Search results for "Immunologic Memory"
showing 10 items of 88 documents
Highly protective in vivo function of cytomegalovirus IE1 epitope-specific memory CD8 T cells purified by T-cell receptor-based cell sorting.
2005
ABSTRACTReconstitution of antiviral CD8 T cells is essential for controlling cytomegalovirus (CMV) infection after bone marrow transplantation. Accordingly, polyclonal CD8 T cells derived from BALB/c mice infected with murine CMV protect immunocompromised adoptive transfer recipients against CMV disease. The protective population comprises CD8 T cells with T-cell receptors (TCRs) specific for defined and for as-yet-unknown viral epitopes, as well as a majority of nonprotective cells with unrelated specificities. Defined epitopes include IE1/m123 and m164, which are immunodominant in terms of the magnitude of the CD8 T-cell response, and a panel of subordinate epitopes (m04, m18, M45, M83, a…
A Critical Regulatory Role of Leucin Zipper Transcription Factor c-Maf in Th1-Mediated Experimental Colitis
2004
Abstract In this study, we investigated the role of c-Maf, a transcription factor known to induce IL-4 production, in inflammatory bowel diseases and experimental colitis. Although Crohn′s disease (CD) is associated with low IL-4 production by T-bet-expressing Th1 cells in the lamina propria, surprisingly a higher expression of c-Maf in these cells was found as compared with control patients. The relevance of this finding was further evaluated in an animal model of CD induced by adoptive transfer of CD4+CD62L+ T cells in RAG-deficient mice. In this Th1-mediated model, an increase of c-Maf-expressing T lymphocytes in the lamina propria over time was observed. Interestingly, adoptive transfer…
A double-negative (IgD−CD27−) B cell population is increased in the peripheral blood of elderly people
2009
The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper, we describe the IgD(-)CD27(-) double-negative B cell population which (as we have recently described) is higher in the elderly. Most of these cells were IgG(+). Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen…
B cell immunosenescence: different features of naive and memory B cells in elderly.
2011
Elderly people show a reduced protection against new infections and a decreased response to vaccines as a consequence of impairment of both cellular and humoral immunity. In this paper we have studied memory/naive B cells in the elderly, evaluating surface immunoglobulin expression, production of the pro- and anti-inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-10, and presence of somatic hypermutation, focusing on the IgG(+)IgD(-)CD27(-) double negative (DN) B cells that are expanded in the elderly. Our results show that naive B cells from young donors need a sufficiently strong stimulus to be activated "in vitro", while naive B cells from old subjects are able t…
CXCR5 identifies a subset of Vγ9Vδ2 T cells which secrete IL-4 and IL-10 and help B cells for antibody production
2006
Abstract Vγ9Vδ2 T lymphocytes recognize nonpeptidic Ags and mount effector functions in cellular immune responses against microorganisms and tumors, but little is known about their role in Ab-mediated immune responses. We show here that expression of CXCR5 identifies a unique subset of Vγ9Vδ2 T cells which express the costimulatory molecules ICOS and CD40L, secrete IL-2, IL-4, and IL-10 and help B cells for Ab production. These properties portray CXCR5+Vγ9Vδ2 T cells as a distinct memory T cell subset with B cell helper function.
Reversible effect of magnetic fields on human lymphocyte activation patterns: different sensitivity of naive and memory lymphocyte subsets.
2009
The aim of this study was to investigate the influence of 50 Hz magnetic or static magnetic fields of 0.5 mT on subsets of human CD4(+) T cells in terms of cytokine release/content, cell proliferation and intracellular free calcium concentration. CD4(+) T cells can be divided into different subsets on the basis of surface marker expression, such as CD45, and T cells can be divided into naive (CD45RA(+)) and memory (CD45RA(-)) cells. In this study, the effects of magnetic fields after 24 and 48 h of cell culture were analyzed. We found that the CD4(+)CD45RA(-) T subset were more sensitive after 2 h of exposure. Decreases in the release/content of IFN-gamma, in cell proliferation and in intra…
Increase of CCR7- CD45RA+ CD8 T cells (TEMRA) in Chronic Graft-versus-host Disease
2006
Among the late effects of hematopoietic stem cell transplantation (HSCT), chronic graft-vs-host disease (cGVHD) still remains as the major determinant of long-term outcome and quality of life. The disease typically appears between 3 months to 1.5 years following an allogeneic transplantation and is characterized by symptoms similar to those of autoimmune disease.
Upregulation of the netrin receptor (DCC) gene during activation of b lymphocytes and modulation by interleukins.
2001
The DCC (deleted in colon cancer) gene has a brain restricted high expression pattern. It encodes a transmembrane protein of the immunoglobulin superfamily identified as the netrin-1 receptor. It might be a member of the so called "brain-lymphoid" molecules, which control key cell surface events. To test this hypothesis we have assessed the DCC mRNA level in human normal and malignant myeloid and lymphoid cells. A high mRNA content has been observed only in mature B cells at the secreting or presecreting stage. Expression of DCC was also assessed in the anti-CD40 model of immunopoiesis. Activation of purified tonsillar B cells by anti-CD 40 antibody strongly increased the DCC mRNA level and…
Partial and Ineffective Activation of Vγ9Vδ2 T Cells by Mycobacterium tuberculosis-Infected Dendritic Cells
2010
Abstract γδ T cells and dendritic cells (DCs) participate in early phases of immune response against Mycobacterium tuberculosis. We investigated whether a close functional relationship exists between these two cell populations using an in vitro coculture in a human system. Vγ9Vδ2 T cells induce full maturation of M. tuberculosis-infected immature DCs, as demonstrated by upregulation of the costimulatory CD80, CD86, CD40, and HLA-DR molecules on infected DCs after 24 h of coculture. Reciprocally, infected DCs induced substantial activation of Vγ9Vδ2 T cells upon coculture, which was cell-to-cell contact and TCR dependent, as demonstrated in transwell experiments. However, infected DCs select…
Memory B Cell Subpopulations in the Aged
2006
The literature on immunosenescence has focused mainly on T cell impairment. With the aim of gaining insight into B cell immunosenescence, the authors investigated the serum IgD levels in 24 young and 21 old people and analyzed their relationship with the number of CD19 CD27 memory cells. Serum IgD were quantified by the use of radial immunodiffusion and the lymphocyte population CD19 CD27 was identified by a FACScan flow cytometer. Serum IgD levels were significantly lower (p 0.0001) in old subjects, and the percentage of CD19 CD27 lymphocytes were significantly increased (p 0.01) in old subjects. Finally, a significant negative correlation was found (p 0.01) between serum concentrations of…