401
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Anti-CD2 mAbs suppress cytotoxic lymphocyte activity by the generation of Th2 suppressor cells and receptor blockade. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1994; 152:3729-39. [PMID: 7908306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The mechanism by which anti-CD2 mAbs inhibit hapten-specific and alloantigen specific CTL was explored. In vivo administration of alpha-CD2 mAbs resulted in 80 to 100% inhibition of alloantigen specific CTLs. Mixing cells from control animals with cells from alpha-CD2-treated groups demonstrated transferable suppression of CTL (40-67% suppression). These suppressor cells were CD4+CD8- and associated with increased IL-4 and TGF-beta in culture as compared with controls. Anti-CD2 mAbs added at the initiation of culture resulted in 60 to 72% inhibition of trinitrophenyl-CTL, whereas mAbs added at the time of assay resulted in less than 50% inhibition of trinitrophenyl-CTLs. F(ab')2 and Fab alpha-CD2 produced inhibition similar to intact mAbs when added at the time of the lytic assay, whereas both produced only modest inhibition in vivo or when added at the initiation of culture. Alloantigen-specific CTLs were not affected by Ab addition to either culture or assay. The immunosuppressive effects were generalizable because a panel of alpha-CD2 mAbs were all comparably effective in suppressing hapten-specific CTLs when administered in vivo. The results demonstrate that the inhibitory effects are the result of blockade of receptor adhesion function during Ag priming or target recognition, Fc-related effects, and the generation of a negative regulatory, CD4+CD8-, IL-4- and TGF-beta-producing TH2 suppressor T cell.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antigens, Differentiation, T-Lymphocyte/immunology
- CD2 Antigens
- CD4-Positive T-Lymphocytes/immunology
- Cytokines/metabolism
- Cytotoxicity, Immunologic
- Dose-Response Relationship, Immunologic
- Immunologic Memory
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Receptors, Immunologic/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Helper-Inducer/immunology
- T-Lymphocytes, Regulatory/immunology
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402
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Anti-CD2 monoclonal antibodies synergize with FK506 but not with cyclosporine or rapamycin to induce tolerance. Transplantation 1994; 57:736-40. [PMID: 7511258 DOI: 10.1097/00007890-199403150-00017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
CsA, FK506, and rapamycin prolong allograft survival; however, each has significant associated side effects at therapeutic doses. Anti-CD2 mAbs also prolong survival but without toxicity. We tested whether alpha CD2 mAbs in combination with subtherapeutic immunosuppression could prolong allograft survival in a synergistic fashion. C57BL/6 (H-2b) mouse hearts were transplanted to CBA (H-2k) mice in a heterotopic, non-vascularized cardiac allograft model. Recipients received immunosuppressants intraperitoneally for 14 days and/or alpha CD2 mAb intravenously for 2 days starting at the time of grafting. Survival was determined by electrocardiogram monitoring. Anti-CD2 alone prolonged survival to 22.4 +/- 1.0 days versus 13.4 +/- 0.5 days for untreated controls (P < 0.05), while low dose FK506 minimally prolonged survival to 16.7 +/- 0.7 days (P < 0.057). However, FK506 plus alpha CD2 resulted in synergistic prolongation of graft survival to 28.0 +/- 2.1 days. Several doses of CsA and rapamycin in combination with alpha CD2 did not prolong survival over alpha CD2 administered alone. A 60-day course of low dose FK506 plus alpha CD2 resulted in indefinite graft survival (> 165 days). These animals were tolerant since they accepted a second donor-specific graft. CTL and MLR activity in long-term recipients were normal to both donor-specific and third party alloantigen. The combination of alpha CD2 with low dose FK506 is synergistic in prolonging cardiac allograft survival, while combinations with CsA and rapamycin are not. Continuous administration of low dose FK506 plus alpha CD2 results in a state of tolerance. This suggests that FK506 acts at a different locus in allograft immunity compared with the other immunosuppressants and this may be related to the alternative CD2 T cell activation pathway.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Antigens, Differentiation, T-Lymphocyte/immunology
- CD2 Antigens
- Cyclosporine/pharmacology
- Drug Synergism
- Female
- Graft Survival/drug effects
- Immune Tolerance/drug effects
- Lymphocyte Culture Test, Mixed
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Polyenes/pharmacology
- Pregnancy
- Receptors, Immunologic/immunology
- Sirolimus
- T-Lymphocytes, Cytotoxic/physiology
- T-Lymphocytes, Helper-Inducer/drug effects
- Tacrolimus/pharmacology
- Time Factors
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403
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kat: a high-efficiency retroviral transduction system for primary human T lymphocytes. Blood 1994; 83:43-50. [PMID: 8274751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We describe a novel retroviral packaging system in which high titer amphotropic retrovirus was produced without the need to generate stable producer clones. kat expression vectors, which produce high levels of retroviral vector transcripts and retroviral packaging functions, were transfected into 293 cells followed by virus harvest 48 hours posttransfection. Viral titers as high as 3.8 proviral copies/cell/mL of frozen supernatant in 3T3 cells were obtained, 10- to 50-fold greater than transient viral titers reported using 3T3-based retroviral packaging lines. Cocultivation of primary human CD8+ T lymphocytes after transient transfection of 293 cells with kat plasmids resulted in transduction efficiencies of 10% to 40%, 5- to 10-fold greater compared to cocultivation with a high titer PA317 producer clone and significantly greater than previously reported results for transduction of primary human T lymphocytes with retroviral vectors. Virus produced using the kat system was shown to be free of detectable replication competent retrovirus by an extended provirus mobilization assay, demonstrating that this system is as safe as currently available stable packaging lines. The kat virus production system should be of general use for the rapid production of high titer viral supernatants, as well as for high-efficiency transduction hematopoietic cell types refractory to retroviral transduction.
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404
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Abstract
Indefinite graft survival was obtained with murine cardiac allografts using the combined administration of monoclonal antibodies (mAbs) directed against the receptor ligand pair CD2-CD48. Although each antibody could prolong graft survival when given alone, neither resulted in the indefinite graft survival seen with the combination. Combined mAb administration is associated with inhibition of T cell priming and help and subsequent cytotoxic T lymphocyte generation. This indicates that the interaction between CD2 and its ligand is important for antigen priming and recognition, and combined mAbs may prove to be a useful therapeutic regimen for transplantation.
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MESH Headings
- Animals
- Antibodies, Monoclonal/therapeutic use
- Antigens, CD/immunology
- Antigens, Differentiation, T-Lymphocyte/immunology
- CD2 Antigens
- CD48 Antigen
- Drug Synergism
- Female
- Graft Survival/immunology
- Heart Transplantation/immunology
- Lymphocyte Culture Test, Mixed
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Receptors, Immunologic/immunology
- T-Lymphocytes, Cytotoxic/immunology
- Transplantation, Homologous
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405
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Combined anti-CD2 and anti-CD3 receptor monoclonal antibodies induce donor-specific tolerance in a cardiac transplant model. THE JOURNAL OF IMMUNOLOGY 1993. [DOI: 10.4049/jimmunol.151.12.7249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Administration of mAb against either the CD2 or CD3 receptor prolongs graft survival in CBA recipients in a heterotopic, nonvascularized cardiac transplant model, whereas the combination of mAb produces indefinite survival. Combined alpha-CD2 plus alpha-CD3 mAb synergistically prolonged allograft survival indefinitely for C57BL/6 donor hearts (> 150 vs 13.4 +/- 0.5 days for controls, p < 0.001, Wilcoxon's sign rank). All second donor-specific C57BL/6 allografts survived > 100 days (p < 0.001) without any additional immunosuppression. Third-party BALB/c allografts were rejected in a first set fashion (14.2 +/- 0.5 days). Anti-CD2 mAb of other epitopic specificities and isotypes demonstrate equivalent immunosuppressive capacity. The combination of mAb resulted in indefinite graft survival in other strain combinations. Therefore, these results are not restricted to a particular alpha-CD2 mAb or MHC combination. Combinations of alpha-CD2 plus mAb with specificities other than to CD3 did not result in tolerance, showing that the CD2-CD3 interaction was critical for tolerance induction. CTL and MLR responses from tolerant animals were normal both to H-2b and H-2d stimulators, indicating that clonal deletion of effector T cells did not occur. Adoptive transfer of naive recipient type cells broke tolerance, showing that graft adaptation was not the major determinant of tolerance maintenance. Flow cytometric analysis demonstrated that tolerance was not associated with deletion of T cells. The results imply that the mechanism of tolerance induction is related to suppression and/or anergy of helper and effector cells at the time of allografting, whereas maintenance of tolerance is associated with anergy in the Th cell compartment.
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406
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Combined anti-CD2 and anti-CD3 receptor monoclonal antibodies induce donor-specific tolerance in a cardiac transplant model. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1993; 151:7249-59. [PMID: 7903105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Administration of mAb against either the CD2 or CD3 receptor prolongs graft survival in CBA recipients in a heterotopic, nonvascularized cardiac transplant model, whereas the combination of mAb produces indefinite survival. Combined alpha-CD2 plus alpha-CD3 mAb synergistically prolonged allograft survival indefinitely for C57BL/6 donor hearts (> 150 vs 13.4 +/- 0.5 days for controls, p < 0.001, Wilcoxon's sign rank). All second donor-specific C57BL/6 allografts survived > 100 days (p < 0.001) without any additional immunosuppression. Third-party BALB/c allografts were rejected in a first set fashion (14.2 +/- 0.5 days). Anti-CD2 mAb of other epitopic specificities and isotypes demonstrate equivalent immunosuppressive capacity. The combination of mAb resulted in indefinite graft survival in other strain combinations. Therefore, these results are not restricted to a particular alpha-CD2 mAb or MHC combination. Combinations of alpha-CD2 plus mAb with specificities other than to CD3 did not result in tolerance, showing that the CD2-CD3 interaction was critical for tolerance induction. CTL and MLR responses from tolerant animals were normal both to H-2b and H-2d stimulators, indicating that clonal deletion of effector T cells did not occur. Adoptive transfer of naive recipient type cells broke tolerance, showing that graft adaptation was not the major determinant of tolerance maintenance. Flow cytometric analysis demonstrated that tolerance was not associated with deletion of T cells. The results imply that the mechanism of tolerance induction is related to suppression and/or anergy of helper and effector cells at the time of allografting, whereas maintenance of tolerance is associated with anergy in the Th cell compartment.
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MESH Headings
- Animals
- Animals, Newborn
- Antibodies, Monoclonal/pharmacology
- Antigens, Differentiation, T-Lymphocyte/immunology
- CD2 Antigens
- CD3 Complex
- Female
- Fetal Tissue Transplantation
- Graft Survival
- Heart Transplantation/immunology
- Immune Tolerance
- Lymphocyte Culture Test, Mixed
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Models, Biological
- Pregnancy
- Receptors, Immunologic/antagonists & inhibitors
- T-Lymphocytes, Cytotoxic/immunology
- Time Factors
- Transplantation, Homologous
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407
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Transient absorption spectra and photochromic mechanism of schiff bases. RESEARCH ON CHEMICAL INTERMEDIATES 1993. [DOI: 10.1163/156856793x00118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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408
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Field evaluation of bednets impregnated with deltamethrin for malaria control. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1993; 24:664-71. [PMID: 7939937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Trials were undertaken in a hypoendemic area of malaria in an area bordering Vietnam, in Napo County of Guangxi Zhuang Autonomous Region, China. The aim was to compare the relative cost effectiveness of DDT residual spraying and of bednets impregnated with deltamethrin in the malaria control program. The trials were divided into three subgroups: (1) two farming areas and one coal mining area with a total population > 20,000, where the trial consisted of mass bednets impregnated with deltamethrin 15 mg/m2 net surface once a year, (2) one farming area with a population of approximately 3,600 where DDT residual spraying at 2g/m2 was carried out twice a year in May and August; (3) one farming area and one coal mining village with a population of > 4,000 were used as a control. The malaria vector population consisted mainly of Anopheles minimus and An. anthropophagus with a small contribution from An. sinensis. After bednets were impregnated with deltamethrin the mosquitos resting on the surface of the bednets decreased significantly, although there was less effect on the total vector population. The results showed that malaria incidence decreased significantly both in areas where impregnated bednets were used and in areas where residual spraying was undertaken. The positive IFAT rates of residents who slept under impregnated bednets decreased significantly in farming areas, especially in that area where bednet impregnation as a vector control measure had been undertaken for two years, but there was no change in the IFAT rate in DDT sprayed or control areas.(ABSTRACT TRUNCATED AT 250 WORDS)
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409
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Combination anti-CD2 and anti-CD3 monoclonal antibodies induce tolerance while altering interleukin-2, interleukin-4, tumor necrosis factor, and transforming growth factor-beta production. Ann Surg 1993; 218:492-501; discussion 501-3. [PMID: 8215640 PMCID: PMC1243005 DOI: 10.1097/00000658-199310000-00009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE These studies were designed to elucidate the mechanism by which signals delivered by anti-CD2 monoclonal antibody (MoAb) interfere with activational signals delivered by anti-CD3 MoAb and induce long-term graft survival and tolerance. SUMMARY BACKGROUND DATA Anti-CD2 or anti-CD3 MoAb can prolong allograft survival when administered alone. In combination, they synergistically prolong survival while reducing anti-CD3-associated cytokine toxicity. It was postulated that the mechanism of synergism and reduced cytokine toxicity was related to anti-CD2-induced alterations in anti-CD3-induced T-cell activation. METHODS C57BL/6 (H-2b) mouse hearts were transplanted to CBA (H-2k) mice. The recipients received anti-CD2 and/or anti-CD3 MoAb intravenously only at the time of initial allografting. Serum from treated animals and culture supernatants from lymphocytes stimulated in vitro with anti-CD3 were examined for interleukin (IL)-2, -4, -6, and -10, tumor necrosis factor (TNF), and transforming growth factor-beta (TGF beta). RNA was isolated from lymphocytes from treated animals and examined for receptor and cytokine gene expression by northern hybridization or reverse transcribed and amplified by the polymerase chain reaction (PCR). RESULTS Anti-CD2 and anti-CD3 MoAbs alone prolonged graft survival (22.0 +/- 0.5 days and 28.0 +/- 0.5 days, respectively; p < 0.02 and p < 0.01 vs. control, by Wilcoxon signed-rank test). Combined anti-CD2/anti-CD3 MoAbs synergistically prolonged survival indefinitely (> 150 days, p < 0.01) while decreasing cytokine toxicity. Second donor-specific allografts also showed long-term survival. The peak serum TNF concentration (2100 units/mL) was reduced 78% by anti-CD2 treatment (455 units/mL). Anti-CD2 inhibited anti-CD3-stimulated proliferation and in vitro production of IL-2 and IL-4, with no alteration of IL-6, IL-10, or TNF. Conversely, there was an increase in the immunosuppressive cytokine TGF beta. PCR analysis showed that anti-CD2 reduced anti-CD3-stimulated IL-2 messenger RNA expression, and by northern analysis, anti-CD2 inhibited anti-CD3-stimulated increases in messenger RNA for the CD2 and CD3 receptors themselves. CONCLUSIONS The combination of anti-CD2 and anti-CD3 MoAbs induced a state of tolerance while decreasing anti-CD3-associated cytokine toxicity. The mechanism was related to anti-CD2-generated alterations in T-cell activation and gene expression.
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410
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Importance of protein rearrangement in the electron-transfer reaction between the physiological partners cytochrome f and plastocyanin. Biochemistry 1993; 32:6073-80. [PMID: 8507642 DOI: 10.1021/bi00074a019] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cytochrome f from turnip and plastocyanin from French bean were noninvasively cross-linked in the presence of the carbodiimide EDC so that the exposed heme edge in the former protein abuts the acidic patch remote from the copper site in the latter [Morand, L.Z., Frame, M.K., Colvert, K.K., Johnson, D.A., Krogmann, D.W., & Davis, D.J. (1989) Biochemistry 28, 8039]. The molecular mass, reduction potentials, and UV-visible and ESR spectra of the covalent complex were consistent with the composition cyt/pc and with a lack of noticeable structural perturbations of the protein molecules. Isoelectric focusing showed the presence of N-acylurea groups, byproducts of the cross-linking reaction [Zhou, J.S., Brothers, H.M. II, Neddersen, J.P., Peerey, L.M., Cotton, T.M., & Kostić, N.M. (1992) Bioconjugate Chem. 3, 382]. Laser flash spectroscopy, with riboflavin semiquinone as the reductant, showed that the electrontransfer reaction within the covalent complex cyt(II)/pc(II) is either undetectably slow or reversible. The question was resolved by monitoring, during redox titrations, the 1H NMR line widths of the heme methyl groups in free ferricytochrome f and in this protein cross-linked to plastocyanin.(ABSTRACT TRUNCATED AT 250 WORDS)
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411
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Anti-CD2 and anti-CD3 monoclonal antibodies synergize to prolong allograft survival with decreased side effects. Transplantation 1993; 55:901-8. [PMID: 8097344 DOI: 10.1097/00007890-199304000-00040] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Anti-CD3 monoclonal antibody suppresses immunity and prolongs allograft survival; however, it induces T cell activation and overproduction of soluble factors that result in a deleterious cytokine syndrome. Anti-CD2 mAb also prolongs allograft survival, by suppression of mature and precursor CD4 and CD8 T cells and NK cells, without an associated cytokine release. Because of the close physical and functional association of CD2 and CD3 on the T cell surface, we tested whether alpha CD2 mAb in combination with alpha CD3 mAb could act synergistically to prolong allograft survival, and whether the combination would affect the alpha CD3-associated cytokine syndrome. C57BL/6 (H-2b) hearts were transplanted to CBA (H-2k) recipients in a heterotopic nonvascularized model. Recipients received alpha CD2 (12-15) or alpha CD3 (145-2C11) mAb i.v. alone or in combination. Lymphocytes from treated animals were also analyzed by fluorescent flow cytometry and stimulated in vitro and assessed for proliferation and lymphokine production. Anti-CD2 and alpha CD3 each prolong allograft survival (mean survival time 22.4 +/- 1.0 and 27.4 +/- 3.3 days, respectively vs. 14.0 +/- 0.6 for control mAb, P < 0.001 for both vs. control). Combinations of mAbs show a more complicated interaction. Very low doses (1 microgram) of alpha CD2 and alpha CD3, which have no effect when given alone, are synergistic (16.5 +/- 1.3 days, P < 0.02). A high dose of alpha CD2 (100 micrograms), which is immunosuppressive, is additive with a moderate dose of alpha CD3 (10 micrograms), which is immunostimulatory. The two mAbs are again synergistic when a high dose of alpha CD2 (100 micrograms) is combined with a high dose of alpha CD3 (1 mg) (> 51.5 +/- 23.0 days, P < 0.001). Furthermore, high-dose alpha CD2 administered 48 h prior to high-dose alpha CD3 was a more effective combination for prolonging allograft survival than both antibodies administered simultaneously (67.1 +/- 10 vs. 35.8 +/- 0.7 days, P < 0.05). Anti-CD2 also diminishes the alpha CD3-associated cytokine syndrome, and prior in vivo treatment with alpha CD2 decreases the subsequent in vitro proliferative response to alpha CD3 and the alpha CD3-stimulated production of IL-2 and IL-4. Flow cytometry demonstrates that in general these mAbs do not deplete but leave T cell populations intact with altered receptor expression. These results show that the combination of alpha CD2 and alpha CD3 mAbs prolongs cardiac allograft survival in a synergistic fashion while decreasing the side effects of alpha CD3 mAb alone.(ABSTRACT TRUNCATED AT 400 WORDS)
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412
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[Progress in the study of protein kinase C]. SHENG LI KE XUE JIN ZHAN [PROGRESS IN PHYSIOLOGY] 1993; 24:123-6. [PMID: 8211061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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413
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Anti-CD2 monoclonal antibodies synergize with anti-CD3 to prolong allograft survival and decrease cytokine production. Transplant Proc 1993; 25:823-4. [PMID: 8094913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
MESH Headings
- Animals
- Antibodies, Monoclonal/therapeutic use
- Antigens, Differentiation, T-Lymphocyte/immunology
- Antigens, Differentiation, T-Lymphocyte/physiology
- Antigens, Surface/immunology
- CD2 Antigens
- CD3 Complex/immunology
- Cytokines/antagonists & inhibitors
- Cytokines/biosynthesis
- Drug Synergism
- Flow Cytometry
- Graft Survival/immunology
- Heart Transplantation/immunology
- Immunosuppressive Agents/therapeutic use
- Lymphocyte Activation
- Lymphocytes/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Receptors, Immunologic/immunology
- Receptors, Immunologic/physiology
- Transplantation, Homologous
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414
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Electron-transfer reactions of cytochrome f with flavin semiquinones and with plastocyanin. Importance of protein-protein electrostatic interactions and of donor-acceptor coupling. Biochemistry 1992; 31:5145-50. [PMID: 1606137 DOI: 10.1021/bi00137a008] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Reduction of turnip ferricytochrome f by flavin semiquinones and oxidation of this ferrocytochrome f by French bean cupriplastocyanin are studied by laser flash photolysis over a wide range of ionic strengths. Second-order rate constants (+/- 15%) at extreme values of ionic strength, all at pH 7.0 and 22 degrees C, are as follows: with FMN semiquinone at 1.00 and 0.0040 M, 5.0 x 10(7) and 3.9 x 10(8) M-1 s-1; with riboflavin semiquinone at 1.00 and 0.0040 m, 1.7 x 10(8) and 1.9 x 10(8) M-1 s-1; with lumiflavin semiquinone at 1.00 and 0.0045 M, 1.8 x 10(8) and 4.5 x 10(8) M-1 s-1; with cupriplastocyanin at 1.00 and 0.100 M, 1.4 x 10(6) and 2.0 x 10(8) M-1 s-1. These reactions of cytochrome f are governed by the local positive charge of the interaction domain (the exposed heme edge), not by the overall negative charge of the protein. Lumiflavin semiquinone behaves as if it carried a small negative charge, probably because partial localization of the odd electron gives this electroneutral molecule some polarity; local charge seems to be more important than overall charge even for relatively small redox agents. The dependence of the rate constants on ionic strength was fitted to the equation of Watkins; this model recognizes the importance of local charges of the domains through which redox partners interact. There is kinetic evidence that a noncovalent complex between cytochrome f and plastocyanin exists at low ionic strength.(ABSTRACT TRUNCATED AT 250 WORDS)
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415
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Abstract
Murine T cells synthesize and express a cell-surface glycophospholipid anchored 40 kDa and a secreted water-soluble 39 kDa Qa-2 polypeptide. We have examined the biosynthetic pathways which lead to the production of the membrane-bound and water-soluble isoforms of the Qa-2 molecule. Using the detergent TX-114, both detergent (membrane)-bound and soluble Qa-2 polypeptides can be identified in cell lysates and can be distinguished by charge and molecular weight. Two membrane-bound forms, a 40-kDa Endo H resistant cell-surface form and a 38 kDa-Endo H sensitive form can be identified, both of which can be biosynthetically labeled with 3H-ethanolamine and can be converted to water soluble forms by digestion with a phosphatidylinositol specific phospholipase C. In addition, several water soluble polypeptides at 39, 37, 35 kDa, and a minor species at 33 kDa were identified, none of which radiolabel with 3H-ethanolamine. While the 39-kDa polypeptide was Endo H resistant, the other isoforms were sensitive to Endo H digestion. Pulse chase experiments and molecular weights of the deglycosylated core polypeptides suggest a precursor to product relationship between the intracellular water-soluble species and the mature 39-kDa secreted Qa-2 molecule. This relationship is supported by the observation that murine L cells transfected with the Qa-2 encoding class I gene Q7 fail to express membrane-bound Qa-2 molecules yet synthesize both intracellular water-soluble and secreted Qa-2 molecules. These findings argue for a pathway in which secreted soluble Qa-2 molecules are derived from intracellular precursors.
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416
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Electron-transfer reactions involving diprotein complexes of cytochromes and plastocyanin. J Inorg Biochem 1991. [DOI: 10.1016/0162-0134(91)84089-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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417
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[Isolation and identification of aloesin from the leaves of Aloe vera L. var, chinensis (Haw.) Berger]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1991; 16:292-3, 319. [PMID: 1781897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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418
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[Chemical constituents of Alyxia levinei Merr]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1991; 16:229-30, 255. [PMID: 1863334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Three compounds were isolated from the stem and leaves of Alyxia levinei. On the basis of spectrometric analysis and physico-chemical constants they were identified as oleanolic acid, betulin and beta-sitosterol-D-glucoside respectively.
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419
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[Psychologic analysis and nursing care of aged patients treated by counterpulsation]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1991; 26:81-2. [PMID: 1998980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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420
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[Analgesic and anti-inflammatory effects and toxicity of houjianxi]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1990; 15:235-8, 256. [PMID: 2206377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It is effective for acute and chronic laryngopharyngitis clinically. Houjianxi can raise the pain thresholds during hot-plate test in mice, tail flick test in rats, and writhing test in mice with single dose ig 0.125 to 2.0 g/kg. Houjianxi can also inhibit the swelling of hind paw induced by sc 1% carrageenin 0.1 ml in rats as well as the increased vascular permeability induced by ip 0.7% HAC in mice. Toxic side effects were not observed for Houjianxi ig 48 g/kg x 3 within a day in mice and 1.8 g/kg daily for 90 d in rats.
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421
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[Protective effect of extracts from Aloe vera L. var. chinensis (Haw.) Berg. on experimental hepatic lesions and a primary clinical study on the injection of in patients with hepatitis]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1989; 14:746-8. [PMID: 2635602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The injection(10-15 ml/kg/d, ip x 4), total glycoside (125-225 mg/kg/d, ip x (3-4); 600 mg/kg/d, ig x 3) and crystal III (120 mg/kg/d, ip x 4) of Aloe vera var. chinensis were found to be effective in lowering the elevated sGPT induced by CCl4, thioacetamide and D-aminogalactose in mice or rats. It was also observed that these agents could protect hepatic cells from the CCl4-induced injury. When dogs were given in with Aloe injection of 0.1 ml/kg/d x 180, no toxicity was noted. The total effective sGPT-lowering rate of Aloe injection on 38 patients of chronic hepatitis with positive HBsAg was 86.8%.
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422
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Pharmacologic effects of codonopsis pilosula-astragalus injection in the treatment of CHD patients. J TRADIT CHIN MED 1988; 8:1-8. [PMID: 3393012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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