Immunopathology of Coccidioidal Granulomata and the Regulation of Interleukin-12 Signal Transduction in Human Coccidioidomycosis

Persistent Link:
http://hdl.handle.net/10150/193826
Title:
Immunopathology of Coccidioidal Granulomata and the Regulation of Interleukin-12 Signal Transduction in Human Coccidioidomycosis
Author:
Li, Lijin
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Coccidioidomycosis is a growing problem in the United States. There is still an incomplete understanding of the immunological response associated with human coccidioido-mycosis, although previous studies have indicated that cell-mediated immunity (CMI) is critical in the control of this disease. We have examined necrotizing pulmonary coccidioidal granulomata using immunohistochemical staining for lymphocyte subsets and for the cytokines interleukin-10 (IL-10) and gamma interferon (IFN-?). Discrete perigranulomatous lymphocytic clusters were identified containing roughly equal numbers of T (CD3+) and B (CD20+) lymphocytes. While the number of cells expressing IL-10 was similar in the mantle and in the perigranulomatous clusters, there were significantly more cells expressing IFN-? in the mantle compared to the clusters (P = 0.037). Confocal microscopy revealed that CD4+ T lymphocytes and B lymphocytes are associated with IL-10 production. CD4+CD25+ T lymphocytes were also identified in the perigranulomatous clusters but were not associated with IL-10 production. This is the first report noting perigranulomatous lymphocyte clusters and IL-10 in association with human coccidioidal granulomata, suggesting a down-regulation of cellular immune response.IL-12 is critical in driving a T helper type 1 (Th1) immune response. To understand the mechanism associated with hyporesponsiveness to IL-12 stimulation seen in some anergic patients with disseminated coccidioidomycosis, IL-12 receptor expression and function were determined in PBMCs from immune and nonimmune healthy donors. By using a relative quantitative RT-PCR technique, we found that IL-12R?1 is constitutively expressed in PBMCs and is equally up-regulated by coccidioidal antigen preparation T27K in both immune and nonimmune donors. On the other hand, the IL-12R?2 expression level is increased by T27K only in PBMCs from immune but not nonimmune donors. In addition, the increased IL-12R?2 expression in immune PBMCs is correlated with Stat4 activation and the induction of IFN-? production by IL-12. These data suggest that the IL-12R?2 expression and signal transduction is functional in host immunity against Coccidioides infection. Subsequent research, which involved the stimulation of lymphocytes with autologous dendritic cells (DCs) pulsed with T27K, revealed that the up-regulation of IL-12R?2 expression and signal transduction is associated with the induction of IFN-? production by DCs pulsed with T27K.
Type:
text; Electronic Dissertation
Keywords:
coccidioidomycosis; human; immunology; granuloma; interleukin-12
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Microbiology & Immunology; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Ampel, Neil M.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleImmunopathology of Coccidioidal Granulomata and the Regulation of Interleukin-12 Signal Transduction in Human Coccidioidomycosisen_US
dc.creatorLi, Lijinen_US
dc.contributor.authorLi, Lijinen_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractCoccidioidomycosis is a growing problem in the United States. There is still an incomplete understanding of the immunological response associated with human coccidioido-mycosis, although previous studies have indicated that cell-mediated immunity (CMI) is critical in the control of this disease. We have examined necrotizing pulmonary coccidioidal granulomata using immunohistochemical staining for lymphocyte subsets and for the cytokines interleukin-10 (IL-10) and gamma interferon (IFN-?). Discrete perigranulomatous lymphocytic clusters were identified containing roughly equal numbers of T (CD3+) and B (CD20+) lymphocytes. While the number of cells expressing IL-10 was similar in the mantle and in the perigranulomatous clusters, there were significantly more cells expressing IFN-? in the mantle compared to the clusters (P = 0.037). Confocal microscopy revealed that CD4+ T lymphocytes and B lymphocytes are associated with IL-10 production. CD4+CD25+ T lymphocytes were also identified in the perigranulomatous clusters but were not associated with IL-10 production. This is the first report noting perigranulomatous lymphocyte clusters and IL-10 in association with human coccidioidal granulomata, suggesting a down-regulation of cellular immune response.IL-12 is critical in driving a T helper type 1 (Th1) immune response. To understand the mechanism associated with hyporesponsiveness to IL-12 stimulation seen in some anergic patients with disseminated coccidioidomycosis, IL-12 receptor expression and function were determined in PBMCs from immune and nonimmune healthy donors. By using a relative quantitative RT-PCR technique, we found that IL-12R?1 is constitutively expressed in PBMCs and is equally up-regulated by coccidioidal antigen preparation T27K in both immune and nonimmune donors. On the other hand, the IL-12R?2 expression level is increased by T27K only in PBMCs from immune but not nonimmune donors. In addition, the increased IL-12R?2 expression in immune PBMCs is correlated with Stat4 activation and the induction of IFN-? production by IL-12. These data suggest that the IL-12R?2 expression and signal transduction is functional in host immunity against Coccidioides infection. Subsequent research, which involved the stimulation of lymphocytes with autologous dendritic cells (DCs) pulsed with T27K, revealed that the up-regulation of IL-12R?2 expression and signal transduction is associated with the induction of IFN-? production by DCs pulsed with T27K.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectcoccidioidomycosisen_US
dc.subjecthumanen_US
dc.subjectimmunologyen_US
dc.subjectgranulomaen_US
dc.subjectinterleukin-12en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMicrobiology & Immunologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairAmpel, Neil M.en_US
dc.contributor.committeememberGalgiani, John N.en_US
dc.contributor.committeememberDial, Sharon M.en_US
dc.contributor.committeememberAkporiaye, Emmanuel T.en_US
dc.contributor.committeememberLake, Douglas F.en_US
dc.identifier.proquest1181en_US
dc.identifier.oclc659747455en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.