Cellular senescence of granulosa cells in the pathogenesis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age, but its pathology has not been fully characterized and the optimal treatment strategy remains unclear. Cellular senescence is a permanent state of cell-cycle arrest that can be induced by multiple stresses. Senescent cells contribute to the pathogenesis of various diseases, owing to an alteration in secretory profile, termed 'senescence-associated secretory phenotype' (SASP), including with respect to pro-inflammatory cytokines. Senolytics, a class of drugs that selectively eliminate senescent cells, are now being used clinically, and a combination of dasatinib and quercetin (DQ) has been extensively used as a senolytic. We aimed to investigate whether cellular senescence is involved in the pathology of PCOS and whether DQ treatment has beneficial effects in patients with PCOS. We obtained ovaries from patients with or without PCOS, and established a mouse model of PCOS by injecting dehydroepiandrosterone. The expression of the senescence markers p16INK4a, p21, p53, γH2AX, and senescence-associated β-galactosidase (SA-β-gal); and the SASP-related factor interleukin (IL)-6; were significantly higher in the ovaries of patients with PCOS and PCOS mice than in controls. To evaluate the effects of hyperandrogenism and DQ on cellular senescence in vitro, we stimulated cultured human granulosa cells (GCs) with testosterone and treated them with DQ. The expression of markers of senescence and a SASP-related factor was increased by testosterone, and DQ reduced this increase. DQ reduced the expression of markers of senescence and a SASP-related factor in the ovaries of PCOS mice and improved their morphology. These results indicate that cellular senescence occurs in PCOS. Hyperandrogenism causes cellular senescence in GCs in PCOS and senolytic treatment reduces the accumulation of senescent GCs and improves ovarian morphology under hyperandrogenism. Thus, DQ might represent a novel therapy for PCOS.

Effects of the prenatal and postnatal nurturing environment on the phenotype and gut microbiota of mice with polycystic ovary syndrome induced by prenatal androgen exposure: a cross-fostering study

The gut microbiome is implicated in the pathogenesis of polycystic ovary syndrome (PCOS), and prenatal androgen exposure is involved in the development of PCOS in later life. Our previous study of a mouse model of PCOS induced by prenatal dihydrotestosterone (DHT) exposure showed that the reproductive phenotype of PCOS appears from puberty, followed by the appearance of the metabolic phenotype after young adulthood, while changes in the gut microbiota was already apparent before puberty. To determine whether the prenatal or postnatal nurturing environment primarily contributes to these changes that characterize prenatally androgenized (PNA) offspring, we used a cross-fostering model to evaluate the effects of changes in the postnatal early-life environment of PNA offspring on the development of PCOS-like phenotypes and alterations in the gut microbiota in later life. Female PNA offspring fostered by normal dams (exposed to an abnormal prenatal environment only, fostered PNA) exhibited less marked PCOS-like phenotypes than PNA offspring, especially with respect to the metabolic phenotype. The gut microbiota of the fostered PNA offspring was similar to that of controls before adolescence, but differences between the fostered PNA and control groups became apparent after young adulthood. In conclusion, both prenatal androgen exposure and the postnatal early-life environment created by the DHT injection of mothers contribute to the development of PCOS-like phenotypes and the alterations in the gut microbiota that characterize PNA offspring. Thus, both the pre- and postnatal environments represent targets for the prevention of PCOS and the associated alteration in the gut microbiota in later life.

The Role of Cellular Senescence in Cyclophosphamide-Induced Primary Ovarian Insufficiency

Young female cancer patients can develop chemotherapy-induced primary ovarian insufficiency (POI). Cyclophosphamide (Cy) is one of the most widely used chemotherapies and has the highest risk of damaging the ovaries. Recent studies elucidated the pivotal roles of cellular senescence, which is characterized by permanent cell growth arrest, in the pathologies of various diseases. Moreover, several promising senolytics, including dasatinib and quercetin (DQ), which remove senescent cells, are being developed. In the present study, we investigated whether cellular senescence is involved in Cy-induced POI and whether DQ treatment rescues Cy-induced ovarian damage. Expression of the cellular senescence markers p16, p21, p53, and γH2AX was upregulated in granulosa cells of POI mice and in human granulosa cells treated with Cy, which was abrogated by DQ treatment. The administration of Cy decreased the numbers of primordial and primary follicles, with a concomitant increase in the ratio of growing to dormant follicles, which was partially rescued by DQ. Moreover, DQ treatment significantly improved the response to ovulation induction and fertility in POI mice by extending reproductive life. Thus, cellular senescence plays critical roles in Cy-induced POI, and targeting senescent cells with senolytics, such as DQ, might be a promising strategy to protect against Cy-induced ovarian damage.

Roles of endoplasmic reticulum stress in the pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-age women, affecting up to 15% of women in this group, and the most common cause of anovulatory infertility. Although its etiology remains unclear, recent research has revealed the critical role of endoplasmic reticulum (ER) stress in the pathophysiology of PCOS. ER stress is defined as a condition in which unfolded or misfolded proteins accumulate in the ER because of an imbalance in the demand for protein folding and the protein-folding capacity of the ER. ER stress results in the activation of several signal transduction cascades, collectively termed the unfolded protein response (UPR), which regulates various cellular activities. In principle, the UPR restores homeostasis and keeps the cell alive. However, if the ER stress cannot be resolved, it induces programmed cell death. ER stress has recently been recognized to play diverse roles in both physiological and pathological conditions of the ovary. In this review, we summarize current knowledge of the roles of ER stress in the pathogenesis of PCOS. ER stress pathways are activated in the ovaries of both a mouse model of PCOS and in humans, and local hyperandrogenism in the follicular microenvironment associated with PCOS is responsible for activating these. The activation of ER stress contributes to the pathophysiology of PCOS through multiple effects in granulosa cells. Finally, we discuss the potential for ER stress to serve as a novel therapeutic target for PCOS.

Germinal Center B-Cell-Associated Nuclear Protein (GANP) Involved in RNA Metabolism for B Cell Maturation

Germinal center B-cell-associated nuclear protein (GANP) is upregulated in germinal center B cells against T-cell-dependent antigens in mice and humans. In mice, GANP depletion in B cells impairs antibody affinity maturation. Conversely, its transgenic overexpression augments the generation of high-affinity antigen-specific B cells. GANP associates with AID in the cytoplasm, shepherds AID into the nucleus, and augments its access to the rearranged immunoglobulin (Ig) variable (V) region of the genome in B cells, thereby precipitating the somatic hypermutation of V region genes. GANP is also upregulated in human CD4(+) T cells and is associated with APOBEC3G (A3G). GANP interacts with A3G and escorts it to the virion cores to potentiate its antiretroviral activity by inactivating HIV-1 genomic cDNA. Thus, GANP is characterized as a cofactor associated with AID/APOBEC cytidine deaminase family molecules in generating diversity of the IgV region of the genome and genetic alterations of exogenously introduced viral targets. GANP, encoded by human chromosome 21, as well as its mouse equivalent on chromosome 10, contains a region homologous to Saccharomyces Sac3 that was characterized as a component of the transcription/export 2 (TREX-2) complex and was predicted to be involved in RNA export and metabolism in mammalian cells. The metabolism of RNA during its maturation, from the transcription site at the chromosome within the nucleus to the cytoplasmic translation apparatus, needs to be elaborated with regard to acquired and innate immunity. In this review, we summarize the current knowledge on GANP as a component of TREX-2 in mammalian cells.

Molecular mechanism of immunoglobulin V-region diversification regulated by transcription and RNA metabolism in antigen-driven B cells

The immune system produces specific antibodies (Ab) against any antigens (Ag) of exogenous and endogenous origins with a diverse repertoire of V-region specificities. The primary V-region repertoire is created by the rearrangement of immunoglobulin (Ig) V-region, D- and J-segments with the insertion of N- and P-sequences during early B cell differentiation. Recent studies revealed that secondary diversification of the IgV-region generated in the peripheral lymphoid organs plays a critical role in the generation of effective Ab production for protection from various pathogens. Naïve B cells that react with Ags initiate proliferation and differentiation in the follicular region and create the germinal centres (GCs), where activation-induced cytidine deaminase (AID)-dependent IgV-region somatic hypermutation (SHM) and class-switch recombination generate high-affinity and class-switched mature Ag-specific B cells. Our studies have discovered a 210-kDa nuclear protein, named GC-associated nuclear protein (GANP) that is up-regulated in GC B cells during the T cell-dependent (TD) immune responses. By studying mice with mutant forms of the ganp gene, we demonstrated that GANP is essential for the generation of high-affinity B cells against TD-Ag by affecting SHM at the IgV-regions. GANP is associated with AID in the cytoplasm and the GANP/AID complex is recruited to the nucleus, specifically, the chromatin, and targeted selectively to the IgV-region gene in B cells. GANP augments the access of AID towards IgV-regions in B cells. Here, we review the role of GANP in acquired immunity through the detailed analysis of the molecular mechanism generating SHM specifically at IgV-regions in B cells.

Cytokine production profile of splenocytes derived from zymosan A-treated SKG mice developing arthritis

OBJECTIVE

SKG mice have a point mutation of the zeta-associated protein of 70 kD (ZAP-70) and spontaneously develop a severe polyarthritis in the conventional condition, whereas they are healthy under the specific pathogen free (SPF) condition. The purpose of this study was to investigate the cytokine production from splenocytes in SKG mice developing arthritis under the SPF condition.

MATERIAL

SKG and BALB/c mice were intraperitoneally injected with zymosan A under the SPF condition. Spleen was isolated 1, 2 or 8 weeks after the intraperitoneal injection of saline or zymosan A. Splenocytes were cultured with concanavalin A. Cytokine production and proliferation were measured 48 and 72 h after the culture.

RESULTS

An intraperitoneal injection of zymosan A induced severe polyarthritis with increased levels of rheumatoid factor and interleukin 6 (IL-6) only in SKG mice. Splenocytes from SKG mice did not proliferate well maybe because of less productivity of IL-2. The IL-4 production from splenocytes of SKG mice was higher, while interferon-gamma production was lower than those of BALB/c mice. An injection of zymosan A reduced the IL-4 production only in SKG mice.

CONCLUSIONS

SKG mice do not develop arthritis under the SPF condition possibly because of a low proliferative activity of T cells and Th2-predominance.

Antiapoptotic function of 17AA(+)WT1 (Wilms' tumor gene) isoforms on the intrinsic apoptosis pathway

The WT1 gene is overexpressed in human primary leukemia and a wide variety of solid cancers. The WT1 gene is alternatively spliced at two sites, yielding four isoforms: 17AA(+)KTS(+), 17AA(+)KTS(-), 17AA(-)KTS(+), and 17AA(-)KTS(-). Here, we showed that 17AA(+)WT1-specific siRNA induced apoptosis in three WT1-expressing leukemia cell lines (K562, HL-60, and Kasumi-1), but not in WT1-non-expressing lymphoma cell line (Daudi). 17AA(+)WT1-specific siRNA activated caspase-3 and -9 in the intrinsic apoptosis pathway but not caspase-8 in the extrinsic one. On the other hand, 17AA(-)WT1-specific siRNA did not induce apoptosis in the three WT1-expressing cell lines. The apoptosis was associated with activation of proapoptotic Bax, which was activated upstream of the mitochondria. Constitutive expression of 17AA(+)WT1 isoforms inhibited apoptosis of K562 leukemia cells induced by apoptosis-inducing agents, etoposide and doxorubicin, through the protection of mitochondrial membrane damages, and DNA-binding zinc-finger region of 17AA(+)WT1 isoform was essential for the antiapoptotic functions. We further studied the gene(s) whose expression was altered by the expression of 17AA(+)WT1 isoforms and showed that the expression of proapoptotic Bak was decreased by the expression of 17AA(+)KTS(-)WT1 isoform. Taken together, these results indicated that 17AA(+)WT1 isoforms played antiapoptotic roles at some points upstream of the mitochondria in the intrinsic apoptosis pathway.

Amla (Emblica officinalis Gaertn.) Extracts Reduce Oxidative Stress in Streptozotocin-Induced Diabetic Rats

The antioxidant properties of amla extracts and their effects on the oxidative stress in streptozotocin-induced diabetes were examined in rats. Amla in the form of either the commercial enzymatic extract SunAmla (Taiyo Kagaku Co. Ltd., Yokkaichi, Japan) (20 or 40 mg/kg of body weight/day) or a polyphenol-rich fraction of ethyl acetate extract (10 or 20 mg/kg of body weight/day) was given orally for 20 days to the streptozotocin-induced diabetic rats. Amla extracts showed strong free radical scavenging activity. Amla also showed strong inhibition of the production of advanced glycosylated end products. The oral administration of amla extracts to the diabetic rats slightly improved body weight gain and also significantly alleviated various oxidative stress indices of the serum of the diabetic rats. The elevated serum levels of 5-hydroxymethylfurfural, which is a glycosylated protein that is an indicator of oxidative stress, were significantly reduced dose-dependently in the diabetic rats fed amla. Similarly, the serum level of creatinine, yet another oxidative stress parameter, was also reduced. Furthermore, thiobarbituric acid-reactive substances levels were significantly reduced with amla, indicating a reduction in lipid peroxidation. In addition, the decreased albumin levels in the diabetic rats were significantly improved with amla. Amla also significantly improved the serum adiponectin levels. These results form the scientific basis supporting the efficacy of amla for relieving the oxidative stress and improving glucose metabolism in diabetes.

Autoantibodies to NMDA receptor in patients with chronic forms of epilepsia partialis continua

BACKGROUND

Antibody-mediated and cytotoxic T cell-mediated pathogenicity have been implicated as the autoimmune pathophysiologic mechanisms in Rasmussen's encephalitis.

METHODS

The authors investigated autoantibodies against the NMDA glutamate receptor (GluR) epsilon2 subunit and their epitopes in serum and CSF samples from 15 patients with chronic epilepsia partialis continua (EPC), 17 with West syndrome, 10 with Lennox-Gastaut syndrome, and 11 control subjects.

RESULTS

In 15 patients with chronic EPC, we detected NMDA-type GluR epsilon2 autoantibodies in histologically proven Rasmussen's encephalitis (3/3 patients), clinical Rasmussen's encephalitis (6/7 patients), acute encephalitis/encephalopathy (2/3 patients), and nonprogressive EPC (2/2 patients). Serum IgM autoantibodies were found in the early phase of EPC and became negative later in four patients. The autoantibodies were not detected in West syndrome, Lennox-Gastaut syndrome, or controls. Among 10 patients with histologically proven or clinical Rasmussen's encephalitis, epitope analyses showed that the autoantibodies were predominantly against C-terminal epitopes and rarely against N-terminal epitope, with inconsistency in profile during the courses of disease. Epitope recognition spectrum of autoantibodies was broader in CSF than in serum, and the serum or CSF profile showed an increase in number of epitopes as disease progressed in some patients.

CONCLUSIONS

The presence of autoantibodies against NMDA GluR epsilon2 suggests autoimmune pathologic mechanisms but is not a hallmark of Rasmussen's encephalitis. Patients with Rasmussen's encephalitis may have autoantibodies against several neural molecules, and these autoantibodies may be produced in the CNS after cytotoxic T cell-mediated neuronal damage.

Immunologic tolerance maintained by CD25+ CD4+ regulatory T cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance

There is accumulating evidence that T-cell-mediated dominant control of self-reactive T-cells contributes to the maintenance of immunologic self-tolerance and its alteration can cause autoimmune disease. Efforts to delineate such a regulatory T-cell population have revealed that CD25+ cells in the CD4+ population in normal naive animals bear the ability to prevent autoimmune disease in vivo and, upon antigenic stimulation, suppress the activation/proliferation of other T cells in vitro. The CD25+ CD4+ regulatory T cells, which are naturally anergic and suppressive, appear to be produced by the normal thymus as a functionally distinct subpopulation of T cells. They play critical roles not only in preventing autoimmunity but also in controlling tumor immunity and transplantation tolerance.

PU.1 is involved in the regulation of B lineage-associated and developmental stage-dependent expression of the germinal center-associated DNA primase GANP

Germinal center-associated DNA primase (GANP) associated with MCM3 of the DNA replication complex is up-regulated selectively in germinal center B cells. We studied promoter activity of the 5' region involved in the developmental stage-dependent expression in B lineage cells by luciferase reporter assay. Selective regulation of ganp expression was observed in the -737-bp promoter region in B and plasma cell lines but was significantly low in pre-B and T cell lines. The deletion constructs displayed a gap decrease after shortening the region from -134 to -108 bp. Further narrowing suggested the involvement of the PU.1 consensus sequence at -126 bp by electrophoretic mobility shift assay. The protein component PU.1 complex is not inhibited with mutated probes at the consensus site but is inhibited with the known PU.1 probe of CD72 and with anti-PU.1 antibody. Moreover, introduction of PU.1 cDNA enhanced the reporter gene activity in a dose-dependent manner in B cells, whereas the reporter construct with the mutated PU.1 site did not respond. Anti-CD40 stimulation induced the reporter activity with a 100% increase, which is not observed with the PU.1-mutated reporter construct. These results demonstrate that the germinal center-associated DNA primase expression is partly regulated by the transcription factor PU.1 expressed in B lineage cells.

Immunologic self tolerance maintained by T-cell-mediated control of self-reactive T cells: implications for autoimmunity and tumor immunity

T-cell-mediated dominant control of self-reactive T cells is one mechanism for maintaining immunologic self tolerance. It also hampers the generation of immunity to autologous tumor cells. Abrogation of the control can evoke potent tumor immunity as well as autoimmunity in normal animals. This common regulatory mechanism for autoimmunity and tumor immunity can be exploited to devise a novel immunotherapy against cancer.

Germinal center-associated nuclear protein (GANP) has a phosphorylation-dependent DNA-primase activity that is up-regulated in germinal center regions

Antigen stimulation induces a rapid proliferation of B cells for expansion of specific B cell clones and their further differentiation into antibody-producing cells in germinal centers of T-dependent antigen-immunized mice. Previously, we identified a 210-kDa germinal center-associated nuclear protein (GANP) that is up-regulated selectively in germinal centers and carries an MCM-binding domain in the carboxyl-terminal side. In addition, here, we found a region (from 414 to 550 aa) in GANP molecule that is slightly similar to the known DNA-primase component p49. The recombinant GANP fragment covering this region synthesizes RNA primers for extension by DNA polymerase I with single-stranded DNA templates in vitro. GANP DNA-primase activity is controlled by phosphorylation at Ser(502) that is induced by CD40-mediated signaling in vitro and in the germinal center B cells stimulated with antigen in vivo. Overexpression of ganp cDNA in Daudi B cells caused the increased DNA synthesis more than the levels of the mock-transfectants. These evidences suggested that the novel DNA-primase GANP is involved in regulation of cell proliferation of antigen-driven B cells in germinal centers.

Immunologic tolerance maintained by CD25+ CD4+ regulatory T cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance

There is accumulating evidence that T-cell-mediated dominant control of self-reactive T-cells contributes to the maintenance of immunologic self-tolerance and its alteration can cause autoimmune disease. Efforts to delineate such a regulatory T-cell population have revealed that CD25+ cells in the CD4+ population in normal naive animals bear the ability to prevent autoimmune disease in vivo and, upon antigenic stimulation, suppress the activation/proliferation of other T cells in vitro. The CD25+ CD4+ regulatory T cells, which are naturally anergic and suppressive, appear to be produced by the normal thymus as a functionally distinct subpopulation of T cells. They play critical roles not only in preventing autoimmunity but also in controlling tumor immunity and transplantation tolerance.

IL-1 enhances T cell-dependent antibody production through induction of CD40 ligand and OX40 on T cells

IL-1 is a proinflammatory cytokine that plays pleiotropic roles in host defense mechanisms. We investigated the role of IL-1 in the humoral immune response using gene-targeted mice. Ab production against SRBC was significantly reduced in IL-1alpha/beta-deficient (IL-1(-/-)) mice and enhanced in IL-1R antagonist(-/-) mice. The intrinsic functions of T, B, and APCs were normal in IL-1(-/-) mice. However, we showed that IL-1(-/-) APCs did not fully activate DO11.10 T cells, while IL-1R antagonist (-/-) APCs enhanced the reaction, indicating that IL-1 promotes T cell priming through T-APC interaction. The function of IL-1 was CD28-CD80/CD86 independent. We found that CD40 ligand and OX40 expression on T cells was affected by the mutation, and the reduced Ag-specific B cell response in IL-1(-/-) mice was recovered by the treatment with agonistic anti-CD40 mAb both in vitro and in vivo. These observations indicate that IL-1 enhances T cell-dependent Ab production by augmenting CD40 ligand and OX40 expression on T cells.

Direct observation of a Ti/Cu interface with atomic displacement under electron irradiation

A Ti film was deposited onto a Cu substrate by means of a radio frequency magnetron sputtering

METHOD

Cross-sectional thin foils for TEM observation were prepared using a focused ion beam. Electron irradiation was carried out using a high-resolution high-voltage electron microscope operated at 1.25 MV. The Cu/Ti interface of the foils was irradiated at 623 K. In-situ observation images during electron irradiation were recorded by a CCD camera with a digital video cassette. The (020)Cu plane on the Cu/Ti interface preferentially moved towards the Ti film with irradiation. Composition analysis of the diffused region showed that its composition corresponded to Ti3Cu2.

Reference values and limited serological survey for the Iriomote cat in Japan

Clinical investigations and hematological, serum biochemical, and serological surveys were carried out on 11 male and 6 female Iriomote cats (Felis iriomotensis) in Japan. Examined Iriomote cats were considered clinically healthy by the inspection for the general physical conditions. However, urinalysis suggested the inflammation of the urinary tract in all the cats. Antibody for feline panleukopenia virus was positive in one of the examined Iriomote cats, which suggested a previous infection.

Role of genetic factors in organ-specific autoimmune diseases induced by manipulating the thymus or T cells, and not self-antigens

There are accumulating demonstrations that manipulation of the T-cell immune system, such as elimination of a particular T-cell subpopulation from the periphery or removal of the thymus during a critical neonatal period, can elicit activation/expansion of pathogenic self-reactive T cells from the remaining T cells and produce a wide spectrum of organ-specific autoimmune diseases in otherwise normal mice or rats. The genetic makeup of the hosts appears to play a key role in determining which self-reactive T-cell clones are prone to be activated under such circumstances, since a comparable degree of the immunologic abnormality elicits autoimmune disease in different spectrums of organs, with different incidences and severities, depending on the mouse or rat strains used. These findings indicate that one aspect of natural immunologic self-tolerance is maintained by a T cell-mediated control of potentially pathogenic self-reactive T cells in the periphery, and that defective control, caused by environmental insults or genetic abnormalities, suffices to cause autoimmune disease; furthermore, in the presence of such a T-cell abnormality, host genetic factors including MHC and non-MHC genes may determine the specificity and intensity of the autoimmune responses, and consequently the phenotype of the autoimmune disease.

Histological diversity of vasculitic lesions in MPO-ANCA-positive autopsy cases

To investigate the variety of histological features of vasculitic lesions in myeloperoxidase-specific antineutrophil cytoplasmic antibody (pANCA)-related vasculitis, retrospective pathological analysis was done on 13 autopsy cases, collected from 1990 to 1998 at five hospitals. These cases were classified into three groups: (i) pulmonary-renal syndrome characterized by capillaritis of lung and glomeruli with occasional small-vessel arteritis and/or phlebitis; (ii) glomerular capillaritis without pulmonary involvement associated with significant small-vessel arteritis; and (iii) extensive distribution of small-vessel arteritis with no capillary involvement. The results suggest that pANCA-related vasculitis encompasses a wide variety of vasculitic syndromes, including pulmonary-renal syndrome, microscopic polyarteritis nodosa, and classic polyarteritis nodosa. pANCA may contribute to pathogenesis in all of these cases.

Localization of recombination activating gene 1/green fluorescent protein (RAG1/GFP) expression in secondary lymphoid organs after immunization with T-dependent antigens in rag1/gfp knockin mice

Secondary rearrangements of immunoglobulin gene segments that generate a new antibody repertoire in peripheral B cells have been described as receptor revision and occur by as yet unknown mechanisms. To determine the importance of recombination activating gene (RAG) expression in receptor revision, heterozygous rag1/green fluorescent protein (gfp) knockin mice were used to examine the location of RAG1 expression in the germinal centers (GCs) of lymphoid follicles after immunization with a variety of T-cell-dependent antigens. Immunization of rag1/gfp heterozygous mice or rag1 homozygous knockout mice reconstituted with rag1/gfp heterozygous spleen cells caused the down-regulation of RAG1/GFP signal in GCs. Although some RAG1/GFP(+) cells appeared in regions surrounding the peanut agglutinin (PNA)(+)GL-7(+) GC area, RAG1/GFP(+) cells did not accumulate in the central region. In addition, the stimulation of spleen B cells with anti-mu antibody plus interleukin-4 (IL-4) or with anti-CD40 monoclonal antibody plus IL-7 did not induce GFP signals at detectable levels in vitro. These results clearly demonstrate that RAG1 re-expression either does not occur or is at extremely low levels in antigen-driven B cells in GCs of secondary lymphoid follicles, suggesting that other mechanisms may mediate the gene rearrangements observed in receptor revision.

CD40 expression is induced by the introduction of IgM receptor on the surface of pro-B cell line NFS70

To examine the molecular mechanism of B cell differentiation, we introduced rearranged immunoglobulin (Ig) mu- and kappa-chain genes into the NFS70 pro-B cell line and observed their maturation. The IgR(+)-transfectants had characteristics of mature surface IgM (sIgM)+ B220high CD40+ CD38+ CD25+ B cells. CD40 expression levels were regulated by stimulation via the IgR. In comparison to wild type NFS70 cells, NF-kappaB activity was up-regulated in the IgR transfectants. Anti-IgR crosslinking of IgR+ cells induced down-regulation of CD40 expression that correlated with down-regulation of NF-kappaB activity in the IgR(+)-transfectants. Immature CD19+ sIgD- B cells from bone marrow also showed an alteration of CD40 expression in response to anti-IgR crosslinking. The results suggest that expression of IgR on the surface is one of the factors responsible for further maturation of B cells.

A rat model of hypereosinophilic syndrome

Hypereosinophilia-occurring rats without chemical and antigen treatment have been maintained in our laboratory. The rat, Matsumoto Eosinophilia Shinshu (mes), showed hypereosinophilia at the age of 9 weeks or older and developed eosinophil-related inflammatory lesions in many organs. These lesions included: aortitis, granulomatous lesion in the mesenteric lymph node, inflammatory fibroid polyp of the stomach and pulmonary vasculitis with septal infiltration. These lesions were involved with cellular infiltration of eosinophils and macrophages, and deposition of eosinophilic crystals which immunohistologically showed major basic protein and eosinophilic peroxidase derived from eosinophilic lysosomal constituents. Although the distribution of lesions in mes is a little different from that of hypereosinophilic syndrome (HES) in humans, in that endomyocardial fibrosis appears in HES while aortitis appears in mes, mes is probably comparable with HES. The present paper describes the pathological aspects of the lesions in mes and discusses the pathogenesis of tissue injury related to eosinophilic infiltration.

X-ray absorption spectral analyses by theoretical calculations for TiO2 and Ni-doped TiO2 thin films on glass plates

Ni L- and Ti L-edge as well as Ti K-edge X-ray absorption experiments for TiO2 thin films and Ni-doped TiO2 thin films coated on glass plates were performed using synchrotron radiation to investigate the structures around Ni and Ti ions in the films. The obtained spectra were compared with the results of theoretical calculations. It has consequently been found that the spectral features were affected by a change in the oxidizing form of Ni ions due to hydrogen reduction, by the charge variation and/or slight orbital splitting of Ti ions, and by the magnitude of the interaction between the center Ti ion and neighboring Ti ions.

Increased T cell autoreactivity in the absence of CD40-CD40 ligand interactions: a role of CD40 in regulatory T cell development

Mutations in the CD40 ligand (CD40L) gene lead to X-linked immunodeficiency with hyper-IgM, which is often associated with autoimmune diseases. To determine the contribution of defective CD40-CD40L interactions to T cell autoreactivity, we reconstituted CD40-CD40L interactions by transferring T cells from CD40-deficient mice to syngenic athymic nude mice and assessed autoimmunity. T cells from CD40-deficient mice triggered autoimmune diseases accompanied with elevations of various autoantibodies, while those from wild-type mice did not. In CD40-deficient mice, the CD25(+) CD45RB(low) CD4(+) subpopulation which regulates T cell autoreactivity was markedly reduced. CD40-deficient APCs failed to induce T regulatory cells 1 producing high levels of an inhibitory cytokine, IL-10 in vitro. Furthermore, autoimmune development was inhibited when T cells from CD40-deficient mice were cotransferred with CD45RB(low) CD4(+) T cells from wild-type mice or with T regulatory cells 1 induced on CD40-expressing APCs. Collectively, our results indicate that CD40-CD40L interactions contribute to negative regulation of T cell autoreactivity and that defective interactions can lead to autoimmunity.

Role of reactive oxygen species in gallic acid-induced apoptosis

We earlier demonstrated that gallic acid (3,4,5-trihydroxybenzoic acid) induced apoptosis in promyelocytic leukemia HL-60RG cells, which was inhibited by catalase and intracellular Ca2+ chelator. In this study, we further studied the involvement of reactive oxygen species (ROS) and intracellular Ca2+ in gallic acid-induced apoptosis. The enhancement of intracellular ROS in HL-60RG cells was detected dose-dependently as early as 5 min after stimulation with gallic acid by using 5,6-carboxy-2',7'-dichlorofluorescin diacetate (DCFH-DA). Further studies that used various antioxidants and ROS scavengers showed that the intracellular peroxide level was well correlated with the potency to induce apoptosis and that the increased intracellular peroxides after gallic acid treatment seemed likely to result from the influx of H2O2 derived from superoxide which were generated extracellularly. In addition, gallic acid, HX/XO, and H2O2-induced apoptosis was completely inhibited by pretreatment with intracellular Ca2+ chelator 1,2-bis(2-aminophenoxyethane)-N,N,N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM), but increase of intracellular peroxide levels by gallic acid were suppressed only slightly. It is suggested that intracellular ROS induced by gallic acid plays an important role in eliciting an early signal in apoptosis. Especially, H2O, which is derived from superoxide anion generated extracellularly may increase intracellular Ca2+ levels or cooperate with intracellular Ca2+, thus resulting in apoptosis induction.

Structure, expression, and chromosomal localization of the human gene encoding a germinal center-associated nuclear protein (GANP) that associates with MCM3 involved in the initiation of DNA replication

A 210kDa protein named GANP is upregulated in germinal center (GC)-B cells in the spleen of antigen-immunized mouse. We studied a human ganp gene (hganp) encoding a putative polypeptide of 1980 amino acids. The carboxyl-terminal 721-amino-acid sequence of hGANP is identical to Map80, that is presumably generated by alternative splicing of hganp/Map80 gene. The genomic segment carrying hganp and Map80 genes was isolated, and the chromosomal location was determined on 21q22.3. Northern blot analysis with RNAs from various organs demonstrated a single band of 7kb hganp mRNA, which suggests a preferential transcription of hganp gene from the hganp/Map80 locus. The hGANP expression was upregulated in GCs of the tonsil, as demonstrated by in-situ RNA hybridization and immunohistochemical analyses. The hGANP, with the domain (Map-box) capable of binding to MCM3 in B cells, might be involved in regulation of cell-cycle progression and DNA replication of GC-B cells.

Recurrent idiopathic iridocyclitis after autologous peripheral blood stem-cell transplantation followed by G-CSF administration for acute lymphoblastic leukemia

We describe a patient who experienced a recurrence of idiopathic iridocyclitis on day 12 after autologous peripheral blood stem-cell transplantation (auto-PBSCT) followed by G-CSF administration for acute lymphoblastic leukemia (ALL). Autologous SCT has been reported to be effective and safe in achieving dose intensification of chemotherapeutic drugs for the treatment of hematopoietic malignancies, but its therapeutic effect on autoimmune diseases is not definite. The findings from the present case suggest that auto-PBSCT followed by G-CSF administration for patients with a history of some kind of autoimmune disorders may induce exacerbation or recurrence of its symptoms after hematopoietic recovery.

LDL receptor-related protein as a component of the midkine receptor

Midkine (MK) is a heparin-binding growth factor with migration-promoting and survival-promoting activities. To identify signaling receptor(s) of MK, membrane glycoproteins with MK-binding activity were isolated from day 13 mouse embryos by lectin- and MK-affinity chromatography. SDS-PAGE followed by protein sequence analysis revealed the presence of LDL receptor-related protein (LRP) and NCAM in the fraction. The dissociation constant of binding between LRP and MK was 3.5 nM. Receptor-associated protein (RAP), which interfered with the binding, inhibited MK-dependent survival of embryonic neurons. Brushin/megalin, which is also a high molecular weight protein belonging to the LDL receptor family, bound to MK less strongly than LRP. These findings suggest that LRP is a component of the receptor complex for MK.

A novel nuclear phosphoprotein, GANP, is up-regulated in centrocytes of the germinal center and associated with MCM3, a protein essential for DNA replication

Antigen (Ag) immunization induces formation of the germinal center (GC), with large, rapidly proliferating centroblasts in the dark zone, and small, nondividing centrocytes in the light zone. We identified a novel nuclear protein, GANP, that is up-regulated in centrocytes. We found that GANP was up-regulated in GC B cells of Peyer's patches in normal mice and in spleens from Ag-immunized mice. GANP-positive cells appeared in the light zone of the GC, with coexpression of the peanut agglutinin (PNA) (PNA)-positive B220-positive phenotype. The expression of GANP was strikingly correlated with GC formation because Bcl6-deficient mice did not show the up-regulation of GANP. GANP-positive cells were mostly surrounded by follicular dendritic cells. Stimulation with anti-micro and anti-CD40 induced up-regulation of ganp messenger RNA as well as GANP protein in B220-positive B cells in vitro. GANP is a 210-kd protein localized in both the cytoplasm and nuclei, with a homologous region to Map80 that is associated with MCM3, a protein essential for DNA replication. Remarkably, GANP is associated with MCM3 in B cells and MCM3 is also up-regulated in the GC area. These results suggest that the up-regulation of GANP might participate in the development of Ag-driven B cells in GCs through its interaction with MCM3.

Cutting edge: absence of expression of RAG1 in peritoneal B-1 cells detected by knocking into RAG1 locus with green fluorescent protein gene

It has been proposed that Ig gene rearrangement in the peritoneal cavity (Pc) B-1 cells might be involved in autoantibody generation. To study possible secondary B cell maturation, we prepared mice carrying a target integration of gfp gene into a rag1 locus (rag1/gfp mice). The GFP+ cells express rag1 mRNA and are undergoing Ig gene rearrangement. RAG1 expression was studied in Pc B-1 cells to detect cells during the stage of Ig gene rearrangement. In contrast to previous reports, Pc B-1 cells did not show RAG1 expression in adolescent or elderly mice. RAG1 expression was not induced in Pc B-1 cells in vivo after stimulation by oral or i.p. administration of LPS. Our results suggest that RAG1 expression in Pc B-1 cells is inhibited for a long period under normal condition and that this suppression is an essential state which maintains allelic exclusion of Ig genes.

Activity and substrate specificity of the murine STK2 Serine/Threonine kinase that is structurally related to the mitotic regulator protein NIMA of Aspergillus nidulans

We isolated a murine STK2 (mSTK2) cDNA that is homologous to murine Nek1 serine/threonine kinase, a family member related to the cell cycle regulator kinase NIMA of Aspergillus nidulans. Structural comparison demonstrated that the kinase domain of mSTK2 is highly similar to NIMA/Nek family but the C-terminal region is not similar to any proteins except for human STK2 (hSTK2). Similarly to Nek1, mSTK2 is expressed ubiquitously among various organs and is upregulated in the testis. The expression and localization of mSTK2 are not associated with the cell cycle progression of mitogen-activated lymphocyte and DNA-transfected fibroblast. The substrate specificity of mSTK2 is similar to NIMA, but the phosphorylation is observed exclusively upon threonine residues rather than serine. The mSTK2 is shown to be a new member of the NIMA/Nek family with similar substrate specificity, which might participate in a different role from NIMA kinase involved in the cell cycle regulation.

A new member of the alpha4-related molecule (alpha4-b) that binds to the protein phosphatase 2A is expressed selectively in the brain and testis

A murine alpha4, identified in lymphocytes, binds to protein phosphatase 2A (PP2A). We found another murine alpha4-related gene (named alpha4-b) expressed selectively in the brain and testis. The alpha4-b transcript is expressed in the brain and testis, but is not detected in the spleen, thymus, bone marrow, liver, kidney, lung, heart or muscle. In-situ RNA hybridization analysis suggested that alpha4-b is expressed in most neuronal cells in the brain, but it is not expressed in the glial cells. The alpha4-b cDNA encodes a putative protein that is highly homologous (66% identity in amino-acid sequence) to the alpha4 molecule. The alpha4-b protein associates with the catalytic subunit of PP2A (PP2Ac), suggesting that the alpha4-b protein is involved in the regulation of phosphatase activity in neuronal cells.

Effect of streptozotocin-induced diabetes mellitus on type 1 deiodinase (D1) in inherited D1-deficient mice

We investigated the effects of streptozotocin (STZ)-induced diabetes on thyroid hormone levels, type 1 deiodinase (D1) activity and messenger RNA (mRNA) levels in inherited D1 deficient C3H mice in a comparative manner with control C57 mice. The apparent maximum velocity (Vmax) D1 values in C3H mice were 3% (liver) and 26% (kidney) of those in C57 mice. In C3H mice, similar serum T3, slightly higher T4, and 2.6-fold higher rT3 levels were observed compared with C57 mice. In STZ-induced diabetes, serum T4 level markedly decreased in both C3H and C57 mice. Serum T3 levels in STZ-C3H mice similarly decreased as in STZ-C57 mice. On the other hand, serum rT3 levels increased to 3.3-fold higher in STZ-C3H than in STZ-C57 mice. The Vmax values were decreased to 12% (STZ-C3H) and to 30% (STZ-C57) in liver, and decreased to 33% (both STZ-C3H and STZ-C57) in kidney. The changes in D1 mRNA levels in diabetes versus control were comparable to those of D1 activities in both strains. In summary, similar mechanism(s) to those which decrease the D1 expression and the serum T3 level in diabetes, function in D1 deficient C3H mice as in C57 mice. It appears that hepatic and renal D1 activity alone can not explain the similar reduction in T3 level in STZ-C3H mice and STZ-C57 mice.

Involvement of a rapamycin-sensitive pathway in CD40-mediated activation of murine B cells in vitro

Activation of resting B cells requires an initial triggering of the B cell antigen receptor (BCR) and secondary stimuli through various cytokine receptors and B cell activation molecules including CD40. We found that activation of B cells through CD40 is selectively inhibited by an immunosuppressant drug, rapamycin. This effect of rapamycin on anti-CD40-mediated activation of B cells was observed using three different in vitro assays. Rapamycin suppressed the anti-CD40-induced proliferation of splenic B cells, suppressed differentiation to surface IgMhigh/IgDlow B cells, and inhibited an anti-CD40-mediated prevention of apoptosis induced by BCR cross-linkage of WEHI-231 cells. We next examined several known CD40 signal transduction pathways to identify the target of rapamycin in stimulated B cells. Rapamycin did not inhibit the activation of c-Jun N-terminal kinases (JNKs) induced by anti-CD40 stimulation nor the activation of immediate nuclear transcription factors of NF-kappaB. Therefore, rapamycin affects a novel element of the CD40 signal transduction pathway which influences the proliferation, differentiation, and prevention of apoptosis of B cells.

Virus and autoimmunity: induction of autoimmune disease in mice by mouse T lymphotropic virus (MTLV) destroying CD4+ T cells

Neonatal infection of the mouse T lymphotropic virus (MTLV), a member of herpes viridae, causes various organ-specific autoimmune diseases, such as autoimmune gastritis, in selected strains of normal mice. The infection selectively depletes CD4+ T cells in the thymus and periphery for 2-3 wk from 1 wk after infection. Thymectomy 3 wk after neonatal MTLV infection enhances the autoimmune responses and produces autoimmune diseases at higher incidences and in a wider spectrum of organs than MTLV infection alone. On the other hand, inoculation of peripheral CD4+ cells from syngeneic noninfected adult mice prevents the autoimmune development. These autoimmune diseases can be adoptively transferred to syngeneic athymic nude mice by CD4+ T cells. The virus is not detected by bioassay in the organs/tissues damaged by the autoimmune responses. Furthermore, similar autoimmune diseases can be induced in normal mice by manipulating the neonatal thymus/T cells (e.g., by neonatal thymectomy) without virus infection. These results taken together indicate that neonatal MTLV infection elicits autoimmune disease by primarily affecting thymocytes/T cells, not self Ags. It may provoke or enhance thymic production of CD4+ pathogenic self-reactive T cells by altering the thymic clonal deletion mechanism, or reduce the production of CD4+ regulatory T cells controlling self-reactive T cells, or both. The possibility is discussed that other T cell-tropic viruses may cause autoimmunity in humans and animals by affecting the T cell immune system, not the self Ags to be targeted by the autoimmunity.

Thymus and autoimmunity: production of CD25+CD4+ naturally anergic and suppressive T cells as a key function of the thymus in maintaining immunologic self-tolerance

This study shows that the normal thymus produces immunoregulatory CD25+4+8- thymocytes capable of controlling self-reactive T cells. Transfer of thymocyte suspensions depleted of CD25+4+8- thymocytes, which constitute approximately 5% of steroid-resistant mature CD4+8- thymocytes in normal naive mice, produces various autoimmune diseases in syngeneic athymic nude mice. These CD25+4+8- thymocytes are nonproliferative (anergic) to TCR stimulation in vitro, but potently suppress the proliferation of other CD4+8- or CD4-8+ thymocytes; breakage of their anergic state in vitro by high doses of IL-2 or anti-CD28 Ab simultaneously abrogates their suppressive activity; and transfer of such suppression-abrogated thymocyte suspensions produces autoimmune disease in nude mice. These immunoregulatory CD25+4+8- thymocytes/T cells are functionally distinct from activated CD25+4+ T cells derived from CD25-4+ thymocytes/T cells in that the latter scarcely exhibits suppressive activity in vitro, although both CD25+4+ populations express a similar profile of cell surface markers. Furthermore, the CD25+4+8- thymocytes appear to acquire their anergic and suppressive property through the thymic selection process, since TCR transgenic mice develop similar anergic/suppressive CD25+4+8- thymocytes and CD25+4+ T cells that predominantly express TCRs utilizing endogenous alpha-chains, but RAG-2-deficient TCR transgenic mice do not. These results taken together indicate that anergic/suppressive CD25+4+8- thymocytes and peripheral T cells in normal naive mice may constitute a common T cell lineage functionally and developmentally distinct from other T cells, and that production of this unique immunoregulatory T cell population can be another key function of the thymus in maintaining immunologic self-tolerance.

Cell death-inducing activity by gallic acid derivatives

In this study, the cytotoxic activity of gallic acid derivatives (GDs) was studied using some cancer cell lines. Among them, 3,4-methylenedioxyphenyl 3,4,5-trihydroxybenzoate (GD-1) and S-(3,4-methylenedioxyphenyl)-3,4,5-trihydroxy-thiobenzoate (GD-3) were found to induce cell death in cancer cell lines with IC50s ranging from 2.9 to 114.4 microM, a concentration comparable with or lower than that of gallic acid. On the other hand, although gallic acid did not show any cytotoxicity against primary cultured rat hepatocytes and human keratinocytes, GD-1 and -3 showed slightly higher sensitivity against such normal cells, when compared with gallic acid. The cell death induced by gallic acid and GD-1 was accompanied by internucleosomal DNA fragmentation characteristic of apoptosis, whereas only smear DNA degradation was detected following GD-3 treatment. When the mechanism by which GD-1 and -3 caused cell death in HL-60RG cells was examined, GD-1 and -3-induced cell death was inhibited by the intracellular Ca2+ chelator, bis-(o-aminophenoxy)-N,N,N,N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM), calmodulin inhibitor, W-7, and the Ca2+/Mg2+ -dependent endonuclease inhibitor zinc sulfate. In contrast, catalase, N-acetylcysteine (NAC), and ascorbic acid inhibited gallic acid-induced apoptosis in HL-60RG cells, whereas they had no effect on GD-1- and -3-induced cell death. This result suggests that GD-1 and -3 induced cell death in a different manner to gallic acid. In conclusion, esterification of gallic acid with a 3,4-methylenedioxyphenyl group yielded potent agents to treat cancer with a different signaling pathway from gallic acid, although selectivity was lost.

Alpha4 protein as a common regulator of type 2A-related serine/threonine protein phosphatases

The catalytic activity of the C subunit of serine/threonine phosphatase 2A is regulated by the association with A (PR65) and B subunits. It has been reported that the alpha4 protein, a yeast homolog of the Tap42 protein, binds the C subunit of serine/threonine phosphatase 2A and protein phosphatase 2A-related protein phosphatases such as protein phosphatase 4 and protein phosphatase 6. In the present study, we showed that alpha4 binds these three phosphatases and the association of alpha4 reduces the activities of these phosphatases in vitro. In contrast, PR65 binds to the C subunit of serine/threonine phosphatase 2A but not to protein phosphatase 4 and protein phosphatase 6. These results suggest that the alpha4 protein is a common regulator of the C subunit of serine/threonine phosphatase 2A and protein phosphatase 2A-related protein phosphatases.

Metabolic fate of gallic acid orally administered to rats

The metabolic behavior of orally administered gallic acid was investigated by HPLC and 4-O-methyl gallic acid was found to be the main metabolite in rat peripheral blood and urine. After oral administration of gallic acid, maximum concentration in portal vein and inferior vena cava occurred at 15 and 30 min, respectively. In portal vein, gallic acid was preferentially detected relative to 4-O-methyl gallic acid, whereas gallic acid and 4-0-methyl gallic acid were equally detected in inferior vena cava. On the other hand, 4-O-methyl gallic acid but not gallic acid was found in liver. The contents of gallic acid and 4-O-methyl gallic acid in urine were nearly 100 times higher than those in blood. The ratio of 4-O-methyl gallic acid to total gallic acid metabolites in urine was from 0.55 to 0.76, indicating that a considerable amount of gallic acid was excreted without being metabolized. In this study we found that gallic acid administered orally existed in the blood for 6 h at most, and more than half was metabolized to 4-O-methyl gallic acid, followed by excretion into urine.

Intravascular fasciitis of the forearm vein: a case report with immunohistochemical characterization

Intravascular fasciitis is a very unusual variant of nodular fasciitis. A unique case of this lesion occurring in the proximal portion of the superficial vein of the forearm in an otherwise healthy 26-year-old man is reported. The intravascular polypoid lesion grew longitudinally along the vascular lumen, was loosely attached to the intimal layer, and was partly anchored beyond the internal elastic lamina into the medial smooth muscle layer. However, extravascular involvement was absent. The histological features were identical to those observed in ordinary cellular nodular fasciitis. Because of its myofibroblastic phenotype exhibited by highly proliferative spindle cells, certain intimomedial myofibroblasts are thought to be the indigenous source of this unique fibroproliferative lesion. Unless the diagnosis of intravascular fasciitis is considered and appropriate differential markers examined, it may be confused with other intravascular lesions, such as intravascular leiomyoma, intravenous pyogenic granuloma, organized thrombus and, even, fibromuscular dysplasia if it arises in the arteries. A simple excision is considered curable. Even so, two recurrent cases have been documented to date.

Effect of nicotine on type 2 deiodinase activity in cultured rat glial cells

Intracellular generation of triiodothyronine (T3) from thyroxine (T4) by type 2 deiodinase (D2) in the mammalian brain, plays a key role in thyroid hormone action. The presence of D2 in rat astrocytes suggests the importance of glial cells in the regulation of intracellular T3 levels in the rat central nervous system (CNS). To analyze further the factors that regulate D2 activity in the CNS, we investigated the effects of nicotine and of mecamylamine, which inhibits the binding of nicotine with nicotinic acetylcholine receptors, on D2 activity in cultured mixed glial cells of the rat brain. We incubated cultured mixed glial cells obtained from neonatal Wistar rats in the presence of 10 mM dithiothreitol, 2 nM [125I] reverse T3 and 1 mM 6-N-propyl-2-thiouracil for 2 h at 37 degrees C, and the released 125I- was counted in a gamma counter. D2 activity of cultured cells was dependent on the temperature and the amount of protein. The basal D2 activity of rat mixed glial cells was 1.9 +/- 0.2 fmol of I- released/mg protein/h (mean +/- SEM). The addition of 10(-11), 2 x 10(-11), 10(-10), and 10(-9) M nicotine significantly increased D2 activity to approximately 2.2-, 2.4, 3.5- and 2.9-fold the basal level, respectively. D2 activity stimulated by 10(-8) M nicotine (2.5-fold) reached a peak after 9 h incubation. The stimulatory effect of nicotine was completely blocked by 10(-6) M mecamylamine. In conclusion, nicotine increases D2 activity probably via nicotinic acetylcholine receptors, and may influence brain function, at least in part, by affecting thyroid hormone metabolism.

Immunologic self-tolerance maintained by CD25+CD4+ naturally anergic and suppressive T cells: induction of autoimmune disease by breaking their anergic/suppressive state

Elimination of CD25+ T cells, which constitute 5-10% of peripheral CD4+ T cells in normal naive mice, leads to spontaneous development of various autoimmune diseases. These immunoregulatory CD25+CD4+ T cells are naturally unresponsive (anergic) in vitro to TCR stimulation, and, upon stimulation, suppress proliferation of CD25-CD4+ T cells and CD8+ T cells. The antigen concentration required for stimulating CD25+CD4+ T cells to exert suppression is much lower than that required for stimulating CD25-CD4+ T cells to proliferate. The suppression, which results in reduced IL-2 production by CD25-CD4+ T cells, is dependent on cellular interactions on antigen-presenting cells (and not mediated by far-reaching or long-lasting humoral factors or apoptosis-inducing signals) and antigen non-specific in its effector phase. Addition of high doses of IL-2 or anti-CD28 antibody to the in vitro T cell stimulation culture not only breaks the anergic state of CD25+CD4+ T cells, but also abrogates their suppressive activity simultaneously. Importantly, the anergic/suppressive state of CD25+CD4+ T cells appeared to be their basal default condition, since removal of IL-2 or anti-CD28 antibody from the culture milieu allows them to revert to the original anergic/suppressive state. Furthermore, transfer of such anergy/suppression-broken T cells from normal mice produces various autoimmune diseases in syngeneic athymic nude mice. These results taken together indicate that one aspect of immunologic self-tolerance is maintained by this unique CD25+CD4+ naturally anergic/suppressive T cell population and its functional abnormality directly leads to the development of autoimmune disease.

Maternal thyroid function in multiple pregnancy: the variable thyrotropic activity of human chorionic gonadotropin

The present study was undertaken to evaluate thyroid function and thyrotropic action of hCG in multiple pregnancy. We examined serum samples from 9 multiple pregnant women (3 triplets and 6 twins) and 27 singleton pregnant women as control subjects. Serum hCG levels in multiple pregnancy were higher than those in singleton pregnancy in the second and third trimesters (P < 0.01). The mean free T3 and T4 concentrations in multiple pregnancy did not differ from those in singleton pregnancy in each trimester. Serum hCG levels showed a statistically significant positive correlation with free T3 and T4 levels in singleton pregnancy (P < 0.001). However, these correlations were not observed in multiple pregnancy. Thyroid stimulation activity (TSA) determined by cAMP accumulation in FRTL-5 cells in multiple pregnancy sera was significantly higher than that in singleton pregnancy in the first trimester (P < 0.05), but did not differ in the second and third trimesters. Moreover, TSA did not show any correlation with serum hCG levels in multiple pregnancy in contrast with the results in normal pregnancy. A bioactivity/immunoreactivity ratio of hCG in multiple pregnancy was lower than in singleton pregnancy in the second and third trimesters. The discrepancy between immunoreactivity and thyrotropic activity of hCG may be caused by the variable thyrotropic potency of heterogeneous hCG molecules in multiple pregnancy.

Monoclonal antibody NU-B1 reacts with novel antigen on human B cells in mantle and marginal zones distinct from known CD molecules

To analyze the cellular antigens of human B-cell lineage, a monoclonal antibody, NU-B1, was raised using the acute lymphoblastic leukemia (ALL) cell line NALM-16 as the immunogen. NU-B1 reacted with 7.7+/-3.9% of the healthy adult peripheral blood mononuclear cells but not with neutrophils, monocytes, red blood cells or thymocytes. In order to distinguish the reaction specificity of NU-B1, two-color immunofluorescence staining using tonsillar cells was performed, and it was demonstrated that NU-B1-positive cells coexpressed CD20, which is a representative B-cell antigen. The expression of NU-B1 was highly restricted to cells of B-cell lineage when a panel of hematopoietic cell lines was examined. In a pathoimmunohistological study using human lymph node tissue, NU-B1-positive cells were localized in the mantle and marginal zones. In a clinical study, NU-B1 reacted specifically with leukemias/lymphomas of B-cell lineage: all 43 cases of ALL including common ALL and biphenotypic leukemia, all 4 cases of B-cell ALL, 6/7 B-cell type malignant lymphomas and 2/4 B-cell chronic lymphocytic leukemias. NU-B1 did not react with multiple myeloma, T-cell or myeloid leukemias/lymphomas. Immunoprecipitation of NU-B1 revealed two clear bands at 50 kDa and 42 kDa under either reducing or nonreducing conditions. Although anti-IgM treatment induced dramatic down modulation of CD79b, the NU-B1 antigen was also down modulated, but only slightly. However, crosslinking of NU-B1 did not induce tyrosine phosphorylation of intracellular proteins or the mobilization of calcium in NALM-16. The present results revealed that the antigenic determinant recognized by NU-B1 is not surface immunoglobulin chains, HLA-DR, a receptor for C3, Fc for immunoglobulin chains or any known CD molecule. We conclude that monoclonal antibody NU-B1 recognizes a novel human B-cell restricted antigen distinct from known CD molecules, and that it is a useful antibody in the immunophenotyping and classification of leukemias/lymphomas.