berghei infection. Increased expression of ECM components was observed in thymi from infected mice. In contrast, down-regulated surface expression of fibronectin and laminin receptors was observed in thymocytes from these animals. Moreover, in thymi from infected mice there was increased CXCL12 and CXCR4, and a decreased expression of CCL25 and CCR9. An altered thymocyte migration towards ECM elements
and chemokines was seen when the thymi from infected mice were analysed. Evaluation of ex vivo migration patterns of CD4/CD8-defined thymocyte subpopulations revealed that double-negative (DN), and CD4+ and CD8+ single-positive (SP) cells from P. berghei-infected mice have higher migratory responses compared with controls. Interestingly, selleck chemicals increased numbers of DN and SP subpopulations were found in the spleens of infected mice. Overall, we show that the thymic atrophy observed in P. berghei-infected mice is accompanied by thymic microenvironmental changes that comprise altered expression of thymocyte
migration-related SCH727965 concentration molecules of the ECM and chemokine protein families, which in turn can alter the thymocyte migration pattern. These thymic disturbances may have consequences for the control of the immune response against this protozoan. The immune response during malaria is highly complex; this is partially the result of the intricate molecular structure of Plasmodium sp., the aetiological agent of the disease. This protozoan stimulates multifaceted immune responses, including antibodies, natural killer (NK) and NKT cells, and CD4+ and
CD8+ T cells.1,2 The immune response to the intraerythrocytic stages of the parasite has been better characterized by the use of murine experimental models. In this stage the CD4+ T helper type 1 response is essential for the development of the next events of the immune response in experimental malaria.3,4 We previously reported that the thymus gland is also a target organ in Plasmodium berghei infection: Racecadotril there is atrophy with depletion of CD4+ CD8+ double-positive (DP) thymocytes, and histological alterations with loss of delimitation between the cortical and medullar regions. Moreover, we detected the intrathymic presence of parasites.5 The thymus is a primary lymphoid organ, responsible for the differentiation of T lymphocytes, including the shaping of an appropriate T-cell repertoire. This process is controlled by the cells and molecules of the thymic microenvironment, a tri-dimensional network essentially formed by epithelial cells, together with small numbers of dendritic cells, macrophages and fibroblasts.