Parasite interactions with dendritic cells and macrophages: Implications for cutaneous Leishmaniasis caused by Leishmania amazonensis

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dc.contributor.advisor Lynn Soong en_US
dc.contributor.committeeMember Vivian L . Braciale en_US
dc.contributor.committeeMember Rolf Konig en_US
dc.contributor.committeeMember Joseph M . Vinetz en_US
dc.contributor.committeeMember David M . Mosser en_US
dc.contributor.committeeMember Barbara L . Doughty en_US
dc.creator Hai Qi en_US 2011 -12 -20T16 :04 :36Z 2014 -02 -19T22 :05 :05Z 2003 -04 -10 en_US 2011 -12 -20T16 :04 :36Z 2014 -02 -19T22 :05 :05Z 2003 -04 -09 en_US 2003 -03 -26 en_US
dc.identifier.other etd -04092003 -232134 en_US
dc.identifier.uri http : / /hdl .handle .net /2152 .3 /94
dc.description.abstract Protozoan Leishmania is an important human pathogen that affects millions people worldwide . Investigation of experimental Leishmania infection in mice has been instrumental to our understanding of interactions between the parasite and the host immune system . Previous studies have established the model of Th1 -Th2 paradigm : gamma interferon (IFN -g ) -secreting Th1 cells protect the host from developing progressive diseases , while interleukin (IL ) -4 -producing Th2 cells drive the disease pathogenesis . Focused on L . amazonensis infection in mice , this dissertation study is mainly intended to understand the cellular mechanism underlying the generation of parasite -specific Th2 cells and to ascertain the role for IFN -g in parasite -macrophage interactions . We showed that L . amazonensis parasites infected and activated dendritic cells (DCs ) , a population of phagocytic antigen -presenting cells specialized in activating naïve T cells . We found that DCs from susceptible or resistant mice differentially responded to amastigotes in CD40 -dependent cytokine production and that amastigote -infected DCs favor Th2 priming in susceptible but not resistant mice . IFN -g is believed to be crucial for activating macrophages to kill intracellular parasites such as L . major . However , we found that L . amazonensis amastigotes but not promastigotes could not only survive but also replicate better in IFN -g -activated macrophages . The promastigote was evidently killed in IFN -g -activated macrophages . On the other hand , macrophages activated with IFN -g and LPS were able to limit intracellular amastigote replication . When tested in vivo , endogenous IFN -g apparently exerted minimal effects on the course of amastigote infection . It is likely that IFN -g plays a bidirectional role during L . amazonensis infection : when optimally coupled with other factors , it can activate macrophages to control parasite infection ; while in the absence of such synergy , it would promote amastigote propagation by itself . Collectively , results presented in this dissertation have pointed to the unique ability of L . amazonensis amastigotes to modulate host immune system to the advantage of their own survival . en_US
dc.format.medium electronic en_US
dc.language.iso eng en_US
dc.rights Copyright © is held by the author . Presentation of this material on the TDL web site by The University of Texas Medical Branch at Galveston was made possible under a limited license grant from the author who has retained all copyrights in the works . en_US
dc.subject Th cells en_US
dc.subject T cells en_US
dc.subject protozoan parasites en_US
dc.subject macrophages en_US
dc.subject Leishmania en_US
dc.subject dendritic cells en_US
dc.subject cytokine en_US
dc.title Parasite interactions with dendritic cells and macrophages : Implications for cutaneous Leishmaniasis caused by Leishmania amazonensis en_US
dc.type.genre dissertation en_US
dc.type.material text en_US PhD en_US Doctoral en_US The University of Texas Medical Branch en_US Pathology en_US


Parasite interactions with dendritic cells and macrophages: Implications for cutaneous Leishmaniasis caused by Leishmania amazonensis. Doctoral dissertation, The University of Texas Medical Branch. Available electronically from http : / /hdl .handle .net /2152 .3 /94 .

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