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Differential immune regulation of activated T cells between cutaneous and mucosal leishmaniasis as a model for pathogenesis
Author(s) -
CARVALHO L. P.,
PASSOS S.,
BACELLAR O.,
LESSA M.,
ALMEIDA R. P.,
MAGALHÃES A.,
DUTRA W. O.,
GOLLOB K. J.,
MACHADO P.,
Ribeiro DE JESUS A.
Publication year - 2007
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1111/j.1365-3024.2007.00940.x
Subject(s) - immune system , immunology , biology , cd28 , antigen , peripheral blood mononuclear cell , cutaneous leishmaniasis , t cell , tumor necrosis factor alpha , antibody , inflammation , leishmaniasis , in vitro , biochemistry
SUMMARY Cutaneous (CL) and mucosal leishmaniasis (ML) are characterized by a predominant type 1 immune response (IFN‐γ and TNF‐α production) and strong inflammatory response in the lesions with few parasites. This exacerbated type 1 response is more evident in ML as compared to CL. Our main hypothesis is that a differential immune regulation of T cell activation leads to over reactive T cells in ML. In the present study, we investigated immunological factors that could explain the mechanisms behind it by comparing some immune regulatory mechanisms between ML and CL patients: frequency of cells expressing co‐stimulatory molecules, apoptotic markers, T cell activation markers; and ability of neutralizing antibodies to IL‐2, IL‐12 and IL‐15 do down‐regulate IFN‐γ production in leishmania antigen‐stimulated peripheral blood mononuclear cells (PBMC). Interestingly, in CL anti‐IL‐2 and anti‐IL‐15 significantly suppressed antigen‐specific IFN‐γ production, while in ML only anti‐IL‐2 suppressed IFN‐γ production. Finally, higher frequency of CD4+ T cells expressing CD28−, CD69+ and CD62Llowwere observed in ML as compared to CL. These data indicate that an exacerbated type 1 response in ML is differentially regulated and not appropriately down modulated, with increased frequencies of activated effectors T cells, maintaining the persistent inflammatory response and tissue damage observed in ML.