Dissection of the role of macrophages in triggering T lymphocytes for interleukin 2 production by monoclonal antibody OKT3

Unfractionated human peripheral blood mononuclear cells produce a small amount of interleukin 2 (IL 2) by stimulation with a monoclonal anti-T3 antibody (OKT3) in vitro. The IL 2 production could be greatly augmented by the addition of a phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). In the presence of TPA, the T cell enriched fraction deprived of macrophages did not produce IL 2, but the T cells pulse-incubated with OKT3 and reconstituted with macrophages efficiently produced IL 2 in subsequent culture in the presence of TPA as did T cells reconstituted with OKT3-pulse-incubated macrophages. The stimulating effect of OKT3 in the presence of macrophages was inhibited dose-dependently by the addition of immunoglobulins, particularly by mouse IgG2a which is the same isotype as that of the OKT3 antibody, showing that it inhibits by blocking the binding of OKT3 to Fc receptors on macrophages. The same extent of IL 2 production was induced in T cells when paraformaldehyde-fixed macrophages were substituted for intact macrophages. Remarkable IL 2 production was also induced by OKT3 when latex beads coated with rabbit anti-mouse IgG2a antibody and TPA were added to the culture. It was confirmed that the production induced by these stimulations was due to an increase of IL 2 mRNA. These results show that effective signals for IL 2 production are generated by efficient crosslinking of T3 molecules which results from multi-interaction of T3 molecules on the T cell membrane and anti-T3 antibody molecules on macrophage membrane or on the surface of the latex particle.     

Agricultural Activities of a Meadow Eliminated Plant Litter from the Periphery of a Farmland in Inner Mongolia,China

The purpose of our investigation was to clarify the effects of agriculture on the process of loss of litter at the periphery of a farmland. This study revealed the generation process of an ecologically unusual phenomenon that is observed around cropland in semi-arid regions. We hypothesized that the vegetation around a farmland cannot supply plant litter to the ground surface because the ecological structure has been changed by agricultural activities. The study was conducted at Xilingol steppe, Xilingol League, Inner Mongolia Autonomous Region, China. Four study lines were established from the edge of an arable field to the surrounding meadow and parallel to the wind direction during the strong wind season. Key measurement for each line was set at the border between the farmland and steppe. Four study sites were set at intervals along each line. Plant litter, soil particle size distribution, plant species composition, plant volume, and species diversity were investigated. Despite using the same mowing method at the meadows of all study sites, the litter at the only periphery of the farmland completely disappeared. Soil particle size distribution in steppe, which was adjacent to the farmland, was similar to that of the farmland. Plant community structure at the periphery of the farmland was different from that of the far side from the farmland. This implies that soil scattered from the farmland affected the species composition of the steppe. Consequently, the change in plant community structure induced litter loss because of mowing. We concluded that plant litter was lost near the farmland because of the combined effects of farming and mowing. The results support our hypothesis that the vegetation around a farmland cannot supply plant litter because the ecological structure has been changed by agricultural activities.     

Isolation and Chemical Structure of New Oxidation Product of 5-Ketogluconic Acid,and a Hypothetical Pathway from Glucose to Tartaric Acid through this New Compound

In the course of study on the mechanism of the tartaric acid formation from 5-ketogluconic acid, a new intermediary substance with mauve color to Abdel-Akhel and Smith’s reagent was isolated from intact cell culture liquid. The chemical structure of this substance was determined as 1,2-dihydroxyethyl hydrogen L(+) tartrate from the results of hydrolysis experiments and from the identifications of the constituents of the molecule, and named “pretaric acid.” Tartaric acid was evidently produced from pretaric acid by intact cell culture. Clearly, then, pretaric acid appears to be an intermediate in the formation of tartaric acid from 5-ketogluconic acid. The authors assumed that in the formation of pretaric acid from 5-ketogluconic acid, a Baeyer-Villiger type oxidation occurred.     

Primary structures of two types of alpha-subunit of rat brain Na+,K+,-ATPase deduced from cDNA sequences

A rat brain cDNA library was screened by using as a probe a fragment of cDNA encoding the alpha-subunit of human Na+,K+-ATPase. Two different cDNA clones were obtained and analyzed. One of them was concluded to be a cDNA encoding the alpha-subunit of the weakly ouabain-sensitive rat kidney-type Na+,K+-ATPase. The deduced amino acid sequence consists of 1,018 amino acids. The alpha-subunit of the rat kidney-type Na+,K+-ATPase shows 97% homology in amino acid sequence with the alpha-subunit of human, sheep, or pig enzyme and 87% with that of Torpedo. Based on a comparison of the amino acid sequence at the extracellular domain of the alpha-subunit between weakly ouabain-sensitive rat kidney-type enzyme and the ouabain-sensitive human, sheep, pig, or Torpedo enzyme, it was proposed that only two significant amino acid replacements are unique to the rat kidney-type alpha-subunit. Another cDNA clone obtained showed 72% homology in nucleotide sequence with the former cDNA coding the alpha-subunit of the rat kidney-type Na+,K+-ATPase and the deduced amino acid sequence exhibited 85% homology with that of the alpha-subunit of rat kidney-type Na+,K+-ATPase.     

Nuclear DNA content as an indicator of chemosensitivity in small-cell carcinoma of the lung

The relationship between the nuclear DNA histogram pattern of tumor cells obtained by bronchoscopic brushing and the response to combination chemotherapy (Cytoxan + Adriamycin + Vincristine) was studied in 28 patients with small-cell carcinoma of the lung. Microspectrophotometric analysis of the tumor cells showed a near-diploid nuclear DNA pattern in 18 patients and a hyperdiploid pattern in 10 patients. Eight of the ten patients with the hyperdiploid pattern showed a good response (complete or partial response) to the chemotherapy. However, of the 18 patients with the near-diploid DNA pattern, only 2 displayed a good response; the remaining 16 patients exhibited no response. The hyperdiploid DNA pattern of tumor cells was thus associated with a better response to chemotherapy than was the near-diploid pattern. These results indicate that the nuclear DNA histogram pattern may be an indicator for predicting the degree of response to chemotherapy in small-cell carcinoma of the lung.     

Methylation strongly enhances DNA bending in the replication origin region of the Escherichia coli chromosome

Summary Two-dimensional gel electrophoresis, at high and low temperatures, and gel mobilities of circularly permuted DNA segments showed a large bending locus about 50 bp downstream from the right border of the 245 by oriC box, a minimal essential region of autonomous replication on the Escherichia coli chromosome. Bending was strongly enhanced by Dam methylation. In DNA from a Dam^– strain, the mobility anomaly arising from altered conformation was much reduced, but was raised to the original level by methylation in vivo or in vitro. Enhancement of the mobility anomaly was also observed by hybrid formation of the Dam^– strand with the Dam⁺ strand. Near the bending center, GATC, the target of Dam methylase, occurs seven times arranged essentially on the same face of the helix with 10.5 by per turn. We concluded that small bends at each Dam site added up to the large bending detectable by gel electrophoresis.     

Differences in lectin binding patterns of normal human endometrium between proliferative and secretory phases

Lectin binding patterns in normal human endometrium were examined by light and electron microscopy using seven different lectins (ConA, WGA, RCA, PNA, UEA-1, DBA, and SBA). For light microscopic observations, criteria based on the incidence and intensity of cells positive for the lectin staining were adopted to evaluate the different staining patterns of the proliferative and secretory endometria obtained by the avidin-biotin-peroxidase complex (ABC) technique. At the light microscopic level, ConA, WGA, and RCA stained endometrial glandular cells in both phases. The number of PNA-positive cells with the binding sites entirely limited to the apical surface tended to be reduced slightly in the secretory phase. UEA-1 weakly stained the apical surface of glandular cells in the proliferative phase but not in the secretory phase. Among the lectins used in this study, DBA and SBA displayed remarkable changes between the phases. That is, in the proliferative phase they produced only a faint or slight positive stain at the apical surface, but the incidence and intensity of DBA- and the SBA-positive glandular cells increased in the secretory phase. By electron microscopy, the reaction product of ConA was observed in the plasma membrane, endoplasmic reticulum, nuclear envelope, and the Golgi apparatus, and the binding sites of RCA and DBA were observed in the plasma and Golgi membranes. Between both phases, the reactivity of ConA and RCA showed almost no change. However, the secretory endometrial cells containing the DBA-positive Golgi apparatus were markedly increased in number compared with the proliferative ones bearing the lectin-positive organelles.(ABSTRACT TRUNCATED AT 250 WORDS)     

A newly established human acute lymphoblastic leukemia cell line with characteristics of the earliest B-cell maturation

A new human acute lymphoblastic leukemia (ALL) cell line, designated HBL-3, was established from the bone marrow of a patient with non-T-ALL. The HBL-3 cell line expressed B4 (CD 19), BA-1 (CD 24) and HLA-DR antigens, but not surface immunoglobulin (SIg) or cytoplasmic immunoglobulin (CIg). The cell line lacked the common acute lymphoblastic leukemia antigen (CALLA) and antigenic markers characteristic of T-cell and myeloid cell lineages. The HBL-3 cells had structural rearrangements of both the homologous chromosome 9s, including a translocation with chromosome 1 which has been reported in a patient with common ALL. The cell line had rearranged immunoglobulin heavy chain genes but retained germ-line κ light chain genes and germ-line T-cell receptorβ- and γ-chain genes. The HBL-3 cell line was strongly positive for terminal deoxynucleotidyl transferase (TdT). These findings indicate that the HBL-3 cell line is derived from the earliest B-cell committed to B-cell lineage.