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Biomedical subjects

K Takeya

Publications and source records attributed to K Takeya.

At least 145 records · Page 8Linked to original sources
PubMed1981

Effect of stimulation and blockade of mononuclear phagocyte system on the induction of suppressor T cells of delayed footpad reaction to SRBC in mice.

The role of mononuclear phagocyte system (MPS) in the induction of suppressor T cells which depress the delayed footpad reaction to sheep erythrocytes (SRBC) was studied in mice in which MPS was blocked or stimulated. Colloidal carbon and diethylstilbestrol were used for blockade and stimulation respectively. Adoptive transfer of suppressor T cells was achieved by spleen cells of mice immunized intraperitoneally with varying doses of SRBC. In nontreated mice, 1 x 10(9) SRBC were required to induce suppressor T cells, while 6 x 10(8) could not induce the suppressor T cells. In MPS-blocked mice, however, even 6 x 10(8) SRBC could induce the suppressor T cells. On the other hand, 3 x 10(10) SRBC were required for the induction of suppressor T cells in MPS-stimulated mice. These results suggest that the activity of macrophages as scavenger cells modulates the subsequent induction of suppressor T cells after immunization with high doses of SRBC.

Animals↗
PubMed1981

Modification of protective mechanisms against Listeria monocytogenes during pregnancy.

Protective mechanisms against Listeria monocytogenes were examined at different stages of pregnancy in C3H/He mice. Bacterial growth at an early phase of infection was depressed from day 10 of gestation to day 5 postpartum, whereas bacterial growth at a late phase of infection was enhanced on day 10 of gestation. Spleen cells from nonimmunized mice on day 10 of gestation suppressed the expression of acquired resistance to infection in immunized mice. We conclude that the augmented resistance during pregnancy at an early phase of primary infection is due to the activation of nonimmune macrophages, which compensates for the depressed cell-mediated immunity at a late phase of infection that may be due to the function of nonspecific suppressor cells detectable in the spleen of the pregnant mice.

Animals↗
PubMed1981

Analysis of elements determining the generation of cytotoxic T lymphocytes. I. Irradiated F1 recipients in which antigenic stimulation occurs consistently at an excess dose.

Specific cytotoxicity against histocompatibility antigens of a parental strain was induced in the spleens of sublethally irradiated F1 mice after intravenous transfer of lymphoid cells from another parental strain. Such cytotoxicity reached the highest level at 10 days after the transfer of 3 to 5 X 10(7) spleen cells and was ascribed to be T lymphocytes of donor parental origin. Secondary response of the generation of cytotoxicity was compared among in vivo rechallenge, in vitro MLC and transfer to irradiated F1 mice. Cytotoxicity was not so augmented by in vivo rechallenge. It may be attributable to early elimination of grafts. In in vitro MLC and transfer to irradiated F1 mice, the generation of cytotoxicity appeared earlier with higher magnitudes as compared to primary response. The transfer system to irradiated F1 recipients appears to be more suitable for analyses of the generation of cytotoxic T lymphocytes from memory cells than in vivo rechallenge.

Animals↗
PubMed1981

Effects of cholera toxin on lymphoid system. I. Reduction of thymus cells after cholera toxin injection.

One microgram of cholera toxin was injected intravenously into DDD and AKR mice and its effects on lymphoid tissues were examined at various intervals. A remarkable reduction of thymus cells were revealed from days 1 to 11 and from days 1 to 7 in DDD and AKR mice, respectively. Only slight effects were detected on the numbers of spleen cells and peripheral blood leukocytes in both strains throughout the observation period.

Animals↗
PubMed1981

Effects of cholera toxin on the lymphoid system II. Selective augmentation of delayed footpad reaction in mice.

Effects on immune responses to sheep erythrocytes (SRBC) were examined at various intervals after an intravenous injection of 1 microgram of cholera toxin in DDD and AKR mice. Delayed footpad reaction was augmented by pretreatment with cholera toxin 1, 7 or 10 days before immunization in both strains. The delayed reaction was not suppressed even in the presence of a prominent antibody production. In mice given cholera toxin, macrophage migration inhibition was not positive 5 days after immunization, but became weakly positive 10 days after immunization. Antibody production against SRBC especially of IgG class, was facilitated, when cholera toxin was given one day before immunization, on the other hand, antibody production was suppressed irrespective of immunizing routes and mouse strains. Similar results were observed in guinea pigs which were injected with 1 microgram of cholera toxin 0 or 7 days before immunization with bovine gamma globulin in complete or incomplete Freund's adjuvant. Erythema was augmented strikingly by cholera toxin, while macrophage migration inhibition was affected scarcely.

Animals↗
PubMed1981

Restorative effects of nandrolone decanoate on the mononuclear phagocyte system in tumor-bearing mice.

The effects of nandrolone decanoate on the mononuclear phagocyte system (MPS) were examined in normal or tumor-bearing mice. Bactericidal activity against Listeria monocytogenes, carbon clearance test and leukocyte accumulation into the site of inflammation were depressed when viable cells of sarcoma-180 were inoculated subcutaneously into ddY mice 24hr before the assays. Pretreatment with nandrolone decanoate prevented such depression in tumor-bearing mice and increased MPS activities of normal or tumor-bearing mice above the level of non-treated normal mice. Nandrolone decanoate may be useful for the augmentation of antimicrobial activity in tumor-bearing hosts.

Anabolic Agents↗
PubMed1980

Relationship between structure, positive inotropic potency and lethal dose of grayanotoxins in guinea pig.

Relationship between chemical structure, positive inotropic potency and lethal dose of grayanotoxins and the related compounds was studied using guinea pigs. The positive inotropic effect (PIE) was examined in their papillary muscle isolated from the heart. The potency of these compounds was expressed by pD2 values, and was determined by depicting the concentration-PIE curve for each compound. The study has clarified the contribution of functional groups in the molecule; the presence of 3 beta-hydroxyl, 6 beta-hydroxyl and 10 beta-methyl groups attached to the grayanane skeleton is established to be essential for the development of PIE. The inotropic potency of compounds carrying these essential groups is increased by a 10 alpha-hydroxyl group and the acylation of the 14 beta-hydroxyl group. LD50 value of 10 compounds with a high cardiotonic potency (pD2 greater than 4) was determined by up and down method using male guinea pigs. The relation of LD50 to pD2 bore a significant correlation (r = 0.68, p less than 0.05). The most cardiotropic and toxic compound found in this study was asebotoxin III.

Animals↗
PubMed1980

Importance of antiserum and phagocytic cells in the protection of mice against infection by Klebsiella pneumoniae.

Rabbit antiserum to Klebsiella pneumoniae showed a powerful protective effect against intramuscular infection in normal mice. No protective effect was observed in mice whose monocytes and polymorphonuclear cells were depleted by X-irradiation. The antiserum had approximately the same protective effect in mice whose macrophages were blocked selectively by carrageenan as in normal mice. It is concluded that antiserum exerted its effect by opsonic function and that opsonized K. pneumoniae were eliminated mainly by polymorphonuclear cells rather than macrophages, at least in an early phase of the infection. these findings were supported by histological examination and observation of intracellular killing in vitro.

Animals↗
PubMed1980

Enhanced elimination of Listeria monocytogenes at the site of delayed footpad reaction.

The protective activity against a challenge infection with Listeria monocytogenes was investigated at the site of a delayed footpad reaction in mice immunized with viable or killed listeria. Delayed footpad reactivity was induced only in mice immunized with viable bacteria. Rapid and marked elimination of challenge bacteria was observed only at the site of reaction in mice immunized with viable bacteria but not in mice immunized with killed bacteria. Macrophage migration inhibitory activity was observed equally in both groups of mice. These results suggest that the delayed footpad reaction contributes directly to the elimination of bacteria irrespective of macrophage migration inhibitory activity.

Animals↗
PubMed1980

Relationship between non-specific activity of macrophages and immune responses to Listeria monocytogenes.

Delayed footpad reactions and acquired cellular resistance to Listeria monocytogenes were studied in mice whose mononuclear phagocyte system (MPS) had been blocked or stimulated. Colloidal carbon was used for the blockade of MPS and Corynebacterium parvum used for the stimulation. Strong delayed footpad reactions. On the other hand, the i.v. injection of 3 X 10(1) listeria induced an appreciable level mice, while in MPS-stimulated mice, i.v. injection with even 4 X 10(3) listeria could not induce such strong delayed footpad reaction. On the other hand, the i.v. injection of 3 X 10(1) listeria induced an appreciable level of delayed footpad reaction only in MPS-blocked mice. Acquired cellular resistance was depressed by MPS stimulation, whereas it was augmented by MPS blockade. These results suggested that non-specific activity of MPS modulates subsequent immune responses after inoculation of listeria.

Animals↗
PubMed1980

Characteristics of resistance to Listeria monocytogenes enhanced by Corynebacterium parvum in mice.

In mice pre-treated with Corynebacterium parvum, Listeria monocytogenes was cleared rapidly from the blood and bacterial growth in the liver and spleen was inhibited effectively during the early phase of infection. This enhanced resistance could be transferred with peritoneal exudate cells (PEC) but not with non-adherent spleen cells. In spite of earlier elimination of bacteria, pre-treated mice developed lower levels of delayed-type hypersensitivity (DTH) to bacteria than untreated immune control mice, but the control levels of DTH could be reached by increasing the challenge dose of bacteria in C. parvum-pre-treated mice. Additionally, C. parvum did not inhibit the expression of antibacterial immunity when immune mice were rechallenged. It appeared that the active suppression of the T-cell mediated immune response by C. parvum-activated macrophages was not seen during the course of L. monocytogenes infection, and that the lower levels of DTH seen in mice pre-treated with C. parvum were attributable to an insufficient antigenic stimulus following the accelerated elimination of bacteria by non-specifically activated macrophages during the early phase of infection.

Animals↗
PubMed1979

Differing contribution of polymorphonuclear cells and macrophages to protection of mice against Listeria monocytogenes and Pseudomonas aeruginosa.

Bacterial growth and lethality of Listeria monocytogenes in mice were augmented by carrageenan-treatment and X-irradiation (8 J kg-1), whereas growth and lethality of Pseudomonas aeruginosa were augmented by X-irradiation but not by carrageenan-treatment. Protection against L. monocytogenes, at least in the early phases, appears to depend mainly on macrophages, since carrageenan depletes macrophages but not polymorphonuclear cells (PMN), whereas protection against P. aeruginosa appears to depend mainly on PMN. Ineffectiveness of PMN in elimination of L. monocytogenes is supported by histological examination and observation of intracellular killing in vitro.

Animals↗
PubMed1979

Effects of in vivo priming on in vitro induction of cytotoxicity. I. Non-specific augmentation by in vivo presensitization with allogeneic or xenogeneic cells.

In vivo presensitization of donor mice of responding cells with third party cellular antigens augmented in vitro generation of cytotoxic T lymphocytes in allogeneic and xenogeneic combinations. In vitro induction of detectable cytotoxicity in presensitized responding cells required the incubation period needed for in vitro primary response. However, such cytotoxic T lymphocytes were generated after in vitro stimulation with monolayers of methylcholanthrene-induced tumor cells, UV-irradiated or heated spleen cells which had proved to be effective in secondary but not in primary response. Presensitized responding cells exposed to 600R-irradiation did not augment in vitro induction of cytotoxicity in normal responding cells. The augmenting effect of presensitized responding cells may be attributable to radiosensitive T cells which are in a transitional state in differentiation from typical unprimed cells to typical primed cells.

Animals↗