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Biomedical subjects

C Morimoto

Publications and source records attributed to C Morimoto.

At least 199 records · Page 11Linked to original sources
PubMed1988

Abnormalities in CD4+ T-lymphocyte subsets in inflammatory rheumatic diseases.

The monoclonal antibodies anti-2H4 and anti-4B4 identify the suppressor-inducer (CD4+2H4+) and helper-inducer (CD4+4B4+) subpopulations of CD4 (T4+) lymphocytes, respectively. The cell surface phenotype of peripheral blood lymphocytes and synovial fluid lymphocytes in patients with rheumatoid arthritis and other inflammatory joint diseases was analyzed by use of these and other well-characterized anti-T-cell monoclonal antibodies. In the synovial fluid of patients with rheumatoid arthritis, there was a markedly decreased percentage of T4+2H4+ suppressor-inducer cells (3.1 +/- 1 percent) and an increased percentage of T4+4B4+ helper-inducer cells (29.1 +/- 9 percent) as compared with the proportions found in the peripheral blood of normal individuals (T4+2H4+: 19.0 +/- 6 percent, T4+4B4+: 23.0 +/- 7 percent). Moreover, patients with other chronic and acute inflammatory joint diseases exhibited highly similar synovial T-cell findings to those of the patients with rheumatoid arthritis (T4+2H4+: 4.2 +/- 3 percent, T4+4B4+: 33.1 +/- 9 percent). In contrast, there were no significant differences between the normal control subjects and patients with rheumatoid arthritis in the percentage of T4+2H4+ cells in peripheral blood lymphocytes, nor were there significant differences between normal control subjects, patients with rheumatoid arthritis, and patients with other joint diseases (osteoarthritis, gout, B27+ spondyloarthropathy, and psoriatic arthritis) in the number of T4+4B4+ cells or in the T4/T8 ratio of peripheral blood lymphocytes. However, very low numbers of T4+2H4+ (suppressor-inducer) peripheral blood lymphocytes were seen in a subgroup of patients, including five of seven with Reiter's syndrome and several patients with systemic rheumatic disease syndromes. In addition, although the percentage of T4+2H4+ cells in peripheral blood lymphocytes of patients with osteoarthritis (13.7 +/- 7 percent) and gout (14.3 +/- 7 percent) was decreased compared with that of normal controls (19.0 +/- 6 percent) (osteoarthritis versus normal controls p less than 0.025), this difference appeared to reflect alterations due to age rather than disease. Consistent with the phenotypic changes observed, synovial T cells were also functionally defective, since autologous mixed lymphocyte reaction-activated T4 cells from the synovial fluid of patients with rheumatoid arthritis failed to exhibit suppressor-inducer activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1988

Generation of CD8 (T8) cytotoxic cells has a preferential requirement for CD4+2H4- inducer cells.

CD8 (T8) cells are capable of both suppression and cytotoxicity. However, we have found that the activation of CD8 cytotoxic cells has a preferential requirement for a different CD4 (T4) subset from that previously reported for the activation of CD8 suppressor cells. We have recently characterized two monoclonal antibodies which subdivide CD4 cells into inducers of help for antibody production (CD4+ 4B4+) and inducers of CD8 mediated suppression (CD4+2H4+). We now report that CD4+4B4+2H4- cells also preferentially induce CD8-mediated cytotoxicity. Human peripheral blood T cells were fractionated into CD8, CD4, CD4+2H4+, and CD4+2H4- populations by both the adherence to antibody-coated plates and the fluorescence-activated cell sorter. The cells were cultured 6 days with irradiated allogeneic non-T cells and a cytotoxicity assay was then performed using cryopreserved non-T cells as targets. It was found that the combination of CD4+2H4- cells and CD8 cells resulted in greater cytotoxicity than either CD4 + CD8, or CD4+2H4+ + CD8. The combination of CD4+2H4+ cells with CD8 cells resulted in minimal cytotoxicity, which was similar to that generated by CD8 cells alone. These results were confirmed using anti-4B4 to positively select the reciprocal CD4 subset. Furthermore, the cytotoxicity induced by CD4+2H4- cells was alloantigen specific and Class I major histocompatibility complex restricted. As both CD4+2H4+ and CD4+2H4- cells proliferate equally well to alloantigen and produce similar levels of interleukin 2 (IL-2), it is likely that the generation of CD8 cytotoxic cells requires a signal in addition to IL-2.

Antibodies, Monoclonal↗
PubMed1988

CD11 molecule defines two types of suppressor cells within the T8+ population.

It has been shown that T8+ cells are comprised of functionally heterogeneous subpopulations such as suppressor, cytotoxic, and NK cells. In this report, we attempted to delineate the functional heterogeneity of T8 cells defined by anti-CD11 antibody (anti-Mol). Although allospecific cytotoxic activity was restricted to the T8+Mol- subset, suppression of PWM IgG synthesis could be elicited in both the T8+Mol+ and the T8+Mol- subset of cells. However, the mechanism of suppression was different in these two subsets. Suppression by the T8+Mol- subset of cells required the interaction with the T4+2H4+ suppressor inducer cells, whereas the T8+Mol+ subset of cells could suppress in the absence of the suppressor inducer cells. Moreover, recombinant interleukin-2 alone could augment this suppression by the T8+Mol+ subset, but did not induce suppression by the T8+Mol- subset. In contrast, NK and LAK activity was exclusively found in the T8+Mol+ subset of cells but not in the T8+Mol- subset of cells. These results suggest that the CD11 molecule is useful for distinguishing novel subsets of T8 cells.

Antibodies, Monoclonal↗
PubMed1988

Crosslinking CD3 with CD2 using sepharose-immobilized antibodies enhances T lymphocyte proliferation.

T lymphocyte proliferation can be triggered through interactions with either CD3:Ti, the target of antigen-specific activation, or CD2, the target of an antigen-independent activation pathway. Sepharose-immobilized antibody reactive with CD3 was used to aggregate the T cell receptor complex resulting in T lymphocyte activation. When CD3 was simultaneously crosslinked with CD2 using Sepharose beads coupled to antibodies directed at both determinants, T cell proliferation was markedly enhanced (stimulation index = 8- to 11-fold). A smaller enhancement was induced when CD3 was crosslinked with several other functionally relevant T cell surface molecules. The relative mitogenic potency of the accessory molecules tested was CD2 greater than CD4 greater than CD8 greater than 2H4. Little or no increased proliferation resulted from crosslinking CD3 with class I or class II major histocompatibility antigens. The added proliferation induced by CD3: CD2 crosslinking did not occur in the presence of soluble antibodies directed against CD2. Human thymocytes, the majority of which express both CD3 and CD2, were similarly activated by Sepharose-immobilized antibodies. Our results suggest that specific interactions between T cell surface molecules may play a role in the regulation of lymphocyte activation.

Antibodies, Monoclonal↗
PubMed1988

Monoclonal antibody 4B4 blocks suppression of the immune response to Cryptomeria japonica pollen antigen.

The monoclonal antibody 4B4 blocked the T8+ T cell-mediated suppression of IgE response to Cryptomeria japonica pollen antigen (CPAg). The helper T cells for IgE response to CPAg expressed 4B4 specificity, whereas the suppressor T cells did not. The 4B4 molecule on PBL was a heterodimer and three additional bands were detected on activated CPAg-specific T4+ T cells. They were not closely associated with HLA molecules. It is thus conceivable that the 4B4 molecule is not only a marker of helper T cells but also has an important role in the suppressor-helper interactions in the regulation of IgE response to CPAg.

Antibodies, Monoclonal↗
PubMed1988

Ca2+ uptake in bovine adrenocortical microsomes: formation of phosphorylated intermediate of Ca2+ dependent ATPase.

Bovine adrenocortical microsomes were prepared and partially purified by discontinuous sucrose density gradient. Light fractions of the microsomes at the interface between 15 and 30% sucrose solution, exhibited ATP dependent Ca2+ uptake. The Ca2+ uptake was dependent on temperature and stimulated by free Ca2+ (the concentration for half maximal activation = 1.0 microM) and Mg2+. The Ca2+ uptake was inhibited by ADP but not affected by 10 mM NaN3 or 0.5 mM ouabain. Calcium release from the microsomes was accelerated by a Ca2+ ionophore, A23187, but not by a Ca2+ antagonist, diltiazem. A microsomal protein with a molecular weight of 100-110 kDa was phosphorylated by [gamma-32P]ATP in the presence of Ca2+, and the Ca2+ dependency was over the same range as the Ca2+ uptake (the concentration for half maximal activation = 3.0 microM). The phosphorylated protein (EP) was stable at acidic pH but labile at alkaline pH and sensitive to hydroxylamine. The rate of EP formation at 0 degrees C in the presence of 1 microM ATP and 10 microM Ca2+ (half time = 0.2 s) was less than that in the sarcoplasmic reticulum (SR) of rabbit skeletal muscle (half time = 0.1 s). The rate of EP decomposition at 0 degrees C after adding EGTA was about 6.7 times slower (rate constant: kd = 4.3 X 10(-3) s-1) than that of SR. It was suggested that adrenocortical microsomes contain a Ca2+ dependent ATPase which function as a Ca2+ pump with similar properties to that of SR.

Adenosine Diphosphate↗
PubMed1988

Requirements for the construction of antibody heterodimers for the direction of lysis of tumors by human T cells.

We constructed a series of MAb heterodimers consisting of the J5 (anti-common acute lymphoblastic leukemia antigen [CALLA]) antibody and antibodies to a variety of structures present on the surface of activated human T cells, including CD3 antigen (T cell receptor-associated glycoproteins), CD2 antigen (T11/E-rosette receptor), CD25 antigen (IL-2 receptor), and the transferrin receptor. We tested the ability of these heterodimers to direct a CD2 + CD3 + CD8 + CD4 - CD25 + transferrin receptor + MHC-restricted human cytolytic T lymphocyte (CTL) clone to lyse a CALLA + human tumor in vitro. Only heterodimers containing an anti-CD3 antibody or activating antibodies to CD2 could direct the clone to lyse these human tumor targets, even when the clone was additionally activated with anti-CD3 or anti-CD2 antibodies. Our findings may have implications in the design of strategies for the use of such reagents in the treatment of human neoplasia.

Antibodies↗
PubMed1988

Urushiol (poison ivy)-triggered suppressor T cell clone generated from peripheral blood.

Allergic contact dermatitis to Toxicodendron radicans (poison ivy) is mediated by the hapten urushiol. An urushiol-specific, interleukin 2 (IL-2)-dependent T cell clone (RLB9-7) was generated from the peripheral blood of a patient with a history of allergic contact dermatitis to T. radicans. This clone proliferated specifically to both leaf extract and pure urushiol. Although the clone had the phenotype CD3+CD4+CD8+, proliferation to antigen was blocked by anti-CD8 and anti-HLA-A, B, C, but not by anti-CD4, suggesting that CD4 was not functionally associated with the T cell receptor. Furthermore, studies with antigen-presenting cells from MHC-typed donors indicated that the clone was MHC class 1 restricted. RLB9-7 was WT31 positive, indicating it bears the alpha beta T cell receptor. The clone lacked significant natural killer cell activity and produced only low levels of IL-2 or gamma-interferon upon antigen stimulation. Addition of RLB9-7 to autologous peripheral blood mononuclear cells in the presence of urushiol inhibited the pokeweed mitogen-driven IgG synthesis. This suppression was resistant to irradiation (2,000 rad) and was not seen when RLB9-7 was added to allogeneic cells, even in the presence of irradiated autologous antigen-presenting cells, suggesting that suppression was MHC restricted and not mediated by nonspecific soluble factors. However, RLB9-7 cells in the presence of urushiol inhibited the synthesis of tetanus toxoid-specific IgG by autologous lymphocytes, indicating that the suppression, although triggered specifically by urushiol, was nonspecific.

Antibody Specificity↗
PubMed1988

Defective expression of the 2H4 molecule after autologous mixed lymphocyte reaction activation in systemic lupus erythematosus patients.

Previous studies demonstrated that patients with active systemic lupus erythematosus (SLE), especially those with active renal disease, had a marked reduction in T4+2H4+ suppressor inducer cells in their peripheral blood. However, it was puzzling to find that active SLE patients without renal diseases often had normal percentages of T4+2H4+ cells. In the present study, we attempted to determine whether active SLE patients bearing normal percentages of T4+2H4+ cells had a defect in their expression of the 2H4 molecule on T4+ cells after autologous mixed lymphocyte reaction (AMLR) activation. The peripheral blood lymphocytes (PBL) from 50 SLE patients with normal percentages of T4+2H4+ cells (greater than or equal to 7% in PBL) were studied and the results were compared with those of 40 normal individuals. The density of the 2H4 molecule on T4 cells from normal controls increased during the 7-d AMLR; in contrast T4 cells from patients with SLE, especially those with active SLE, had defective expression of the 2H4 antigen after AMLR activation. Patients with inactive SLE, like normals, showed an increase in the 2H4 molecule after AMLR activation. Moreover, a strong correlation was observed between percent suppression of pokeweed mitogen (PWM)-driven IgG synthesis and the density of the 2H4 antigen on AMLR-activated T4 cells. Serial analysis of patients with SLE showed that the density of the 2H4 antigen expression and the suppressor inducer activity of AMLR-activated T4 cells were inversely correlated with disease activity. Thus, defective expression of the 2H4 antigen may be an important mechanism for the failure of active SLE patients with normal percentages of T4+2H4+ cells to generate suppression.

Adolescent↗
PubMed1987

The subdivision of the T4 (CD4) subset on the basis of the differential expression of L-C/T200 antigens.

The T4 (CD4) subset of T lymphocytes has been subdivided into two major subsets, a suppressor/inducer subset (T4+,2H4+) and a helper subset (T4+,2H4-) on the basis of the differential expression of the L-C/T200 (CD45) antigens. The 2H4 antigen itself comprises at least three distinct polypeptides at 125,200, and 220 X 10(3) Mr, of which the 200 and 220 X 10(3) Mr polypeptides constitute the highest Mr isoforms of a pool of five distinct L-C/T200 antigens. The T4+,2H4+ subset expresses at least four of these isoforms at 180, 190, 200, and 220 X 10(3) on the cell surface, while the T4+,2H4- subset expresses only the 180 and 190 X 10(3) Mr forms. Pulse-chase analysis and endoglycosidase treatment revealed that the 125 X 10(3) Mr chain of the 2H4 antigen is nonglycosylated, while the 200 and 220 X 10(3) polypeptides are structurally related and derived by N- and O-linked glycosylation from two nascent subunits at 150 and 160 X 10(3) Mr. The function of the T4+,2H4+ subset could be blocked only by an antibody reactive with the L-C/T200 isoforms enriched with O-linked oligosaccharides at 200 and 220 X 10(3) Mr.

Antibodies, Monoclonal↗
PubMed1987

Identification of the sequence required for expression of the 2H4 epitope on the human leukocyte common antigens.

The anti-2H4 antibody, which subdivides the T4+ population of human T lymphocytes into T4+, 2H4+ suppressor-inducer cells and T4+, 2H4- helper cells, recognizes an epitope on a subset of the human leukocyte common antigens (LCAs). LCAs are a family of cell surface glycoproteins generated from a single gene by the differential usage of three exons near the NH2-terminus. Using cDNA clones corresponding to four of the different forms of LCA molecules, extracellular domains of the LCA molecules were synthesized in vitro. Immunoprecipitation of these molecules with the anti-2H4 antibody demonstrated that exon A is required for the expression of the 2H4 epitope.

Animals↗
PubMed1987

The T4 molecule differentially regulating the activation of subpopulations of T4+ cells.

It has been demonstrated that the T4+2H4+ subset functioned as a suppressor inducer cell, whereas the reciprocal T4+2H4- subset provided help for B cell Ig production. In the present studies, a series of monoclonal antibodies to cell surface structures expressed on these subsets of cells were examined for their effects on the proliferative and immunoregulatory functions generated in AMLR. We demonstrated that anti-T4 antibody preferentially inhibited the proliferative response of the T4+2H4+ but not T4+2H4- cells against self-MHC antigens. In contrast, anti-T3 and anti-Ia antibodies inhibited the response of both subsets of cells. This subset preference of anti-T4 antibody was not attributable to either the isolation procedures used or a shift in the kinetics of proliferation to autologous self-MHC antigens. Moreover, both IL 2 production and the immunoregulatory function of the T4+2H4+ subset was profoundly inhibited by anti-T4 antibody, whereas the T4+2H4- subset was minimally influenced. In the absence of Ia molecules, T4+2H4+ but not T4+2H4- cell proliferation was inhibited with anti-T4 antibody. Together, these results suggest that the T4 molecule plays a distinct functional role in the differential triggering of subsets of T4+ cells.

Antibodies, Monoclonal↗
PubMed1987

Cross-linking of T3 (CD3) with T4 (CD4) enhances the proliferation of resting T lymphocytes.

Monoclonal antibodies reactive with defined T lymphocyte surface antigens were covalently coupled to protein A-Sepharose beads using the bifunctional imidoester, dimethyl pimelimidate. Sepharose-immobilized antibody reactive with T3 induced the proliferation of resting T lymphocytes in the presence of either recombinant interleukin 2 or phorbol myristate acetate. When monoclonal antibodies reactive with T3 and T4 were coupled to the same Sepharose bead (hereafter designated Sepharose (T3:T4)), proliferation was enhanced an average of three-fold. Similarly prepared Sepharose beads coupled to anti-T3 and anti-T8 also enhanced proliferation over that observed with anti-T3 alone. Sepharose (T3:T4) similarly increased the proliferation of T4+ lymphocytes and a T4+ clone but failed to enhance the proliferation of T8+ lymphocytes. The increased proliferation of T4+ lymphocytes resulted from a preferential activation of the T4+2H4- helper population over the T4+2H4+ suppressor-inducer population. The enhanced proliferation induced by Sepharose (T3:T4) could be completely inhibited by soluble anti-T4. These results suggest that perturbation of T3 may be a minimal signal for T cell activation and that the assembly of a multimeric complex including T3 and T4 may be required for optimal T cell activation.

Antibodies, Monoclonal↗
PubMed1987

Selective loss of the suppressor-inducer T-cell subset in progressive multiple sclerosis. Analysis with anti-2H4 monoclonal antibody.

The T4+ lymphocyte population includes a subset that induces suppressor T lymphocytes (T8+ cells) and can be distinguished by dual-color fluorescence analysis with anti-2H4 and anti-T4 monoclonal antibodies. To investigate the possible role of these cells in multiple sclerosis, we used anti-2H4 antibody to characterize peripheral-blood lymphocyte subsets in 63 patients with multiple sclerosis that was progressive, stable, or acute (relapsing-remitting). Twenty-three of 37 patients with progressive multiple sclerosis had a selective decrease in the number and percentage of peripheral-blood T cells that induce suppressor cells (T4+2H4+ cells), whereas only 3 of 16 patients with stable disease and 2 of 10 patients in the midst of an acute attack had a significant decrease. These selective decreases of circulating T4+2H4+ cells occurred in only 1 of 34 patient controls with other neurologic diseases and in 2 of 50 healthy controls (P less than 0.0001 by Fisher's exact test). The absolute number of T4+2H4+ cells and the percentage of reactivity in the populations studied were 187 +/- 28 per cubic millimeter and 8.3 +/- 1 percent in patients with progressive multiple sclerosis; 353 +/- 60 per cubic millimeter and 14.5 +/- 2 percent in patients with stable disease; 368 +/- 72 and 14.6 +/- 2.1 percent in patients with acute disease; 402 +/- 64 and 15.6 +/- 2 percent in controls with other neurologic diseases; and 519 +/- 44 and 19.7 +/- 1 percent in healthy controls. Functional studies using a pokeweed mitogen-driven IgG assay demonstrated a correlation between decreased numbers of T4+2H4+ cells and increased production of IgG in vitro. Family studies showed that the 2H4 antigen was not part of an inherited polymorphic antigenic determinant. Our results suggest that in progressive multiple sclerosis decreases in inducers of suppressor T cells may permit the activation of cells reactive with elements of the central nervous system.

Adult↗
PubMed1987

Induction of suppression following autologous mixed lymphocyte reaction; role of a novel 2H4 antigen.

In this study, we have investigated the cellular and molecular basis for immunoregulatory function of T4+ cells after autologous mixed lymphocyte reaction (AMLR) activation. We demonstrated that the T4+ 2H4+ subset but not the T4+2H4- subset can proliferate maximally in response to autologous non-T cells. T4+ cells activated by AMLR exerted suppressor activity on pokeweed mitogen-driven IgG synthesis of autologous peripheral blood lymphocytes. The suppressor activity by AMLR-activated T4+ cells required the presence of fresh T8+ cells in the secondary culture, indicating that AMLR-activated T4+ cells functioned as a suppressor inducer rather than as a suppressor effector population. Following activation of T4+ cells in AMLR, it is the T4+2H4+ subset which induces suppression through the T8 population. Moreover, the treatment of AMLR-activated T4+2H4+ cells with anti-2H4 antibody, but not other antibodies, resulted in the abolishment of suppressor inducer function of such cells, suggesting that the 2H4 molecule itself may be involved in the suppressor inducer function. The 2H4 antigen on such cells was shown to be comprised of 220-kDa and 200-kDa glycoproteins. These results support the notion that the AMLR may play an important role in generating suppressor inducer signals and in down-regulating the immune response following self major histocompatibility complex recognition. More importantly, the present studies indicate that the 2H4 antigen on T4 cells serves not only as a phenotypic marker of suppressor inducer cells, but may have a functionally important role itself inducing suppression.

Antibodies, Monoclonal↗