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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Effects of Plasmodium berghei on thymus: High levels of apoptosis and premature egress of CD4(+)CD8(+) thymocytes in experimentally infected mice

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Author(s):
Francelin, Carolina [1] ; Paulino, Luciana Campos [2] ; Gameiro, Jacy [3] ; Verinaud, Liana [1]
Total Authors: 4
Affiliation:
[1] State Univ Campinas UNICAMP, Dept Anat Cell Biol & Physiol, Inst Biol, BR-13083970 Sao Paulo - Brazil
[2] Fed Univ ABC UFABC, Ctr Nat & Human Sci, Sao Paulo - Brazil
[3] Fed Univ Juiz de Fora UFJF, Dept Parasitol Microbiol & Immunol, Juiz De Fora, MG - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Immunobiology; v. 216, n. 10, p. 1148-1154, OCT 2011.
Web of Science Citations: 17
Abstract

We have previously showed alterations in the thymus during experimental infection with Plasmodium berghei, the causative agent of Malaria. Such alterations comprised histological changes with loss of delimitation between cortical and medullar regions, a profound atrophy with depletion of CD4(+)CD8(+) double-positive (DP) thymocytes, and severe changes in the expression of cell migration-related molecules, belonging to the extracellular matrix and chemokine protein families. Taken together, these considerations prompted us to evaluate if the acute thymic atrophy observed during Plasmodium infection was correlated with increased apoptotic levels of thymocytes or with their premature emigration to the periphery. Our results confirmed that the marked reduction of the thymus weight in infected animals was accompanied by histological alterations, which included a very large number of cells showing nuclear condensation and karyorrhectic changes surrounded by histiocytes suggesting increased levels of apoptosis. This was confirmed by immunohistochemistry and flow cytometry techniques. In order to verify if an accelerated emigration of thymic cells to the peripheral lymphoid organs was also occurring we analyzed the spleen and mesenteric lymph nodes from control and infected mice. No significant differences were found in the spleen, but were seen after 14 days of infection between control and infected mice in the mesenteric lymph nodes. The main alteration was the presence of double negative (CD4(-)CD8(-)) and double positive (CD4(+)CD8(+)) cells. We concluded that both apoptosis of thymocytes and premature egress of immature cells take place during infection. Additional studies will be necessary to verify how such alterations might influence the systemic immune response to the parasite. (c) 2011 Elsevier GmbH. All rights reserved. (AU)