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Inflammatory and Anti-inflammatory Responses Co-exist Inside Lung Granuloma of Fatal Cases of Coccidioidomycosis: A Pilot Report. Mycopathologia 2018; 183:709-716. [PMID: 29736739 DOI: 10.1007/s11046-018-0264-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 04/20/2018] [Indexed: 10/17/2022]
Abstract
Coccidioidomycosis is a fungal disease caused by Coccidioides immitis or Coccidioides posadasii. These fungi are endemic in the southern USA and northern Mexico. Immunocompromised patients are susceptible to develop severe forms of this fungal infection. Cytokines play an important role in controlling the fungal infection, but little is known about the predominant immunological environment in human lung tissue from fatal cases. Our aim was to analyze the pro-inflammatory and anti-inflammatory cytokines and monocyte/macrophages markers (CD14 and CD206) in the granulomas of six fatal cases of coccidioidomycosis. Cytokines and surface markers were higher in coccidioidomycosis cases when compared to control (P < 0.05). CD14 positive cells were increased inside the coccidioidal granuloma when compared to the outside (P < 0.05). No differences were found in the number of CD206+ cells inside the granuloma when compared to the outer population (P > 0.05). Interestingly, an analysis of stain intensity signals showed an increased signaling of CD14, CD206, IL-10 and TNFα inside the granuloma when compared to the outside (P < 0.05). iNOS and IL-12 gene expression were not detected in coccidioidomycosis cases, while IL-10, IL-6 and TGFβ gene expression were detected, but the differences when compared to healthy lungs were not significant (P > 0.05). TNFα gene expression was lower in coccidioidomycosis cases when compared to healthy lung (P = 0.05). In conclusion, pro- and anti-inflammatory responses co-exist inside of the granulomas of fatal cases of coccidioidomycosis and the absent of iNOS and IL-12 gene expression may be related with patient's outcome.
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Woelk CH, Zhang JX, Walls L, Viriyakosol S, Singhania A, Kirkland TN, Fierer J. Factors regulated by interferon gamma and hypoxia-inducible factor 1A contribute to responses that protect mice from Coccidioides immitis infection. BMC Microbiol 2012; 12:218. [PMID: 23006927 PMCID: PMC3528620 DOI: 10.1186/1471-2180-12-218] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 07/20/2012] [Indexed: 01/05/2023] Open
Abstract
Background Coccidioidomycosis results from airborne infections caused by either Coccidioides immitis or
C. posadasii. Both are pathogenic fungi that live in desert soil in the New World and can infect normal hosts, but most infections are self-limited. Disseminated infections occur in approximately 5% of cases and may prove fatal. Mouse models of the disease have identified strains that are resistant (e.g. DBA/2) or susceptible (e.g. C57BL/6) to these pathogens. However, the genetic and immunological basis for this difference has not been fully characterized. Results Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. Differentially expressed genes were mapped onto biological pathways, gene ontologies, and protein interaction networks, which revealed that innate immune responses mediated by Type II interferon (i.e., IFNG) and the signal transducer and activator of transcription 1 (STAT1) contribute to the resistant phenotype. In addition, upregulation of hypoxia inducible factor 1A (HIF1A), possibly as part of a larger inflammatory response mediated by tumor necrosis factor alpha (TNFA), may also contribute to resistance. Microarray gene expression was confirmed by real-time quantitative PCR for a subset of
12 genes, which revealed that IFNG HIF1A and TNFA, among others, were significantly differentially expressed between the two strains at day 14 post-infection. Conclusion These results confirm the finding that DBA/2 mice express more Type II interferon and interferon stimulated genes than genetically susceptible strains and suggest that differential expression of HIF1A may also play a role in protection.
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Affiliation(s)
- Christopher H Woelk
- Veterans Affairs San Diego Healthcare System, Mail Code 9111-F, San Diego, California 92161, USA
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Liu M, Clemons KV, Bigos M, Medovarska I, Brummer E, Stevens DA. Immune responses induced by heat killed Saccharomyces cerevisiae: a vaccine against fungal infection. Vaccine 2011; 29:1745-53. [PMID: 21219976 DOI: 10.1016/j.vaccine.2010.12.119] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 12/04/2010] [Accepted: 12/23/2010] [Indexed: 01/30/2023]
Abstract
Heat-killed Saccharomyces cerevisiae (HKY) used as a vaccine protects mice against systemic aspergillosis and coccidioidomycosis. Little is known about the immune response induced by HKY vaccination, consequently our goal was to do an analysis of HKY-induced immune responses involved in protection. BALB/c mice were vaccinated subcutaneously 3 times with HKY, a protective reagent, and bronchoalveolar lavage fluid, spleen, lymph nodes, and serum collected 2-5 weeks later. Cultured spleen or lymph node cells were stimulated with HKY. Proliferation of HKY-stimulated spleen or lymph node cells was tested by Alamar Blue reduction and flow cytometry. Cytokines from lymphocyte supernatants and antibody to glycans in serum collected from HKY-vaccinated mice were measured by ELISA. The results show that HKY promoted spleen cell and lymph node cell proliferation from HKY-vaccinated mice but not from PBS-vaccinated control mice (all P<0.05). Cytokine measurement showed HKY significantly promoted IFNγ, IL-6 and IL-17A production by spleen cells and lymph node cells (all P<0.05 and P<0.01, respectively). Cytokine production by HKY-stimulated cells from PBS-vaccinated mice was lower than those from HKY-vaccinated (P<0.05). Cytokines in BAL from HKY-vaccinated were higher, 1.7-fold for IFNγ and 2.1-fold for TNFα, than in BAL from PBS-vaccinated. Flow cytometry of lymphocytes from HKY-vaccinated showed 52% of CD3(+) or 56% of CD8(+) cells exhibited cell division after stimulation with HKY, compared to non-stimulated controls (26 or 23%, respectively) or HKY-stimulated cells from PBS-vaccinated (31 or 34%). HKY also induced antibody against Saccharomyces glucan and mannan with titers 4- or 2-fold, respectively, above that in unvaccinated. Taken together, the results suggested that HKY vaccination induces significant and specific Th1 type cellular immune responses and antibodies to glucan and mannan.
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Affiliation(s)
- Min Liu
- California Institute for Medical Research, San Jose, CA, USA
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Mitter SS, Derhovanessian A, Hillman JD, Uslan DZ. Disseminated coccidioidomycosis in a patient managed with adalimumab for Crohn's disease. Nat Rev Gastroenterol Hepatol 2010; 7:231-5. [PMID: 20376095 DOI: 10.1038/nrgastro.2010.20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND A 50-year-old man presented with a 2-3 month history of left lower quadrant abdominal pain, right periorbital headache, blurry vision, tinnitus, polydipsia, right elbow pain, and a 32 kg weight loss over the past year. He had a 34-year history of complicated Crohn's disease that was notable for surgical stricture repair and partial colectomy for bowel perforation. The patient was receiving mesalazine and 6-mercaptopurine and, 2 months before admission, had stopped a 4-month therapy course with the biologic agent adalimumab for treatment of Crohn's disease. INVESTIGATIONS Physical examination, brain and elbow MRI scans, chest CT scan, routine blood analyses, assessment of coccidioidomycosis antibody levels, immunodiffusion and complement fixation studies in serum and cerebrospinal fluid, full-body technetium-99m nuclear bone scan, hematoxylin and eosin staining of resected tissue specimens. DIAGNOSIS Disseminated coccidioidomycosis with meningeal, bone, soft tissue and pulmonary involvement. MANAGEMENT The patient underwent treatment with amphotericin B liposomal complex and oral fluconazole and right elbow surgical debridement and irrigation. All immunosuppressive therapy was stopped.
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Affiliation(s)
- Sumeet S Mitter
- David Geffen School of Medicine, UCLA, 10833 LeConte Avenue, 37-121 CHS, Los Angeles, CA 90095, USA
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Siqueira KZ, Campos Soares ÂMVD, Dias-Melicio LA, Calvi SA, Peraçoli MTS. Interleukin-6 treatment enhances human monocyte permissiveness forParacoccidioides brasiliensisgrowth by modulating cytokine production. Med Mycol 2009; 47:259-67. [DOI: 10.1080/13693780802244204] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Pulmonary immune responses induced in BALB/c mice by Paracoccidioides brasiliensis conidia. Mycopathologia 2008; 165:313-30. [DOI: 10.1007/s11046-007-9072-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Singh N, Perfect JR. Immune reconstitution syndrome and exacerbation of infections after pregnancy. Clin Infect Dis 2007; 45:1192-9. [PMID: 17918082 DOI: 10.1086/522182] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 07/21/2007] [Indexed: 11/03/2022] Open
Abstract
Pregnancy is a state of subtle immunosuppression characterized by physiologic suppression of proinflammatory host responses that are meant to promote embryonic implantation. Rapid reversal of these changes and a rebound of inflammatory responses during the postpartum period can result in quiescent or latent infection manifesting as symptomatic disease. Infections due to several microbial pathogens and noninfectious diseases with an autoimmune basis have been shown to worsen or begin during the postpartum period. Awareness that symptoms resulting from immune reconstitution can occur in any host with a rapidly changing immunologic repertoire, including women in the postpartum phase, is a critical first step in fully understanding this phenomenon. Future studies to discern the precise pathophysiologic basis of immune reconstitution, to identify pregnant women at risk, and to determine markers that may be diagnostically helpful have significant implications for optimizing treatment of these patients.
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Affiliation(s)
- Nina Singh
- Veterans Affairs Medical Center, Infectious Diseases Section, Pittsburgh, PA 15240, USA.
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Abstract
Coccidioides is a fungal respiratory pathogen of humans that can cause disease in both immunosuppressed and immunocompetent individuals. We describe here three mechanisms by which the pathogen survives in the hostile host environment: production of a dominant spherule outer wall glycoprotein (SOWgp) that modulates host immune response and results in compromised cell-mediated immunity to coccidioidal infection, depletion of SOWgp presentation on the surface of endospores, which prevents host recognition of the pathogen when the fungal cells are most vulnerable to phagocytic defenses, and induction of elevated production of host arginase I and coccidioidal urease, which contribute to tissue damage at sites of infection. Arginase I competes with inducible nitric oxide synthase (iNOS) in macrophages for the common substrate, L-arginine, and thereby reduces nitric oxide (NO) production and increases the synthesis of host orinithine and urea. Host-derived L-ornithine may promote pathogen growth and proliferation by providing a pool of the monoamine, which could be taken up and used for synthesis of polyamines via metabolic pathways of the parasitic cells. We have shown that high concentrations of Coccidioides- and host-derived urea at infection sites in the presence of urease produced and released by the pathogen, results in secretion of ammonia and contributes to alkalinization of the microenvironment. We propose that ammonia and enzymatically active urease released from spherules during the parasitic cycle of Coccidioides exacerbate the severity of coccidioidal infection by contributing to a compromised immune response to infection and damage of host tissue at foci of infection.
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Affiliation(s)
- Chiung-Yu Hung
- Department of Biology, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249-0662, USA.
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Gonzalez A, Lenzi HL, Motta EM, Caputo L, Sahaza JH, Cock AM, Ruiz AC, Restrepo A, Cano LE. Expression of adhesion molecules in lungs of mice infected with Paracoccidioides brasiliensis conidia. Microbes Infect 2005; 7:666-73. [PMID: 15857804 DOI: 10.1016/j.micinf.2005.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 12/20/2004] [Accepted: 01/10/2005] [Indexed: 11/18/2022]
Abstract
In infected tissues, leukocyte recruitment is mediated by interactions between adhesion molecules, expressed on activated vascular endothelial cells, and ligands present on circulating cells. We evaluated the inflammatory response and the expression of cellular adhesion molecules (ICAM-1, VCAM-1, CD18, LFA-1 and Mac-1) in lungs of BALB/c mice infected with Paracoccidioides brasiliensis conidia. When compared with uninfected animals, infected mice had a significant increase in the inflammatory response during the first 4 days, peaking 2-3 days post-challenge, 40.3% vs. 0.0% and 41.8% vs. 0.7%, respectively. This inflammatory infiltrate was composed mainly of neutrophils and macrophages with a few eosinophils and lymphocytes. An increase in the intensity of immunofluorescence (IF) for ICAM-1 was also observed during days 1-4. ICAM-1 was present in bronchiolar epithelium, type II pneumocytes, and macrophages, as well as on vascular endothelium. The control animals presented ICAM-1 constitutively. In infected mice, VCAM-1 was only observed on vascular endothelium during the first 2 days, with some macrophages expressing this molecule throughout the study periods. CD18 and Mac-1 but not LFA-1 were expressed with a high intensity on neutrophils and macrophages present in the inflammatory infiltrate. In addition, we observed a significant decrease in Colony forming units (CFUs) after the first 2 days post-challenge. These findings suggest that during these early stages, up-regulation of ICAM-1, VCAM-1, CD18 and Mac-1 expression occurs, participating in the inflammatory process and as such, in the pathogenesis of paracoccidioidomycosis (PCM).
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Affiliation(s)
- Angel Gonzalez
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB); Carrera 72 A No 78 B 141, A.A. 73 78, Medellín, Colombia, South America.
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Silva AJ, Benitez JA. Th1-type immune response to aCoccidioides immitisantigen delivered by an attenuated strain of the non-invasive enteropathogenVibrio cholerae. ACTA ACUST UNITED AC 2005; 43:393-8. [PMID: 15708313 DOI: 10.1016/j.femsim.2004.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 09/21/2004] [Accepted: 10/06/2004] [Indexed: 11/29/2022]
Abstract
The antigen-2 or proline rich antigen (Ag2/PRA) from Coccidioides immitis, known to protect mice against experimental Coccidioidomycosis, was expressed in the genetically attenuated cholera vaccine candidate Vibrio cholerae 638 and its thymine auxotrophic derivative 638T. Intranasal immunization of mice with strains producing Ag2/PRA induced serum vibriocidal antibody and Ag2/PRA-specific total IgG responses in outbred Swiss Webster and inbred BALB/c mice. Analysis of IgG subclasses showed a predominance of IgG2a subclass antibodies. Lymphocytes from immunized mice stimulated with pure Ag2/PRA showed a significant proliferative response with production of interferon-gamma. Positive selection for plasmid maintenance in vivo did not enhance immune response to Ag2/PRA. These results demonstrate that genetically attenuated strains of the non-invasive pathogen V. cholerae can be used to express and deliver foreign antigens to stimulate a Th1 type of immune response.
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Affiliation(s)
- Anisia J Silva
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, 720 Westview Dr., SW Atlanta, GA 30310-1495, USA
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Cox RA, Magee DM. Coccidioidomycosis: host response and vaccine development. Clin Microbiol Rev 2004; 17:804-39, table of contents. [PMID: 15489350 PMCID: PMC523560 DOI: 10.1128/cmr.17.4.804-839.2004] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coccidioidomycosis is caused by the dimorphic fungi in the genus Coccidioides. These fungi live as mycelia in the soil of desert areas of the American Southwest, and when the infectious spores, the arthroconidia, are inhaled, they convert into the parasitic spherule/endospore phase. Most infections are mild, but these organisms are frank pathogens and can cause severe lethal disease in fully immunocompetent individuals. While there is increased risk of disseminated disease in certain racial groups and immunocompromised persons, the fact that there are hosts who contain the initial infection and exhibit long-term immunity to reinfection supports the hypothesis that a vaccine against these pathogens is feasible. Multiple studies have shown that protective immunity against primary disease is associated with T-helper 1 (Th-1)-associated immune responses. The single best vaccine in animal models, formalin-killed spherules (FKS), was tested in a human trial but was not found to be significantly protective. This result has prompted studies to better define immunodominant Coccidioides antigen with the thought that a subunit vaccine would be protective. These efforts have defined multiple candidates, but the single best individual immunogen is the protein termed antigen 2/proline-rich antigen (Ag2/PRA). Studies in multiple laboratories have shown that Ag2/PRA as both protein and genetic vaccines provides significant protection against mice challenged systemically with Coccidioides. Unfortunately, compared to the FKS vaccine, it is significantly less protective as measured by both assays of reduction in fungal CFU and assays of survival. The capacity of Ag2/PRA to induce only partial protection was emphasized when animals were challenged intranasally. Thus, there is a need to define new candidates to create a multivalent vaccine to increase the effectiveness of Ag2/PRA. Efforts of genomic screening using expression library immunization or bioinformatic approaches to identify new candidates have revealed at least two new protective proteins, expression library immunization antigen 1 (ELI-Ag1) and a beta-1,3-glucanosyltransferase (GEL-1). In addition, previously discovered antigens such as Coccidioides-specific antigen (CSA) should be evaluated in assays of protection. While studies have yet to be completed with combinations of the current candidates, the hypothesis is that with increased numbers of candidates in a multivalent vaccine, there will be increased protection. As the genome sequences of the two Coccidioides strains which are under way are completed and annotated, the effort to find new candidates can increase to provide a complete genomic scan for immunodominant proteins. Thus, much progress has been made in the discovery of subunit vaccine candidates against Coccidioides and there are several candidates showing modest levels of protection, but for complete protection against pulmonary challenge we need to continue the search for additional candidates.
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Affiliation(s)
- Rebecca A Cox
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, Texas Research Park, 15355 Lambda Dr., San Antonio, TX 78245-3027, USA.
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Bergstrom L, Yocum DE, Ampel NM, Villanueva I, Lisse J, Gluck O, Tesser J, Posever J, Miller M, Araujo J, Kageyama DM, Berry M, Karl L, Yung CM. Increased risk of coccidioidomycosis in patients treated with tumor necrosis factor ? antagonists. ACTA ACUST UNITED AC 2004; 50:1959-66. [PMID: 15188373 DOI: 10.1002/art.20454] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To describe a group of patients who were treated with tumor necrosis factor alpha (TNF alpha) antagonists and who developed coccidioidomycosis, and to test the hypothesis that patients with inflammatory arthritis receiving TNF alpha antagonist therapy are at higher risk for developing symptomatic coccidioidomycosis. METHODS Cases of coccidioidomycosis were identified and reviewed from among patients receiving TNF alpha antagonist therapy from May 1998 through February 2003 in 5 practices within the areas endemic for coccidioidomycosis (Arizona, California, and Nevada). In addition, the relative risk of developing symptomatic coccidioidomycosis was calculated in patients with inflammatory arthritis who were receiving treatment with infliximab, in comparison with patients with inflammatory arthritis who were not receiving infliximab, from January 2000 to February 2003 in a single medical center. RESULTS Thirteen cases of documented coccidioidomycosis were associated with TNF alpha antagonist therapy. Twelve cases were associated with the use of infliximab and 1 case with etanercept. Among the cohort of patients from a single medical center, 7 of the 247 patients receiving infliximab and 4 of the 738 patients receiving other therapies developed symptomatic coccidioidomycosis (relative risk 5.23, 95% confidence interval 1.54-17.71; P < 0.01). CONCLUSION Patients with inflammatory arthritis who are undergoing treatment with infliximab appear to be at higher risk for developing symptomatic coccidioidomycosis as compared with those not receiving infliximab.
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Gonzalez A, Sahaza JH, Ortiz BL, Restrepo A, Cano LE. Production of pro-inflammatory cytokines during the early stages of experimentalParacoccidioides brasiliensisinfection. Med Mycol 2003; 41:391-9. [PMID: 14653515 DOI: 10.1080/13693780310001610038] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Pro-inflammatory cytokines play an important role in both recruitment and activation of leukocytes migrating into tissues in response to invading pathogens. In this study the production of pro-inflammatory cytokines, determined by ELISA assays, and the recruitment of leukocytes into the lungs of BALB/c mice infected with Paracoccidioides brasiliensis conidia were evaluated during the early stages of infection. The results showed that infected mice had a significant increase in leukocytes in the lung during the first 4 days with a peak at day 2 post-challenge; infiltrates were composed mainly of polymorphonuclear neutrophils (PMN). Pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF-alpha), interleukin (IL) 6, IL-1beta and macrophage inflammatory protein (MIP) 2 were produced at elevated levels during the first 4 days post-challenge, but only in pulmonary samples and not in sera. Additionally, during the early stages of infection, overall weight loss was recorded in infected mice. These results suggest that pro-inflammatory cytokines could be responsible for the recruitment of leukocytes into the lung during the early stages of P. brasiliensis infection. In addition, both pro-inflammatory cytokine production and leukocyte recruitment may participate in the control of infection by influencing the organization of the immune response in the host exposed to P. brasiliensis conidia.
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Affiliation(s)
- Angel Gonzalez
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas, Medellín, Colombia.
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Sorensen KN, Clemons KV, Stevens DA. Murine models of blastomycosis, coccidioidomycosis, and histoplasmosis. Mycopathologia 2000; 146:53-65. [PMID: 10822504 DOI: 10.1023/a:1007081707287] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Animal models have contributed much to the knowledge of fungal infections and their corresponding therapeutic treatments. This is true for animal models of the primary fungal pathogens, Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma capsulatum. This review gives a brief background of human diseases associated with these organisms and describes the development, details, and utility of murine models of blastomycosis, as well as coccidioidomycosis and histoplasmosis.
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Affiliation(s)
- K N Sorensen
- Department of Medicine, Santa Clara Valley Medical Center, San Jose, California 95128, USA
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Abstract
We have previously reported on the alternate regulation of gamma interferon (IFN-gamma) and interleukin-4 (IL-4) in inbred mouse strains which differ in their susceptibility to Coccidioides immitis. The genetically resistant DBA/2 mice manifest a predominant T-helper 1 (Th1) response, with early production of IFN-gamma, whereas susceptible BALB/c mice show an early production of the Th2 cytokine IL-4. Since IL-12 is one cytokine that can act early during host defenses to promote the differentiation of cytokine production towards IFN-gamma and thus may promote expression of a protective immune response, we investigated the role of IL-12 in resistance to C. immitis. Administration of recombinant IL-12 to the susceptible mouse strain before and after systemic (intraperitoneal) challenge with C. immitis significantly ameliorated the course of the disease, as measured by a reduction in the fungal load in the lungs, liver, and spleen. Analysis of the cytokine mRNA in lungs from infected BALB/c mice revealed that the protective effect of recombinant IL-12 was accompanied by a shift from a Th2 to a Th1 response. The importance of IL-12 in resistance to this fungus was further established by showing that neutralization of endogenous IL-12 in the resistant DBA/2 mouse strain led to a significant increase in the fungal burden in pulmonary and extrapulmonary tissues. These results establish that IL-12 plays a pivotal role in the host defense against systemic challenge with C. immitis.
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Affiliation(s)
- D M Magee
- Department of Clinical Investigation, Texas Center for Infectious Diseases, San Antonio 78223, USA.
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