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T Koga

Publications and source records attributed to T Koga.

At least 451 records · Page 25Linked to original sources
PubMed1990

Intranasal immunization of mice with recombinant protein antigen of serotype c Streptococcus mutans and cholera toxin B subunit.

The cholera toxin subunit and the recombinant cell-surface antigen (molecular mass of 190,000 Da) were administered intranasally to BALB/c mice. After 30 days, the mice were immunized intranasally with the recombinant protein antigen alone. High serum IgG and salivary IgA responses to the protein antigen were induced by the intranasal immunization.

Administration, Intranasal↗
PubMed1990

Characterization of the antibody response against the type II collagen induced by anti-idiotypic antibody.

We reported that rabbit anti-idiotypic antibody (Ab2) against mAb, termed 1-5 (Ab1) and reactive with human type II collagen (CII) induced antibody response to CII in DBA/1J mice susceptible to collagen-induced arthritis. In the present study, we further characterized the anti-CII antibody response elicited by Ab2 with respect to epitope specificity, putative genetic background, and IgG subclass. Most of anti-CII antibodies (polyclonal Ab3) derived from Ab2-immunized mice were of the IgG1 subclass. We purified polyclonal Ab3, using a CII-coupled immunoadsorbent column and we developed monoclonal Ab3 from Ab2-immunized mice. Both purified polyclonal Ab3 and two monoclonal Ab3s specifically reacted with a selected epitope on CII, recognized by Ab1. The anti-CII antibody response stimulated by Ab2 was observed in DBA/1J (H-2q, Igh-1c) and DBA/2 (H-2q, Igh-1c) mice, but not in the BALB/c (H-2d, Igh-1a) and C57BL/6 (H-2b, Igh-1b) strains, thereby suggesting that the anti-CII antibody response elicited by Ab2 is controlled by the Igh gene.

Animals↗
PubMed1990

Ca2+/calmodulin independent inositol 1,4,5-trisphosphate 3-kinase activity in guinea pig peritoneal macrophages.

1. The Ca2+/calmodulin (CaM) independent activity of inositol 1,4,5-trisphosphate (InsP3) 3-kinase in macrophages could be separated from the dependent activity by serial column chromatography, gel filtration, Orange A and DEAE-5PW. 2. An InsP3 analog which has an aminobenzoyl group on the 2nd carbon of the inositol ring inhibited the conversion of [3H]InsP3 to [3H]InsP4 (inositol 1,3,4,5-tetrakisphosphate) in a dose-dependent manner. The concentration required for half-maximal inhibition (IC50) with the Ca2+/CaM independent enzyme activity was also dependent on the free Ca2+ concentration, as with the dependent activity. 3. These results suggest that a conformational change in the enzyme occurs in response to a change in free Ca2+ concentration, and thus the potency to recognize the InsP3 analog would change, even when the Ca2+/CaM independent enzyme activity was used.

Animals↗
PubMed1990

Cross-reactive polysaccharide antigens (types a, d, and h) of the mutans group of streptococci: different molecular forms of the type as distinguishable by monoclonal antibodies.

As compared to the previous precipitin inhibition tests differences were found in the reactivities of monoclonal antibodies (MAbs), a-4 and a-84 with Streptococcus cricetus (serotype a) in an enzyme immunoassay using whole cells, purified cell wall antigen and haptenic sugars coated onto microtitre wells. Investigation into the differences led to the finding that the purified antigen from S. cricetus cells consisted mainly of three forms with different molecular weights and sugar contents. MAb a-4 reacted with a high molecular weight form (AgI, molecular weight of 46,000) and low molecular weight forms (AgII and AgIII, molecular weights of 9,800 and 20,000, respectively) whereas MAb a-84 reacted only with the high-molecular form. Gas chromatographic analysis revealed that all antigens contained rhamnose, galactose and glucose but in different ratios of the sugars. Although the binding site of AgII/AgIII with MAb a-4 seemed to be slightly different from that of AgI with MAb a-84, the predominant immunodeterminant of the antigens was considered to be the same. On the basis of these results, the chemical structures of the antigenic determinants are suggested. The nature of the antigen-antibody reactions is discussed.

Antibodies, Monoclonal↗
PubMed1990

Monoclonal antibody-coated latex agglutination assay for identification of Actinobacillus actinomycetemcomitans.

Three monoclonal antibodies (MAbs) to lipopolysaccharide of Actinobacillus actinomycetemcomitans strain Y4 (serotype b) and eight MAbs to a serotype b-specific polysaccharide antigen of strain Y4 were obtained. Latex particles sensitized with an MAb to the Y4 lipopolysaccharide produced a positive agglutination with whole cells of all three serotypes of A. actinomycetemcomitans, but not with Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzae, Porphyromonas (Bacteroides) gingivalis, "Bacteroides" intermedius, Fusobacterium nucleatum and Escherichia coli. On the other hand, latex particles sensitized with an MAb to the serotype b-specific polysaccharide antigen agglutinated with whole cells of serotype b A. actinomycetemcomitans and P. gingivalis, but not with heated and trypsinized cells of P. gingivalis. The simple and rapid latex agglutination assay using MAbs may be useful for the identification of A. actinomycetemcomitans.

Actinobacillus↗
PubMed1990

Origin of osteoclasts: mature monocytes and macrophages are capable of differentiating into osteoclasts under a suitable microenvironment prepared by bone marrow-derived stromal cells.

We previously reported that osteoclast-like cells were formed in cocultures of a mouse marrow-derived stromal cell line (ST2) with mouse spleen cells in the presence of 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. In this study, we developed a new coculture system to determine the origin of osteoclasts. When relatively small numbers of mononuclear cells (10(3)-10(5) cells per well) obtained from mouse bone marrow, spleen, thymus, or peripheral blood were cultured for 12 days on the ST2 cell layers, they formed colonies with a linear relationship between the number of colonies formed and the number of hemopoietic cells inoculated. Tartrate-resistant acid phosphatase (TRAPase)-positive mononuclear and multinucleated cells appeared in the colonies (TRAPase-positive colonies) in response to 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. When hemopoietic cells suspended in a collagen-gel solution were cultured on the ST2 cell layers to prevent their movement, TRAPase-positive colonies were similarly formed, indicating that each colony originated from a single cell. All of the colonies consisted of nonspecific esterase-positive cells. The monocyte-depleted population prepared from peripheral blood failed to form colonies, whereas the monocyte-enriched population produced a large number of TRAPase-positive colonies. In addition, alveolar macrophages formed TRAPase-positive colonies most efficiently on the ST2 cell layers in the presence of the two hormones. Salmon 125I-labeled calcitonin specifically bound to the TRAPase-positive cells. Resorption lacunae were formed on dentine slices on which cocultures were performed. When direct contact between the peripheral blood cells and the ST2 cells was inhibited by a collagen-gel sheet, no TRAPase-positive cells were formed. These results indicate that osteoclasts are also derived from the mature monocytes and macrophages when a suitable microenvironment is provided by bone marrow-derived stromal cells.

Acid Phosphatase↗
PubMed1990

Bacteroides lipopolysaccharides (LPS) induce anaphylactoid and lethal reactions in LPS-responsive and -nonresponsive mice primed with muramyl dipeptide.

Lipopolysaccharides (LPS) (100 micrograms/mouse) from Bacteroides gingivalis elicited anaphylactoid reactions in N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) (100 micrograms)-primed C3H/HeN mice 0-48 h after MDP injection. The reaction resulted in death within 1 h when the LPS was injected 2-10 h after the MDP injection. LPS prepared from other Bacteroides and Salmonella species but not from others, including Escherichia coli, could induce the reaction. LPS-nonresponsive C3H/HeJ and C57BL/6 and C57BL/10 strains were also responsive to the reaction, while AKR, BALB/c, DBA/2, and ICR mice were not. By contrast, Bacteroides LPS exhibited weak lethal toxicity compared with E. coli LPS in galactosamine-sensitized C3H/HeN mice, while neither LPS had activity in C3H/HeJ mice. LPS from E. coli and Bacteroides intermedius induced serum tumor necrosis factor (TNF) activity in MDP-primed mice, except for C3H/HeJ mice; B. gingivalis LPS rarely induced TNF in C3H/HeN or C3H/HeJ mice, indicating no involvement of TNF in the anaphylactoid reaction. Serotonin could substitute for MDP for the reaction, and methysergide, a serotonin antagonist, inhibited the activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Different types of antigen-presenting cells affect the induction of experimental autoimmune arthritis.

We obtained a type II collagen-specific murine T cell line containing at least two T cell clones, one reacting with only native collagen II and the other with both denatured and native molecules. Only the former could induce arthritis. The arthritogenic T cell clone(s) was preferentially stimulated to grow when epidermal cells were used as antigen-presenting cells. Conversely, the non-arthritogenic T cell clone(s) was mainly stimulated when spleen cells were used. Thus, it is speculated that different types of antigen-presenting cells preferentially present different epitopes on the same antigen, affecting the resulting in vivo immune phenomena.

Animals↗
PubMed1990

Construction of NotI restriction map of the Streptococcus mutans genome.

Streptococcus mutans and Streptococcus sobrinus are the major causative organisms of human dental caries. Pulsed-field gel electrophoresis (PFG) showed that the restriction enzyme NotI produced ten and six DNA fragments from the genomes of S. mutans strain MT8148 and S. sobrinus strain 6715, respectively. The sizes of the chromosomes of S. mutans and S. sobrinus were each estimated to be about 2200 kb. The NotI restriction map of S. mutans MT8148 genome was constructed by Southern blot analysis with probes that overlapped two adjacent NotI fragments. Several virulence-associated genes of S. mutans were placed on the NotI restriction map. In addition, unique 'fingerprints' of S. mutans chromosomal DNA digested with NotI were produced by PFG, and these may be useful for epidemiological studies.

Base Sequence↗
PubMed1990

Antimicrobial activities of thiolactomycin against gram-negative anaerobes associated with periodontal disease. f1.

Thiolactomycin (TLM), (4R)-(2E,5E)-2,4,6-trimethyl-3-hydroxy-2,5, 7-octatriene-4-thiolide, purified from a culture filtrate of a strain of the Nocardia species, was examined for antimicrobial activities against more than 100 strains of oral and periodontally associated bacteria. Nine other commonly used antibiotics were also included for the test. We found that TLM exhibited strong and selective antimicrobial activities against Bacteroides gingivalis and other oral black-pigmented Bacteroides species that may be etiologically associated with adult periodontitis. TLM also inhibited the growth of Actinobacillus actinomycetemcomitans, but did not affect the growth of oral streptococcal species and Eubacterium species. Strains of Eikenella corrodens were moderately susceptible to TLM, while Actinomyces viscosus strains were only slightly susceptible to it. Other antibiotics used for comparison showed a broad spectrum of antimicrobial activities in general. In conclusion, TLM exhibited highly selective antimicrobial activities to black-pigmented Bacteroides species and A. actinomycetemcomitans, both of which are implicated in the pathogenesis of human periodontal disease.

Actinobacillus↗
PubMed1990

Surface hydrophobicity, adherence, and aggregation of cell surface protein antigen mutants of Streptococcus mutans serotype c.

The pac gene of the serotype c strain Streptococcus mutans MT8148 encodes a cell surface protein antigen (PAc) of approximate 190 kilodaltons. The serotype c strain S. mutans GS-5 does not produce the 190-kilodalton PAc but produces a lower-molecular-weight protein that reacts with anti-PAc serum. The SphI-BamHI fragment of the pac gene was ligated with the S. mutans-Escherichia coli shuttle vector pSA3. The chimeric shuttle vector was transformed into strain GS-5, and two transformants (TK15 and TK18) were isolated. These transformants produced a large amount of cell-free and cell-bound PAc of 190 kilodaltons. No plasmid was isolated from these transformants, and the EcoRI fragments of their chromosomal DNA hybridized with the erythromycin resistance gene in the shuttle vector DNA, indicating insertion of the chimeric shuttle vector DNA into the chromosomal DNA. The cell hydrophobicity of strains TK15 and TK18 as well as PAc-defective mutants constructed by inserting an erythromycin resistance gene into the pac gene of strain MT8148 was analyzed. Strains MT8148, TK15, and TK18 were hydrophobic. On the other hand, strain GS-5 and PAc-defective MT8148 transformants were hydrophilic. Resting cells of the hydrophobic strains attached in larger numbers to saliva-coated hydroxyapatite than did the hydrophilic strains. Human whole saliva induced the aggregation of cells of the hydrophobic strains but not that of cells of the hydrophilic strains. These results suggest that cell surface PAc of S. mutans serotype c participates in attachment of the streptococcal cell to experimental pellicles.

Antigens, Bacterial↗
PubMed1990

Oral immunization with recombinant Streptococcus lactis carrying the Streptococcus mutans surface protein antigen gene.

A recombinant Streptococcus lactis strain which carries the structural gene for a surface protein antigen (PAc) of 190,000 daltons from Streptococcus mutans serotype c was constructed for development of an oral vaccine against dental caries. The gene from S. mutans MT8148 joined to shuttle vector pSA3 was successfully transformed into S. lactis IL1403. A small amount of PAc was detected in the cell homogenate and cytoplasmic fraction of the recombinant S. lactis, but not in the culture supernatant of the recombinant, by Western immunoblotting and dot immunoblotting. The level of PAc-specific mRNA in the recombinant strain was lower than that in S. mutans MT8148. However, significant salivary immunoglobulin A and serum immunoglobulin G responses to PAc were induced in mice immunized orally with the recombinant S. lactis.

Animals↗
PubMed1990

Decrease in endothelium dependent hypotension in spontaneously hypertensive rats.

Endothelium-dependent and independent hypotension, vasodilation and relaxation were examined comparatively, in vivo and in vitro, in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats (WKY). In conscious and unrestrained animals, the dose-dependent hypotensive responses to both acetylcholine and adenosine triphosphate (ATP) were attenuated in SHR, compared to findings in the WKY, while sodium nitroprusside lowered mean arterial pressure (MAP), to a similar degree in SHR and WKY. Acetylcholine, ATP and nitroprusside increased the heart rate of SHR and WKY, in a dose-related manner. Mesenteric and femoral blood flow was altered by acetylcholine, ATP and nitroprusside, in a similar manner in the SHR and WKY anesthetized with urethane. However, an ATP-induced reduction in renal blood flow was greater in the SHR than in the WKY. Acetylcholine and nitroprusside led to a concentration-dependent relaxation in the isolated mesenteric artery, to a similar extent in both strains of rats. The relaxation response to acetylcholine was nearly abolished by mechanical removal of the endothelium, but the nitroprusside-induced relaxation was not altered by this denudation. ATP did not influence contraction of the mesentric artery but did produce endothelium-dependent relaxation of aorta, in a dose-dependent manner. All these events suggest that suppression of the endothelium dependent relaxation of resistant arterioles relates to the maintenance of hypertension, in the SHR.

Acetylcholine↗
PubMed1990

Cloning and expression of a pili gene of Corynebacterium renale in Escherichia coli.

A plasmid gene library of Corynebacterium renale piliated strain No. 109P+ was prepared in Escherichia coli in order to study the chemical structure of the pili of C. renale. Of 3,000 recombinant clones tested, 5 reacted with anti-pili anti-serum. The gene products of these clones reacted with anti-pili monoclonal antibodies 8/4, 5/2 and B20/3 but lacked the reactivity with 13/4. SDS-PAGE analysis revealed that the expressed protein had a molecular mass of 48 kilodalton and deletion analysis showed that the encoding region for this protein was localized within a 1.4 kilobase gene including a promoter sequence. Immunoelectron microscopy showed that mouse antibodies raised to the expressed protein bound to the entire surface of the pili of C. renale. These results indicate that the cloned gene encodes a major structural protein of C. renale pili.

Animals↗
PubMed1990

Characteristic behavior of the respiratory muscles, esophagus, and external anal and urethral sphincters during straining, retching, and vomiting in the decerebrate dog.

To ascertain differences in the brainstem pattern generators for straining and retching, discharges of 230 respiratory single motor units from the intercostal nerves and discharges of the nerves to accessory respiratory muscles, the esophagus, and external anal and urethral sphincters were observed during straining, retching, and vomiting (fictive expulsion) in decerebrate and paralyzed dogs. Straining and retching were identified with coactivation of the phrenic nerve and the nerve to the rectus abdominis, which was elicited by distension of the rectum and stomach, respectively. Synchronous discharges with each retch and straining were always exhibited by the phrenic nerve, the nerves innervating the abdominal part of the rectus abdominis and the external anal and urethral sphincters. In contrast, different behaviours were constantly observed in four nerves. 1) The nerves to the serratus dorsalis cranialis was inhibited during straining, but activated synchronously with each retch and vomiting. 2) Vagal pharyngeal branches innervating the upper esophagus and branches of the recurrent nerve innervating the lower part of the cervical esophagus fired synchronously with straining. The esophageal nerves, on the other hand, did not fire with each retch, but did fire strongly between retches. 3) The nerve to the sacrocaudalis dorsalis lateralis discharged concomitantly with straining but did not with retches. Straining and retching behaviors exhibited by the nerves innervating other thoracic accessory inspiratory muscles (the intercartilagineus, rectus thoracis, scalenus) varied from dog to dog. The nerves innervating the thoracic parts of the rectus abdominis and obliquus externus abdominis always discharged synchronously with straining, and discharged with retches in the majority of dogs, but did not in a minority of dogs. The expiratory units from the internal intercostal nerves showed intense discharges synchronously with coactivation in straining (96%), retching (65%), and vomiting (100%). In contrast, none of the inspiratory units from the external intercostal nerves exhibited such intense discharges with straining and retching. These results suggest that the functional difference in straining and retching mainly depends on the differences in the behavior of the serratus dorsalis cranialis and esophagus. The forms of this dependence were discussed.

Anal Canal↗