Functional significance of CD23- on CD23-transfected Th2 clone

CD23, a low-affinity IgE Fc receptor, is not displayed on most resting T cells but its expression has been shown to be transiently induced in vivo and in vitro on some CD4+ T cells [1-4] and in vivo on CD8+ T cells by IgE-secreting hybridoma tumors [5]. To investigate the functional role of CD23 on T cells, we inserted a CD23 construct into an expression vector driven by a CD2 promoter and transfected it into a murine Th2 clone D10.G4.1 (D10). We stimulated the transfected D10 cells (D10.3M.24) with anti-TCR antibody in the presence or absence of IgE, and measured IL-4, IL-5 and IL-6 production in the culture supernatants. Activation of D10.3M.24 cells by anti-TCR antibody induced greater levels of IL-4, IL-5 and IL-6 production, when the TCR and CD23 were co-crosslinked by TNP anti-TCR and IgE anti-TNP antibodies. IgG anti-TNP antibody did not enhance lymphokine production by D10.3M.24 cells. The enhanced lymphokine production by IgE was blocked by monoclonal anti-CD23 antibody. IgE anti-TNP antibody did not enhance lymphokine production by the wild-type D10 cells induced by TNP anti-TCR antibody. These studies show that when co-crosslinked with the TCR, CD23 can modulate the lymphokine production in activated Th2 cells. Since CD23 binds to IgE and also binds to CD21 [6], a complement receptor commonly expressed on B cells, T-cell CD23 could play an immunoregulatory role during cognate T-B cell interaction and during IgE antibody responses.

Functional consequences of the interaction between T-cell antigen receptors and Fc gamma Rs on T cells

Two series of experiments are presented indicating that Fc gamma II receptors can interfere with the antigen receptor-induced signaling on T cells. It has been previously described that a 13 amino acid motif on the cytoplasmic portion of Fc gamma II beta 1 can abrogate the antigen receptor-initiated signals mediated through consensus motifs present on the cytoplasmic portion of Ig alpha and Ig beta chains. Similar activating motifs are crucial to T-cell receptor (TCR) signaling. A splenic gamma/delta T-cell hybridoma that expressed the Fc gamma RII beta 1 receptor helped to establish that this receptor can also interfere with TCR-induced activation. The cytoplasmic portion of human Fc gamma RIIa has an activation motif similar to the activation motifs present on the TCR. Using a transgenic mouse in which the T cells express the human Fc gamma RIIa transgene, we demonstrated that despite the common activation motif, the TCR and human Fc gamma RIIa-induced signals are different. Additionally, the human Fc gamma RIIa expressing T cells exhibit an enhanced TCR response both in vitro and in vivo.

Roles of eosinophils and catecholamines in pathophysiology of exercise-induced asthma

To study the roles of eosinophils and catecholamines in the pathophysiology of exercise-induced asthma (EIA), an exercise challenge test was performed in 22 asthmatic children, using a bicycle ergometer, and the changes in lung function, plasma norepinephrine (NE), epinephrine (E) and eosinophil cationic protein (ECP) levels with exercise were evaluated. Subjects were classified into three groups from the results of lung function test, respectively: EIA-negative group. EIA-positive groups with good recovery and poor recovery. Eosinophil counts before exercise in the EIA-positive groups were significantly higher than those in the EIA-negative group. The ECP levels rose with exercise in all groups. Five minutes after exercise, ECP values fell to the pre-exercise level in the EIA-negative group, but rose to higher levels in EIA-positive groups. Plasma E levels rose with exercise and showed 4-fold increase in the EIA-negative group, whereas only 1.5-fold increase of plasma E levels was observed in the EIA-positive group with poor recovery. From these findings, a possible contribution of sympathoadrenal hypofunction and a probable involvement of eosinophils in the pathophysiology of EIA have been suggested.

Induction of phosphatidylinositol-linked Fc gamma receptor III expression on an eosinophilic cell line, EoL-1, by dibutyryl cyclic AMP and interferon-gamma

The expression of Fc gamma receptor III (Fc gamma RIII) on a human eosinophilic leukemia cell line, EoL-1, was examined and compared with its expression on normal blood eosinophils. Surface Fc gamma RIII expression on EoL-1 cells could be induced in vitro with a combination of dibutyryl cAMP (dbcAMP) and gamma-interferon (IFN-gamma), but not with IFN-gamma or dbcAMP alone. Pretreatment of EoL-1 cells with dbcAMP induced EoL-1 cells to express Fc gamma RIII when stimulated with IFN-gamma, but EoL-1 cells pretreated with IFN-gamma and then stimulated with dbcAMP failed to express Fc gamma RIII. Cyclic AMP was shown to play a role in the effect of dbcAMP. Both the treatment with phosphatidyl-inositol-specific phospholipase C (PI-PLC) and the restriction enzyme digestion of Fc gamma RIII cDNA showed that the Fc gamma RIII on EoL-1 cells was a phosphatidylinositol-linked form. On the other hand, freshly isolated blood eosinophils constitutively expressed few, if any, Fc gamma RIII, and IFN-gamma induced Fc gamma RIII expression on them in vitro. Dibutyryl cAMP did not induce Fc gamma RIII expression and even suppressed the IFN-gamma-induced Fc gamma RIII expression on normal eosinophils. The EoL-1 cell line appears to be a useful in vitro model for the expression and function of the phosphatidylinositol-linked form of Fc gamma RIII on eosinophils.

Treatment of patients with chronic hepatitis using ursodeoxycholic acid

We treated 82 patients of chronic hepatitis using 300 mg. of ursodeoxycholic acid (UDCA) daily and observed them for a mean of 10 mo before and 16 mo after UDCA administration. Seven liver function tests (AST, ALT, ALP, LAP, GTP, Ch-E and T-cholest) were assessed monthly. The values were compared before and after the administration of UDCA. The AST, ALT, LAP and GTP improved significantly in the UDCA treated patients, whereas ALP, Ch-E and T-cholest. did not show any change throughout the study. Amongst the liver function tests that improved, the serum--GTP level, in particular decreased markedly and rapidly in patients treated with UDCA. Although UDCA 600-mg daily was administered in patients who showed lack of improvement with 300-mg UDCA treatment, no significant improvement was obtained. Repeated liver biopsies were carried out in six of the 42 patients in whom liver biopsy had been performed before the administration of UDCA. We detected no histological changes during the UDCA treatment. There were no side effects related to therapy with UDCA. In conclusion, we confirmed that UDCA is a safe and effective drug for treating patients with chronic hepatitis and may help in prevention of progression of the disease, particularly in patients with a high serum--GTP level.

Inhibitory effects of azelastine hydrochloride on Ca2+ influx, actin polymerization and release of eosinophil cationic protein of an eosinophilic leukaemia cell line EoL-1

The inhibitory effects of azelastine hydrochloride on PAF-induced and fMLP-induced Ca2+ influx, actin polymerization and calcium ionophore A23187-induced and aggregated IgG-induced release of eosinophil cationic protein (ECP) of an eosinophilic leukaemia cell line, EoL-1, were examined. EoL-1 cells cultured with 0.2 mM dibutyryladenosine-cyclic monophosphate for 48 hours showed an increase in intracellular free Ca2+ concentration ([Ca2+]i) and actin polymerization when stimulated by PAF and fMLP. Azelastine hydrochloride inhibited PAF-induced and fMLP-induced Ca2+ influx ([Ca2+]i) in a dose-dependent manner with an IC50 of 1 x 10(-8) M and 1 x 10(-7) M, respectively. It also inhibited PAF-induced and fMLP-induced actin polymerization in a dose-dependent manner up to 40% and 30%, respectively. EoL-1 cells were differentiated to contain ECP in their eosinophilic granules when cultured for 9 days with supernatants of a human adult T cell leukaemia cell line, HIL-3 (HIL-3 sup). Calcium ionophore A23187 and aggregated IgG induced the secretion of ECP by EoL-1 cells. Azelastine hydrochloride inhibited the secretion of ECP in a dose-dependent manner. These inhibitory effects were seen even at therapeutic concentrations of 10(-8) M to 10(-9) M. These results indicate that the therapeutic effects of azelastine hydrochloride as an anti-allergic agent may include inhibition of the accumulation of eosinophils into the locus of allergic inflammation and of the release of cytotoxic granules from eosinophils.

Regulation of the expression of leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) on a human eosinophilic leukemia cell line EoL-3

The effects of several cytokines and phorbol myristate acetate (PMA) on LFA-1 and ICAM-1 expression on a human eosinophilic leukemia cell line, EoL-3, were investigated and compared with those of a human monocytic leukemia cell line, U937. EoL-3 cells expressed large amounts of LFA-1 and small amounts of ICAM-1, and their expression was regulated similarly in EoL-3 cells and U937 cells. Interferon-gamma (IFN-gamma) enhanced ICAM-1 expression but not LFA-1 expression, and PMA augmented both LFA-1 and ICAM-1 expression. IFN-gamma and PMA showed an additive effect on ICAM-1 expression. These results collectively suggest that expression of LFA-1 and ICAM-1 is regulated differently and that IFN-gamma and PMA regulate the expression through different mechanisms. PMA but not IFN-gamma induced homotypic adhesion of EoL-3 and U937 cells, suggesting that PMA but not IFN-gamma activated the adhesive function of these cells. Staurosporin, an inhibitor of protein kinases (PKs), partly suppressed IFN-gamma- and PMA-augmented expression of ICAM-1 on EoL-3 and U937 cells, but did not affect PMA-augmented LFA-1 expression, suggesting that staurosporin-sensitive PKs are involved in IFN-gamma- and PMA-augmented ICAM-1 expression but not in PMA-augmented LFA-1 expression. The role of protein kinase C (PK-C) in these mechanisms was not revealed because a PK-C inhibitor, H-7, did not show any definitive effect on IFN-gamma- and PMA-induced expression of LFA-1 and ICAM-1. Moreover, cyclic AMP (cAMP)- and cGMP-dependent pathways were not shown to be involved in the augmentation of the expression of these molecules.

Dibutyryl cyclic AMP induces formyl peptide receptor expression and chemotactic responses in a human eosinophilic cell line, EoL-1

We investigated actin polymerization and the increase of cytosolic free calcium concentration ([Ca2+]i) in a human eosinophilic leukemia cell line, EoL-1, in response to stimulation with chemotactic factors; we also investigated the effect of dibutyryl cyclic AMP (dbcAMP) on the responses. EoL-1 cells under normal culture conditions did not show either actin polymerization or an increase in [Ca2+]i when stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP). Expression of formyl peptide receptors was not detectable on untreated EoL-1 cells, either. Dibutyryl cAMP induced the expression of formyl peptide receptors and the responsiveness to fMLP. The responsiveness of EoL-1 cells to the complement fragment C5a and platelet-activating factor (PAF) was also induced or enhanced by dbcAMP. The growth of EoL-1 cells was decreased and the proportion of cells in the G0/G1 phase of the cell cycle was increased by the treatment of EoL-1 cells with dbcAMP. The proportion of eosinophilic granule-containing cells and the content of eosinophil cationic protein (ECP) in EoL-1 cells was also increased when they were stimulated with dbcAMP for a longer period. The responsiveness of EoL-1 cells to fMLP, C5a, and PAF was shown to be regulated independently. EoL-1 cells and dbcAMP seem to be useful for examining chemotactic receptor expression and its signal transduction mechanisms.

[An operative case of solitary interruption of the aortic arch in adult]

A 43-year-old lady was hospitalized due to easy fatiguability in the legs during exercise, and for evaluation of an abnormal shadow in the chest X-ray, and hypertension. Her blood pressure was 200/80 mmHg in the right arm, 140/70 mmHg in the left, and 110/70 mmHg in both lower extremities. Systolic vascular bruit radiating to her neck and back was audible in the Erb's area. DSA and aortogram disclosed extremely dilated vessels around the origin of the left common carotid artery. The left subclavian artery was opacified retrogradely as a subclavian blood steal via the left vertebral artery, and mild stenosis was seen at its origin. There was no evidence of associated congenital anomaly such as VSD, PDA, or ASD. The final diagnosis, solitary interruption of the aortic arch (S-IAA, type B), was made by MRI. The patient had an extra-anatomical bypass operation by using Cooley woven dacron graft from the ascending to the abdominal aorta. The result was good. S-IAA is a very rare congenital anomaly. As far as we know, only 21 patients with S-IAA including this case have been reported. A physician should be aware that a patient with S-IAA tends to have a difference of blood pressure not only between the upper and lower extremities but also between both arms, and pressure in the right arm is usually higher than that in the left. These are good signs to suspect S-IAA. And they also can be helpful to differentiate S-IAA from coarctation of the aorta.

Regulation of Fc gamma receptor subtype expression on a human eosinophilic leukemia cell line EoL-3: participation of cAMP and protein kinase C in the effects of interferon-gamma and phorbol ester

We investigated the effects of interferon-gamma (IFN-gamma), phorbol myristate acetate (PMA), and dibutyryl cAMP (Bt2cAMP) on Fc gamma R subtype expression on a human eosinophilic leukemia cell line, EoL-3. Unstimulated EoL-3 cells expressed Fc gamma RII as determined by monoclonal antibody (mAb) IV-3, whereas there was little or no Fc gamma RI and Fc gamma RIII expression as determined by mAbs 32.2 and 3G8, respectively. IFN-gamma induced Fc gamma RI expression, and Bt2 cAMP, which did not induce Fc gamma RI expression by itself, showed an additive effect on IFN-gamma-induced Fc gamma RI expression. Fc gamma RII expression was augmented by IFN-gamma, PMA, and Bt2 cAMP. Bt2 cAMP also showed an additive effect on IFN-gamma-augmented Fc gamma RII expression. Fc gamma RIII expression could be induced only by IFN-gamma plus Bt2 cAMP. H-7, a protein kinase C (PK-C) inhibitor, suppressed the enhancement of Fc gamma R subtype expression induced by these reagents. These results show that Fc gamma R subtype expression on EoL-3 cells is regulated differently in each subtype and that cAMP and PK-C play important roles in the regulation.

Growth regulation of a human mature B cell line, B104, by anti-IgM and anti-IgD antibodies

An EBNA- human B lymphoma cell line, B104, was established. B104 cells express IgD as well as IgM on their surface, which is thought to be a basic characteristic of mature B cells. The growth of B104 cells was inhibited by treatment with a panel of anti-IgM antibodies. Cell cycle analyses revealed that the transition of B104 cells from the G2/M to the G0/G1 phase of the cell cycle was markedly inhibited by treatment with anti-IgM antibodies. Progression of B104 cells to the M phase of the cell cycle was found to be suppressed in the presence of anti-IgM antibodies. In contrast, both the entrance of G0/G1 phase cells into the S phase and the progression of S phase cells to the G2/M phase of the cell cycle did not seem to be inhibited significantly by treatment with anti-IgM antibodies. These results indicate that the mechanism of the inhibition of growth of B104 cells by anti-IgM antibodies is blockage of the transition from the G2 to the M phase of the cell cycle. In contrast to anti-IgM antibodies, anti-IgD antibodies could not cause growth inhibition of B104 cells at all. B cell growth factors such as IL-4 and IL-6 had no effect on the inhibition of growth of B104 cells by anti-IgM antibody. IFN-alpha and -beta, which have no B cell growth factor activity, did increase the number of cells that survived the treatment with anti-IgM antibodies. B104 is an excellent experimental model for the study of the mechanism of signal transduction through sIg as well as the functional difference between sIgM and sIgD.

Growth regulation of a human mature B cell line, B104, by anti-IgM and anti-IgD antibodies

An EBNA- human B lymphoma cell line, B104, was established. B104 cells express IgD as well as IgM on their surface, which is thought to be a basic characteristic of mature B cells. The growth of B104 cells was inhibited by treatment with a panel of anti-IgM antibodies. Cell cycle analyses revealed that the transition of B104 cells from the G2/M to the G0/G1 phase of the cell cycle was markedly inhibited by treatment with anti-IgM antibodies. Progression of B104 cells to the M phase of the cell cycle was found to be suppressed in the presence of anti-IgM antibodies. In contrast, both the entrance of G0/G1 phase cells into the S phase and the progression of S phase cells to the G2/M phase of the cell cycle did not seem to be inhibited significantly by treatment with anti-IgM antibodies. These results indicate that the mechanism of the inhibition of growth of B104 cells by anti-IgM antibodies is blockage of the transition from the G2 to the M phase of the cell cycle. In contrast to anti-IgM antibodies, anti-IgD antibodies could not cause growth inhibition of B104 cells at all. B cell growth factors such as IL-4 and IL-6 had no effect on the inhibition of growth of B104 cells by anti-IgM antibody. IFN-alpha and -beta, which have no B cell growth factor activity, did increase the number of cells that survived the treatment with anti-IgM antibodies. B104 is an excellent experimental model for the study of the mechanism of signal transduction through sIg as well as the functional difference between sIgM and sIgD.

Transforming growth factor beta and dexamethasone suppress the expression of Fc epsilon receptor 2 (CD23) on a human eosinophilic cell line EoL-3

The effects of interferon-alpha (IFN-alpha), INF-gamma, transforming growth factor beta (TGF-beta) and dexamethasone on low-affinity Fc receptors for IgE (Fc epsilon R2/CD23) expression on a human eosinophilic leukemia cell line, Eol-3, were examined. Fc epsilon R2/CD23 expression was enhanced by both IFN-alpha and IFN-gamma, and suppressed by TGF-beta and dexamethasone. Northern blot analysis revealed that these reagents regulate the Fc epsilon R2/CD23 expression from mRNA level: both IFN-alpha and IFN-gamma increased the amount of Fc epsilon R2/CD23 mRNA, while both dexamethasone and TGF-beta decreased Fc epsilon R2/CD23 mRNA, where the effect of dexamethasone was much stronger than that of TGF-beta. In comparison with IFN-alpha, IFN-gamma seemed to enhance preferentially the release of surface Fc epsilon R2/CD23, which resulted in the increase of soluble Fc epsilon R2/CD23. These results suggest that these reagents may play important regulatory roles in allergy and in helminth infections via their effects on Fc epsilon R2/CD23 expression on eosinophils.

Indocyanine green (ICG) test before and after exercise in patients with chronic liver diseases

The indocyanine green (ICG) test (serum disappearance rate: K and 15 min. retention rate: R15) was performed in 15 patients with chronic hepatitis (CH) and 22 patients with liver cirrhosis (LC) before and after exercise (Master's two step method for three min.). In LC, ICG K was 0.063 +/- 0.026 (mean +/- SD) before exercise and 0.083 +/- 0.028 after exercise. ICG R15 was 31.6 +/- 15.6% and 23.3 +/- 15.3%, respectively. In CH, ICG R15 before exercise was 8.2 +/- 4.0%, as compared with that (5.7 +/- 3.6%) after exercise. Namely, the ICG test significantly (P less than 0.05) improved after exercise in chronic liver diseases. Excretion of ICG into bile after exercise increased both in gallstone patients without abnormal liver function and LC, and it markedly increased in patients with decompensated LC. There was no significant difference in ICG excreted into urine before and after exercise. These results suggest that hepatic blood flow increases through moderate exercise in chronic liver diseases.

Detection of liver membrane antibodies in patients with non-insulin-dependent diabetes mellitus

Circulating liver membrane antibodies (LMAb) were examined in 71 patients with non-insulin-dependent diabetes mellitus (NIDDM) without liver dysfunction and 16 cases of KK mouse as a model of obese diabetic animals. LMAb were detected in 10 NIDDM patients (14.1%). Fasting blood glucose, glycosylated serum albumin (G-Alb), and glycosylated hemoglobin A1 (HbA1) levels were compared with LMAb-positive and negative groups. The G-Alb levels and HbA1 levels of the LMAb-positive group were significantly higher (p less than 0.05 and p less than 0.01, respectively) than those of the LMAb-negative group. In addition, there were no differences in histological findings in KK mouse liver between the LMAb-positive and negative cases. These results revealed that the state of continued high blood glucose directly or indirectly influence the autoimmunity and clinical features of NIDDM patients.

Regulation of Fc gamma receptor expression and phagocytosis of a human monoblast cell line U937. Participation of cAMP and protein kinase C in the effects of IFN-gamma and phorbol ester

We investigated the positive and negative effects of IFN-gamma, PMA, dibutyryl cAMP (Bt2cAMP), dexamethasone and transforming growth factor-beta (TGF-beta) on Fc gamma R subtype expression and phagocytosis of a human monoblast cell line, U937. IFN-gamma increased and Bt2cAMP decreased Fc gamma RI expression determined by a mAb 32.2, whereas PMA and Bt2cAMP increased Fc gamma RII expression determined by a mAb IV-3. Phagocytosis was measured microscopically by counting ingested aggregated human IgG- or BSA-treated ox E (Eo'-IgG or Eo'-BSA). IFN-gamma increased the phagocytosis of Eo'-IgG but not that of Eo'-BSA, and PMA increased the phagocytosis of both Eo'-IgG and Eo'-BSA. Bt2cAMP decreased both basal and IFN-gamma- and PMA-augmented phagocytosis of U937 cells. Dexamethasone also inhibited both basal and IFN-gamma-augmented Fc gamma RI expression and PMA-augmented Fc gamma RII expression and phagocytosis, but did not affect IFN-gamma-augmented phagocytosis of Eo'-IgG. The augmentation of phagocytosis of Eo'-IgG by IFN-gamma thus seems to be due mainly to the increased internalizing process rather than to increased Fc gamma RI expression. TGF-beta slightly decreased Fc gamma R expression. In a study of the participation of protein kinase C (PK-C), it was found that H-7, a PK-C inhibitor, did not inhibit either IFN-gamma- or PMA-enhanced Fc gamma RI and Fc gamma RII expression, respectively, and 1-oleoyl-2-acetylglycerol and N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide, both PK-C activators, did not show any apparent increase in Fc gamma R expression and phagocytosis. These results show that Fc gamma RI and Fc gamma RII expression on U937 cells is regulated by different mechanisms and that IFN-gamma and PMA play their roles in Fc gamma R expression and phagocytosis by different pathways. It is possible that cAMP but not PK-C plays an important role in the regulation of Fc gamma R expression and phagocytosis.

Regulation of Fc gamma receptor expression and phagocytosis of a human monoblast cell line U937. Participation of cAMP and protein kinase C in the effects of IFN-gamma and phorbol ester

We investigated the positive and negative effects of IFN-gamma, PMA, dibutyryl cAMP (Bt2cAMP), dexamethasone and transforming growth factor-beta (TGF-beta) on Fc gamma R subtype expression and phagocytosis of a human monoblast cell line, U937. IFN-gamma increased and Bt2cAMP decreased Fc gamma RI expression determined by a mAb 32.2, whereas PMA and Bt2cAMP increased Fc gamma RII expression determined by a mAb IV-3. Phagocytosis was measured microscopically by counting ingested aggregated human IgG- or BSA-treated ox E (Eo'-IgG or Eo'-BSA). IFN-gamma increased the phagocytosis of Eo'-IgG but not that of Eo'-BSA, and PMA increased the phagocytosis of both Eo'-IgG and Eo'-BSA. Bt2cAMP decreased both basal and IFN-gamma- and PMA-augmented phagocytosis of U937 cells. Dexamethasone also inhibited both basal and IFN-gamma-augmented Fc gamma RI expression and PMA-augmented Fc gamma RII expression and phagocytosis, but did not affect IFN-gamma-augmented phagocytosis of Eo'-IgG. The augmentation of phagocytosis of Eo'-IgG by IFN-gamma thus seems to be due mainly to the increased internalizing process rather than to increased Fc gamma RI expression. TGF-beta slightly decreased Fc gamma R expression. In a study of the participation of protein kinase C (PK-C), it was found that H-7, a PK-C inhibitor, did not inhibit either IFN-gamma- or PMA-enhanced Fc gamma RI and Fc gamma RII expression, respectively, and 1-oleoyl-2-acetylglycerol and N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide, both PK-C activators, did not show any apparent increase in Fc gamma R expression and phagocytosis. These results show that Fc gamma RI and Fc gamma RII expression on U937 cells is regulated by different mechanisms and that IFN-gamma and PMA play their roles in Fc gamma R expression and phagocytosis by different pathways. It is possible that cAMP but not PK-C plays an important role in the regulation of Fc gamma R expression and phagocytosis.