Biomedical subjects

M Sano

Publications and source records attributed to M Sano.

At least 91 records · Page 5Linked to original sources

PubMed2000

Comprehensive cloning and expression analysis of glycolytic genes from the filamentous fungus, Aspergillus oryzae.

We cloned all the glycolytic genes from Aspergillus oryzae and analyzed their transcriptional regulation by the carbon source in the medium. The deduced amino-acid sequences of the glycolytic genes showed high identity (approximately 41-93%) to those from other lower eukaryotes. Genomic Southern hybridization indicated that all the genes existed as a single copy in the genome. Comparison of mRNA levels between mycelia grown on glucose and on pyruvate showed that most of the A. oryzae glycolytic genes were induced by glucose in the medium. The overall expression profiles of the A. oryzae glycolytic genes resembled those of Saccharomyces cerevisiae. The expression of one of the phosphofructokinase genes (pfkB), however, was repressed by glucose while both PFK1 and PFK2 were induced in S. cerevisiae. These findings indicate that further analysis of the transcriptional regulation of the A. oryzae glycolytic genes will be useful for investigating the evolutionary change of transcription regulation in lower eukaryotes and to construct promoters for industrial applications.

Aspergillus oryzae↗

PubMed2000

Constant involvement of the Betz cells and pyramidal tract in multiple system atrophy: a clinicopathological study of seven autopsy cases.

We investigated clinicopathologically the pyramidal signs, including spasticity, hyperreflexia, and Babinski's sign, and the involvement of the pyramidal tract and primary motor cortex, in seven Japanese autopsy cases of multiple system atrophy (MSA). Pyramidal signs were observed in six (86%) of the seven autopsy cases. Hyperreflexia and Babinski's sign were each evident in five patients, but spasticity was observed in only one patient. Loss of Betz cells and presence of glial cytoplasmic inclusions in the primary motor cortex were noticed in all seven cases. Astrocytosis in the fifth layer of the primary motor cortex was noticed in five cases, but its presence was not related to the duration of the disease. Involvement of the pyramidal tract in the spinal cord, particularly of the small myelinated fibers, was observed in all seven cases, but no involvement of the pyramidal tract in the midbrain was evident in any of the six cases in which this structure was examined. In MSA, pyramidal signs were shown to be present more frequently than believed before, and the clinicopathological correlation between pyramidal signs and involvement of the pyramidal tract was obvious. Constant involvement of Betz cells in MSA has not been reported. Our clinicopathological findings may also make a contribution to the understanding of the clinicopathological hallmarks of MSA.

Female↗

PubMed2000

Intra-abdominal desmoplastic small round cell tumor (IDSRT).

Intra-abdominal desmoplastic small round cell tumor (IDSRT) is a rare neoplasm that develops in the abdominal cavity in young people. We experienced a 27-year-old man who visited with ascites of unknown cause. Compression of the colon was found by barium enema examination. On colonoscopic examination, diffuse white elevated lesions, about 5 mm in diameter, surrounded by rubedo, so-called aphthoid lesions, were also observed. IDSRT was diagnosed by biopsy at laparotomy, and chemotherapy with cyclophosphamide, etoposide, doxorubicin, and cisplatin was performed. The tumors shrank temporarily (partial response), but subsequently grew in size again. The patient died during the second course of chemotherapy after relapse. We present one case report, together with a review of the literature.

Abdominal Neoplasms↗

PubMed2000

Quantitative analysis of cell allocation during liver development, using the spf(ash)-heterozygous female mouse.

Mosaicism of ornithine transcarbamylase (OTC) expression in hepatocytes was quantitatively analyzed during liver development of the spf(ash)-heterozygous female mouse. Because the mosaic patterns depend on cell migration and cell mixing, such analysis could give insights on the growth pattern or allocation pattern of hepatocytes during liver development. Complex mosaic patterns of OTC-positive and -negative hepatocytes were observed in sections of fetal and postnatal livers. Sizes of patches, which were aggregates of OTC-positive or -negative hepatocytes, increased during development. Patches were slender and comparatively simple in 15.5- and 17.5-day fetal and neonatal livers. Quantitative analysis of patch shapes demonstrated that undulation of patches was maximal at 7 postnatal days. Patches with nodular shapes also started to increase in number at this stage. Isolated patches in sections of fetal livers and postnatal livers three-dimensionally connected with one another. However, especially in fetal livers, in which OTC-positive patches were minor, due to the presence of abundant hemopoietic cells, isolated three-dimensional patches consisting of approximately 5 to 70 cells were often found. They were shaped like slender branching or zigzag-shaped cords, but no definite orientation such as portal-central was observed in them at any stage. These results suggest that hepatocytes contiguously allocate their daughter cells as zigzag-shaped or branching cords at younger stages. Some hepatocytes grow with nodular formation after 7 postnatal days. Migration and mixing of hepatocytes appear to be more extensive at fetal stages than in the adult liver. Immunohistochemical analysis of intercellular junction proteins (E-cadherin, connexins 26 and 32, occludin, and ZO-1) also revealed that their expression and distribution changed in hepatocytes during development, which may be correlated with the OTC mosaic patterns.

Aging↗

PubMed2000

Acute myeloid leukemia possessing jumping translocation is related to highly elevated levels of EAT/mcl-1, a Bcl-2 related gene with anti-apoptotic functions.

Jumping translocations (JTs) are unbalanced chromosomal translocations in which an identical chromosomal region is translocated to the telomeric region of different chromosomes. JTs are rare in hematological malignancies where they are second translocations and may be an indicator of poor prognosis. We report a case of acute myeloid leukemia with t(16;21) and a JT in which the long arm of chromosome 1 distal to q21 is translocated to the terminal region of chromosome 10. The leukemic cells exhibit high expression of EAT/mcl1, an anti-apoptotic Bcl-2 related gene. Since EAT/mcl1 is mapped to 1q21 near the breakpoint in the JTs, high level expression of EAT/mcl1 may be associated with the poor prognosis of leukemia with JTs.

Adolescent↗

PubMed2000

Detailed characterization of an anti-factor IX monoclonal antibody that neutralizes the prolonged ox brain prothrombin time of hemophilia B(M) by synthetic peptides.

In a previous study, we prepared a monoclonal antibody (MoAb) to coagulation factor IX (FIX), designated 65-10, which interfered with the activation of FIX by the activated factor XI/Ca(2+) and neutralized the prolonged ox brain prothrombin time of hemophilia B(M) [11,12]. The location of the epitope on the FIX for 65-10 MoAb is (168) Ile-Thr-Gln-Ser-Thr-Gln-Ser-Phe-Asn-Asp-Phe-Thr-Arg-Val-Val(182) [21]. In this paper, we studied in more detail an epitope on FIX using the systematic substitution of different amino acids at each residue of the epitope peptides and the influence of the epitope peptide on the prolonged ox brain prothrombin time of the hemophilia B(M) plasma of 65-10 MoAb. In the replacement set of amino acids, peptides showing low or no reactivity to 65-10 were (175)Phe --> Asp, Glu, Gly, Lys, Arg, Thr, Val, (176)Asn --> Asp, Glu, Phe, Ile, Lys, Leu, Pro, Val, Tyr, (177)Asp --> Cys, Glu, Phe, Ile, Lys, Leu, Met, Pro, Gln, Arg, Ser, Thr, Val, Trp, Tyr, and (178) Phe --> Pro. These results imply that a hydrophobic molecule of (175) Phe, a hydrophilic molecule of (176)Asn, and a negative charge molecule of (177)Asp were important to the epitope. The 65-10 MoAb antibody neutralized the prolonged ox brain prothrombin time of hemophilia B(M) Nagoya 2 ((180)Arg -->Trp) and Kashihara ((181)Val --> Phe) as well as B(M) Kiryu ((313)Val --> Asp) and Niigata ((390)Ala --> Val). This reaction was inhibited by preincubation with a (168) Ile-Thr-Gln-Ser-Thr-Gln-Ser-Phe-Asn-Asp-Phe-Thr-Arg-Val-Val(182) peptide conjugated with bovine serum albumin (BSA). 65-10 MoAb that has been useful in detailing epitopes will be useful for qualitative analysis of hemophilia B(M).

Amino Acid Sequence↗

PubMed2000

Involvement of angiotensin II and endothelin-1 in the development of submandibular gland hypertrophy in response to isoproterenol in rats.

We investigated whether angiotensin II (Ang II) and endothelin-1(ET-1) are involved in submandibular hypertrophy in response to repeated treatment with isoproterenol (ISO) in rats. The immunoreactive Ang II (IRAng II) and immunoreactive ET-1 (IRET-1) contents of ISO-induced hypertrophy were significantly higher than those of control glands. Treatment of isolated gland tissues with ISO (1 microM) or dobutamine (1 microM) caused significant increases in the IRAng II and IRET- 1 contents of the glands compared with controls. These increases were suppressed by pretreatment with enalapril (3 microM) or captopril (3 microM). Treatment with Ang II (10 microM) also caused an increase in IRET-1 content. Our findings suggest that Ang II and ET-1 are involved in the submandibular gland hypertrophy that develops in rats repeatedly treated with ISO, and that these biologically active peptides may act as growth factors. They also imply that the tissue renin-angiotensin system and Ang II specific receptors are present in the submandibular glands.

Adrenergic beta-Agonists↗

PubMed2000

Suppression of slag foaming by a sound wave.

The aim of this work was to study the effects of sound frequency, sound intensity and viscosity of slag on the slag foaming rate and the steady-state foam height. Experiments were carried out using two slags (BaO-B2O3) melted at a temperature of 1223 or 1273 K, as well as water-glycerin solutions at room temperature. Low frequency sound waves (< 1.3 kHz) are found to be more effective in the slag foaming suppression than high frequency waves (1.3-12 kHz). The steady-state foam height decreases abruptly when the sound pressure reaches a threshold value that depends on sound frequency and liquid viscosity. The results can be explained in terms of enhancing the rates of liquid drainage and film rupture induced by sound.

Journal Article↗

PubMed2000

Inhibitory effects of tea catechins and O-methylated derivatives of (-)-epigallocatechin-3-O-gallate on mouse type IV allergy.

The inhibitory effects of tea catechins, the O-methylated derivatives of (-)-epigallocatechin-3-O-gallate (EGCG), and the polyphenol extracts from tea leaves (Camellia sinensis L.) on oxazolone-induced type IV allergy in male ICR mice were investigated. Four major tea catechins and two O-methylated derivatives, (-)-epigallocatechin-3-O-(3-O-methyl)gallate (EGCG3' 'Me) and (-)-epigallocatechin-3-O-(4-O-methyl)gallate (EGCG4' 'Me), showed significant inhibitory effects on mouse type IV allergy after a percutaneous administration at a dose of 0.13 mg/ear. Among tea catechins, the compounds including galloyl moieties, such as EGCG and (-)-epicatechin-3-O-gallate (ECG), showed the strongest inhibitory activities on mouse type IV allergy. The inhibitory activities of EGCG3' 'Me and EGCG4' 'Me were higher than that of EGCG at a dose of 0.05 mg/ear. Polyphenol extract from tea leaves of Benihomare cultivar, which includes EGCG3' 'Me, strongly inhibited mouse type IV allergy after percutaneous administration in comparison with that from Yabukita cultivar, which does not include EGCG3' 'Me, at doses of 0.05 and 0.13 mg/ear. EGCG3' 'Me is thought to contribute, at least in part, to the inhibitory ability of Benihomare tea leaves on mouse type IV allergy. EGCG and the polyphenol extracts from Benihomare and Yabukita tea leaves also inhibited mouse type IV allergy by oral administration at 1 h before the sensitization and at 1 h before the challenge with oxazolone. Therefore, daily intake of tea drinks could have potential to prevent type IV allergy.

Administration, Topical↗

PubMed2000

Differential regulation of metalloproteinase production, proliferation and chemotaxis of human lung fibroblasts by PDGF, interleukin-1beta and TNF-alpha.

Fibroblast migration, proliferation, extracellular matrix protein synthesis and degradation, all of which play important roles in inflammation, are themselves induced by various growth factors and cytokines. Less is known about the interaction of these substances on lung fibroblast function in pulmonary fibrosis. The goal of this study was to investigate the effects of PDGF alone and in combination with IL-1beta and TNF-alpha on the production of human lung fibroblast matrix metalloproteinases, proliferation, and the chemotactic response. The assay for MMPs activity against FITC labeled type I and IV collagen was based on the specificity of the enzyme cleavage of collagen. Caseinolytis and gelatinolytic activities of secreted proteinases were analyzed by zymography. Fibronectin in conditioned media was measured using human lung fibronectin enzyme immunoassay. Cell proliferation was measured by 3H-Thymidine incorporation assay. Cell culture supernatants were tested for PGE2 content by ELISA. Chemotactic activity was measured using the modified Boyden chamber. Matrix metalloproteinase assay indicated that IL-1beta, TNF-alpha and PDGF induced intestitial collagenase (MMP-1) production. MMP assay also indicated that IL-1beta and TNF-alpha had inhibitory effects on MMP-2,9(gelatinaseA,B) production. Casein zymography confirmed that IL-1beta stimulated stromlysin (matrix metalloproteinase 3; MMP-3) and gelatin zymography demonstrated that TNF-alpha induced MMP-9 production in human lung fibroblast, whereas PDGF alone did not. PDGF in combination with IL-1beta and TNF-alpha induced MMP-3 and MMP-9 activity, as demonstrated by zymography. PDGF stimulated lung fibroblast proliferation in a concentration-dependent manner, whereas IL-1beta and TNF-alpha alone had no effect. In contrast, the proliferation of human lung fibroblasts by PDGF was inhibited in the presence of IL-1beta and TNF-alpha, and this inhibition was not a consequence of any elevation of PGE2. PDGF stimulated fibroblast chemotaxis in a concentration-dependent manner, and this stimulation was augmented by combining PDGF with IL-1beta and TNF-alpha. These findings suggested that PDGF differentially regulated MMPs production in combination with cytokines, and further that MMP assay and zymography had differential sensitivity for detecting MMPs. The presence of cytokines with PDGF appears to modulate the proliferation and chemotaxis of human lung fibroblasts.

Cell Division↗

PubMed2000

Effect of heparin and related glycosaminoglycan on PDGF-induced lung fibroblast proliferation, chemotactic response and matrix metalloproteinases activity.

Fibroblast migration, proliferation, extracellular matrix protein synthesis and degradation are the key events in various biological and pathological processes in pulmonary fibrosis. In addition, biopsy specimens from the lungs of patients with pulmonary fibrosis show increased numbers of mast cells which have metachromatic granules containing heparin, histamine and proteases. Little is known about how these products influence pulmonary fibrosis. In the present study, we investigated the effect of heparin and related glycosaminoglycans on PDGF-induced lung fibroblast proliferation and chemotactic response in vitro. In addition, we examined the effect of heparin on both the induction of matrix metalloproteinases (MMPs) and MMPs activity in lung fibroblasts in vitro. Heparin, de-N-sulphated heparin but not heparan sulphate inhibited PDGF-induced lung fibroblast proliferation. In contrast, only heparin inhibited PDGF-stimulated human lung fibroblast chemotaxis. Negatively charged poly-L-glutamic acid had no effect on either fibroblast proliferation or chemotaxis. Thus the negative charge alone cannot account for the ant-proliferative and anti-chemotactic effects of heparin. Furthermore, heparin and heparan sulphate also had no inhibitory effect on induction of MMPS, including MMP-1 (interstitial collagenase), MMP-2 (gelatinase A) and MMP-9 (gelatinase B). Only heparin inhibited both MMP-1 and MMP-2/MMP-9 activity. Additionally, tissue inhibitor of metalloproteinase type 1 (TIMP-1) and type 2 (TIMP-2) inhibited PDGF-stimulated human lung fibroblast chemotaxis. The ability of heparin to inhibit fibroblast chemotaxis may account for the inhibitory effect of heparin on MMP activity. The above results suggested that heparin and related glycosaminoglycans differentially regulate PDGF-induced lung fibroblast proliferation, chemotaxis and MMPs activity and further that these effects may have a key role in extracellular matrix remodeling in inflammatory lung disease.

Becaplermin↗

PubMed2000

Mitogenic activity of gelatin to murine spleen cells.

We reported previously that gelatin stimulates the growth of spleen cells in vitro. Tritium thymidine (3H-TdR) uptake into phytohemagglutinin (PHA)-stimulated spleen cells as well as intact spleen cells was augmented by gelatin. These findings suggest that gelatin serves as a mitogen for lymphoid cells. In this study, the target of action of gelatin was investigated. Tritium thymidine uptake into T cell-rich fraction was enhanced by incubation with 7.5 mg/ml of gelatin for 48 hours. The level of 3H-TdR uptake into B cell-rich fraction was not definitely increased by gelatin. Flow cytometric analysis confirmed these findings. Namely, it showed that treatment of spleen cells with 7.5 mg/ml gelatin increased a ratio of CD3-positive cells and decreased that of CD19-positive cells. Tritium thymidine uptake into natural killer cell-rich fraction was augmented by gelatin in a similar fashion to T cell-rich fraction. Tritium thymidine uptake into macrophages was very low and not affected by gelatin. Tritium thymidine uptake into macrophage-precursors was very low but was enhanced by gelatin. These findings suggest that gelatin could be used as an agent of cancer biotherapy.

Animals↗

PubMed2000

Effect of red blood cells on the antitumor activity of oxycellulose.

The antitumor activity of oxycellulose to MH134 tumor cells, evaluated with microscopic viable cell count, was suppressed by murine red blood cells (MRBCs) in a dose-dependent manner. The antitumor activity of oxycellulose was suppressed by MRBCs also when evaluated with 3H-TdR uptake. However, that of mitomycin C or 5-fluorouracil was not suppressed by MRBCs. On the other hand, the antitumor activity of oxycellulose was suppressed by MRBCs also when evaluated with 51Cr release assay. At that time, the antitumor activity of cisplatin to MH134 tumor cells were not suppressed by MRBCs. The antitumor activity of oxycellulose to MH134 tumor cells was suppressed by the membrane or the cytosol fraction of the lysate of MRBCs as well as intact MRBCs. When heated at 56 degrees C for 30 min, MRBCs were unable to suppress the activity of oxycellulose. It was examined whether or not proteins related to MRBCs (hemoglobin, catalase, superoxide dismutase or taurine) suppressed the activity of oxycellulose. They did not suppress the activity of oxycellulose.

Animals↗

PubMed2000

Construction of a ribozyme-expression system that effectively transports ribozymes to the cytoplasm.

In our previous studies, it was demonstrated that the activity of a ribozyme in vivo was governed by several parameters, which include a high level-expression of ribozyme, the intracellular stability of the ribozyme and colocalization of the ribozyme with its target RNA in the same cellular compartment. To generate ribozymes with significant activity in vivo, we have developed a ribozyme-expression system based on a human tRNA(Val) promoter. Our tRNA-embedded ribozymes produced by our ribozyme-expression system remain relatively stable in cultured cells with half-lives longer than 30 min. Moreover, tRNA-ribozymes with a cloverleaf structure were efficiently exported from the nucleus to the cytoplasm, where they would effectively cleave target RNAs. In the present study, we investigated the relationship between the secondary structure of the tRNA-ribozymes and the transport efficacy of them in mammalian cells by using a screening system in vivo. Furthermore, we also investigated the mechanism of the export of tRNA-embedded ribozymes both in mammalian cells and in Xenopus oocytes.

Animals↗

PubMed2000

Second cancers after adjuvant tamoxifen therapy for breast cancer in Japan.

BACKGROUND: Women treated with tamoxifen for breast cancer are at increased risk of endometrial cancer. We conducted a retrospective cohort study to evaluate the risk of second primary cancers after adjuvant tamoxifen therapy for breast cancer in Japan. PATIENTS AND METHODS: The subjects of the study were 6148 women who had been diagnosed with stage I, II, or IIIA unilateral primary breast cancer and had received surgical treatment during the period from January 1982 through December 1990 at nine institutions in Japan. The information on each patient was obtained from medical records or a prospectively compiled computer database at each institution. RESULTS: Of the 6148 women, 3588 (58.4%) were administered tamoxifen as an adjuvant treatment and 2560 (41.6%) were not administered. Median follow-up periods were 7.64 years for tamoxifen-treated patients and 8.10 years for non-tamoxifen-treated patients, respectively. The duration of tamoxifen treatment was mostly two years or less (80.7%), and few patients received tamoxifen for more than five years. The cumulative incidence rates of all second cancers at 10 years were 4.61% and 4.09% among tamoxifen-treated and non-tamoxifen-treated patients (P = 0.62), respectively, and the incidence rate ratio (IRR) for all second cancers was 1.06 (95% confidence interval (CI): 0.77-1.47) after adjustment of several covariates. The numbers of endometrial cancers was 9 and 3 among tamoxifen-treated and non-tamoxifen-treated patients, respectively, and the IRR was 2.37 (95% CI: 0.64-8.77, P = 0.20). Of the 12 patients who developed endometrial cancer, 4 died of cancer (for 3 of them, the cause of death was breast cancer), and the other 8 patients were alive as of March 1996. Stomach cancer was the most frequent second cancer and the IRR was 1.34 (95% CI: 0.76-2.38, P = 0.31). There was no substantial increase in any other type of gastrointestinal cancer such as colorectal and liver cancers among tamoxifen-treated patients. CONCLUSIONS: The incidence and risk of second primary cancers associated with tamoxifen therapy is low. The potential benefit of adjuvant tamoxifen therapy in breast cancer patients outweighs the risk of second primary cancers for Japanese breast cancer patients.

Adult↗

PubMed2000

Significance of ERK cascade compared with JAK/STAT and PI3-K pathway in gp130-mediated cardiac hypertrophy.

We compared the role of the Raf-1/mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MEK)/extracellular signal-regulated protein kinase (ERK)/p90(RSK) cascade in gp130-mediated cardiac hypertrophy with the contribution of the Janus kinase (JAK)/signal transduction and activation of transcription (STAT) and phosphatidylinositide 3-kinase (PI3-K) pathways. Primary cultured neonatal rat cardiomyocytes were stimulated with leukemia inhibitory factor (LIF). LIF sequentially activated Raf-1, MEK1/2, ERK1/2, and p90(RSK). We used PD-98059 (a specific MEK inhibitor), AG-490 (a JAK2 inhibitor), and wortmannin (a PI3-K inhibitor) to confirm that this cascade was independent of the JAK/STAT and PI3-K/p70 S6 kinase (S6K) pathways. PD-98059, AG-490, and wortmannin suppressed the LIF-induced increase in [(3)H]phenylalanine uptake by 54.7, 21.5, and 25.6%, respectively, and inhibited the increase in cell area by 61.2, 42.8, and 39.2%, respectively. Reorganization of myofilaments was predominantly suppressed by AG-490. LIF-induced expression of c-fos, brain natriuretic peptide, and skeletal alpha-actin mRNA was markedly suppressed by PD-98059 and moderately suppressed by wortmannin and AG-490. Atrial natriuretic peptide was significantly suppressed by AG-490. These findings indicate that this pathway is critically involved in protein synthesis, induction of c-fos, brain natriuretic peptide, and skeletal alpha-actin expression and is partially involved in myofilament reorganization and atrial natriuretic peptide induction in gp130-mediated cardiac hypertrophy.

Androstadienes↗

PubMed2000

Isolation, characterization and mapping of the mouse and human PRG4 (proteoglycan 4) genes.

PRG4 (proteoglycan 4) has been identified as megakaryocyte stimulating factor and articular superficial zone protein. PRG4 has characteristic motifs including somatomedin B and hemopexin domains, a chondroitin sulfate-attachment site and mucin-like repeats. During a screen of genes implicated in ectopic ossification, we found a novel mouse gene highly homologous to human and bovine PRG4 genes. Here, we report isolation, characterization and mapping of the gene, Prg4 together with characterization of its human orthologue. Prg4 cDNA was 3,320 bp long, encoding a 1,054 amino-acid protein. Human and mouse PRG4 genes each consisting of 12 exons spanned 18 and 16 kb, respectively. Characteristic motifs were conserved across species; however, the mucin-like repeat regions were highly diverse in length between species with a tendency that larger animals had longer repeats. Expression of human and mouse PRG4 genes was similar and found not only in cartilage, but also in liver, heart, lung, and bone. Expression of the mouse gene increased with progression of ectopic ossification. Multiple tissue-specific splicing variants lacking some of the motifs were found in both human and mouse. Although a specific role in the articular joint has previously been reported, the presence of multi-functional motifs as well as unique expression and alternative splicing patterns suggest that PRG4 functions in several distinctive biological process including regulation of ossification.

Alternative Splicing↗

PubMed2000

Novel rosette formation of murine spleen cells with autologous red blood cells.

Spleen cells of normal BALB/c mice formed rosettes with autologous red blood cells, and the formation was calcium ion dependent. Peritoneal exudate cells, bone marrow cells and thymocytes did not form such rosettes. Spleen cells were passed over a Sephadex G-10 column or incubated on a plastic surface in order to eliminate adherent cells from them. Cells obtained by both these methods were unable to form rosettes. B cell-, T cell- and natural killer cell-enriched fractions in spleen cells were unable to form rosettes either. Some of the mouse IgG subclasses suppressed rosette formation when added to its site. These are monoclonal antibodies whose specificities are directed against Aspergillus niger glucose oxidase. Moreover, Aspergillus niger glucose oxidase suppressed the rosette formation when spleen cells had been treated with it as well as when it had been added to the site of rosette formation. These findings suggest that some murine spleen cells have receptors to a structure on autologous red blood cells, which is recognized by an anti-Aspergillus niger glucose oxidase monoclonal antibody.

Animals↗