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IL-2 and 'T POT. REG' cells in polyclonal lymphocyte activation (PLA) induced by Plasmodium chabaudi infection

C Zago K R B Bastos; L R Sardinha; F D Pretel; S I Castillo; Ises de Almeida Abrahamsohn; José Maria Alvarez; Maria Regina D'Império Lima; Meeting of the Brazilian Society for Immunology (31. 2006 Búzios)

Abstracts São Paulo, SP: Brazilian Society for Immunology, 2006

São Paulo 2006

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  • Título:
    IL-2 and 'T POT. REG' cells in polyclonal lymphocyte activation (PLA) induced by Plasmodium chabaudi infection
  • Autor: C Zago
  • K R B Bastos; L R Sardinha; F D Pretel; S I Castillo; Ises de Almeida Abrahamsohn; José Maria Alvarez; Maria Regina D'Império Lima; Meeting of the Brazilian Society for Immunology (31. 2006 Búzios)
  • Assuntos: IMUNOLOGIA
  • É parte de: Abstracts São Paulo, SP: Brazilian Society for Immunology, 2006
  • Notas: Disponível em CD-ROM
  • Descrição: Introduction and Objectives: IL-2 was described as an important T cell growth factor, which also shows apoptotic activity. Recently, IL-2 has been implicated in CD4+CD25+ (Treg) cell generation and maintenance, being responsible for self-tolerance and autoimmune disease control. PLA and autoantibody production are common features of the m alaria immune response. As PLA includes CD4+ T cells that secrete cytokines and help antibody production, we have analyzed IL-2 secretion and IL-2R expression at the first days of P. chabaudi infection, and also the effects of anti-IL-2 treatment on the different CD4+ T cell subsets. Methods and Results: IL-2 secretion by CD4+ T cells was revealed by the Cytokine Secretion Assay (PharMingen) in C57BL/6 mice infected with 106 P. chabaudi parasitized erythrocytes. It began at day 5 of infection and remained until the 7th day. Among CD4+ T cells, large cells expressing CD25 and CD122 (á and â chains of IL-2R, respectively) were the major source of IL-2. These cells also expressed very high levels of CTLA-4, mTGF-â, GITR and CD45RB. We also observed a Treg cell-like population, i.e., small lymphocytes with high levels of Foxp3, CTLA-4, mTGF-â, GITR and low levels of CD45RB and CD122. Moreover the number of Foxp3+ cells remained unchanged on day 7 of infection (around 9.0%). In order to evaluate the role of IL-2 in the polyclonal CD4+ T cell response, mice were treated with anti-IL-2 mAbs (S4B6) on days
    0, 2 and 4 after infection. At day 7 of infection, these mice showed significantly higher frequencies of large CD4+ T cells expressing CD44, CD69 and CD122 (a part also expressing CD25), when compared to untreated infected mice. However, anti-IL-2 treatment led to a reduction in the percentage of Foxp3+ cells, from 9.0% to 3.9% in non-infected mice and from 9.4% to 3.9% in 7 days-infected mice. Conclusions: Our findings suggest that IL-2 secreted by activated CD4+ T cells during acute P. chabaudi infection is not essential for CD4+ T cell proliferation, but it is required for maintaining Treg cell activity.
  • Editor: São Paulo
  • Data de criação/publicação: 2006
  • Formato: res. IR.044.
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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