Document 0377
 DOCN  M9650377
 TI    Chagasic patients lack CD28 expression on many of their circulating T
       lymphocytes.
 DT    9605
 AU    Dutra WO; Martins-Filho OA; Cancado JR; Pinto-Dias JC; Brener Z;
       Gazzinelli G; Carvalho JF; Colley DG; Centro de Pesquisas Rene Rachou,
       FIOCRUZ, Belo Horizonte,; Brazil.
 SO    Scand J Immunol. 1996 Jan;43(1):88-93. Unique Identifier : AIDSLINE
       MED/96151206
 AB    A balanced host-parasite interaction during Trypanosoma cruzi infection
       allows for the establishment of a chronic infection that can last for
       many years. T cells are a major element responsible for parasite
       specific and non-specific immunity during the complex immune response of
       the host. However, the subpopulations of T cells involved in the
       response, as well as the exact mechanisms through which those cells are
       activated or rendered unresponsive, are not well defined. It is known
       that co-stimulatory signals, some of which are mediated via CD28, are of
       critical importance in the triggering of appropriate T cell responses.
       In this study the authors performed double-labelling studies to
       determine the frequency of expression of CD28 by CD4+ and CD8+ T
       lymphocytes in the peripheral blood of patients with Chagas' disease.
       The results show that chagasic patients throughout the spectrum of
       chronic clinical forms of the infection have significantly higher mean
       frequencies of CD4+CD28- and CD8+CD28-T cells, as compared with
       non-chagasic individuals. Considering the importance of CD28 for T-cell
       activation, the observed down-regulation or loss of CD28 during
       infection may indicate a possible basis for observed immunoregulatory
       events or distinct stages of T-cell activation in this infection. Recent
       evidence from patients with HIV/AIDS indicates that CD28- cell
       populations are more likely to undergo apoptosis, and increased
       apoptosis has been observed in experimental Chagas disease.
 DE    Adult  Aged  Aged, 80 and over  Antibodies, Monoclonal  Antigens,
       CD28/*BIOSYNTHESIS  Chagas Disease/*IMMUNOLOGY  CD4-Positive
       T-Lymphocytes/*IMMUNOLOGY  CD8-Positive T-Lymphocytes/*IMMUNOLOGY  Flow
       Cytometry  Human  Lymphocyte Transformation  Middle Age  Support,
       Non-U.S. Gov't  Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).