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Biomedical subjects

O Saiki

Publications and source records attributed to O Saiki.

At least 19 recordsLinked to original sources

Acquired T cell specific deficiency other than acquired immunodeficiency syndrome (AIDS).

Evidence of an acquired T cell-specific deficiency distinct from acquired immunodeficiency syndrome (AIDS) in a 63-yr-old Japanese female is provided. Recently, this patients suffered from primary invasive pulmonary aspergillosis. Skin tests to purified protein derivative of tuberculin (PPD) and Aspergillus antigens were negative. Upon admission to our hospital, her lymphocytes were exclusively unresponsive to T cell mitogens (concanavalin A, phytohemagglutinin, and OKT 3). The level of cells defined by monoclonal antibodies (CD1, CD2, CD3, CD4, WT31, and CD5) was less than 3%. In contrast, no decrease in the number of red blood cells, platelets, neutrophils or B cells was apparent. Five years ago, the patient had a normal white blood cell and lymphocyte count. However, over the following 4 yr, she developed lymphopenia. With medication, her pulmonary disease recovered, while lymphopenia still continued. The levels of immunoglobulins, complements and enzyme activities (adenosine deaminase and purine nucleoside phosphorylase) were normal. Moreover, several tests for HIV (ELISA and Western bolt) were negative suggesting that the T cell-specific deficiency was not a congenital immunodeficiency or AIDS but rather a new type of acquired immunodeficiency.

Acquired Immunodeficiency Syndrome

Defective expression of p70/75 interleukin 2 receptor in T cells from patients with systemic lupus erythematosus: a possible defect in the process of increased intracellular calcium leading to p70/75 expression.

Phytohemagglutinin (PHA) stimulated T cells from patients with systemic lupus erythematosus (SLE) showed hyporesponsiveness to interleukin 2 (IL-2) and expressed less p70/75 IL-2R than healthy controls. Ionomycine (IM, calcium ionophore) which selectively upregulated p70/75 expression, induced less p70/75 in patients with SLE than in healthy controls. However, intracellular calcium levels of T cells from patients with SLE increased as much as those from healthy controls, when T cells were stimulated by IM or PHA. Our results suggest that an impaired expression of p70/75 IL-2R in T cells from patients with SLE is not due to a defective calcium influx but to the events after the rise of calcium levels.

Adult

Different induction of p55 and p70/75 interleukin-2 receptor subunits in human cells.

There are two interleukin-2 receptor (IL-2R) subunits (p55 and p70/75) on human lymphocytes. Induction of the expressions of these IL-2R subunits was examined by the protein kinase-C (PK-C) activator (phorbol myristate acetate, PMA) and the calcium ionophore, ionomycine (IM). IM induced predominantly p70/75 expression on human T and B cells as indicated by the results of chemical crosslinking studies and binding assays. In contrast, PMA induced p55 expression significantly. These results suggest that the calcium-calmodulin and PK-C pathways regulate p70/75 and p55 expressions differently, and indicate that these intracellular signal messengers could control the responsiveness to IL-2, changing the affinity and number of receptors in vivo.

B-Lymphocytes

Decreased expression of interleukin-2 binding molecules (p70/75) in T cells from patients with systemic lupus erythematosus.

Using radiolabeled interleukin-2 (IL-2), affinity cross-linking and binding assays revealed that the expression of intermediate-affinity IL-2 binding molecules (p70/75) on freshly prepared T cells from patients with systemic lupus erythematosus (SLE) was significantly decreased in comparison with that in normal subjects. The proliferative response of T cells to high doses of IL-2 was also reduced in patients with SLE. The decreased expression of p70/75 reflects the hyporesponsiveness to IL-2 of T cells in patients with SLE.

Adult

Administration of recombinant IL-2 augments the level of serum IgM in an IL-2 deficient patient.

A patient with ataxia telangiectasia was treated with recombinant interleukin-2 (rIL-2) and the resulting immunological effects evaluated. The patient lacked IL-2 production, and immunoglobulin synthesis was also impaired. Treatment with IL-2 selectively increased serum IgM without any significant side effects. Therapy also restored B-cell function in vitro. IgM production as well as the proliferative response to Staphylococcus aureus strain Cowan I. These results suggest that IL-2 treatment may correct both T-cell and B-cell defects.

Adolescent

Age-related changes of expression of IL-2 receptor subunits and kinetics of IL-2 internalization in T cells after mitogenic stimulation.

The age-associated changes of the expression of IL-2 binding molecules p55/Tac(alpha chain) and p70/75(beta chain) were examined after phytohemagglutinin (PHA) stimulation. The expressions of both p55/Tac molecules and p70/75 molecules were significantly reduced in the aged compared with those in the young persons. The amounts of p55/Tac and p70/75 molecules on T cells from the aged were 55% and 59% of those on young ones, respectively. The ratio of the amount of p70/75 to that of p55/Tac in aged T cells was 0.28 and that in young ones was 0.26. The ratio was somewhat higher in the aged but not significantly. We also examined the kinetics of IL-2 internalization mediated by its receptor. The calculated t1/2 of receptor-mediated IL-2 internalization was 17 min in the aged and 16 min in the young, respectively. There was no kinetic difference between the 2 groups. The percentage of the internalized IL-2 to the sum total was 58.2% in the aged and 73.4% in the young (P less than 0.02). the amount of internalized IL-2 in T cells from the aged was 48.6% of that from the young (P less than 0.01).

Adult

Expression and the functional role of a p70/75 interleukin 2-binding molecule in human B cell.

Expression of p70/75 IL-2-binding molecules and their functional roles in induction of Ig secretion by IL-2 were examined in human B cells. IL-2, at high concentrations induced higher levels of Ig secretion in Staphylococcus aureus strain Cowan I (SAC)-activated B cells than at low concentrations. About 50% of SAC-activated B cells, lacking Tac antigen, were also responsive to Ig secretion by IL-2, although the required dose of IL-2 was higher than that for Tac-positive B cells. H-31 antibody which recognizes Tac antigen did not inhibit the induction of Ig secretion by high concentrations of IL-2 in both Tac-negative and Tac-positive B cells, suggesting that IL-2 might induce Ig secretion through a receptor distinct from Tac antigens. In contrast, IL-2 was ineffective in the absence of SAC stimulation even at high concentrations. Upon analysis by SDS-PAGE, p70/75 IL-2-binding molecules were detected on Tac-negative SAC-activated B cells. Similar IL-2-binding molecules distinct from Tac antigen (p55) were detected in both Tac-positive B and T cells. However, neither p55 nor p70/75 IL-2-binding molecules could be detected in the absence of SAC stimulation. These observations suggest that p70/75 IL-2 binding molecules are induced in human B-cells in the presence or absence of Tac antigen by SAC stimulation and these determinants play an important function in the transduction of IL-2 associated signal for B cell differentiation.

Antibodies, Monoclonal

Novel receptor-mediated internalization of interleukin 2 in B cells.

Novel IL-2-binding molecules (p70 and p75) mediating internalization and degradation of IL-2 were examined by employing a human B lymphoblastoid line, SKW6-4 cells. High concentrations of IL-2 induced IgM secretion in these cells through a receptor distinct from Tac antigen. The acid-wash technique revealed that more than 60% of 125I-labeled IL-2 bound to the cells became acid-unremovable in the first 30 min of incubation at 37 degrees C and degradation products of 125I-IL-2 increased after 30 min of incubation. Treatment of the cells with NaN3 buffer inhibited the appearance of acid-unremovable 125I-IL-2, suggesting that acid-unremovable 125I-IL-2 was not due to fluid-phase pinocytosis but due to internalization. Loss of labeled bands by incubation of cells with 125I-IL-2 at 37 degrees C before affinity cross-linking demonstrated that 125I-IL-2 was internalized via novel IL-2-binding molecules. These results suggest that novel IL-2-binding molecules are responsible for internalization and may mediate signal transduction in B cells in the absence of Tac antigen.

Azides

Interleukin 2 functions through novel interleukin 2 binding molecules in T cells.

In this report, we examined whether novel interleukin 2 (IL-2) binding molecules (p70/75) are responsible for signal transduction and internalization of IL-2 in T cells by using a monoclonal antibody H-31 to Tac antigens. We found that H-31 inhibited the binding of IL-2 to Tac antigens but not novel IL-2 binding molecules. Scatchard plot analysis revealed that in the presence of H-31, intermediate affinity sites (Kd = 1 to 1.5 nM) were detectable and the number of them was similar to that of high affinity IL-2 receptor (IL-2R) (Kd = 10 to 15 pM) in the absence of H-31. Furthermore, the kinetics of endocytosis of IL-2 via p70/75 showed the same pattern as via high affinity IL-2R. Finally, high doses of IL-2 (100 to 10,000 U/ml) are required for the proliferation of T cells in the presence of H-31, whereas in the absence of H-31, physiologic doses of IL-2 (1 to 100 U/ml) induced the proliferation. These results taken together suggest that novel IL-2 binding molecules are related to signal transduction of IL-2 and that Tac antigens are essential for constructing of high affinity IL-2R, although Tac antigens may not be responsible for signal transduction.

Antibodies, Monoclonal

Cellular and genetic analyses of IL-2 production and IL-2 receptor expression in a patient with familial T-cell-dominant immunodeficiency.

Cellular and genetic analyses of interleukin-2 (IL-2) production and IL-2 receptor (IL-2R) expression were examined in a immunodeficient patient and his family members. Mononuclear cells (MNC) of the patient showed no proliferative response (stimulation index, less than 2) to T-cell mitogens (PHA and Con A) and were defective in IL-2 production and IL-2R expression (less than 1%), whereas productions of other lymphokines (B-cell differentiation factor and IFN-gamma) were not impaired significantly. His brother died of the same disease and his father also lacked in proliferative response and IL-2 production by PHA stimulation. In Southern blot analyses using DNA probes of IL-2 and IL-2R, patterns of the patient were the same as those of healthy volunteers, whereas the transcription of DNA coding for IL-2R to mRNA was lacking in the patient. These results suggest that inheritant defects of IL-2 production and IL-2R expression reside in this family and the defects are not linked to DNAs coding for IL-2 and IL-2R but to a transcriptional deficiency.

Concanavalin A

Expression of novel interleukin 2 binding molecules and their functional roles in human B cell differentiation.

Expressions and functional roles of novel IL-2 binding molecules (p70, 75) in the differentiation of B cells into Ig secreting cells were explored by using human several B cell lines and tonsillar B cells. Affinity-crosslinking studies revealed that five of nine B cell lines expressed p70 and p75 without detectable Tac antigen (p55) expression and the expression was associated with B cell maturation. In tonsillar B cells, small high-density B cells did not express p70 and p75, whereas large low-density B cells, which were thought to be activated in vivo, expressed them. Binding assays of radiolabeled IL-2 showed that the affinity of these molecules was intermediate (kD = 1-3 nM, 700-3,000 sites/cell). Furthermore, high concentrations of IL-2 (greater than 100 U/ml) induced Ig productions in large B cells and two of five cell lines. These results taken together suggest that B cells may express novel IL-2 binding molecules, associated with B cell differentiation and differentiate into Ig secreting cells by IL-2 through novel IL-2 binding molecules.

Antigens, Surface

Development of selective IgM deficiency in systemic lupus erythematosus patients with disease of long duration.

Statistical analysis of serum immunoglobulin levels in 54 systemic lupus erythematosus (SLE) patients showed a decrease in serum IgM (normal 77 +/- 26 mg/dl; P less than 0.001) that was closely related to disease duration. The longer the duration of SLE, the more striking the decrease in serum levels of IgM (r = -0.74, P less than 0.01). Selective IgM deficiency (less than 47 mg/dl) occurred in SLE patients whose disease was clinically inactive or less active.

Adolescent

Functional interleukin 2 receptors on B cells lacking Tac antigens.

Human B lymphoblastoid line, SKW 6-4, cells were induced to IgM-secreting cells by high concentrations of interleukin 2 (IL 2). These cells were found to be unreactive with anti-Tac antibody and did not express mRNA detectable for Tac antigen. In Scatchard plot analysis, low-affinity IL 2-binding sites were found on SKW 6-4 cells. Moreover, analysis of the IL 2-binding molecules revealed ones (molecular weight 70,000 and 75,000) distinct from Tac antigen. It is conceivable that IL 2 exerts its effect through its interaction with these novel IL 2-binding molecules in SKW 6-4 cells.

Antigens, Surface

Age-related changes of the function of T cell subsets: predominant defect of the proliferative response in CD8 positive T cell subset in aged persons.

The proportion of CD8 positive cells in the peripheral blood AET-rosette forming T cells from aged persons was significantly reduced than that from young persons. The difference in the proportion between aged and young groups became more significant after proliferative response to a mitogen phytohemagglutinin (PHA) or a specific antigen tuberculin active peptide (TAP). The purified macrophage-deprived T cells (Twp), CD4 (T4) positive cells or CD8 positive cells were prepared from aged or young persons. These cell preparations lost proliferative response to PHA or TAP but showed marked proliferative response to the combined stimulation to 1 microM of ionomycin and 1 nM of phorbol-12-myristate-13-acetate (PMA) at usual culture cell density (2.5 X 10(5)/ml). Proliferative responses of these cell preparations to the combined stimulation were significantly reduced in the aged than those in the young and the magnitude of the difference in the proliferative responses between aged and young groups was more pronounced in CD8 positive cell population than in CD4 positive cell population. Although the cell preparations were relatively independent of exogenous IL-2 for the proliferative response to the combined stimulation of ionomycin and PMA at usual culture cell density, they needed exogenous IL-2 for sustained proliferation at lower culture cell density (5 X 10(3)/ml). These IL-2-dependent proliferative responses to the combined stimulation in the aged were significantly lower than those in the young and again the difference in the proliferative magnitude between aged and young groups was greater in CD8 positive population. The mechanism(s) of age-related change of the proportion and proliferative ability of T subsets were discussed.

Adult

Age-associated changes in proliferative and differentiative response of human B cells and production of T cell-derived factors regulating B cell functions.

The abilities of highly purified B cells to repeat replication for clonal expansion and to differentiate into immunoglobulin secreting cells (ISC) were examined in the aged and young groups. B cells from the aged showed twofold less proliferative response to B cell mitogen Cowan 1 (SAC) than those from the young. The original clone size of SAC responding B cells determined by colchicine block and [3H] thymidine [( 3H] TdR) uptake was not significantly reduced in the aged whereas the ability to repeat replication to expand clonal size was significantly reduced. B cells from aged and young persons were induced into ISC by combined stimulation with SAC and partially purified B cell differentiation factor (BCDF) free of IL-2 activity. ISCs for IgG and IgA were rather increased or at least not reduced in number in the aged as compared with those in the young. We also determined the IL-2 and BCDF activity produced by T cells from aged and young persons. Upon PHA stimulation, the aged T cells produced tenfold less IL-2 activity and threefold higher BCDF activity than did young T cells. Approximately threefold increase in spontaneous secretion of BCDF activity by aged T cells was found as compared with young T cells. The inverse correlation between the IL-2 activity and BCDF activity was found when both activities were determined in the same samples.

Adult

Mechanisms of age-related decline in antigen-specific T cell proliferative response: IL-2 receptor expression and recombinant IL-2 induced proliferative response of purified Tac-positive T cells.

Proliferative response of T cells from aged persons was significantly reduced to a specific antigen tuberculin-active peptide (TAP) determined by [3H]TdR uptake and FCM in comparison to that from the young. Cytokinetic analysis for the proliferative response to TAP showed that, in the aged, the clonal size or the number of the first generation responding cells to TAP was not significantly reduced but the ability to repeat replication was more profoundly affected. Neither the delayed entry into the cell replication nor prolongation of the cell cycle time could explain these results. Similar results have been reported on the proliferative response of T cells to mitogen: PHA (Phytohemagglutinin). Expression of Tac-antigen on T cells determined by anti-Tac antibody binding with FACS after stimulation with either TAP or PHA was found to be reduced significantly in the aged. Both the numbers of high and low affinity IL-2 receptors determined by radiolabelled IL-2 binding assay were also reduced in the aged, but the degree of reduction in number of high affinity ones was more pronounced than that in low affinity ones. Tac-positive T cells were isolated with the use of anti-Tac rosette methods and stimulated with recombinant IL-2 (r-IL-2). Their proliferative response was significantly lower in the aged than that in the young at any concentration of r-IL-2 examined. The number of the first generation responding cells to r-IL-2 in purified Tac-positive T cells from the aged was 82% of that from the young whereas the proliferative response by aged T cells was 39% of that by young ones when the cells were allowed to repeat replication for 3 days. The mechanisms of these multifactorial defects in proliferation of T cells from aged persons were discussed.

Adult

Rescue of IgM, IgG, and IgA production in common varied immunodeficiency by T cell-independent stimulation with Epstein-Barr virus.

We previously defined three categories of B-cell defects in common varied immunodeficiency (CVI): failure to produce IgG and IgA in response to T cell-dependent (TD) stimulation by Staphylococcus bacteria (Sac) plus pokeweed mitogen or B-cell inducing factor (BIF), failure to produce any immunoglobulin, and failure of Sac-induced proliferation and differentiation. The present study includes the responses of 22 CVI patients to T cell-independent (TI) stimulation by Epstein-Barr virus (EBV). In the majority of patients, EBV-stimulated B cells showed normal proliferation and IgM production. In addition, IgG and IgA production was in the range of that for EBV-stimulated normal cells in many patients. Among 11 patients with no TD production of immunoglobulin of any isotype, two showed normal IgM secretion in response to EBV and five others had significant but subnormal responses. Four patients never had humoral responses despite repeated testing and removal of potentially suppressing T cells and monocytes. Concanavalin A stimulation of the T cells from all the patients tested resulted in the production of B-cell inducing factor at higher levels than for normal donor T cells, as assayed on normal Sac-stimulated B cells. These results show that many cases of B-cell defects in CVI patients involving TD production of IgM, switching to TD production of IgG and IgA, and mitogen responses to Sac are not absolute defects. The B cells will respond normally to some stimuli.

Adolescent

Spontaneous immunoglobulin A secretion and lack of mitogen-responsive B cells in systemic lupus erythematosus.

In an analysis of lymphocyte functions of systemic lupus erythematosus (SLE) patients, B cell abnormalities such as a lack of mitogen-responsive B cells and a predominance of spontaneous IgA-secreting cells (SC) were found. Lymphocyte functions of 20 SLE patients were studied. Impaired proliferative response to B cell mitogen, Staphylococcus aureus strain Cowan I (Cowan I), was observed, whereas the response to T cell mitogen phytohemagglutinin was normal. High levels of spontaneous IgA-SC were observed in SLE patients (greater than 10(2) cells/10(4) peripheral blood mononuclear cells [PBMC]), whereas spontaneous IgM-, IgG-, or IgE-SC were not proportionately increased. The number of spontaneous IgA-SC decreased with time in culture and became undetectable by day 5 of culture. In contrast, spontaneous immunoglobulin- (IgM, IgG, and IgA) SC were not observed in healthy volunteers (less than 10 cells/10(4) PBMC). Moreover, in SLE patients failure of induction of immunoglobulin-secreting cells (ISC) was observed when B cells were stimulated by Cowan I and B cell differentiation factor at any day tested, whereas ISC were induced in healthy volunteers on day 6 of culture. Depletion of T cells or macrophages did not affect the results obtained. These results suggest that the abnormalities observed in SLE B cells are not due to the in vitro direct effects of suppressor macrophages or suppressor T cells, and that the condition of the predominance of spontaneous IgA-SC and the unresponsiveness to exogenous stimulation may be emblematic of hyperactive B cells in SLE.

Antibody-Producing Cells