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Y Nojima

Publications and source records attributed to Y Nojima.

At least 19 recordsLinked to original sources
PubMed1992

Ligation of VLA-4 on T cells stimulates tyrosine phosphorylation of a 105-kD protein.

The VLA/integrins are a family of heterodimeric adhesion receptors shown to be involved in cell-to-cell and cell-to-extracellular matrix (ECM) interactions. Given recent evidence that VLA molecules can synergize with the CD3/T cell receptor (TCR) pathway to activate T cells, it is important to identify biochemical event(s) generated by these molecules. Here, we report that the engagement of VLA-4 on T cells with specific antibodies or its ligand activates protein-tyrosine kinase (PTK) activity as detected by antiphosphotyrosine immunoblotting. The crosslinking of VLA-beta 1 (CD29) with a specific monoclonal antibody (mAb) (anti-4B4) plus anti-mouse immunoglobulin resulted in the rapid tyrosine phosphorylation of a 105-kD protein (pp105) in the human T cell line H9, as well as in peripheral resting T cells. The increase in tyrosine phosphorylation of pp105 was specifically mediated by VLA-4, since mAbs against alpha 4, but not against other VLA alpha chains, could induce this phosphorylation. In addition, the binding of T cells with the CS1 alternatively spliced segment of fibronectin (the binding site recognized by VLA-4) induced pp105 tyrosine phosphorylation. Crosslinking the CD3 complex or VLA-4 molecules with mAbs demonstrated that each of these molecules stimulated the tyrosine phosphorylation of unique sets of proteins with different kinetics, suggesting that these two receptor systems are coupled to distinct PTKs. Since tyrosine phosphorylation of cellular proteins has been shown to be a crucial biochemical event in cell growth, our findings suggest that the induction of pp105 tyrosine phosphorylation via VLA-4 may play a role in the transduction of activation signals through this molecule.

Antigens, CD↗
PubMed1992

Correlation of antibodies to ribosomal P protein with psychosis in patients with systemic lupus erythematosus.

Ninety one Japanese patients with systemic lupus erythematosus (SLE) were studied to determine the clinical significance of antibodies to ribosomal P protein (anti-P). Anti-P was detected by western blotting in 38 of 91 patients (42%). Clinical symptoms of SLE were compared between patients with and without anti-P. The occurrence of lupus psychosis was significantly higher in patients with anti-P than in those without anti-P (9/38 v 1/53). No significant association was found between anti-P and other symptoms of SLE. These data strongly support the suggestion proposed by previous workers that anti-P is a marker autoantibody for the development of lupus psychosis.

Autoantibodies↗
PubMed1991

A novel species of cytochrome P-450 (P-450ib) specific for the small intestine of rabbits. cDNA cloning and its expression in COS cells.

We have isolated a cDNA clone for a P-450, designated P-450ib (Ichihara, K., Kusunose, E., Kaku, M., Yamamoto, S., and Kusunose, M. (1985) Biochim. Biophys. Acta 831, 99-105), from a cDNA library of rabbit small intestine mucosa by using synthetic DNA fragment by the polymerase chain reaction, as a hybridization probe. The cDNA with a 1,829-base pair insert encodes a polypeptide of 501 amino acids. The deduced amino acid sequence contains all of the sequences of the NH2-terminal and 14 tryptic fragments from purified P-450ib. As the NH2-terminal methionine was not found in the sequence from the purified protein, the apoprotein of P-450ib is composed of 500 amino acids with a molecular weight of 57,193. P-450ib shows 35-41% sequence similarity with several members of 8 subfamilies in the P-450 II family, whereas it has a less than 30% sequence similarity with other P-450 families, suggesting that this P-450 is the first member of a novel subfamily within the P-450 II family. RNA blot analysis shows that mRNA hybridized to the cDNA is expressed in the small intestine, but not significantly in other tissues including liver, colon, kidney, lung, spleen, brain, stomach, and cecum, indicating that P-450ib is a P-450 specific to the small intestine. The protein expressed in COS-7 cells using the cDNA in an expression vector, pKCRH2, shows benzphetamine N-demethylase activity and gives a band identical with that of P-450ib in its mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Amino Acid Sequence↗
PubMed1991

The 1A4 molecule (CD27) is involved in T cell activation.

We developed a new mAb, anti-1A4, which recognizes an epitope on the CD27 molecule distinct from those recognized by several known anti-CD27 mAb. Although it has been suggested that the CD27 molecule is a T cell activation Ag, there was little direct evidence that the structure was involved in the T cell activation process. In this study, we showed that anti-1A4 inhibited anti-CD2, anti-CD3, mitogens, or soluble Ag-induced T cell proliferation as well as PWM-driven B cell IgG synthesis. Interestingly, anti-1A4 inhibited IL-2 secretion without affecting IL-2R expression. In addition, pretreatment of T cells with anti-1A4 inhibited the normally sustained intracellular calcium mobilization seen after triggering of T cells via the CD2 or CD3 pathways. Thus, binding of anti-1A4 to the CD27 molecule appears to induce a negative effect on T cell activation. This may be due to either a direct signal to T cells or the blocking of an interaction between T cells and accessory cells or both. These findings support the notion that the CD27 molecule plays an integral role in the process of T cell activation.

Animals↗
PubMed1991

Autoantibodies to nucleolin in systemic lupus erythematosus and other diseases.

The 110-kDa intracellular phosphoprotein (110K) described previously by this laboratory as a common IgM autoantigen in SLE and certain other systemic autoimmune disorders and viral infections is identified as nucleolin in the present investigation. Using rabbit antiserum to rat nucleolin as a probe, IgM autoantibody-reactive 110K co-migrated with human lymphocyte nucleolin in one- and two-dimensional immunoblots. Rabbit anti-nucleolin also specifically depleted autoreactive 110K from detergent lysates of human cells. Because nucleolin shares amino acid sequence similarity and/or forms dynamic particles with other prominent autoantigens, the present observation raises the possibility that the nucleolin/anti-nucleolin system may be of special significance for the development of humoral autoreactivity to nuclear Ag.

Antibody Specificity↗
PubMed1991

Activation of human CD4 T lymphocytes. Interaction of fibronectin with VLA-5 receptor on CD4 cells induces the AP-1 transcription factor.

Fibronectin synergized with anti-CD3 antibody to promote CD4 cell proliferation in a serum-free culture system whereas no proliferation was observed when CD4 cells were cultured with anti-CD3 alone or fibronectin alone. In addition, anti-CD29 (integrin beta 1) as well as anti-VLA-5 (human fibronectin receptor) antibodies blocked this CD4 cell activation in this system. Although anti-CD3 alone or fibronectin alone cannot induce IL-2 message by CD4 cells, the combination of anti-CD3 plus fibronectin induced IL-2 message by CD4 cells. In an analysis of the molecular mechanism by which IL-2 message was generated, we showed that a fibronectin-VLA-5 fibronectin receptor interaction may contribute an independent signal distinct from the CD3 pathway of activation by the induction of an AP-1 transcriptional factor. Thus the VLA-5 fibronectin receptor on CD4 cells can play a complementary role in CD3-TCR-mediated signal transduction through its interaction with fibronectin.

Antibodies, Monoclonal↗
PubMed1991

Cross-linking of VLA/CD29 molecule has a co-mitogenic effect with anti-CD3 on CD4 cell activation in serum-free culture system.

In this study, we demonstrated that antibodies reactive with a common beta 1 subunit (CD29) of the VLA family of antigens could synergize with CD3 but not CD2 in inducing CD4 cell proliferation in a serum-free culture system. The extent of activation was similar to that obtained when CD4 cells were cultured with anti-CD3 plus fibronectin. The proliferative response induced via the CD3-CD29 pathway was associated with the interleukin (IL) 2 autocrine pathway, including IL 2 production and IL 2 receptor expression. Specifically, cross-linking of VLA-5, but not other members of the VLA family of antigens with the CD3 molecule induced strong CD4 cell activation. However, cross-linking of CD3 with other cell surface antigens such as CD4 did not induce CD4 cell activation in this serum-free culture system. The above results strongly suggest that the VLA/CD29 family of antigens may play an important role in regulating CD4 T cell activation via the CD3-T cell receptor pathway.

Antibodies, Monoclonal↗
PubMed1991

Specificity of autoantibodies to histone H1 in SLE: relationship to DNA-binding domains.

Autoantibodies in the sera of patients with systemic lupus erythematosus were examined with respect to their specificity for proteolytic fragments of histone H1 that retain, or do not retain, DNA-binding domains. 16 of 31 sera contained IgG and IgM antibodies to histone H1. IgM antibodies to H1 in 8 sera (50%) were directed at 18 kD and 20 kD alpha-chymotrypic H1 fragments that bore binding sites for DNA, as identified by staining immunoblots containing the fragments with ssDNA plus 6/0, a mouse monoclonal antibody against ssDNA, IgM with this type of histone H1 specificity did not react with comparably-sized V8 protease fragments of H1. IgM antibodies to H1 in the other patients were directed against entirely different epitopes which were preserved in V8 protease digests of H1. In serial studies of three patients during different phase of their SLE, the level of antibodies against the 18 kD and 20 kD histone H1 fragments varied in parallel with the level of anti-ssDNA antibodies in one and varied inversely in the other two. The data suggest that a significant proportion of autoantibodies to histone H1 are directed at a limited number of epitopes localized to H1 fragments containing DNA-binding sites.

Animals↗
PubMed1990

VLA-4 mediates CD3-dependent CD4+ T cell activation via the CS1 alternatively spliced domain of fibronectin.

We previously showed that fibronectin (FN) synergized with anti-CD3 in induction of CD4+ T cell proliferation, and that VLA-5 acted as a functional FN receptor in a serum-free culture system. In the present study, we showed that VLA-4 is also involved in this CD3-dependent CD4 cell activation through its interaction with the alternatively spliced CS1 domain of FN. When highly purified CD4 cells were cultured on plates coated with anti-CD3 plus synthetic CS1 peptide-IgG conjugate, significant proliferation could be observed. Neither CS1 alone nor anti-CD3 alone induced this activation. This proliferation was completely blocked by anti-VLA beta 1 (4B4) and anti-VLA-4 (8F2), while anti-VLA-5 (monoclonal antibody [mAb] 16 and 2H6) had no effect. These data indicate that VLA-4 mediates CD3-dependent CD4 cell proliferation via the CS1 domain of FN. Anti-VLA-4 also partially (10-40%) inhibited CD4 cell proliferation induced by native FN plus anti-CD3, implying that the CS1 domain is active in the native plasma FN. However, this native FN-dependent proliferation was entirely abolished by addition of anti-VLA-5 alone. Moreover, when native FN-coated plates were pretreated with anti-FN (mAb 333), which blocks RGDS sites but not CS1 sites, no CD4 cell activation could be observed. These results strongly suggest that CD4 cell activation induced by plasma FN/anti-CD3 may be dependent on both VLA4/CS1 and VLA5/RGDS interactions, although the latter interaction may be required for function of the former.

Amino Acid Sequence↗
PubMed1990

Systemic lupus erythematosus associated with antiribosomal P protein antibody.

Three patients with systemic lupus erythematosus had positive antiribosomal P protein antibodies. The patients are women who had mild diseases that did not involve prominent internal organs. By using an immunofluorescence method for the detection fo antinuclear antibodies that employs HEp-2 cells, these serum samples produced intense stainings on cytoplasm and nucleoli that were digested with RNase. With the use of an immunoblotting technique, these serum samples recognized three ribosomal P proteins, called PO (38 kd), P1 (19 kd), and P2 (17 kd). We suggest that antiribosomal P protein antibodies can be detected in patients with systemic lupus erythematosus and associated mild clinical features.

Adolescent↗
PubMed1989

Identification of an acidic ribosomal protein reactive with anti-Sm autoantibody.

Autoantibody to Sm Ag is a highly specific marker for the diagnosis of SLE. The Sm Ag exists in the cell nucleus as part of a ribonucleoprotein complex containing five small nuclear RNA. The major immunoreactive Sm species have been reported to be three polypeptides of m.w. 28,000/29,000 (B/B') and 16,000 (D). We report here that a m.w. 21,000 peptide is another major target of anti-Sm antibody. This peptide was originally identified by Western blotting as an acidic ribosomal protein (RP21) reactive with IgG from some SLE patients. Anti-RP21 is distinct from anti-ribosomal P protein antibody (anti-P) which has been previously identified as a lupus-specific autoantibody. Cell fractionation experiments showed that RP21 existed only in the ribosomal fraction and was never detected in other cellular compartments including nuclei. However, when nuclear extracts were used as Ag sources in immunoblotting, affinity-purified anti-RP21 was found to react with m.w. 28,000 and 16,000 peptides, suggesting that anti-RP21 reactivity might be due to the cross-reaction of anti-Sm. This was further confirmed by the evidence that two kinds of murine anti-Sm mAb independently derived from MRL/lpr mouse recognized RP21. These results indicate that anti-Sm antibodies in SLE are reactive with both nuclear and ribosomal ribonucleoproteins. Previous reports have described certain similarities, i.e., antibody subclass restriction and incidence, of anti-Sm and anti-P in both humans and autoimmune mice. Our present study demonstrated a close physical association of target molecules reactive with anti-Sm and anti-P, and might, therefore, provide some clue to the origin of these two types of lupus-specific autoantibodies.

Animals↗
PubMed1989

[Toxicity studies on T-3262 in rat upon intravenous injection for 14 days].

T-3262 is a new antibacterial drug which has been developed for oral administration in clinical use. It is known that T-3262 has cytotoxicity in cultured mammalian cells. Therefore, it is necessary to determine the cytotoxicity-related effects of T-3262 (if it is absorbed in a large quantity in animal). In this study, the toxicity of T-3262 was investigated in Sprague-Dawley rats upon intravenous injection of T-3262 at 50 mg/kg/day for 14 days, and the results were compared to those obtained with ofloxacin (OFLX) and mitomycin C (MMC). The results are summarized as follows. 1. In the T-3262-treated group, no animal died and no abnormal changes occurred regarding general symptoms during the treatment. There were no significant abnormalities in hematological, blood biochemical, ophthalmological and anatomical examinations nor changes in nucleate cells of bone marrow and myelogram. Crystal sediment (test material-like) was observed in urine of 8 of 10 rats examined. The weights of heart and prostate (including seminal vesicle) decreased and the weight of cecum increased. In histological examinations, dilatation of renal tubuli was observed in kidneys of 2 of 7 rats examined. 2. In the OFLX-treated group, no treatment-related changes were found. In histological examinations, the dilatation of renal tubuli was not observed. 3. In the MMC-treated group, the following changes were observed: decrease in body weight gain, in white blood cell (WBC) counts and number of nucleate cell in bone marrow, increase in myeloid vs. erythroid ratio. Hypoplasia of bone marrow was also observed. From the above results, no significant abnormalities occurred in rats treated intravenously with 50 mg/kg/day of T-3262 for 14 days. The cytotoxicity of T-3262 observed in cultured mammalian cells was not reflected in animals in this study.

Animals↗
PubMed1989

[Cytotoxicity studies on T-3262 in cultured Chinese hamster cells].

T-3262 is an antibacterial drug which belongs to the group of pyridonecarboxylic acids. In this study, we investigated cytotoxicity of T-3262 for inhibition of cell growth and effects on viability of, and morphological changes in cultured Chinese hamster cells (V79 cells). The following results were obtained. 1. The 50% inhibition dose of T-3262 for cell growth (ID50, cultured for 48 hours) was 12 micrograms/ml, showing that the inhibitory effect of T-3262 on the cell growth was stronger than that of enoxacin (ENX: ID50 44 micrograms/ml), norfloxacin (NFLX: ID50 105 micrograms/ml) or ofloxacin (OFLX: ID50 145 micrograms/ml). 2. The number of cells increased and dead cells were scarcely seen at the highest concentration tested in culture medium (40 micrograms/ml of T-3262 for 48 hours). At this concentration, degeneration of cytoplasm (atrophy and round shape) and decrease of mitotic cells were observed. These morphological changes were similar to those of the cells treated 400 micrograms/ml of NFLX or OFLX for 48 hours. 3. After the removal of T-3262 from culture medium, the cells began to grow actively and recovered from the morphological changes. The similar phenomenon was observed with ENX treated cells but not with fluorouracil or mitomycin C treated cells.

4-Quinolones↗
PubMed1986

Correlative expression of C3b receptors in the glomerulus and on erythrocytes.

The reactivity of glomerular C3b receptors (CR1) measured by the number of sheep erythrocytes bearing C3b (EAC) that adhered to glomeruli in frozen sections, was compared with the reactivity of erythrocyte CR1, which was determined by immune adherence hemagglutination (IAHA), in 22 patients with renal and non-renal diseases. Among seven patients with primary glomerulonephritis whose erythrocytes were positive for IAHA, the reactivity of glomerular CR1 was high in five. In the remaining two, the reactivity of glomerular CR1 was low, accompanied by severe sclerotic glomerular changes. Erythrocytes from five of six patients with systemic lupus erythematosus were IAHA negative, and their glomeruli failed to produce adherence of EAC, even in three cases in which there were no detectable C3 deposits or histopathological changes. In the other nine patients without appreciable glomerular changes, the reactivity of glomerular CR1 was low in three along with negative erythrocyte IAHA, whereas the remaining six exhibited high CR1 reactivity both in glomeruli and on erythrocytes. The results indicate a close correlation between the expression of CR1 in the glomerulus and on erythrocytes.

Antigen-Antibody Complex↗
PubMed1986

Tubulointerstitial immune complex nephritis in a patient with cutaneous vasculitis.

We report a patient who suffered from cutaneous vasculitis with renal involvement comprising tubulointerstitial (TI) nephritis and relatively mild glomerulitis. Renal biopsy revealed immune deposits both in mesangium and along tubular basement membrane (TBM), suggesting that immune complexes played a significant role in the development of renal damage. Although it is well known that vasculitic syndromes commonly affect glomeruli, this report is the first to demonstrate tubulointerstitial immune complex nephritis in a patient with cutaneous vasculitis.

Adult↗