Search results for "compatibility"
showing 10 items of 859 documents
Contact Sensitizers Specifically Increase MHC Class II Expression on Murine Immature Dendritic Cells
2000
Contact sensitivity is a T-cell-mediated immune disease that can occur when low-molecular-weight chemicals penetrate the skin. In vivo topical application of chemical sensitizers results in morphological modification of Langerhans cells (LC). Moreover, within 18 h, LC increase their major histocompatibility complex (MHC) class II antigens expression and migrate to lymph nodes where they present the sensitizer to T lymphocytes. We wanted to determine if such an effect could also be observed in vitro. However, because of the high genetic diversity encountered in humans, assays were performed with dendritic cells (DC) obtained from a Balb/c mouse strain. The capacity of a strong sensitizer, DN…
Human CD8+ memory and EBV-specific T cells show low alloreactivity in vitro and in CD34+ stem cell–engrafted NOD/SCID/IL-2Rγcnull mice
2013
Current strategies in cellular immunotherapy of cancer and viral infections include the adoptive transfer of T cell receptor (TCR) and chimeric antigen receptor engineered T cells. When using transient RNA expression systems in clinical studies, multiple infusions with receptor-redirected T cells appear necessary. However, in allogeneic hematopoietic stem-cell transplantation, repeated transfer of donor-derived T cells increases the risk of alloreactive graft-versus-host disease. We investigated naive-derived (T N ), memory-derived (T M ), and Epstein Barr virus-specific (T EBV ) CD8 + T cell subsets for alloreactivity upon redirection with RNA encoding a cytomegalovirus-specific model TCR.…
Analysis of the (H-2b x H-2k)F1Restricted Response to Insulin.
1984
The aim of these studies was to characterize the (H-2b X H-2k)F1-unique restriction element(s) responsible for presentation of bovine insulin (BI) to a long-term cultured T-cell line (BK-BI-1.2). (B10.BR X bm12)F1 spleen cells, which express a normal Ab alpha Ak beta molecule but a mutated Ak alpha Abm12 beta product on their cell surface, were perfectly able to act as BI-presenting cells. Antibody inhibition experiments with antibodies directed at I-Ak products revealed that monoclonal antibody 10-2.16, which reacts with the Ak beta polypeptide chain, abrogated BI-directed T-cell proliferation, whereas antibody H116-32.R5 with specificity for the Ak alpha chain was not inhibitory. These re…
Bioactive and biodegradable silica biomaterial for bone regeneration.
2014
Biosilica, a biocompatible, natural inorganic polymer that is formed by an enzymatic, silicatein-mediated reaction in siliceous sponges to build up their inorganic skeleton, has been shown to be morphogenetically active and to induce mineralization of human osteoblast-like cells (SaOS-2) in vitro. In the present study, we prepared beads (microspheres) by encapsulation of β-tricalcium phosphate [β-TCP], either alone (control) or supplemented with silica or silicatein, into the biodegradable copolymer poly(d,l-lactide-co-glycolide) [PLGA]. Under the conditions used, ≈5% β-TCP, ≈9% silica, and 0.32μg/mg of silicatein were entrapped into the PLGA microspheres (diameter≈800μm). Determination of …
Isolation and characterization of Oct-4+/HLA-G+ mesenchymal stem cells from human umbilical cord matrix: differentiation potential and detection of n…
2008
The presence of multipotent cells in several adult and embryo-related tissues opened new paths for their use in regenerative medicine. Extraembryonic tissues such as umbilical cord are considered a promising source of stem cells, potentially useful in therapy. The characterization of cells from the umbilical cord matrix (Wharton''s Jelly) and amniotic membrane revealed the presence of a population of mesenchymal-like cells, sharing a set of core-markers expressed by "mesenchymal stem cells". Several reports enlightened the differentiation capabilities of these cells, even if at times the lack of an extensive characterization of surface markers and immune co-stimulators expression revealed h…
Challenges in truncating the hierarchy of time-dependent reduced density matrices equations
2012
In this work, we analyze the Born, Bogoliubov, Green, Kirkwood, and Yvon (BBGKY) hierarchy of equations for describing the full time evolution of a many-body fermionic system in terms of its reduced density matrices (at all orders). We provide an exhaustive study of the challenges and open problems linked to the truncation of such a hierarchy of equations to make them practically applicable. We restrict our analysis to the coupled evolution of the one- and two-body reduced density matrices, where higher-order correlation effects are embodied into the approximation used to close the equations. We prove that within this approach, the number of electrons and total energy are conserved, regardl…
The role of the human cytomegalovirus UL111A gene in down-regulating CD4+ T-cell recognition of latently infected cells: implications for virus elimi…
2009
AbstractThe capacity of human cytomegalovirus (HCMV) to establish and maintain a latent infection from which it can later reactivate ensures its widespread distribution in the population, but the mechanisms enabling maintenance of latency in the face of a robust immune system are poorly understood. We examined the role of the HCMV UL111A gene, which encodes homologs of the immunosuppressive cytokine interleukin-10 in the context of latent infection of myeloid progenitor cells. A UL111A deletion virus was able to establish, maintain, and reactivate from experimental latency in a manner comparable with parental virus, but major histocompatibility complex class II levels increased significantl…
Human cytomegalovirus pp71 stimulates major histocompatibility complex class i presentation of IE1-derived peptides at immediate early times of infec…
2013
ABSTRACT Suppression of major histocompatibility complex (MHC) class I-mediated presentation of human cytomegalovirus (HCMV) peptides is an important mechanism to avoid CD8 T lymphocyte recognition and killing of infected cells. Of particular interest is how MHC class I presentation of essential regulatory immediate early (IE) proteins of HCMV can be effectively compromised at times when known viral immunoevasins are not abundantly expressed. The tegument protein pp71 had been suggested to be involved in MHC class I downregulation. Intriguingly, this polypeptide is also critically engaged in the initial derepression of the major IE gene locus, leading to enhanced expression of IE proteins I…
The immunogenicity of human and murine cytomegaloviruses.
2000
Cytomegaloviruses are strictly host-species-specific. During an aeon of co-evolution, virus and host have found an arrangement: the productive and cytopathogenic cycle of viral gene expression is held in check by the host's immune response. As a consequence, cytomegalovirus disease is restricted to the immunocompromised host. The virus has evolved strategies to avoid its elimination and eventually hides itself in a silent state, referred to as 'viral latency'. Redundant molecular mechanisms have been identified by which cytomegaloviruses interfere with antigen presentation pathways to 'evade' immune control. In the annual period covered by this review, the IE1 protein was revisited as an im…
Inhibition of CD1 antigen presentation by human cytomegalovirus.
2008
ABSTRACTThe betaherpesvirus human cytomegalovirus (HCMV) encodes several molecules that block antigen presentation by the major histocompatibility complex (MHC) proteins. Humans also possess one other family of antigen-presenting molecules, the CD1 family; however, the effect of HCMV on CD1 expression is unknown. The majority of CD1 molecules are classified on the basis of homology as group 1 CD1 and are present almost exclusively on professional antigen-presenting cells such as dendritic cells, which are a major target for HCMV infection and latency. We have determined that HCMV encodes multiple blocking strategies targeting group 1 CD1 molecules. CD1 transcription is strongly inhibited by…