Liver Accumulation of Plasmodium chabaudi-Infected Red Blood Cells and Modulation of Regulatory T Cell and Dendritic Cell Responses

Autor(es)

Medeiros, Marcia M. ^[1] ; da Silva, Henrique B. ^{[1, 2]} ; Reis, Aramys S. ^[3] ; Barboza, Renato ^[3] ; Thompson, Joanne ^[4] ; D'Imperio Lima, Maria Regina ^[2] ; Marinho, Claudio R. F. ^[3] ; Tadokoro, Carlos E. ^[1]

Afiliação do(s) autor(es)

^[1] Inst Gulbenkian Ciencias, Oeiras - Portugal

^[2] Univ Sao Paulo, Inst Ciencias Biomed, Dept Immunol, BR-05508 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Ciencias Biomed, Dept Parasitol, BR-05508 Sao Paulo - Brazil

^[4] Univ Edinburgh, Inst Immunol & Infect Res, Sch Biol Sci, Edinburgh, Midlothian - Scotland

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 8, n. 11 NOV 27 2013.
• Citações Web of Science: 11
• Assunto(s): Malária Óxido nítrico Eritrócitos Plasmodium chabaudi

Resumo

It is postulated that accumulation of malaria-infected Red Blood Cells (iRBCs) in the liver be a Parasitic escape mechanism against full destruction by the host immune system. Therefore, we evaluated the in vivo mechanism of hi accumulation and it potential immunological consequences A massive liver accumulation of P. c. chabaudi AS-iRBCs Pc-iRBCs) was observed by intravital microscopy along with an over expression of ICAM-1 on day 7 of the infection, measured by qRT-PCR. Phenotypic changes were also observed in regulatory T cells (Tregs) and dendritic cells (DCs) that ere isolated from infected livers, which indicate a functional role for Tregs in the regulation of the liver inflammatory Line response. In fact, the suppressive function of liver-Tregs was in vitro tested, which demonstrated the capacity of cells to suppress naive T cell activation to the same extent as that observed for spleen-Tregs. On the other hand, it is already known that CD4+ T cells isolated from spleens of protozoan parasite-infected mice are refractory to proliferate in vivo. In our experiments, we observed a similar lack of in vitro proliferative capacity in liver CD4+ T cells that were isolated on day 7 of infection. it 15 also known that nitric oxide and IL-10 are partially involved in acute phase immunosuppression; we found high expression levels of IL-10 and iNOS mRNA in day 7-infected livers, which indicates a possible role for these molecules in the observed immune suppression. Taken together, these results indicate that malaria parasite accumulation within the liver could be an escape mechanism to avoid sterile immunity sponsored by a tolerogenic environment (AU)

• Processo FAPESP: 09/53889-0 - Estudo dos mecanismos imunopatológicos envolvidos na malária durante a gravidez
• Beneficiário: Cláudio Romero Farias Marinho
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores