Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.32 (bromelain)
 1,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Normal mice spontaneously develop plaque-forming cells (PFC) specific for antigens on modified self erythrocytes (bromelain-treated mouse erythrocytes [BrMRBC] antigens). Our study demonstrates that the sex-linked defect that results in the inability of CBA/N mice to respond to several T-independent antigens (TI-2 antigens) also regulates the autoantibody response to BrMRBC antigens. Thus, in CBA/N homozygous mice and male F1 offspring of CBA/N-mothered crosses, e.g., (CBA/N X NZB)F1 males, such PFC are absent. To examine whether specific autoreactive B cells are present in defective mice, the latter were stimulated either nonspecifically with the mitogen LPS or by infection with lethal malaria (17XL Plasmodium yoelii) known to induce anti-BrMRBC PFC specifically. The results indicate that modest antibody responses to self antigens could be induced in young (5- to 7-wk old) defective mice and that these responses increased as a function of age. The data is consistent with the view that the defect in CBA/N mice does not result from an absence of functional anti-BrMRBC B cells but rather from low frequencies of the specific precursors, which can be triggered and expanded with age probably by environmental stimulations.
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PMID:Influence of the sex-linked defect in CBA/N mice on autoimmune responses to isologous erythrocytes. Ability to overcome the defect with age. 31 95

A high proportion of peritoneal cells from untreated mice, after 4--5 days in culture, develop into plaque-forming cells against bromelain-treated mouse red blood cells. The number of plaque-forming cells was increased significantly by exposing the peritoneal cells to ammonium chloride to lyse red blood cells before culture. Conversely, the increase was significantly inhibited by adding before culture untreated or bromelain-treated sheep or mouse red blood cells. Treated or untreated horse or rat red blood cells did not inhibit the increase. Treating peritoneal cells or subpopulations of peritoneal cells with anti-theta serum and complement before culture caused a significant increase in the number of plaque-forming cells against bromelain-treated red blood cells after 3--4 days of culture. Various procedures were used to fractionate peritoneal cells into B-cell enriched and B-cell depleted subpopulations before culture and after culture, to investigate whether some of the plaque-forming cells could be attributed to phagocytic cells. Generally, changes in the number of plaque-forming cells against bromelain-treated mouse red blood cells paralleled changes in B-cells. In some experiments the proportion of plaque-forming cells observed represented up to 85% of the B-cells present. The results suggest that the high level of autoreactivity is due to antibody production by B-cells and that phagocytic cells are not forming spurious plaques. Further, it appears that the autoimmunity is regulated by T-cells and can also be inhibited by mouse RBC.
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PMID:In vitro investigation of autoantibody-secreting peritoneal cells and their regulation. 38 87

Peritoneal cell cultures from NZB and C57BL/6 mice develop large numbers of PFC directed against antigens present on bromelain-treated isologous erythrocytes. The development of these autoimmune PFC can be suppressed by the addition of small numbers of BrMRBC at the start of the culture period. The possibility that the development of the plaque is prevented by the presence of antigen in vivo is discussed.
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PMID:Antigen suppression of the in vitro development of plaque-forming cells to autologous erythrocyte antigens. 110 5

The differentiation of plaque-forming cell (PFC) precursors against bromelain-treated syngeneic erythrocytes (Br MRBC) into PFC induced in vitro by LPS is down-regulated by nylon non-adherent (nylon-passed--NP) T cells and by nylon adherent (NA) T cells. NA T cells are more potent inhibitors than NP T cells. This regulatory activity of NA and NP T cells results from an interaction between CD4+ radioresistant and CD8+ radiosensitive T cells. Furthermore CD4+ T cells from the NA fraction but not from the NP fraction are activated cells: their inhibitory activity is abrogated after preincubation with cycloheximide. These results are discussed within the overall framework of T-cell regulation of autoimmune anti-Br MRBC B-cell subsets.
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PMID:T-cell regulation of CD5+ B-cell activity in normal mice. 171 3

The effect of interleukin 1 (IL-1)-like factor(s), produced by cells isolated from the synovial fluids of rheumatoid arthritis (RA) patients, on an in vitro murine model of spontaneous autoimmunity, i.e., the development of plaque-forming cells (PFC) to bromelain-treated mouse red blood cells (Br-MRBC) in mouse peritoneal cell (PC) cultures, has been investigated. It has been found that IL-1-containing culture supernatants from cells isolated from joint fluids of RA patients, as well as recombinant IL-1, determine a marked increase in anti-Br-MRBC PFC development. Moreover, factor(s) of 10-20 KD molecular weight, with IL-1-like biological activity, capable of increasing the anti-Br-MRBC PFC development in mouse PC cultures, have been demonstrated in joint fluids from RA patients. The finding that synovial inflammatory cells produce factors that activate autoreactive B cells further supports the role of autoimmunity in the pathogenesis of rheumatoid arthritis, as self-perpetuing disorder.
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PMID:Activation of murine autoreactive b cells by interleukin 1-like factors released from synovial inflammatory cells of rheumatoid arthritis patients. 193 7

After culturing mouse peritoneal cells in vitro for 4 days, high numbers of cells can be detected that secrete autoantibodies against isologous red blood cells (RBC), modified with the proteolytic enzyme bromelain (Brom). Plaque-forming cell numbers against mouse Brom RBC were significantly reduced by pretreating mouse Brom RBC prior to haemolytic assay with phospholipase C, an enzyme that hydrolyzes phospholipids, notably phosphatidylcholine. In contrast, further treatment of mouse Brom RBC with Brom, neuraminidase, beta-chymotrypsin, trypsin, or papain had no effect on plaque-forming cell numbers. These results show that phosphatidylcholine is an integral part of the mouse RBC autoantigen exposed by Brom treatment.
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PMID:Mouse autoantibodies bind to a phospholipase-C-sensitive structure on red blood cells. 217 39

The influence of recombinant interleukin 5 (rIL-5) on murine peritoneal B-cell proliferation and antibody secretion was examined. Larger, low buoyant density peritoneal B cells proliferated better with rIL-5 than the smaller resting B cells. this was also true for splenic B cells; however, comparison of the respective populations showed the large peritoneal B-cell responses to be superior. Limiting dilution analyses showed that from 25% to about 40% of large peritoneal B cells proliferated in response to rIL-5 when lipopolysaccharide (LPS) was present. No detectable difference in the fraction of proliferating splenic B cells was seen in the presence of rIL-5. These results are consistent with expression of IL-5 receptors on about 70% of low-density peritoneal B cells as determined by fluorescent staining with anti-Il-5 receptor monoclonal antibody (MoAb). IL-5 also enhanced spontaneous and mitogen-driven IgM secretion by both peritoneal and splenic B lymphocytes; the increases exhibited by peritoneal B cells, however, were at least twice those exhibited by splenic B cells. Spontaneous and mitogen-driven secretion of auto-antibodies to bromelain-treated mouse erythrocytes (BrMRBC) by peritoneal B cells were also increased by this interleukin. Furthermore, rIL-5 enhanced peritoneal B-cell plaque-forming cell (PFC) responses to TNP-LPS but not to TNP-Ficoll. Both an anti-IL-5R MoAb and an anti-IL-5 MoAb blocked the rIL-5-induced enhancement of proliferation and auto-antibody PFC responses. Hence, IL-5 appears to be important for the regulation of proliferation and antibody secretion by many murine peritoneal B cells.
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PMID:Interleukin 5 regulation of peritoneal B-cell proliferation and antibody secretion. 230 Jul 91

The influence of dietary fat on autoimmunity in lupus-prone (NZB x NZW)F1 mice has been demonstrated. In defining further the effects of dietary lipid on the immune system of this strain, female weanling mice were placed on four diets differing in quantity and type of fat. Their immunologic response was then studied by a variety of tests at 4 and 7 mo of age. Few differences were seen among the four groups at 4 mo of age. At 7 mo of age, however, the mice receiving diets high in saturated and unsaturated fats had a reduced mitogenic response to T cell mitogens and an enhanced response to the B cell mitogen LPS. Immunoglobulin levels and delayed hypersensitivity responses did not show any consistent differences among the diet groups. At 7 mo, however, mice receiving diets high in unsaturated fat demonstrated hyperresponsiveness to injected sheep red blood cells as measured by the hemolytic plaque technique. In addition, peritoneal leukocytes from the same diet group exhibited an increased response to bromelain-treated autologous erythrocytes which was decreased after treatment with anti-Thy-1 antiserum and complement. Phagocytosis by peritoneal macrophages was significantly decreased in the animals fed high-fat diets, particular high saturated fat. Similarly, natural killer cell activity was markedly reduced in the mice with a high intake of saturated lipid, a finding which correlated with the in vitro production of interferon. These results indicate that diets high in fat influence immune responses and thus can affect the onset and severity of autoimmune disease. A low-fat diet can reduce the development of disease by maintaining normal immune responses. The data also suggest that unsaturated fat may influence T helper cell activity and therefore antibody production, whereas saturated fats may affect cellular immune responses which are dependent on membrane contact.
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PMID:Dietary fat and immune function. I. Antibody responses, lymphocyte and accessory cell function in (NZB x NZW)F1 mice. 241 89

Females have better humoral immune responses and are more susceptible to autoimmune diseases than males. Normal female mice (C57BL/6J, C3H/HeJ, and NZW) have significantly increased spontaneous autoimmune plaque-forming cells (APFC) to mouse erythrocytes pretreated with bromelain (Br-ME) in spleen, peritoneal exudate cell, and bone marrow compared to their male counterparts. A minor subpopulation of B cells, CD5+ B, is thought to produce this autoantibody. As determined by dual color flow cytometry, increased APFC to Br-ME in females is not due to quantitative increase of CD5+ B cells. Rather, it is due to increased numbers or percentages) of CD5+ B cells producing these autoantibodies, because CD5+ B cells from females produced greater numbers of APFC to Br-ME than equal numbers of cells derived from males. The increased autoantibody production in females can be attributed to the effect of estrogen on the immune response because this hormone markedly augments APFC to Br-ME in intact or orchidectomized males. Male hormone had little effect. Importantly, estrogen did not increase the numbers of B or CD5+ B cells but augmented the ability of B cells to produce this response. This was verified when a T cell-depleted B cell fraction or fluorescence-activated cell sorter purified CD5+ B cells from estrogen-treated mice proved more efficient in the production of APFC to Br-ME. These results suggest that the number of CD5+ B cells committed to produce autoantibodies to Br-ME is increased under the influence of estrogen. This is the first demonstration that estrogen can augment the production of natural autoantibodies in normal mice. The overall augmented humoral immune responses in females and the B cell hyperactivity in female predominant autoimmune diseases appears to be due to estrogen.
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PMID:Estrogen induces normal murine CD5+ B cells to produce autoantibodies. 246 34

RIIIS/J mice produce low antibody responses to several polysaccharide Ag of bacterial origin. They have low levels of serum IgM and IgG3 and high levels of serum IgG2a and IgG2b. Low serum IgM and IgG3 have been attributed to a low frequency of CD5 (Ly-1) B cells, which play an important role in the production of natural antibodies. Indeed, RIIIS/J mice have a low frequency of CD5 (Ly-1)+, IgM bright+, Ly-5 (B220)dull+ (i.e., CD5 (Ly-1) B) cells in their peritoneum. RIIIS/J mice treated with LPS produce a low anti-bromelain-treated mouse RBC splenic plaque-forming cell response and a normal anti-mouse transferrin splenic PFC response. Those data are compatible with the fact that CD5 (Ly-1) B cells contain the precursors of B lymphocytes secreting anti-bromelain-treated mouse RBC antibody. However, they have a higher frequency of IgM bright+, Mac-1+ cells in their peritoneum. These cells represent the CD5 (Ly-1) "sister population" of CD5 (Ly-1) B cells described by others. This suggests that characteristics usually associated with the CD5 (Ly-1) lineage are applicable only to the CD5 (Ly-1)+ Mac-1+ IgM+ population, but not the related CD5 (Ly-1)- Mac-1+ IgM+ population. RIIIS/J mice should thus prove a valuable model to study the CD5 (Ly-1) B cell lineage.
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PMID:Characterization of the immunodeficiency of RIIS/J [corrected] mice. I. Association with the CD5 (LY-1) [corrected] B cell lineage. 264 74


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