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Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The class of surface immunoglobulin receptors for antigen on B cell precursors of different classes of antibody-forming cells was determined by utilizing a technique of class-specific antigen suicide. Spleen cells are first treated with a class-specific antiserum under conditions that result in the stripping of that class from the cell surface. The cells are then permitted to bind a highly radioactive trinitrophenyl (TNP)-conjugated protein, which leads to lethal irradiation of all TNP-specific B cells except those whose TNP receptors had been removed by the class-specific stripping of surface immunoglobulin. In this way, the class of antibody-forming cells resulting from TNP stimulation of B cells with different classes of surface immunoglobulin can be examined. It was found that the virgin B cell precursors of IgM-producing cells are two types: cells bearing IgM receptors only and those bearing both IgM and IgD receptors. All virgin B cells that gave rise to IgG1 antibody-forming cells had both IgM and IgD on their surfaces, demonstrating that an antigen-dependent switch from IgM and IgD to IgG1 production is a common feature of B cell maturation. In contrast, memory B cell precursors of IgG1 antibody-forming cells had predominantly IgG1 as their surface antigen receptor. The implications of these findings on current models of B cell maturation are analyzed.
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PMID:The class of surface immunoglobulin on virgin and memory B lymphocytes. 6 48

Spleen cells from mice infected with Friend leukemia virus were examined by scanning electron microscopy. Whereas splenocytes from normal noninfected animals showed the expected morphologic classes of lymphocytes, including those with smooth surfaces and with numerous villous projections, an alteration of cell type was evident within a few days after infection. Friend leukemia virus caused a rapid decrease in the number of villous cells, with a concomitant increase in the number of cells with smoother surfaces. By the end of the first 1 to 12 weeks after infection the majority of cells were smooth, many showing distinct morphologic changes, including "holes" and a spongy appearance. Nearly all of the splenocytes were abnormal in appearance by days 17 to 30 after infection, with most showing a spongy topography. These changes paralleled the marked immunosuppression induced by Friend leukemia virus infection, as well as the appearance of virus-associated surface antigen on individual splenocytes. Topographic changes evident by examination with scanning electron microscopy were not readily apparent by either standard histology or transmission electron microscopy.
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PMID:Leukemia virus-induced immunosuppression: scanning electron microscopy of infected spleen cells. 116 15

Neonatal mice (CR:NIH:S) were infected with a cloned human isolate of Giardia lamblia (GS/M-83-H7) and the surface antigens of the intestinal trophozoites, as well as the cellular and humoral immune responses, were analysed during the course of infection. Infections in mice peaked 2-3 weeks after inoculation and were self-cured by day 42 post-infection (p.i.). The proportion of trophozoites expressing the Mr 72,000 surface antigen of the initial inoculum had decreased by day 12 and approached zero by day 22 p.i., similar to infections in humans. The predominant parasite-specific humoral response was an IgM- and IgG-isotype directed to the original Mr 72,000 surface antigen as well as other antigens. T-lymphocytes (predominantly LY4(CD4)+) isolated from Peyer's patches 12 days p.i. and later showed a significant proliferative response to Giardia lamblia antigens. Spleen and lymph node cells showed no lymphoproliferative response. T-cell blot analysis revealed the presence of dominant T-cell epitopes in the areas of Mr 200,000-75,000 and less than 50,000 polypeptides. No response was demonstrated in the Mr 72,000 region (migration site of the major surface antigen), suggesting T-cell dependent mechanisms are most likely not responsible for the surface antigen switch which occurred during the course of infection. This model infection can be used to study the role of immunological mechanisms in Giardia lamblia variant antigen switching and in the control of infections.
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PMID:Antigenic variation in Giardia lamblia: cellular and humoral immune response in a mouse model. 170 8

Spleen cells from C3H/An mice immunized with spleen cells of C57BL/6-H-2k mice were fused with myeloma cell line NS.1. One established hybrid cell line continuously secreted antibody that recognized a new surface antigen provisionally called Ly-m18. The new alloantigen is expressed on 90 percent of thymus cells, 55 percent of spleen cells, and 45 percent of either lymph-node or bone-marrow cells. It is also expressed on cells derived from brain, kidney, and liver. Fifty percent of either peripheral T or B cells express the Ly-m18 antigen, and some tumor cell lines with T, B, pre-B or stem cell characteristics are Ly-m18 (+). The strain distribution pattern distinguishes Ly-m18 antigen from all other murine lymphocyte alloantigens. The typing data of two sets of CXB and AKXL recombinant inbred strains indicate that the Ly-m18 gene is linked to the Ltw-2 locus which has not yet been assigned to a chromosome.
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PMID:A new mouse cell-surface antigen (Ly-m18) defined by a monoclonal antibody. 697 93

Spleen cells from a rat immunized with mouse cerebellar cells were fused with mouse myeloma cells. One of the hybridomas secreted a monoclonal antibody that reacts with a surface antigen on vascular endothelial cells. The antibody stained endothelial cells lining blood vessels in brain, heart, lung, kidney, and liver. It did not, however, stain endothelial cells lining hepatic sinusoids. Parenchymal cells were always negative. So far, an antigen of similar tissue distribution has not been described in the mouse and we have called it mouse endothelial surface antigen-1 (MESA-1). The antibody could be used as a highly specific usefulness for identifying endothelium-derived cells in culture has been demonstrated on cultures of dissociated mouse cerebellum, where it stained a subclass of fibronectin-expressing cells.
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PMID:A surface marker for murine vascular endothelial cells defined by monoclonal antibody. 706 19

Depression of the cellular immune response to Toxoplasma gondii has been reported in both mice and humans. The present study was undertaken to determine the kinetics and mechanism of the observed downregulation of interleukin 2 (IL-2) production during experimental murine toxoplasmosis. For these investigations, the cell-mediated immune response to the wild type (PTg) was compared with that to the less-virulent mutant parasite (PTgB), which is deficient in the major surface antigen, p30 (SAG-1). Spleen cells from infected A/J mice failed to proliferate in response to Toxoplasma antigens during the first week of infection. Both PTg- and PTgB-infected A/J mice exhibited a significant reduction in the concanavalin A (Con A)-induced lymphoproliferative response. Further, the response of splenocytes from mice infected with the wild-type parasite was significantly diminished compared with that of mice infected with PTgB. The lymphoproliferative response to Con A reached its nadir at day 7 and remained below control levels for at least 14 days postinfection. By day 21 postinfection, the response to Con A and to Toxoplasma antigens was restored to the level observed prior to day 7. Con A-stimulated culture supernatants of spleen cells from mice on day 7 postinfection contained significantly less IL-2 than normal mice. There was no significant difference in the numbers of binding sites or capacity of high-affinity IL-2 receptors between infected and normal mouse splenocytes as determined by Scatchard analysis. Exogenous IL-2 at different concentrations failed to restore the proliferative response of lymphocytes from infected mice to Con A. Adherent macrophages from 7-day-infected mice were able to suppress IL-2 production by normal splenocytes following stimulation with Con A. The inhibitory activity mediated by infected cells was reversed by the antibody to IL-10 but not transforming growth factor beta. There were insignificant levels of nitric oxide production in both infected and normal splenocytes. These results indicate that during acute murine toxoplasmosis, there is a well-defined period (day 7) during which both the T-cell mitogen and parasite antigen-associated lymphoproliferative response are reduced. Further, there is a reduction in the production of IL-2 and an increase in IL-10, which appear to mediate, in part, the observed downregulation of immunity to T. gondii.
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PMID:Impairment of the cellular immune response in acute murine toxoplasmosis: regulation of interleukin 2 production and macrophage-mediated inhibitory effects. 800 79

Balb/c mice were immunized with aluminium hydroxide [alum, Al (OH)3]-adjuvanted hepatitis B (HB) vaccines of subtypes adr, ayw or adw. Spleen cells from the immune animals were fused with SP2/O cells. Eight hybridoma clones producing antibodies specific for HB surface antigen (HBsAg) were selected. Monoclonal antibodies (mAbs) of four clones were specific for group-specific antigen/a, and the other of four clones were specific for subtype antigen/d, y, r, or w. The anti-HBs/a mAbs were classified into three non-competitive groups. Quantitation of group-specific determinant a of HBsAg (HBsAg/a) was performed by sandwich enzyme-linked immunosorbent assay (ELISA), in which a solid phase of anti-HBs guinea-pig polyclonal antibodies (pAb), the HBsAg for testing, anti-HBs/a mouse mAb and horseradish peroxidase (HRP)-conjugated anti-mouse IgG were used. The unadsorbed HBsAg was used to establish the standard curve of HBsAg/a. The lower detection limits were 0.5 to 1 ng/ml of HBsAg. Methods of solubilization of alum were investigated to quantify HBsAg/a in adsorbed HB vaccines. The recovery rate was more than 60% if vaccines were prediluted. The recovery of HBsAg/a in HB vaccines produced by the same manufacturer showed the similar recovery rate, and the contents of HBsAg/a in adsorbed HB vaccines could be estimated by the recovery rate determined for adsorbed HB vaccines.
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PMID:Quantitation of group-specific a antigen in hepatitis B vaccines by anti-HBs/a monoclonal antibody. 946 33

Two plasmid DNA vectors, pCAGGS(S) encoding the genes of the major envelope protein of hepatitis B virus (HBV), and pCAGGS(S + preS2) encoding the genes of the middle envelope protein were used to study the mechanism and therapeutic potential of DNA-based immunization. Injection of these plasmids into the regenerating bilateral tibialis anterior muscle (TA) of normal C57BL/6 mice induced hepatitis B surface antigen (HBsAg)-specific humoral and cellular immune responses. Seventy-two hours after injection of pCAGGS(S), infiltrating cells including antigen-presenting dendritic cells (DC) were localized around the injection site and HBsAg was expressed by both muscle cells and infiltrating cells. Spleen DC from the mice were exposed to HBsAg for up to 32 weeks after a single injection of pCAGGS(S), because these DC induced the proliferation of HBsAg-specific memory lymphocytes in culture without exogenous HBsAg. A single injection of pCAGGS(S) or pCAGGS(S + preS2) resulted in the clearance of HBsAg in 28 out of 30 HBV-transgenic (Tg) mice. In contrast, more than 7 monthly injections of an HBsAg-based vaccine were required for the clearance of HBsAg in 6 out of 29 HBV-Tg mice. Infiltrating DC at the DNA vaccine injection site may have a role in initiating HBsAg-specific immune response, whereas the persistence of HBsAg exposed spleen DC may contribute to long-lasting immunity. This study also suggested that DNA-based vaccines may be a potent tool for treating chronic HBV carriers.
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PMID:Mechanism and therapeutic potential of DNA-based immunization against the envelope proteins of hepatitis B virus in normal and transgenic mice. 1138 Jun 96

Hepatitis B virus (HBV) infection is a major health problem worldwide. The diagnosis of acute and chronic hepatitis B infection is based on the detection of hepatitis B surface antigen (HBsAg). We report here the development of hybrid cell producing monoclonal antibodies (MAbs) specific for HBsAg using hybridoma technology. BALB/c mice were immunized with a mixture of HBsAg subtype "ad" and subtype "ay." Spleen and lymph nodes were used as a source of high-titer antibody producing lymphocytes and removed and fused with myeloma cells of F0 origin separately. In the five fusion experiment, enzyme-linked immunosorbent assay (ELISA) tests showed that among 1594 hybridomas only 5 hybrids (9D12, 2B7, 4G5, 2G3, and 6E7) reacted with HBsAg. These MAbs were characterized for use in the development of diagnostic kits based on sandwich ELISA test system. The MAbs were conjugated with horseradish peroxidase (HRP) and used in the quick sandwich ELISA system. This system is a quite practical and time-saving test system when compared with common and commercial sandwich ELISA for diagnosis of hepatitis B surface antigen in human serum.
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PMID:Production and characterization of monoclonal antibodies against hepatitis B viruses and application of a quick sandwich ELISA. 1295 3

Recently a new field of immunological research and clinical application of vaccines for therapeutic purposes (vaccine therapy) has been developed for treating several chronic viral infections including chronic hepatitis B virus (HBV) infection. Administration of vaccine containing hepatitis B surface antigen (HBsAg) for 1 year has resulted in negative HBsAg and development of antibody to HBsAg (anti-HBs) in some, but not in all, HBV transgenic mouse (HBV-Tg). In order to develop more potent regimen of vaccine therapy for chronic HBV carrier, we prepared a dendritic cell (DC)-based therapeutic vaccine and evaluated their therapeutic potential in HBV-Tg. DCs were isolated from single cell suspensions of murine spleen cells by collagenase digestion, density centrifugation and depletion of lymphocytes. Spleen DCs were cultured with HBsAg (100 microg) for 24 h to produce HBsAg-pulsed DCs. HBV-Tg expressing HBsAg and HBV DNA in the sera were randomly assigned to receive either HBsAg-pulsed DCs (n = 20) or unpulsed DC (n = 20) or vaccine containing HBsAg (n = 39) or complete Freund's adjuvant (n = 20) or left untreated (n = 20). Only two intraperitoneal injections of HBsAg-pulsed DCs resulted in negative HBsAg and production of anti-HBs in the sera in all HBV-Tg (n = 20). However, administration of un-pulsed DCs (n = 20) or vaccine containing HBsAg (n = 39) or only complete Freund's adjuvant did not induce negative HBsAg or production of anti-HBs in any HBV-Tg within 6 months of therapy commencement. Taken together, this study showed that HBsAg-pulsed DCs represent a highly potent therapeutic vaccine for chronic HBV infection and inspire optimism of using this vaccine in clinical conditions. A clinical trial of HBsAg-pulsed DC in patients with chronic hepatitis B is warranted.
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PMID:Production and efficacy of a dendritic cell-based therapeutic vaccine for murine chronic hepatitis B virus carrierer. 1525 81


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