Detachment activity but not cytotoxicity induced in a T-cell clone following antigen presentation in the presence of thymic epithelial cells

The selective induction of effector functions of a T-cell clone (DB14), specific to pigeon cytochrome c 43-58 (p 43-58) and restricted to I-Ab, was analyzed using a professional antigen-presenting cell, B hybridoma (Th 2.58), and various non-professional antigen-presenting cells (APC), L cells transfected with I-Ab (I-Ab L cells), a medullary thymic epithelial cell line (m-TEC) and a cortical thymic epithelial cell line (c-TEC). The m-TEC, and c-TEC expressed I-Ab upon induction with interferon gamma (IFN-gamma). When stimulated with p 43-58 in the presence of I-Ab L cells as well as Th 2.58 cells, the DB14 cells showed marked proliferation and, after 18 hr of culturing, exhibited significant cytotoxicity against the APC. By contrast, in the presence of m, c-TEC, the DB14 cells showed neither proliferation nor cytotoxicity against these TEC but exhibited considerable detachment activity towards them. Furthermore, DB14 cells became expressed activation markers CD69 or CD44) following stimulation with p 43-58 plus m-TEC or c-TEC. The addition of rIL-2 to the culture of DC14 cells, p 43-58 and m-TEC or c-TEC, restored the proliferative responses. However, it was shown that anergy was not involved in the negligible proliferative responses of DB14 cells after stimulation with p 43-58 plus m, c-TEC. The present findings indicate that differences in APC functions are present among the non-professional APC and suggest that the selective induction of T-cell functions can be achieved using the appropriate non-professional APC. The characteristic activation of T cells by TEC may be related to their functional roles in situ.

Dissociation of Fas-mediated cytotoxicity and FasL expression in a cytotoxic CD4+ T-cell clone. Comparative analysis of Fas-mediated cytotoxicity between a T-hybridoma and a T-cell clone

Fas-mediated cytotoxicity or activation-induced cell death (AICD) were analyzed and compared between a CD4+ cytotoxic T-cell clone (DB14) and a T-hybridoma (DBhy22) both of which bear the same T-cell antigen receptor (TCR) specific for p43-58 and restricted to I-Ab/d. DBhy22 expressed detectable FasL mRNA 4 h after activation through TCR and the expression of FasL mRNA reached a peak after 8 h of activation. The expression level of FasL mRNA was clearly associated with the level of Fas-mediated cytotoxicity and AICD seen after activation. On the other hand, FasL mRNA and FasL molecules were constitutively expressed in DB14 irrespective of the activation state. However, DB14 exhibited the Fas-mediated cytotoxicity only after activation. The present study suggests that Fas-mediated cytotoxicity requires not only FasL expression but also other activation signals.

Effect of vapor pressure deficit on spinach growth under hypobaric conditions

The effect of vapor pressure deficit (VPD) of air during photoperiod on spinach growth under low total pressure was examined. Spinach plants grown under atmospheric pressure were transplanted into a pressure-reduced growth chamber and cultured hydroponically for eight days. The air temperature in the growth chamber was kept at 25 degrees C during the light period and 20 degrees C during the dark period. In the control, the total pressure was 101 kPa and the VPD was 0.95 kPa. The low pressure treatment had a total pressure of 25 kPa and a VPD of 0.95 kPa. The low pressure and high humidity treatment had a total pressure of 25 kPa, and a VPD of 0.48 kPa. The VPD during the dark period was consistent for all treatments at 0.44 kPa. O2 and CO2 partial pressures were constant at 21 kPa and 40 Pa, respectively. The photosynthetic photon flux density (PPFD) on a plant bed inside the growth chamber was 250 micromoles m-2 s-1 on a plant bed. Relative growth rate (RGR) of spinach in the low pressure and high humidity treatment was significantly greater than in the control. There was no significant difference in RGR between the control and the low pressure treatment. The low pressure and high humidity treatment also had increased leaf area. These results showed that the effect of pressure alone was not significant on RGR, but the combination of low pressure with high humidity was important.

Identification of the spinocerebellar ataxia type 2 gene using a direct identification of repeat expansion and cloning technique, DIRECT

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant, neurodegenerative disorder that affects the cerebellum and other areas of the central nervous system. We have devised a novel strategy, the direct identification of repeat expansion and cloning technique (DIRECT), which allows selective detection of expanded CAG repeats and cloning of the genes involved. By applying DIRECT, we identified an expanded CAG repeat of the gene for SCA2. CAG repeats of normal alleles range in size from 15 to 24 repeat units, while those of SCA2 chromosomes are expanded to 35 to 59 repeat units. The SCA2 cDNA is predicted to code for 1,313 amino acids-with the CAG repeats coding for a polyglutamine tract. DIRECT is a robust strategy for identification of pathologically expanded trinucleotide repeats and will dramatically accelerate the search for causative genes of neuropsychiatric diseases caused by trinucleotide repeat expansions.

Strong linkage disequilibrium and haplotype analysis in Japanese pedigrees with Machado-Joseph disease

To identify the markers tightly linked to Machado-Joseph disease (MJD) and to investigate whether a limited number of ancestral chromosomes are shared by Japanese MJD pedigrees, a detailed linkage analysis employing D14S55, D14S48, D14S67, D14S291, D14S280, AFM343vf1, D14S81, D14S265, D14S62, and D14S65 was performed. The results of multipoint linkage analysis as well as detection of critical recombination events indicate that the gene for MJD is localized in a 4-cM region between D14S280-D14S81. We found strong linkage disequilibria at AFM343vf1 and D14S81, and association of a few common haplotypes with MJD. These results indicate that there is an obvious founder effect in Japanese MJD and suggest the possibility of the existence of predisposing haplotypes which are prone to expansions of CAG repeats.

Soyacystatin, a novel cysteine proteinase inhibitor in soybean, is distinct in protein structure and gene organization from other cystatins of animal and plant origin

Cystatins, cysteine proteinase inhibitors, deserve note because of their regulatory and protective functions in plant tissues. We isolated both genomic DNA and cDNA clones from soybean that encode a cystatin consisting of 245 amino acid residues (soyacystatin). It is, while basically similar in sequence to known cystatins that are generally in the range of 12-15 kDa, characterized by having extremely large extension sequences in both its amino and carboxyl termini. The genomic DNA encoding soyacystatin is also unique in that it consists of four exons with three introns in its coding regions. The mRNA for soyacystatin is distinctly expressed in soybean seeds 2 weeks after flowering. Soyacystatin purified from mature soybean seeds had a molecular mass of about 26 kDa on SDS/PAGE which suggests that it contains the extension sequences. Papain-inhibition experiments demonstrate that this endogenous soyacystatin has almost the same inhibitory activity as that of its deletion mutant (102 amino acid residues) recombinantly produced by truncation of the amino and carboxyl terminal extensions, indicating that the occurrence of the extensions does not affect the cystatin activity. Immunohistochemical experiments reveal that soyacystatin is expressed nearly uniformly in the cotyledons. These results also suggest the possible occurrence of a cysteine proteinase as the target enzyme of soyacystatin.

Giant retroperitoneal cyst in an adult male

This paper presents a case of a symptomatic giant retroperitoneal cyst in an adult male. The unilocular cyst was excised successfully with resolution of the attendant symptoms. Histological findings of the cyst wall suggested a lymphangiomatous etiology. Any good risk patient found to harbor such a cyst should undergo complete excision in view of the potential for the development of symptoms and complications.

Determination of the allele-specific antigen-binding site on I-Ak and I-Ab molecules

Residues 46 and 54 on a pigeon cytochrome c 43-58 analog, 50E, function as major histocompatibility complex class II contact sites. A peptide, 46F50E54A, with phenylalanine (F) at position 46 and alanine (A) at 54 on 50E bound to Ab and a peptide, 46D50E54A, with aspartic acid (D) at 46 and alanine at 54, bound to Ak. To determine the allele-specific peptide contact sites on I-A molecules corresponding to the I-A contact sites of the peptides, we analyzed responses of Ak- and/or Ab-restricted T cell hybridomas to 46F50E54A or 46D50E54A using L cell transfectants expressing recombinant I-A molecules between Ak and Ab or point mutants of Ak as antigen presenting cells. It was shown that the N-terminal half of the alpha helix of the A alpha chain determined the allele-specific T cell responses. Furthermore, with arginine (k type amino acid) or alanine (b type amino acid) at position 56 of the Ak alpha chain, these T cell hybridomas were stimulated predominantly by 46D50E54A (Ak binding peptide) or 46F50E54A (Ab binding peptide), respectively. Thus, the amino acid at position 56 of the A alpha chain determines allele-specific antigen presentation. This postulate was confirmed by direct binding analysis of 50E analogs of various I-A molecules. A single amino acid change (arginine to alanine) at position 56 of the Ak alpha chain altered the peptide binding specificity (46D50E54A to 46F50E54A).

Somatic mosaicism of expanded CAG repeats in brains of patients with dentatorubral-pallidoluysian atrophy: cellular population-dependent dynamics of mitotic instability

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disease caused by unstable expansion of a CAG repeat in the DRPLA gene. We performed detailed quantitative analysis of the size and the size distribution (range) of the expanded CAG repeats in various regions of the CNS of eight autopsied patients with DRPLA. Expanded alleles (AE) showed considerable variations in size, as well as in range, depending on the region of the CNS, whereas normal alleles did not show such variations, which indicates the occurrence of somatic mosaicism of AE in the CNS. The AE in the cerebellar cortex were consistently smaller by two to five repeat units than those in the cerebellar white matter. Moreover, the AE in the cerebral cortex were smaller by one to four repeat units than those in the cerebral white matter. These results suggest that the smaller AE in the cerebellar and cerebral cortices represent those of neuronal cells. The ranges of the AE in the cerebral cortex, cerebral white matter, and cerebellar white matter showed considerable variation ranging from 9 to 23 repeat units, whereas those in the cerebellar cortex showed little variance and were approximately 7 repeat units. The ranges of the AE in the cerebral cortex, cerebral white matter, and cerebellar white matter were much broader in patients with higher ages at death than they were in patients with lower ages at death, raising the possibility that the range of AE increases with time, as the result of mitotic instability of AE.

[A patient with parkinsonism presenting hyperintensity in the globus pallidus on T1-weighted MR images: the correlation with manganese poisoning]

We report a 55-year-old woman who developed symptoms resembling parkinsonism. Her psychiatric symptoms in the early stage, cervical dystonia and tremor increasing on movement were consistent with manganese poisoning. Manganese levels were elevated to 1.5 micrograms/l in the serum (normal; 0.3-1.1 micrograms/l) and to 1.4 micrograms/l in the urine (normal; less than 1.2 micrograms/l). Intravenous infusion of calcium disodium editate (CaEDTA; chelating agent) was followed by the marked excretion of manganese (27.3 micrograms/l) in the urine. These findings support manganese poisoning. Manganese poisoning is a disease which results from chronic exposure to manganese, but the source of manganese exposure remained obscure in this patient. T1-weighted MRI of the brain showed symmetric high signal intensity in the globus pallidus without any abnormality on T2-weighted images. There is a report that manganese induced brain lesions in Macaca fascicularis as revealed by MRI and the fascicularis developed signs of unsteady gait and hypoactivity. The patient responded to treatment with CaEDTA and the second MRI demonstrated regression of abnormal signal intensity. This may be due to enhanced manganese excretion. To our knowledge, this is the first case of probable manganese-induced human parkinsonism whom changes in MRI were noted after treatment with CaEDTA.

Clinical and genetic evaluation of Japanese autosomal dominant cerebellar ataxias; is Machado-Joseph disease common in the Japanese?

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A promiscuous T cell hybridoma restricted to various I-A molecules

In a previous study, we identified T cell receptor and major histocompatibility complex (MHC) contact sites on the pigeon cytochrome c p43-58 peptide. Positions 46 and 54 of p43-58 were shown to be the MHC-binding sites. Specific amino acids were identified on the MHC-binding sites which bound to the relevant I-A molecule. In the present study, using NOD (I-Ag7) mice, we established a T cell hybridoma specific for a p43-58 analog 46R50E54A with arginine (R) and alanine (A) at positions 46 and 54, respectively. Interestingly, NOE 33-1-2 recognized 46R50E54A in the presence of not only I-Ag7, but also I-Ad, s, u and v. In contrast to previous reports that promiscuous T cells were able to recognize peptide antigens with various HLA-DR or I-E molecules consist of monomorphic alpha and polymorphic beta chains, the promiscuous T cell clone NOE33-1-2 recognized peptides with various I-A molecules lacking the monomorphic chain.

A water channel closely related to rat brain aquaporin 4 is expressed in acid- and pepsinogen-secretory cells of human stomach

We isolated a cDNA clone encoding a water channel protein, aquaporin ( AQP), from human stomach. The encoded protein consisted of 323 amino acid residues, containing six putative transmembrane domains. The protein was designated human aquaporin 4 (hAQP4) because of its 94% sequence similarity to rat brain AQP4. Expression of hAQP4 cRNA in Xenopus oocytes resulted in a significant increase in osmotic water permeability, indicating that this protein functions as a water channel. Northern blot analysis demonstrated a strong signal of hAQP4 mRNA in brain, lung, and skeletal muscle as well as in stomach. Immunohistochemical experiments with human stomach tissues showed that hAQP4 as a protein is expressed mainly in cells located in the glandular portion of the fundic mucosa. These include chief cells which secrete pepsinogen and parietal cells which secrete hydrochloric acid. These results strongly indicate that hAQP4 is a principal factor involved in the osmotic regulation of pepsinogen and acid secretion in the stomach.

Fgr expression restricted to subpopulation of monocyte/macrophage lineage in resting conditions is induced in various hematopoietic cells after activation or transformation

The c-fgr gene product (Fgr) is a member of the src-family of protein tyrosine kinases. We have established a monoclonal antibody (2H2) which recognizes the unique N-terminal domain of the murine Fgr. In the present study, using immunohistochemical analysis and immune complex kinase assay with the 2H2, we investigated expression of Fgr in various cell populations and tissues in a murine system. In resting conditions, Fgr expression was confined to subsets of a monocyte/macrophage lineage. Thus, Fgr+ cells were detected in paracortical areas and medullas of lymph nodes, but seen only in marginal zones of the spleen and the medulla of the thymus. No Fgr+ macrophage was detected in other tissues, Peyer's patches, brain, heart, lung, liver, pancreas, kidney and peritoneal cavity. However, immune complex kinase assay revealed that, upon stimulation, T and B cells as well as peritoneal macrophages expressed significant levels of Fgr molecules. Transformed cell lines of lymphoid origin, EL-4 and LK35.2, which are T and B lineage lymphomas, respectively, also expressed Fgr molecules. Thus, various cells of hematopoietic origin appeared to possess a potentiality to express Fgr following activation or transformation. The present findings may help elucidate the functional significance of Fgr in immunologically committed cells in either activated or non-activated conditions.

Type IV collagen-binding proteins of neutrophils: possible involvement of L-selectin in the neutrophil binding to type IV collagen

To isolate type IV collagen-binding proteins, 125I-labeled human-neutrophil extracts were chromatographed on a type IV collagen-Sepharose column. The affinity chromatography-separated fraction contained the four radioactive proteins with apparent molecular masses of 28, 49, 67, and 95 kD on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Western blot analysis indicated that the 95-kD proteins contained both L-selectin and nonspecific cross-reacting antigen 90 (NCA90), and that the 67-kD protein was the 67-kD elastin/laminin-binding protein (67BP). The data obtained with the type IV collagen-affinity chromatography and the immunoaffinity chromatographies using anti-L-selectin and anti-NCA90 monoclonal antibodies (MoAbs) have shown that L-selectin is closely associated with 67BP and the 49-kD protein, and that NCA90 is associated with 67BP, the 28-kD and 49-kD proteins. Among these binding proteins, sialic acid residues were contained in 67BP, L-selectin, and NCA90, but not in the 28-kD and 49-kD proteins. Sialidase treatment completely abolished both the binding affinity of the type IV collagen-binding proteins to type IV collagen and the neutrophil adherence to type IV collagen-coated plastic. Thus, the sialic acid residues of 67BP, L-selectin, and NCA90 seem to be important for the binding of neutrophils to type IV collagen. Furthermore, L-selectin IgG chimeric protein directly bound to type IV collagen-Sepharose column, and anti-L-selectin MoAb DREG56 inhibited the neutrophil adherence to type IV collagen-coated plastic by 51%. These observations suggest that L-selectin likely plays a role in the neutrophil binding to type IV collagen, although neutrophils have several kinds of adhesion molecules for type IV collagen such as L-selectin, NCA90, 67BP, and the 28-kD and 49-kD proteins.

Transgenic rice established to express corn cystatin exhibits strong inhibitory activity against insect gut proteinases

Corn cystatin (CC), a phytocystatin, shows a wide inhibitory spectrum against various cysteine proteinases. We produced transgenic rice plants by introducing CC cDNA under CaMV 35S promoter as a first step to obtain a rice plant with insecticidal activity. This attempt was based on the observation that many insect pests, especially Coleoptera, have cysteine proteinases, probably digestive enzymes, and also that oryzacystatin, an intrinsic rice cystatin, shows a narrow inhibition spectrum and is present in ordinary rice seeds in insufficient amounts to inhibit the cysteine proteinases of rice insect pests. The transgenic rice plants generated contained high levels of CC mRNA and CC protein in both seeds and leaves, the CC protein content of the seed reaching ca. 2% of the total heat soluble protein. We also recovered CC activity from seeds and found that the CC fraction efficiently inhibited both papain and cathepsin H, whereas the corresponding fraction from non-transformed rice seeds showed much lower or undetectable inhibitory activities against these cysteine proteinases. Furthermore, CC prepared from transgenic rice plants showed potent inhibitory activity against proteinases that occur in the gut of the insect pest, Sitophilus zeamais.

[Some problems on neuropathology of Huntington disease]

The most striking neuronal loss in the brains of Huntington disease (HD) occurs in the striatum, predominant in the caudate nucleus. However, pathogenesis of this disease is supposed to be mainly based on the process of "simple atrophy" in the whole brain neurons and their axons. Therefore, although the autopsied brains of HD are atrophic and their weight are light, histopathology based on the classical method shows few abnormal findings in the cerebrum. Against this fact, "numeric atrophy" of the neurons occurs in the striatum of chorea acanthocytosis.

CAG repeat expansion of Machado-Joseph disease in the Japanese: analysis of the repeat instability for parental transmission, and correlation with disease phenotype

Machado-Joseph disease (MJD) is caused by abnormal expansion of an unstable CAG repeat in a novel gene locating on chromosome 14q32.1. We analysed this CAG repeat polymorphism with 66 Japanese MJD patients. All the patients were selectively associated with abnormal expansion of the CAG repeat. Repeat length of the mutant allele did not overlap that of normal allele and closely correlated with not only age at onset but also with clinical phenotypes. CAG repeat size is apparently related to a wide variety of phenotypic presentations in MJD.

Effect of juvenile hormone on the embryogenesis of a polyembryonic wasp, Copidosoma floridanum, in vitro

Single two-cell-stage embryos of a polyembryonic wasp Copidosoma floridanum cultured in 20 microliters droplets of culture medium developed to morulae at the same developmental rate as those in host eggs, but the subsequent development into polymorulae was inferior. This inferior development was markedly improved by addition of juvenile hormone (I, II, or III) or its analogues to the culture medium in a concentration-dependent manner.

Transcriptional activation domains of the Ah receptor and Ah receptor nuclear translocator

The Ah receptor (AhR) and Ah receptor nuclear translocator (Arnt) heterodimer bind the xenobiotic-responsive element (XRE) sequence in the upstream region of the genes for some drug-metabolizing enzymes, such as P4501A1 and glutathione S-transferase Ya, to activate their transcription. This paper describes transcriptional activation domains of the AhR and Arnt as examined in vivo by DNA transfection experiments using GAL4-AhR or GAL4-Arnt chimeric plasmids and a reporter plasmid containing five GAL4 DNA binding sites. The major activation domain of Arnt was localized in a short segment of the C-terminal 34 amino acids, while the glutamine-rich domain of Arnt showed no transcriptional activity. This activation domain of Arnt could be further divided into two subdomains with some sequence similarity. Point mutation analysis of one of the subdomains revealed that bulky hydrophobic amino acids and neighboring acidic amino acids were necessary for the transcription-enhancing activity of Arnt. The C-terminal half of the AhR showed a strong transcription-stimulating activity, apparently five times as strong as that of Arnt. Further analysis of the activity revealed that the C-terminal transcriptional activity was distributed in several activation domains, one of which is rich in glutamine residues. These results indicate that the glutamine-rich domains of the AhR and Arnt function differently in the heterodimer regulatory complex. Previously, we showed that the enhancer activity of XRE was repressed by E1A proteins, especially the 12S form of E1A. Cotransfection experiments using an E1A12S expression plasmid and a GAL4-AhR or GAL4-Arnt expression plasmid demonstrated that E1A protein rather predominantly inhibited the transcriptional activity of Arnt.

Spinocerebellar ataxia 1 (SCA1) in the Japanese in Hokkaido may derive from a single common ancestry

Spinocerebellar ataxia 1 (SCA1) is caused by expansion of an unstable CAG triplet repeat located on the short arm of chromosome 6. Precise mapping has shown a positional relationship to closely linked markers in the order of D6S109-D6S274-D6S288-SCA1-AM10GA-D6S89+ ++-EDN1 from centromere to telomere. The haplotype which cosegregated with the disease was determined in 12 Japanese pedigrees with SCA1. Although the alleles of the SCA1 haplotype varied from pedigree to pedigree, depending on the distance from the SCA1 locus, the affected and presymptomatic subjects carried the same alleles at D6S288 and D6S274. All the families with SCA1 had migrated from either Miyagi or Yamagata Prefectures, neighbouring areas in the Tohoku District, the northern part of Honshu which is the main island of Japan. It seems highly likely that SCA1 in the Japanese, at least those residing in Hokkaido, derives from a single common ancestry.

Production of minor lymphocyte stimulatory-1a antigens from T cell subsets

T cell subsets that produce minor lymphocyte stimulatory (Mls) antigens were analyzed using mixed lymphocyte reaction (MLR) in vitro or clonal elimination assay in vivo. When lymph node T cells from B10.BR(Mls-1b) mice were stimulated with various T cell subsets from AKR (Mls-1a) mice in the presence of B10.BR antigen presenting cells (APC), proportions of Mls-1a reactive T cell blasts (V beta 6+, V beta 8.1+) increased. The stimulatory potency of CD8+ T cells was higher than that of CD4+ T cells. Furthermore, among either CD8+ or CD4+ T cell subset, CD44+ T cells appeared to produce larger amounts of Mls-1a antigens than CD44- T cells. More marked difference was demonstrated, when stimulator AKR T cells were being activated by immobilized anti-T cell antigen receptor (TCR) antibody during MLR. Thus, AKR T cells appeared to produce large amounts of Mls-1a antigens on appropriate stimulations. These findings were confirmed by the semiquantitative analysis of mRNA levels of MTV-7 in the AKR T cell subsets. When CD8+CD44+ T cells from (AKR x B10.BR)F1 mice were injected intravenously into [B10.BR-->B10.BR] syngeneic bone marrow (BM) chimeras 1 week after BM reconstitution and proportions of V beta 6+ T cells were quantitated 7 weeks later, significant clonal elimination of V beta 6+ T cells was induced among both thymocyte population and lymph node T cell population in a dose-dependent manner of the inoculated F1 T cells. Inoculation of CD8+CD44-F1 T cells eliminated V beta 6+ T cells less efficiently from lymph node T cells and inoculation of CD4+F1 T cells induced no significant clonal elimination of the V beta 6+ T cells. The present findings demonstrate clearly that CD8+CD44+ T cells represent the cells producing large amounts of Mls-1a antigens and inducing clonal elimination of V beta 6+ T cells in vivo.