strategies to control the disease.
Collapse
Affiliation(s)
- Carmelo Biondo
- Department of Pathology and Experimental Microbiology, University of Messina, Messina, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Subramaniam K, French N, Pirofski LA. Cryptococcus neoformans-reactive and total immunoglobulin profiles of human immunodeficiency virus-infected and uninfected Ugandans. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 12:1168-76. [PMID: 16210479 PMCID: PMC1247824 DOI: 10.1128/cdli.12.10.1168-1176.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 06/21/2005] [Accepted: 07/26/2005] [Indexed: 11/20/2022]
Abstract
We determined total and Cryptococcus neoformans glucuronoxylomannan (GXM)-reactive antibody repertoires of human immunodeficiency virus (HIV)-infected and HIV-uninfected Ugandans in a retrospective, case-control study of participants in a randomized controlled trial of pneumococcal vaccination. The study included 192 adults: 48 who subsequently developed cryptococcal meningitis (CM); (HIV+ CM+); 2 individuals who matched them in CD4+ T-cell level, stage of HIV disease, and age but did not develop CM (HIV+ CM-); and 48 HIV-uninfected individuals. Total serum immunoglobulin concentrations and titers of immunoglobulin M (IgM), IgG, and IgA to GXM, pneumococcal polysaccharides, and antibodies expressing certain V(H)3 idiotypes were determined with banked sera obtained before the development of cryptococcosis for HIV+ CM+ subjects. The results showed that HIV-infected subjects had significantly lower levels of IgM to GXM but higher levels of total immunoglobulin and IgG and IgA to GXM than those of HIV-uninfected subjects. HIV-infected subjects with a history of pneumonia had higher levels, and those with a history of herpes zoster had lower levels of GXM-binding antibodies than subjects with no history of either disease. Minimal to no cross-reactivity was demonstrated between antibodies to GXM and polysaccharides in a pneumococcal vaccine. No significant differences between the antibody repertoires of HIV+ CM+ and HIV+ CM- subjects were identified, but among subjects without a history of pneumonia, there was a trend towards lower V(H)3-positive antibody levels among HIV+ CM+ than among HIV+ CM- subjects. Our findings demonstrate an association between previous infectious diseases and differences in the total and GXM-reactive antibody repertoires of HIV-infected subjects and suggest the question of whether certain microbes modulate subsequent antibody responses to GXM deserves further study.
Collapse
Affiliation(s)
- Krishanthi Subramaniam
- Department of Microbiology and Immunology, Division of Infectious Diseases, Albert Einstein College of Medicine, Room 709 Forchheimer, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | | | | |
Collapse
|
41
|
Maitta RW, Datta K, Chang Q, Luo RX, Witover B, Subramaniam K, Pirofski LA. Protective and nonprotective human immunoglobulin M monoclonal antibodies to Cryptococcus neoformans glucuronoxylomannan manifest different specificities and gene use profiles. Infect Immun 2004; 72:4810-8. [PMID: 15271943 PMCID: PMC470673 DOI: 10.1128/iai.72.8.4810-4818.2004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The features of protective murine antibodies to the Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan (GXM) have been rigorously investigated; however, the characteristics of protective human antibodies to GXM have not been defined. We produced monoclonal antibodies (MAbs) from XenoMouse mice (transgenic mice that express human immunoglobulin M [IgM], IgG2, and kappa) which were immunized with a C. neoformans serotype D strain 24067 GXM-diphtheria toxoid conjugate. This study reports the specificity and efficacy of three human IgM MAbs, G14, G15, and G19, generated from these mice. Each MAb was specific for GXM, but G14 and G19 had different specificity based on their binding to serotype A strain H99 and SB4 GXMs, to which G15 did not bind. Nucleic acid sequence analysis revealed that G15 uses V(H)3-64 in the germ line configuration. G14 and G19 use V(H)6-1, which has somatic mutations. All of the MAbs use V kappa DPK22/A27. Studies of MAb efficacy in BALB/c mice showed that administration of 0.1 mg, but not 1 or 0.01 mg, of G15 prolonged survival against lethal C. neoformans strain 24067 challenge, whereas G14 and G19 were not protective at any dose. This panel of MAbs illustrates that serotype D GXM has epitopes that elicit human antibodies that can be either protective or nonprotective. Our findings suggest that V(H) gene use may influence GXM specificity and efficacy, and they provide insights into the possible contribution that V(H) gene use may have in resistance and susceptibility to cryptococcosis.
Collapse
Affiliation(s)
- Robert W Maitta
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA
| | | | | | | | | | | | | |
Collapse
|
42
|
Steenbergen JN, Nosanchuk JD, Malliaris SD, Casadevall A. Cryptococcus neoformans virulence is enhanced after growth in the genetically malleable host Dictyostelium discoideum. Infect Immun 2003; 71:4862-72. [PMID: 12933827 PMCID: PMC187309 DOI: 10.1128/iai.71.9.4862-4872.2003] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans is an encapsulated, environmental fungus that can cause life-threatening meningitis. Pathogenicity of C. neoformans for macrophages and vertebrate hosts may be a mechanism selected in evolution for protection against environmental predators. In this study, we investigated whether Dictyostelium discoideum could serve as an alternate host for C. neoformans. D. discoideum has a defined genetic system which provides significant advantages for the study of fungus-amoeba interactions. Our results show that D. discoideum is susceptible to infection with C. neoformans and that the interactions are similar to those described previously for this fungus with macrophages and Acanthamoeba castellanii. Acapsular C. neoformans cells did not replicate when coincubated with D. discoideum. However, incubation of acapsular C. neoformans with D. discoideum mutants defective in myosin VII synthesis resulted in infection, validating the concept that avirulent organisms can be virulent in impaired hosts even at the unicellular level. Phagocytosis of C. neoformans by D. discoideum could be inhibited with capsule-specific antibodies and various sugars. Passage of an encapsulated C. neoformans strain through D. discoideum cultures increased virulence and was accompanied by larger capsules and faster time to melanization. These results add to the evidence implicating soil ameboid predators as important factors for the maintenance of C. neoformans virulence in the environment and suggest that D. discoideum promises to be an extremely useful system for studying the interaction of C. neoformans with phagocytic cells.
Collapse
Affiliation(s)
- Judith N Steenbergen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461,USA
| | | | | | | |
Collapse
|
43
|
Pitzurra L, Perito S, Baldelli F, Bistoni F, Vecchiarelli A. Humoral response against Cryptococcus neoformans mannoprotein antigens in HIV-infected patients. Clin Exp Immunol 2003; 133:91-6. [PMID: 12823282 PMCID: PMC1808755 DOI: 10.1046/j.1365-2249.2003.02181.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Twenty-four sera from healthy donors, 18 from HIV-positive patients (< 200 CD4+/mm3) and 18 sera collected before and during cryptococcosis from HIV-positive patients were analysed for the presence of humoral response to C. neoformans mannoproteins. Our results show that samples from healthy subjects and from HIV-positive patients had one of three antibody response profiles: (i) presence of reactive antibodies against both 105 and 80 kilodalton mannoproteins; (ii) presence of reactive antibodies against one of the two mannoproteins; or (iii) absence of reactive antibodies. Importantly the percentage of unreactive sera increased 6-fold in HIV-positive patients and more than 10-fold in patients with cryptococcosis. In addition, in the latter patients no variation of humoral response before and during cryptococcosis was observed. These results suggest that HIV-positive patients show a marked difficulty in mounting or maintaining antibody response to mannoprotein and this could contribute to predisposition to cryptococcosis.
Collapse
Affiliation(s)
- L Pitzurra
- Microbiology Section, Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy
| | | | | | | | | |
Collapse
|
44
|
Steenbergen JN, Casadevall A. The origin and maintenance of virulence for the human pathogenic fungus Cryptococcus neoformans. Microbes Infect 2003; 5:667-75. [PMID: 12787743 DOI: 10.1016/s1286-4579(03)00092-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The origin of virulence in environmental fungi that have no requirement for animal hosts in their life cycle is enigmatic. Cryptococcus neoformans is a human pathogenic fungus with virulence factors for mammalian pathogenesis that also contribute to environmental survival. C. neoformans virulence may originate from selection pressures imposed by environmental predators.
Collapse
Affiliation(s)
- Judith N Steenbergen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | |
Collapse
|
45
|
Abstract
Cryptococcus neoformans has risen to a worldwide highly recognizable major opportunistic pathogen with deadly consequences. It has become a model fungus to study a variety of paradigms in the host-fungus relationships. Genomic studies are advancing knowledge on its evolution and dissecting its virulence composite. Studies designed to understand host immunology to this fungus are leading to development of active and passive prevention and therapeutic strategies. This article collates and analyzes both new and old knowledge about the pathogen to help frame the meaning of human cryptococcosis as it starts to evolve in the new millennium.
Collapse
Affiliation(s)
- John R Perfect
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, PO Box 3353, Durham, NC 27710, USA.
| | | |
Collapse
|
46
|
Vecchiarelli A, Pietrella D, Bistoni F, Kozel TR, Casadevall A. Antibody to Cryptococcus neoformans capsular glucuronoxylomannan promotes expression of interleukin-12Rbeta2 subunit on human T cells in vitro through effects mediated by antigen-presenting cells. Immunology 2002; 106:267-72. [PMID: 12047756 PMCID: PMC1782713 DOI: 10.1046/j.1365-2567.2002.01419.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The results reported herein show that T cells responding to encapsulated Cryptococcus neoformans cells had reduced expression of interleukin-12 receptor beta2 (IL-12Rbeta2) in comparison to those responding to non-encapsulated cells. This suggested that encapsulation with glucuronoxylomannan (GXM), the principal constituent of the C. neoformans polysaccharide antiphagocytic capsule, inhibited expression of the IL-12Rbeta2 subunit on T cells responding to cryptococcal antigens. Addition of GXM-binding monoclonal antibody (mAb) overcame this effect by promoting IL-12Rbeta2 expression and by decreasing IL-1R expression on T cells. This effect may be a consequence of mAb-induced changes on antigen-presenting cells (APC) that are closely related to increased phagocytosis. Blocking of phagocytosis with monoiodacetic acid (MIA) precluded up-regulation of B7 expression on APC and was associated with diminished IL-12Rbeta2 expression on T cells. The observed effects on T cells were interpreted as a consequence of increased APC function due to enhanced phagocytosis. These findings suggest a mechanism by which specific antibody can promote the polarization of the cellular immune response towards a Th1-like response and thus contribute to an enhanced cellular immune response against C. neoformans.
Collapse
Affiliation(s)
- Anna Vecchiarelli
- Microbiology Section, Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy.
| | | | | | | | | |
Collapse
|
47
|
Biondo C, Beninati C, Delfino D, Oggioni M, Mancuso G, Midiri A, Bombaci M, Tomaselli G, Teti G. Identification and cloning of a cryptococcal deacetylase that produces protective immune responses. Infect Immun 2002; 70:2383-91. [PMID: 11953374 PMCID: PMC127888 DOI: 10.1128/iai.70.5.2383-2391.2002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Revised: 01/30/2002] [Accepted: 02/13/2002] [Indexed: 11/20/2022] Open
Abstract
Cell-mediated immunity plays a crucial role in host defenses against Cryptococcus (Filobasidiella) neoformans. Therefore, the identification of cryptococcal antigens capable of producing T-cell-mediated responses, such as delayed-type hypersensitivity (DTH) reactions, may be useful in the development of immune-based strategies to control cryptococcosis. In order to characterize DTH-producing antigens, culture supernatants from the unencapsulated Cap-67 strain were separated by anion-exchange chromatography. After further fractionation by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a purified protein with an apparent molecular mass of 25 kDa was found to produce DTH, as evidenced by increased footpad swelling in mice immunized with culture supernatants, relative to unimmunized mice. The 20-amino-acid N-terminal sequence of the 25-kDa protein was used to search data of the C. neoformans Genome Project. Based on the genomic DNA sequence, a DNA probe was used to screen a lambda cDNA library prepared from strain B3501. Clones were isolated containing the full-length gene (d25), which showed homology with a number of polysaccharide deacetylases from fungi and bacteria. The recombinant d25 protein expressed in Escherichia coli was similar to the natural one in DTH-producing activity. Moreover, immunization with either the natural or the recombinant protein prolonged survival and decreased fungal burden in mice challenged with the highly virulent C. neoformans strain H99. In conclusion, we have described the first cryptococcal gene whose product, a 25-kDa extracellular polysaccharide deacetylase, has been shown to induce protective immunity responses.
Collapse
Affiliation(s)
- Carmelo Biondo
- Dipartimento di Patologia e Microbiologia Sperimentale, Università di Messina, I-98125 Messina, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Husain S, Wagener MM, Singh N. Cryptococcus neoformansInfection in Organ Transplant Recipients: Variables Influencing Clinical Characteristics and Outcome. Emerg Infect Dis 2001. [DOI: 10.3201/eid0703.017302] [Citation(s) in RCA: 281] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
49
|
Goldman DL, Khine H, Abadi J, Lindenberg DJ, Niang R, Casadevall A. Serologic evidence for Cryptococcus neoformans infection in early childhood. Pediatrics 2001; 107:E66. [PMID: 11331716 DOI: 10.1542/peds.107.5.e66] [Citation(s) in RCA: 280] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Cryptococcus neoformans is an important cause of central nervous system infection in adults with acquired immunodeficiency syndrome (AIDS) but an unusual cause of disease in children with AIDS. The basis for this age-related difference in incidence is not known but may be caused by differences in exposure or immune response. The objective of this study was to determine whether the low prevalence of cryptococcal disease among children is related to a lack of exposure to C neoformans. METHODS Sera were obtained from 185 immunocompetent individuals ranging in age from 1 week to 21 years who were being evaluated in an urban emergency department. Sera were analyzed for antibodies to C neoformans and Candida albicans proteins by immunoblotting. Immunoblot patterns were compared with those obtained from sera of patients with cryptococcosis (n = 10) and workers in a laboratory devoted to the study of C neoformans. The specificity of our results was confirmed by several approaches, including antibody absorption and blocking studies. Sera were also analyzed for the presence of cryptococcal polysaccharide by both enzyme-linked immunosorbent assay and latex agglutination assays. RESULTS Sera from children 1.1 to 2 years old demonstrated minimal reactivity to C neoformans proteins. In contrast, the majority of sera from children >2 years old recognized many (>/=6) C neoformans proteins. For children between 2.1 and 5 years old, 56% of sera (n = 25) reacted with many proteins, whereas for children >5 years old (n = 120), 70% of samples reacted with many proteins. Reactivity was decreased by absorbing sera with C neoformans extracts or by preincubating blots with sera from experimentally infected but not from control rats. Reactivity to C neoformans proteins did not correlate with reactivity to C albicans proteins, which was common in sera from children between the ages of 1.1 and 2 years. Cryptococcal polysaccharide was detected at a titer of 1:16 (~10 ng/mL) in the sera of 1 child, a 5.6-year-old boy who presented to the emergency department with vomiting. CONCLUSIONS Our findings provide both indirect and direct evidence of C neoformans infection in immunocompetent children. Our results indicate that C neoformans infects a majority of children living in the Bronx after 2 years old. These results are consistent with several observations: the ubiquitous nature of C neoformans in the environment, including its association with pigeon excreta; the large number of pigeons in urban areas; and the increased likelihood of environmental exposure for children once they have learned to walk. The signs and symptoms associated with C neoformans infection in immunocompetent children remained to be determined. Primary pulmonary cryptococcosis may be asymptomatic or produce symptoms confused with viral infections and, therefore, not recognized as a fungal infection. Our results suggest that the low incidence of symptomatic cryptococcal disease in children with AIDS is not a result of lack of exposure to C neoformans. These findings have important implications for C neoformans pathogenesis and the development of vaccine strategies.
Collapse
Affiliation(s)
- D L Goldman
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
| | | | | | | | | | | |
Collapse
|
50
|
Husain S, Wagener MM, Singh N. Cryptococcus neoformans infection in organ transplant recipients: variables influencing clinical characteristics and outcome. Emerg Infect Dis 2001; 7:375-81. [PMID: 11384512 PMCID: PMC2631789 DOI: 10.3201/eid0703.010302] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Unique clinical characteristics and other variables influencing the outcome of Cryptococcus neoformans infection in organ transplant recipients have not been well defined. From a review of published reports, we found that C. neoformans infection was documented in 2.8% of organ transplant recipients (overall death rate 42%). The type of primary immunosuppressive agent used in transplantation influenced the predominant clinical manifestation of cryptococcosis. Patients receiving tacrolimus were significantly less likely to have central nervous system involvement (78% versus 11%, p =0.001) and more likely to have skin, soft-tissue, and osteoarticular involvement (66% versus 21%, p = 0.006) than patients receiving nontacrolimus- based immunosuppression. Renal failure at admission was the only independently significant predictor of death in these patients (odds ratio 16.4, 95% CI 1.9-143, p = 0.004). Hypotheses based on these data may elucidate the pathogenesis and may ultimately guide the management of C. neoformans infection in organ transplant recipients.
Collapse
Affiliation(s)
- S Husain
- Veterans Affairs Medical Center and University of Pittsburgh, Thomas E. Starzl Transplantation Institute, Pittsburgh, Pennsylvania 15240, USA
| | | | | |
Collapse
|