Biomedical subjects

F Ota

Publications and source records attributed to F Ota.

At least 37 records · Page 2Linked to original sources

PubMed1992

Effects of protein intake on immune parameters in mice surviving streptococcal infection.

Groups of mice were fed for 2 weeks on isocaloric diets containing 5, 7, 20 and 40% (w/w) casein, respectively, then injected intraperitoneally with group B streptococci, and observed for their survival rates. The mice fed 7% or 20% casein had lower mortalities than those fed 5% or 40% casein. In order to explain the different survival rates, other groups of mice were fed on the experimental diets and examined for the number of leukocytes in the blood, of spleen cells and thymocytes, for IgG and IgM antibody titres to the streptococci, for haemolytic titres of sera, the amount of complement component 3 (C3), for chemiluminescence and opsonic activity of peritoneal exudate cells (PEC) and spleen cells (SP), production of superoxide anion from PEC and SP, and production of immunoglobulins from cultured SP. After 2 weeks on a 7 or 20% casein diet mice showed increased serum levels of IgM antibodies reactive with the whole bacterial cells on days 3-5 when they were immunised with a sublethal dose of group B streptococci. The mice fed on the 7% casein diet also showed a higher C3 titre than the other diet groups when assayed by enzyme immunoassay. Furthermore, opsonophagocytic activity was highest when PEC or SP taken from mice on the 20% case in diet were incubated with radiolabelled microorganisms in the presence of fresh serum taken from the 7% casein group. The production of superoxide anions from PEC and SP was lowest in the mice fed on 5% casein when activity was expressed as nano-mol per animal. It is suggested from these results that the greater activity of phagocytic cells in the presence of increased amounts of C3 and IgM explains the heightened resistance in the mice fed on a 7% casein diet, and that suppressed opsonophagocytic activity resulting from the decreased number of leukocytes in the blood and other phagocytic cells explains the lowest resistance in the 5% casein group. However, mice fed on a 40% casein diet showed all these immunological parameters untouched, and their lowered resistance could not be explained. Different factors seem to be operative in them.

Animals↗

PubMed1991

Structural and stereospecific requirements for the nucleoside-triggered germination of Bacillus cereus spores.

A selection of adenosine analogues was tested for their ability to trigger germination of Bacillus cereus NCIB 8122 spores. The germination-inducing activity was governed by the structural properties of the sugar rather than the base moieties of the nucleosides. Among the sugar-modified analogues, only those containing a 2'-deoxy-D-ribose moiety promoted spore germination. Requirements for a specific molecular structure of the base were not clearly identified, although the highest activity was observed when substituents were inserted at position 6 of the purine ring. All the base-modified analogues, even those such as coformycin and 2'-deoxycoformycin with an expanded base ring, retained the germination-inducing activity of adenosine. However, of the two 2'-deoxycoformycin diastereoisomers characterized by an asymmetric carbon atom at position 8 of the homopurine ring, only the 8S-isomer induced germination, thus indicating that stereospecific configuration of the inducer, at least in the case of 2'-deoxycoformycin, appears to be essential for the initiation of spore germination. The differences in the germination-inducing activity of the various analogues tested were not affected significantly by spore activation at different temperatures, although the higher the activation temperature, the lower was the concentration of each analogue required for maximum germination.

Adenosine↗

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

Enzyme immunoassay and monoclonal antibodies for immunological studies of the mutans group of streptococci.

Monoclonal antibodies (MAbs) were prepared from myeloma cells and splenocytes of mice immunized with Streptococcus cricetus HS1 or Streptococcus downei MF25 cells. Various makes of immunoplates were coated with whole cells or purified polysaccharide antigens of oral streptococcal strains and tested for reactivity in enzyme immunoassay (EIA) using the Mabs. It was revealed that different immunoplates had different reactivities. It was also shown that the EIA system and MAbs were useful for the immunological study and identification of oral streptococci.

Antibodies, Monoclonal↗

PubMed1989

A comparison of competitive enzyme immunoassay and precipitin inhibition tests in the analysis of polysaccharide antigenic determinants of oral streptococci.

A rapid and convenient method of competitive enzyme immunoassay (EIA) was explored for the immunological analysis by MAbs of polysaccharide antigens prepared from the mutans group of streptococci, and optimal conditions for it were established. These included the concentrations of antigen, monoclonal antibodies (MAbs) and labelled antibody, temperature, pH and reaction time. The results were compared with those obtained by precipitin inhibition tests using the classical quantitative precipitin reaction, and they were found to be consistent with the latter method. It was concluded that the EIA system can be extended to the immunological study of polysaccharide antigens of oral streptococci using MAbs which perform poorly in precipitation reactions.

Animals↗

PubMed1989

Directional immobilization of sodium- and potassium-activated ATPase to expose its cytoplasmic part to the liquid phase on microtiter plates by wheat germ agglutinin.

A convenient method for highly efficient and directional immobilization of intact sodium- and potassium-activated ATPase (Na,K-ATPase) using wheat germ agglutinin linked on microtiter plates was developed. Wheat germ agglutinin, which bound tightly to the beta-subunit of Na,K-ATPase and had no effect on the Na,K-ATPase activity, the potassium-activated p-nitrophenylphosphatase activity, or the inhibitory action of ouabain, was covalently linked to microtiter plates and used as an immobilizer of the enzyme. The amount of Na,K-ATPase coupled to microtiter plates in this immobilizing system was more than 10-fold greater than that used in the direct immobilizing system (O. Urayama, M. Nakao, H. Nagamune, and H. Sugiyama, (1984) Anal. Biochem. 141, 194-198). Also in this system, the cytoplasmic domain of Na,K-ATPase was exposed to the liquid phase. This technique was useful for investigating the reactivities of monoclonal antibody specific for the cytoplasmic domain of the enzyme. Moreover, because this technique was used successfully in the immobilization of periodic acid--Schiff positive staining glycoprotein 1 prepared from human erythrocytes and human alpha 2-macroglobulin, the technique should also be useful for other membrane or secreted proteins that possess N-linked sugar chains containing bisecting N-acetylglucosamine or a high amount of sialic acid.

Animals↗

PubMed1989

B-cell-mediated depression of the granulomatous response to BCG in mice.

The depression of the granulomatous response to Mycobacterium bovis strain BCG in mice infected intravenously with 2 x 10(7) CFU of the microorganism turned out to be mediated by various types of cells arising at different times after infection. Anti-PPD B lymphocytes were found to play a major role at Day 1 after infection and to be no longer effective 4 days later. At this time the depression was mediated by anti-idiotype B lymphocytes, whereas T lymphocytes proved to be involved in later phases of the infectious process. These results show that B lymphocytes may be of critical importance in the regulation of cell-mediated immune reactions to this facultative intracellular parasite.

Animals↗

PubMed1989

Type-specific antigen of Streptococcus rattus strains (KAY1 and FA1). I. Characterization.

A serotype-specific antigen was extracted from Streptococcus rattus KAY1 strain isolated first in Japan from human dental plaque and purified on an ion exchange column to compare it chemically and immunologically with that of FA1 strain which had been examined extensively by previous workers. Antigens of both strains reacted in a double diffusion test specifically with anti-FA1 serum which had previously been demonstrated specific for the strains in the same test, agglutination reactions and/or radioimmunoassay using whole cells. After separation on a DEAE-Sephadex A-25 ion exchange column the antigen was found to be resistant to various enzymatic treatments with pronases, lipase and nucleases and produce a single precipitin band against absorbed anti-FA1 serum in immunoelectrophoresis. Chemical analysis of this antigen revealed that it composed of carbohydrate, protein and a few percentages of glycerol and phosphorus. Hapten inhibition tests between antigen and antibody showed that galactose as well as glucose were the most potent inhibitors, suggesting their involvement in the antigenic determinant. Involvement of the sugars was also supported by gas chromatographic analysis and abolishment of reactivity with antiserum after the treatment of antigens with NaIO4. Moreover, protein does not seem to be involved since after SDS-PAGE analysis an enzyme immunoassay gave a negative reaction with immunoblotted antigens.

Antigens, Bacterial↗

PubMed1989

Type-specific antigen of Streptococcus rattus strains (KAY1, FA1 and BHT). II. Ultrastructural localization.

Streptococcus rattus strains (KAY1, FA1 and BHT) were examined by electron microscopy in whole cell-mounted samples and ultrathin sections for the localization of the type-specific antigen, using specific antiserum and ferritin-labelled anti-rabbit IgG as secondary antibody. In thin sections as well as whole cell-mounted samples the antigen was observed as irregular masses over the entire surface of the cells, in particular in the septal region between cells. The localization of the antigen was also examined in thin sections of a cell wall fraction prepared by treating the whole cells with glass beads in a disintegrator. Ferritin particles were observed around the outer surface, but not as many in number as those in whole cell-mounted or sectioned samples and rarely on the inner surface of the cell wall.

Antigens, Bacterial↗

PubMed1988

Optimal protein intake estimated by the resistance to streptococcal infection and the nutritional indices in mice.

Effects of dietary protein levels on the resistance against a bacterial infection and on the nutritional status were studied in mice to obtain basic data for the estimation of an optimal protein intake. Female DDY strain weanling mice were fed 5, 7, 10, 20, 30, or 40% casein diet. At 2 or 4 weeks on the diets, the mice were injected intraperitoneally with 5 x 10(3) or 5 x 10(4) group B streptococci/g body weight and their survival rates were observed for the following 10 days. Nutritional indices and cell numbers of thymus and spleen were also measured. The survival rate was higher in the order of 7, 10, 20, 30, 5, 40% casein diet group. Significant differences were observed between the 7% group and the 30, 5, or 40% group, and between the 10% group and the 5 or 40% group. The nutritional indices and cell numbers of the thymus and spleen were similar among the 20, 30, and 40% casein diet groups and decreased in the order of 10, 7, 5% casein diet groups. From the results, protein levels were categorized into 4 groups: severe protein deficiency with low resistance (5% casein diet), moderate protein deficiency with high resistance (7 and 10% casein diets), normal protein intake with normal resistance (20% casein diet), and high protein intake with low resistance (30 and 40% casein diets). This grouping suggests that when the relation between immunocompetence and nutritional status is considered, both high and low protein intakes are undesirable and the optimal level of dietary protein will be limited to a narrow range.

Animals↗

PubMed1987

Serological typing of reference strains and clinical isolates of Streptococcus mutans by agglutination reactions and/or radioimmunoassay.

Rabbit antisera were prepared against eight different serotypes of Streptococcus mutans. After absorption with heterologous serotype strains the antisera were able to distinguish 21 reference strains of different serotypes of S. mutans by simple agglutination reactions and radioimmunoassay, both using intact whole cells. The reference serotypes a, b, d and g were differentiated by specific agglutination using the corresponding monospecific antiserum. Strains of serotypes c, e, f and h were discriminated by differential agglutination using anti-c, anti-e, anti-f or anti-h serum respectively, but the antisera cross-reacted slightly with other serotype strains. Using these antisera a total of 261 clinical isolates of S. mutans from human dental plaques were serotyped by agglutination reactions, in addition to which radioimmunoassay and the classical immunodiffusion tests in agar were also used in some cases. The results were quite consistent in the three methods. The predominant strain was of serotype c (187), followed by serotype f (28), g (10), d (5), e (4) and b (1). 26 strains were untypable and there were no serotype a or h strains.

Agglutination Tests↗

PubMed1987

Immunological study of cross-reactive polysaccharide antigens (types a, d, and h) of oral Streptococcus spp. with monoclonal antibodies.

Two monoclonal antibodies against the cross-reactive antigens of S. cricetus (type a) and S. sobrinus (type d) were isolated. Galactose and especially melibiose inhibited the precipitin reaction markedly. Inhibition by melibiose was over 200-fold stronger than that by galactose. This may indicate that galactose-alpha 1, 6-glucose is the predominant antigenic determinant of this cross-reactive antigen. This antigen was also found in S. sobrinus type h strains, but no antigen was found in one type d strain (OMZ176).

Antibodies, Monoclonal↗

PubMed1987

E-rosetting of guinea pig lymphocytes with lyophilized rabbit red cells after treatment with papain and glutaraldehyde.

Guinea pig lymphoid cells were reacted to form spontaneous rosettes (E-rosettes) with rabbit red blood cells before and after treatment with papain or a very low concentration (0.01%) of glutaraldehyde alone or both. The papain-glutaraldehyde-treated cells showed as high ability as papain-treated cells to rosette with lymphoid cells prepared from thymus, spleen, lymph node and peripheral blood of guinea pigs. Moreover, papain-glutaraldehyde-treated red cells were lyophilized and stored for 1 year without any change in their ability to form E-rosettes with these lymphoid cells. Binding between lymphocytes and treated or nontreated red cells was completely inhibited by specific anti-guinea pig thymocyte serum. Furthermore, a lymphocyte population enriched for B cells from lymph nodes or leukemic cells of strain 2 guinea pigs (B cells) did not show any substantial E-rosettes with nontreated or treated red cells. Scanning electron microscopy revealed no surface alteration in the treated cells when compared to those in nontreated red cells.

Aldehydes↗

PubMed1986

Monoclonal antibody to Streptococcus mutans type e cell wall polysaccharide antigen.

A monoclonal antibody against the polysaccharide antigen of Streptococcus mutans serotype e was prepared. It was found that beta-methyl-D-glucopyranoside and cellobiose markedly inhibited the precipitin reaction, whereas maltose showed no inhibition. The beta-glucosyl moiety of the type e polysaccharide seems to be the predominant antigenic determinant of the antigen.

Animals↗

PubMed1985