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MHC I (mhc + i)
Selected AbstractsAntigen-loaded ER microsomes from APC induce potent immune responses against viral infectionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2009Vassiliki Sofra Abstract Although matured DC are capable of inducing effective primary and secondary immune responses in vivo, it is difficult to control the maturation and antigen loading in vitro. In this study, we show that ER-enriched microsomal membranes (microsomes) isolated from DC contain more peptide-receptive MHC I and II molecules than, and a similar level of costimulatory molecules to, their parental DC. After loading with defined antigenic peptides, the microsomes deliver antigenic peptide,MHC complexes (pMHC) to both CD4 and CD8 T cells effectively in vivo. The peptide-loaded microsomes accumulate in peripheral lymphoid organs and induce stronger immune responses than peptide-pulsed DC. The microsomal vaccines protect against acute viral infection. Our data demonstrate that peptide,MHC complexes armed microsomes from DC can be an important alternative to DC-based vaccines for protection from viral infection. [source] Retroviral labeling of Schwann cells: In vitro characterization and in vivo transplantation to improve peripheral nerve regenerationGLIA, Issue 1 2001Afshin Mosahebi Abstract Transplantation of Schwann cells (SCs) is a promising treatment modality to improve neuronal regeneration. Identification of the transplanted cells is an important step when studying the development of this method. Genetic labeling is the most stable and reliable method of cell identification, but it is still unclear whether it has deleterious effect on SC characteristics. Our aim was to achieve a stable population of SCs transduced with the lacZ gene at a high frequency using a retroviral vector in vitro, and to follow the labeled SC in vitro to assess their viability and phenotypic marker expression. Furthermore, we transplanted lacZ -labeled SCs in a conduit to repair peripheral nerve to investigate their effect on nerve regeneration in vivo. Rat and human SCs were cultured and transduced with an MFG lacZ nls marker gene, achieving a transduction rate of 80% and 70%, respectively. Rat SCs were kept in culture for 27 weeks and examined every 4 weeks for expression of lacZ, viability, and phenotypic marker expression of GFAP, p75, MHC I and II. Throughout this period, transduced rat SCs remained viable and continued to proliferate. The proportion of cells expressing lacZ dropped only by 10% and the expression of phenotypic markers remained stable. Transduced human SCs were followed up for 4 weeks in culture. They proliferated and continued to express the lacZ gene and phenotypic marker expression of GFAP and p75 was preserved. Primary culture of transduced rat SCs were transplanted, syngeneically, in a conduit to bridge a 10 mm gap in sciatic nerve and the grafts were examined after 3 weeks for the presence and participation of labeled SCs and for axonal regeneration distance. Transplanted transduced rat SCs were clearly identified, taking part in the regeneration process and enhancing the axonal regeneration rate by 100% (at the optimal concentration) compared to conduits without SCs. Thus, retroviral introduction of lacZ gene has no deleterious effect on SCs in vitro and these SCs take part and enhance nerve regeneration in vivo. GLIA 34:8,17, 2001. © 2001 Wiley-Liss, Inc. [source] The phylogenetic origins of the antigen-binding receptors and somatic diversification mechanismsIMMUNOLOGICAL REVIEWS, Issue 1 2004John P. Cannon Summary:, The adaptive immune system arose in ancestors of the jawed vertebrates approximately 500 million years ago. Homologs of immunoglobulins (Igs), T-cell antigen receptors (TCRs), major histocompatibility complex I (MHC I) and MHC II, and the recombination-activating genes (RAGs) have been identified in all extant classes of jawed vertebrates; however, no definitive homolog of any of these genes has been identified in jawless vertebrates or invertebrates. RAG-mediated recombination and associated junctional diversification of both Ig and TCR genes occurs in all jawed vertebrates. In the case of Igs, somatic variation is expanded further through class switching, gene conversion, and somatic hypermutation. Although the identity of the ,primordial' receptor that was interrupted by the recombination mechanism in jawed vertebrates may never be established, many different families of genes that exhibit predicted characteristics of such a receptor have been described both within and outside the jawed vertebrates. Recent data from various model systems point toward a continuum of immune receptor diversity, encompassing many different families of recognition molecules whose functions are integrated in an organism's response to pathogenic invasion. Various approaches, including both genomic and protein-functional analyses, currently are being applied in jawless vertebrates, protochordates, and other invertebrate deuterostome systems and may yield definitive evidence regarding the presence or absence of adaptive immune homologs in species lacking adaptive immune systems. Such studies have the potential for uncovering previously unknown mechanisms of generating receptor diversity. [source] Major histocompatibility complex (MHC) class II but not MHC class I molecules are required for efficient control of Strongyloides venezuelensis infection in miceIMMUNOLOGY, Issue 1pt2 2009Rosângela M. Rodrigues Summary Strongyloides stercoralis is an intestinal nematode capable of chronic, persistent infection and hyperinfection of the host; this can lead to dissemination, mainly in immunosuppressive states, in which the infection can become severe and result in the death of the host. In this study, we investigated the immune response against Strongyloides venezuelensis infection in major histocompatibility complex (MHC) class I or class II deficient mice. We found that MHC II,/, animals were more susceptible to S. venezuelensis infection as a result of the presence of an elevated number of eggs in the faeces and a delay in the elimination of adult worms compared with wild-type (WT) and MHC I,/, mice. Histopathological analysis revealed that MHC II,/, mice had a mild inflammatory infiltration in the small intestine with a reduction in tissue eosinophilia. These mice also presented a significantly lower frequency of eosinophils and mononuclear cells in the blood, together with reduced T helper type 2 (Th2) cytokines in small intestine homogenates and sera compared with WT and MHC I,/, animals. Additionally, levels of parasite-specific immunoglobulin M (IgM), IgA, IgE, total IgG and IgG1 were also significantly reduced in the sera of MHC II,/, infected mice, while a non-significant increase in the level of IgG2a was found in comparison to WT or MHC I,/, infected mice. Together, these data demonstrate that expression of MHC class II but not class I molecules is required to induce a predominantly Th2 response and to achieve efficient control of S. venezuelensis infection in mice. [source] Regional specialization of rat quadriceps myosin heavy chain isoforms occurring in distal to proximal parts of middle and deep regions is not mirrored by citrate synthase activityJOURNAL OF ANATOMY, Issue 1 2007Tertius Abraham Kohn Abstract Myosin heavy chain (MHC) isoform content and citrate synthase (CS) activities were measured in the Quadriceps femoris (QF) muscle of 18 female rats. The muscle group was divided into superficial, middle and deep, distal, central and proximal parts. MHC IIb and IIx were more abundant in superficial regions (P < 0.05) with low CS activities compared with deeper parts. The deeper parts expressed all four isoforms (MHC IIb, MHC IIx, MHC IIa and MHC I), with a concomitantly higher CS activity. MHC I, MHC IIa and MHC IIb isoform content varied significantly along the length of the deep regions. Only MHC IIb and CS activity in the proximal middle part correlated (negatively) with each other. This study showed that the QF has regional specialization and that standardization of sampling site is important. Furthermore, CS activity and MHC isoforms are only loosely associated, or not at all. [source] Regulatory Allospecific NK Cell Function Is Differentially Associated with HLA C AllotypesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2009G. Zenhaeusern Major histocompatibility complex I (MHC I) molecules ,silence' natural killer (NK) cell activity. Conversely, NK cell activity is triggered through cells lacking expression of autologous MHC I. Unexpectedly we found that a subset of NK cells is activated rather than silenced when interacting with cells expressing normal levels of autologous MHC I. Instead of inducing an inflammatory phenotype, however, activation led to the secretion of the regulatory cytokines TGF-, and IL-10. Importantly, in vitro models of allogeneic interactions showed that targets co-expressing HLA C1 and C2 epitopes best supported, or even enhanced, this cell-contact-mediated regulatory NK cell function. Together, these data ascribe a novel pattern of reactivity to NK cells, with potential implications both in autologous and allogeneic systems. [source] Immune response of DNA vaccine against lymphocystis disease virus and expression analysis of immune-related genes after vaccinationAQUACULTURE RESEARCH, Issue 10 2010Feng Rong Zheng Abstract In this study, we found that an intramuscular injection of Japanese flounder (Paralichthys olivaceus, 60,80 g in weight and 15,20 mL in length) with 5 ,g of a DNA vaccine (pEGFP-N2-LCDV-cn-MCP 0.6 kb, containing lymphocystis disease virus major capsid protein gene) induced a strong immune response. Subsequent real-time polymerase chain reaction showed that the expression of immune-related genes [e.g., major histocompatibility complex (MHC) class I ,, MHC II ,, T-cell receptor (TCR), tumour necrosis factor (TNF), tumour necrosis factor receptor (TNFR), Mx, interleukin (IL)-1,, CXC and IL-8R] was significantly changed after DNA vaccination. The most remarkable alternation was the expression of MHC I , and MHC II , genes: MHC II , reached the maximum on day 8 in different tissues, and MHC I , on day 2 in the intestine and gills. The expression of TCR increased and reached a plateau in 2 days in the spleen, gills, kidney and liver after vaccination and then decreased after day 8. In contrast, the expression of TCR in the intestine increased and reached a plateau in 8 days. The expression of IL-8R reached the maximum on day 2 in different tissues and then decreased on day 8. Mx increased in the gills, kidney, spleen and liver on days 2, 8, 2 and 2, but decreased in the intestine, gills, spleen and liver on days 2, 8, 8 and 8 respectively. The TNFR expression increased in the spleen, kidney and gills on days 2, 8 and 8, but decreased in intestine, liver and gills on days 2, 8 and 8 respectively. The expression of TNF, CXC and IL-1, increased 2 and 8 days after the injection of DNA vaccine. However, the expression of TNF, CXC and IL-1, altered on days 2 and 8 with different patterns in different tissues respectively. The fish responded to the DNA vaccine by yielding a specific immunoglobulin against lymphocystis disease virus (LCDV) as observed with indirect ELISA. The DNA vaccine induced a unique humoral response, suggesting that the DNA vaccine activated both cellular and humoral defences of the specific immune system of Japanese flounder. [source] Expression, purification, crystallization and preliminary X-ray diffraction analysis of grass carp ,2 -microglobulinACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2008Weihong Chen ,2 -Microglobulin (,2m) is an essential subunit of MHC I molecules; it stabilizes the structure of MHC I and plays a pivotal role in coreceptor recognition. To date, structures of ,2m have been solved for three different mammals: human, mouse and cattle. In order to illuminate the molecular evolutionary origin of ,2m, an understanding of its structure in lower vertebrates becomes important. Here, grass carp (Ctenopharyngodon idellus) ,2m (Ctid -,2m) was expressed, purified and crystallized. Diffraction data were collected to a resolution of 2.5,Å. The crystal belongs to space group P212121, with unit-cell parameters a = 38.72, b = 40.65, c = 71.12,Å. The Matthews coefficient and the solvent content were calculated to be 2.56,Å,Da,1 and 52.07%, respectively, for one molecule per asymmetric unit. The structure has been solved by molecular replacement using monomeric human ,2m as a model. [source] | |||||||||||||