The pyrogenic (erythrogenic) exotoxins A and C (SPEA and SPEC) of Streptococcus pyogenes belong t... more The pyrogenic (erythrogenic) exotoxins A and C (SPEA and SPEC) of Streptococcus pyogenes belong to the family of mitogenic toxins of which the staphylococcal enterotoxins are the prototypes. The erythrogenic toxin B (SPEB) is a proteinase precursor. All SPE have been reported to be superantigens. Here we have analyzed the human T cell response to these toxins. We used highly purified preparations of SPEA, SPEB, and SPEC from different S. pyogenes strains. These toxins were apparently homogenous in SDS-PAGE, IEF, and HPLC. In addition, recombinant SPEA and SPEC were produced in Escherichia coli. In cultures of PBMC, all three toxins expanded preferentially a fraction of T cells. Using mAb against Vp2,-5,-6,-8, and-1 2, we investigated the phenotype of the stimulated cells. Natural SPEA, SPEB, and SPEC strongly stimulated Vp8+ T cells, whereas recombinant SPEA and SPEC did not. Both natural and recombinant SPEA stimulated Vpl 2+ cells and both natural and recombinant SPEC stimulated Vp2+ cells. In accordance with these findings, a human Vp8+ line responded to all three toxins derived from S. pyogenes but not to the recombinant proteins. An antiserum against natural SPEC neutralized specifically the Vp2-stimulating activity of SPEC and the Vp8-stimulating activity of all three toxins, but had no effect on the response to other superantigens. This shows that trace amounts of a potent novel Vp8-stimulating activity not identical to SPEA and SPEC are responsible for the stimulation of Vp8+ T cells by natural SPEA and SPEC reported previously. In a preliminary screening of S. pyogenes strains from patients, we found that this novel superantigen appears to be more widely distributed than SPEA and SPEC. Furthermore, we present evidence that also the superantigenic properties of SPEB are due to contaminations with this V , 8 stimulator. The response to SPEB usually required 1000 times higher concentrations than to SPEA or SPEC. Antisera to SPEC but not to SPEB inhibited the response of PBMC and Vp8+ Jurkat cells to SPEB. Furthermore, more stringent purification of SPEB yielded SPEB preparations devoid of mitogenic activity. These results indicate that the mitogenicity that is commonly attributed to SPEB is due to minute contaminations of the Vp8 stimulator. These results raise two important caveats for the work with these highly potent T cell mitogens. 1) The mitogenicity of other streptococcal or staphylococcal proteins could be due to similar minute contaminations with potent superantigens that are undetectable by any biochemical method but extremely effective in stimulating sensitive T cells. 2) The reported Vp-specificity of many superantigens has to be carefully re-evaluated using well characterized or recombinant superantigen preparations. journal of
Attitudes of medical students, housestaff, and faculty physicians towards euthanasia and terminat... more Attitudes of medical students, housestaff, and faculty physicians towards euthanasia and termination of lifesustaining treatment. Crit Care Med 1992; 20: 683-90. 19 Nightingale SD, Grant M. Risk preference and decision making in critical care situations. Chest 1988; 93: 684-87. 20 Von-Preyss-Friedman SM, Uhlmann RF, Cain KC. Physicians' attitudes toward tube feeding chronically ill nursing home patients. J Gen Intern Med 1992; 7: 46-51. 21 Charlson ME, Sax FL, MacKenzie R, Fields AD, Braham RL, Douglas G. Resuscitation: how do we decide? A prospective study of physicians' preferences and the clinical course of hospitalized patients.
Synovial fluids of patients with rheumatoid arthritis, osteoarthritis, psoriatic arthritis, react... more Synovial fluids of patients with rheumatoid arthritis, osteoarthritis, psoriatic arthritis, reactive arthritis and Reiter's syndrome were examined for their concentrations of interleukin 6 (IL-6) in a proliferation assay with the IL-6 dependent hybridoma cell line B13.29 (subclone B9). IL-6 activity was significantly higher in the synovial fluids of patients with rheumatoid arthritis and psoriatic arthritis than in patients with osteoarthritis. Significant correlations were shown between the concentrations of synovial fluid IL-6 and IgG. These findings may contribute to the understanding of the enhanced immunoglobulin production by synovial mononuclear cells in patients with inflammatory joint disease.
The murine transmembrane glycoprotein CD83 is an important regulator for both thymic T cell matur... more The murine transmembrane glycoprotein CD83 is an important regulator for both thymic T cell maturation and peripheral T cell responses. Recently, we reported that CD83 also has a function on B cells: Ubiquitous transgenic (Tg) expression of CD83 interfered with the immunoglobulin (Ig) response to infectious agents and to T cell dependent as well as T cell independent model antigen immunization. Here we compare the function of CD83Tg B cells that overexpress CD83 and CD83 mutant (CD83mu) B cells that display a drastically reduced CD83 expression. Correlating with CD83 expression, the basic as well as the lipopolysaccharide (LPS) induced expression of the activation markers CD86 and MHC-II are significantly increased in CD83Tg B cells and reciprocally decreased in CD83mu B cells. Wild-type B cells rapidly upregulate CD83 within three hours post BCR or TLR engagement by de novo protein synthesis. The forced premature overexpression of CD83 on the CD83Tg B cells results in reduced calcium signaling, reduced Ig secretion and a reciprocally increased IL-10 production upon in vitro activation. This altered phenotype is mediated by CD83 expressed on the B cells themselves, since it is observed in the absence of accessory cells. In line with this finding, purified CD83mu B cells displayed a reduced IL-10 production and slightly increased Ig secretion upon LPS stimulation in vitro. Taken together, our data strongly suggest that CD83 is expressed by B cells upon activation and contributes to the regulation of B cell function.
A: Development of T Lymphocytes in the Thymus.- Introductory Remarks.- Development of T Lymphocyt... more A: Development of T Lymphocytes in the Thymus.- Introductory Remarks.- Development of T Lymphocytes Within the Thymus and Within Thymic Nurse Cells. With 3 Figures.- Thymus Development.- Major Histocompatibility-Restricted Cytolytic T-Lymphocyte Precursors from the Thymus of In Vivo Primed Mice: Increased Frequency and Resistance to Anti-Lyt-2 Antibody Inhibition. With 1 Figure.- Thymic Stem Cells: Their Interaction with the Thymic Stroma and Tolerance Induction.- B: Murine T-Cell Receptor Genes.- Organization, Rearrangement, and Diversification of Mouse T-Cell Receptor Genes. With 1 Figure.- Expression of T-Cell Receptor by a Mouse Monoclonal Antigen-Specific Suppressor T-Cell Line.- Somatic Variation of Antigen-Recognition Specificity in H-2b-TNP-Specific Cytotoxic T-Cell Clones.- The Change of Specificity, Karyotype, and Antigen-Receptor Gene Expression is Correlated in Cytotoxic T-Cell Lines.- C: Phenotype and Functional Potential of T-Cell Clones.- Introductory Remarks.- A Study of the Functional Potential of Mouse T-Cell Clones.- Generation, Propagation, and Variation in Cloned, Antigen-Specific, Ia-Restricted Cytolytic T-Cell Lines.- Significance of T4 or T8 Phenotype of Human Cytotoxic T-Lymphocyte Clones. With 1 Figure.- Natural and Unnatural Killing by Cytolytic T Lymphocytes. With 2 Figures.- Acquisition of Suppressive and Natural Killer-Like Activities Associated with Loss of Alloreactivity in Human "Helper" T-Lymphocyte Clones. With 3 Figures.- Expression and Function of Class II I-Ak Antigens on an Antigen-Specific T-Suppressor Cell Clone. With 2 Figures.- D: Signal Requirements for T-Cell Activation.- Introductory Remarks.- Heterogeneity of the Signal Requirements During the Primary Activation of Resting Lyt-2+ Cytotoxic T-Lymphocyte (CTL) Precursors into Clonally Developing CTL. With 2 Figures.- Regulation of Lytic Function by Recombinant IL2 and Antigen. With 4 Figures.- The Target Structure for T11: A Cell Interaction Molecule Involved in T-Cell Activation? With 3 Figures.- Antigen- and Lectin- Sensitized Murine Cytolytic T Lymphocyte- Precursors Require Both Interleukin 2 and Endogenously Produced Immune (?) Interferon for Their Growth and Differentiation. With 3 Figures.- Activation Requirements for Resting T Lymphocytes.- E: Self-Nonself Discrimination in the T-Cell Compartment.- Introductory Remarks.- Functional Clonal Deletion and Suppression as Complementary Mechanisms in T Lymphocyte Tolerance.- Human T Cell Clones, Tolerance, and the Analysis of Autoimmunity. With 1 Figure.- Antiself Suppressive (Veto) Activity of Responder Cells in Mixed Lymphocyte Cultures. With 6 Figures.- Analysis of T Suppressor Cell Mediated Tumor Escape Mechanisms. With 2 Figures.- The T-Cell Receptor Recognizes Nominal and Self Antigen Independently. A Theoretical Alternative to the Modified Self Concept. With 3 Figures.- F: T-Cell-Mediated Autoreactivity.- Introductory Remarks.- T-Cell Reactivity to Polymorphic MHC Determinants. I. MHC-Guided T-Cell Reactivity.- T-Cell Reactivity to Polymorphic MHC Determinants. II. Self-Reactive and Self-Restricted T Cells. With 6 Figures.- T-Cell Reactivity to Polymorphic MHC Determinants. III. Alloreactive and Allorestricted T Cells. With 9 Figures.- Appearance of New Specificities in Lectin-Induced T-Cell Clones Obtained from Limiting Dilution T-Cell Cultures. With 2 Figures.- Syngeneic Cytotoxicity and Veto Activity in Thymic Lymphoid Colonies and Their Expanded Progeny. With 4 Figures.- Functional Analysis of a Self-I-A Reactive T-Cell Clone Which Preferentially Stimulates Activated B Cells.- Indexed in Current Contents.
... 1). (Published with permission from Biochem. J. 239, p. 764 ~ 1986 The Biochemical Society, L... more ... 1). (Published with permission from Biochem. J. 239, p. 764 ~ 1986 The Biochemical Society, London.) References Edith Sire 1 sire, E. and Cross, 53 (1986) 8iochem. ... (1987)Nature 328, 626-629 23 Fazekas de St Groth, B., Gallagher, PF and Miller, JFAP (1986) Proc. ...
Antigen recognition by T lymphocytes initiates a series of events that ultimately lead to express... more Antigen recognition by T lymphocytes initiates a series of events that ultimately lead to expression of functional activities, e.g., lymphokine secretion in helper T cells or delivery of the lethal hit in CTL. The earliest changes detectable after TCR triggering are a rise in the concentration ofpolyphosphoinositide breakdown products, inositoltrisphosphate (IP3) and diacylglycerol (DAG) (1). IP3 appears to cause a rise in cytosolic Ca 2+ concentration by release of Cat + from intracellular stores (2), and DAG is an activator of PKC (3). These consequences ofantigen recognition can be artificially induced by mAbs against the TCR or against the TCRassociated CD3 molecules. In addition, mAbs directed to other surface molecules that define "alternative" activation pathways such as CD2 (4) induce the same events (5). The interaction ofmAbs with most ofthese molecules leads to their transient removal from the cell surface, a process termed modulation. Modulation of CD2 (6) or Tp44 (7, 8) leads to unresponsiveness to the respective mAb but has no influence on other pathways. In contrast, modulation of the TCR/CD3 complex that is also a consequence of antigen-specific triggering results in a transient state of refractoriness to any signal given via a surface molecule (6, 8). The mechanism leading to this general unresponsiveness is not known. Recently it has been shown that in TCR/CD3modulated Jurkat leukemia cells the early metabolic steps, i.e., formation of IP3 and increase in Ca 2+ concentration do not take place (9). In this report, we demonstrate that a TCRassociated GTP-binding protein is functionally inactivated by TCR modulation. Volume 168 August 1988 817-822 Materials and Methods Brief Definitive Report Cells. Human CD8+ CTL clones or lines were obtained as described (10) and propagated in growth medium consisting of RPMI-1640 with 5% AB serum and 20 U/ml rIL-2. Reagents. All chemicals were obtained from Sigma Chemical Co., Munich, FRG. Anti-CD3 or anti-CD8 mAbs were purified from the supernatant of OKT3 or OKT8 hybridoma cell lines. The anti-CD8 mAb BMA081 (IgG2a) and the anti-CD3 mAb BMA030 (IgG2a) were a gift from Dr. R. Kurrle, Behring Werke AG, Marburg. Purified goat anti-mouse IgG antibodies were obtained from Tago Inc ., Burlingame, CA. a toxin from Staphylococcus aureus
Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Sahara... more Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Saharan Africa. In Madagascar, the endemicity of tick-borne rickettsiae and their vectors has been incompletely studied. The first part of the present study was conducted in 2011 and 2012 to identify potential anthropophilic tick vectors for SFG rickettsiae on cattle from seven Malagasy regions, and to detect and characterize rickettsiae in these ticks. Amblyomma variegatum was the only anthropophilic tick species found on 262 cattle. Using a novel ompB-specific qPCR, screening for rickettsial DNA was performed on 111 A. variegatum ticks. Rickettsial DNA was detected in 96 of 111 ticks studied (86.5%). Rickettsia africae was identified as the only infecting rickettsia using phylogenetic analysis of ompA and ompB gene sequences and three variable intergenic spacers from 11 ticks. The second part of the study was a cross-sectional survey for antibodies against SFG rickettsiae in plasma samples taken from healthy, pregnant women at six locations in Madagascar, two at sea level and four between 450 and 1300 m altitude. An indirect fluorescent antibody test with Rickettsia conorii as surrogate SFG rickettsial antigen was used. We found R. conorii-seropositives at all altitudes with prevalences between 0.5% and 3.1%. Our results suggest that A. variegatum ticks highly infected with R. africae are the most prevalent cattle-associated tick vectors for SFG rickettsiosis in Madagascar. Transmission of SFG rickettsiosis to humans occurs at different altitudes in Madagascar and should be considered as a relevant cause of febrile diseases.
This study addresses the role of a bacterial superantigen as a potential virulence factor during ... more This study addresses the role of a bacterial superantigen as a potential virulence factor during an acute systemic infection. BALB/c mice were intravenously infected with a recombinant Staphylococcus aureus strain capable of producing plasmid-encoded staphylococcal enterotoxin B (SEB) or with the SEB plasmid-deficient parental strain. Infection with SEB-producing bacteria resulted in an initial expansion and subsequent decrease of circulating V beta 8+ T lymphocytes. This numeric decrease was accompanied by a SEB-specific state of hyporesponsiveness of splenic T cells. In parallel with SEB-triggered unresponsiveness of a large proportion of T lymphocytes, a weakening of the overall T cell responsiveness towards the invading bacteria was found. Furthermore, the production of SEB altered the kinetics of bacterial clearance: Animals infected with the SEB-producing variant showed a significantly elevated bacterial burden and could less efficiently clear the bacteria. However, the overall effect of SEB production on the course of bacterial infection was surprisingly weak, suggesting that the superantigen was only a minor virulence factor for the bacterium.
Predominance of Thl-type T cells in synovial fluid of patients with Yersinia-induced reactive art... more Predominance of Thl-type T cells in synovial fluid of patients with Yersinia-induced reactive arthritis* The pathogenetic mechanisms underlying the development of reactive arthritis and the functional capacities of synovial T cells specific for Yersinia enterocolitica are still unclear. In this study we have determined the cytokine secretion patterns of 24 CD4+ synovial fluid (SF)-derived Tcell clones from 2 patients with Yersinia-induced reactive arthritis, 16 clones specific for different Yersinia antigens and 8 clones as controls. The clones specific for Yersinia antigens predominantly belong to the T helper cell 1 (Thl) subset with production of interferon (1FN)-y and interleukin (1L)-2, but no IL-4, whereas SF T cells not reactive withyersinia antigens produce IL-2, IL-4 and IFN-y and thus belonged to the Tho subset. Moreover, short-term Tcell lincs established from SF and peripheral blood showed the same pattern. To further analyze the functional relevance of these data we investigated the influence of IFN-y and IL-4 on the intracellular killing of Yersinia in a human glioblastoma cell line. Our data show that theTh1 cytokine IFNy promotes intracellular killing of Yersinia,whereas this effect is antagonized by the Th2 cytokine IL-4. Furthermore, the Th2 cytokine IL-10 inhibited the antigen-specific proliferative response and IFN-y and IL-2 production by the T h l cells. These results provide insight into the antibacterial mechanisms at work in reactive arthritis after infection with Yersinia enterocolitica and, for the first time, reveal the cross-regulatory properties of cytokines derived from Thl and Th2 cells in a human immune response to bacterial antigens.
The idiopathic hypereosinophilic syndrome (HES) comprises a heterogeneous group of disorders with... more The idiopathic hypereosinophilic syndrome (HES) comprises a heterogeneous group of disorders with unknown pathogenesis characterized by persistent peripheral blood and bone marrow eosinophilia and eosinophilic infiltrates of multiple organs leading to severe organ dysfunction. In the present study, T lymphocyte clones were randomly established from the blood of a patient with HES and propagated in culture with mitogen and interleukin 2. Whereas 28 of 29 clones were able to stimulate myeloid colony formation when co-cultured with normal bone marrow cells in a double-layer micro-agar culture system, one third of these clones preferentially stimulated pure eosinophil colonies (up to 98% of all colonies). This pattern differed markedly (p less than 0.001) from the pattern of release of hemopoietic factors by 126 T cell clones established from four other individuals. Eosinophil colony stimulation was due to the release of a lineage-specific eosinophilic colony-stimulating factor (Eo-CSF) by these clones after appropriate stimulation. Production of Eo-CSF in vitro was inhibited by hydrocortisone or cyclosporin A. All Eo-CSF-producing clones had the T4+8-phenotype and were capable of producing in addition interleukin 2 and interferon-gamma. Southern blot analysis of the T cell receptor beta-chain rearrangement of the Eo-CSF-producing clones showed a different rearrangement pattern for each clone. These studies suggest a reactive T cell-mediated eosinophilia as the pathogenetic mechanism in this case of HES and, for the first time, point to a biologic relevance of a lymphokine-induced stimulation of hemopoiesis.
Herpes virus saimiri (HVS) immortalizes T lymphocytes from a variety of primates and causes acute... more Herpes virus saimiri (HVS) immortalizes T lymphocytes from a variety of primates and causes acute T cell lymphomas and leukemias in nonnatural primate hosts. Here we have analyzed the requirements for growth of three HVS-transformed human T cell lines. The cells expressed the phenotype of activated T cells: two were CD4 + , and one was CD8 +. All three cells responded to all allogeneic human cell lines tested with enhanced proliferation, production of interleukin 2 (Ib2), and increased expression of the I1:2 receptor. Binding of CD2 to its ligand CD58 was the critical event mediating stimulation because: (a) monoclonal antibodies (mAbs) to CD2 and to CD58, but not to a variety of other surface structures, blocked induced and spontaneous proliferation and Ib2 production; (b) only anti-CD2 mAbs were stimulatory if crosslinked; (c) a nonstimulatory cell was rendered stimulatory by CD58 transfection; and (d) the cells responded specifically to CD58 on sheep red blood cells. Growth of the cells required activation because cyclosporin A and FK506 blocked stimulator cell-induced II:2 production and proliferation as well as the spontaneous growth of the lines. Antibodies to the I1:2 receptor reduced proliferation of the cells and blocked 11:2 utilization. Taken together, these results show that HVS-transformed T cells proliferate in response to CD2-mediated contact with stimulator cells or with each other in an I1:2-dependent fashion. They suggest that HVS transforms human T cells to an activationdependent autocrine growth.
analysis and cytokine release of liverinfiltrating and peripheral blood T lymphocytes from patien... more analysis and cytokine release of liverinfiltrating and peripheral blood T lymphocytes from patients with chronic hepatitis of different etiology.
The pyrogenic (erythrogenic) exotoxins A and C (SPEA and SPEC) of Streptococcus pyogenes belong t... more The pyrogenic (erythrogenic) exotoxins A and C (SPEA and SPEC) of Streptococcus pyogenes belong to the family of mitogenic toxins of which the staphylococcal enterotoxins are the prototypes. The erythrogenic toxin B (SPEB) is a proteinase precursor. All SPE have been reported to be superantigens. Here we have analyzed the human T cell response to these toxins. We used highly purified preparations of SPEA, SPEB, and SPEC from different S. pyogenes strains. These toxins were apparently homogenous in SDS-PAGE, IEF, and HPLC. In addition, recombinant SPEA and SPEC were produced in Escherichia coli. In cultures of PBMC, all three toxins expanded preferentially a fraction of T cells. Using mAb against Vp2,-5,-6,-8, and-1 2, we investigated the phenotype of the stimulated cells. Natural SPEA, SPEB, and SPEC strongly stimulated Vp8+ T cells, whereas recombinant SPEA and SPEC did not. Both natural and recombinant SPEA stimulated Vpl 2+ cells and both natural and recombinant SPEC stimulated Vp2+ cells. In accordance with these findings, a human Vp8+ line responded to all three toxins derived from S. pyogenes but not to the recombinant proteins. An antiserum against natural SPEC neutralized specifically the Vp2-stimulating activity of SPEC and the Vp8-stimulating activity of all three toxins, but had no effect on the response to other superantigens. This shows that trace amounts of a potent novel Vp8-stimulating activity not identical to SPEA and SPEC are responsible for the stimulation of Vp8+ T cells by natural SPEA and SPEC reported previously. In a preliminary screening of S. pyogenes strains from patients, we found that this novel superantigen appears to be more widely distributed than SPEA and SPEC. Furthermore, we present evidence that also the superantigenic properties of SPEB are due to contaminations with this V , 8 stimulator. The response to SPEB usually required 1000 times higher concentrations than to SPEA or SPEC. Antisera to SPEC but not to SPEB inhibited the response of PBMC and Vp8+ Jurkat cells to SPEB. Furthermore, more stringent purification of SPEB yielded SPEB preparations devoid of mitogenic activity. These results indicate that the mitogenicity that is commonly attributed to SPEB is due to minute contaminations of the Vp8 stimulator. These results raise two important caveats for the work with these highly potent T cell mitogens. 1) The mitogenicity of other streptococcal or staphylococcal proteins could be due to similar minute contaminations with potent superantigens that are undetectable by any biochemical method but extremely effective in stimulating sensitive T cells. 2) The reported Vp-specificity of many superantigens has to be carefully re-evaluated using well characterized or recombinant superantigen preparations. journal of
Attitudes of medical students, housestaff, and faculty physicians towards euthanasia and terminat... more Attitudes of medical students, housestaff, and faculty physicians towards euthanasia and termination of lifesustaining treatment. Crit Care Med 1992; 20: 683-90. 19 Nightingale SD, Grant M. Risk preference and decision making in critical care situations. Chest 1988; 93: 684-87. 20 Von-Preyss-Friedman SM, Uhlmann RF, Cain KC. Physicians' attitudes toward tube feeding chronically ill nursing home patients. J Gen Intern Med 1992; 7: 46-51. 21 Charlson ME, Sax FL, MacKenzie R, Fields AD, Braham RL, Douglas G. Resuscitation: how do we decide? A prospective study of physicians' preferences and the clinical course of hospitalized patients.
Synovial fluids of patients with rheumatoid arthritis, osteoarthritis, psoriatic arthritis, react... more Synovial fluids of patients with rheumatoid arthritis, osteoarthritis, psoriatic arthritis, reactive arthritis and Reiter's syndrome were examined for their concentrations of interleukin 6 (IL-6) in a proliferation assay with the IL-6 dependent hybridoma cell line B13.29 (subclone B9). IL-6 activity was significantly higher in the synovial fluids of patients with rheumatoid arthritis and psoriatic arthritis than in patients with osteoarthritis. Significant correlations were shown between the concentrations of synovial fluid IL-6 and IgG. These findings may contribute to the understanding of the enhanced immunoglobulin production by synovial mononuclear cells in patients with inflammatory joint disease.
The murine transmembrane glycoprotein CD83 is an important regulator for both thymic T cell matur... more The murine transmembrane glycoprotein CD83 is an important regulator for both thymic T cell maturation and peripheral T cell responses. Recently, we reported that CD83 also has a function on B cells: Ubiquitous transgenic (Tg) expression of CD83 interfered with the immunoglobulin (Ig) response to infectious agents and to T cell dependent as well as T cell independent model antigen immunization. Here we compare the function of CD83Tg B cells that overexpress CD83 and CD83 mutant (CD83mu) B cells that display a drastically reduced CD83 expression. Correlating with CD83 expression, the basic as well as the lipopolysaccharide (LPS) induced expression of the activation markers CD86 and MHC-II are significantly increased in CD83Tg B cells and reciprocally decreased in CD83mu B cells. Wild-type B cells rapidly upregulate CD83 within three hours post BCR or TLR engagement by de novo protein synthesis. The forced premature overexpression of CD83 on the CD83Tg B cells results in reduced calcium signaling, reduced Ig secretion and a reciprocally increased IL-10 production upon in vitro activation. This altered phenotype is mediated by CD83 expressed on the B cells themselves, since it is observed in the absence of accessory cells. In line with this finding, purified CD83mu B cells displayed a reduced IL-10 production and slightly increased Ig secretion upon LPS stimulation in vitro. Taken together, our data strongly suggest that CD83 is expressed by B cells upon activation and contributes to the regulation of B cell function.
A: Development of T Lymphocytes in the Thymus.- Introductory Remarks.- Development of T Lymphocyt... more A: Development of T Lymphocytes in the Thymus.- Introductory Remarks.- Development of T Lymphocytes Within the Thymus and Within Thymic Nurse Cells. With 3 Figures.- Thymus Development.- Major Histocompatibility-Restricted Cytolytic T-Lymphocyte Precursors from the Thymus of In Vivo Primed Mice: Increased Frequency and Resistance to Anti-Lyt-2 Antibody Inhibition. With 1 Figure.- Thymic Stem Cells: Their Interaction with the Thymic Stroma and Tolerance Induction.- B: Murine T-Cell Receptor Genes.- Organization, Rearrangement, and Diversification of Mouse T-Cell Receptor Genes. With 1 Figure.- Expression of T-Cell Receptor by a Mouse Monoclonal Antigen-Specific Suppressor T-Cell Line.- Somatic Variation of Antigen-Recognition Specificity in H-2b-TNP-Specific Cytotoxic T-Cell Clones.- The Change of Specificity, Karyotype, and Antigen-Receptor Gene Expression is Correlated in Cytotoxic T-Cell Lines.- C: Phenotype and Functional Potential of T-Cell Clones.- Introductory Remarks.- A Study of the Functional Potential of Mouse T-Cell Clones.- Generation, Propagation, and Variation in Cloned, Antigen-Specific, Ia-Restricted Cytolytic T-Cell Lines.- Significance of T4 or T8 Phenotype of Human Cytotoxic T-Lymphocyte Clones. With 1 Figure.- Natural and Unnatural Killing by Cytolytic T Lymphocytes. With 2 Figures.- Acquisition of Suppressive and Natural Killer-Like Activities Associated with Loss of Alloreactivity in Human "Helper" T-Lymphocyte Clones. With 3 Figures.- Expression and Function of Class II I-Ak Antigens on an Antigen-Specific T-Suppressor Cell Clone. With 2 Figures.- D: Signal Requirements for T-Cell Activation.- Introductory Remarks.- Heterogeneity of the Signal Requirements During the Primary Activation of Resting Lyt-2+ Cytotoxic T-Lymphocyte (CTL) Precursors into Clonally Developing CTL. With 2 Figures.- Regulation of Lytic Function by Recombinant IL2 and Antigen. With 4 Figures.- The Target Structure for T11: A Cell Interaction Molecule Involved in T-Cell Activation? With 3 Figures.- Antigen- and Lectin- Sensitized Murine Cytolytic T Lymphocyte- Precursors Require Both Interleukin 2 and Endogenously Produced Immune (?) Interferon for Their Growth and Differentiation. With 3 Figures.- Activation Requirements for Resting T Lymphocytes.- E: Self-Nonself Discrimination in the T-Cell Compartment.- Introductory Remarks.- Functional Clonal Deletion and Suppression as Complementary Mechanisms in T Lymphocyte Tolerance.- Human T Cell Clones, Tolerance, and the Analysis of Autoimmunity. With 1 Figure.- Antiself Suppressive (Veto) Activity of Responder Cells in Mixed Lymphocyte Cultures. With 6 Figures.- Analysis of T Suppressor Cell Mediated Tumor Escape Mechanisms. With 2 Figures.- The T-Cell Receptor Recognizes Nominal and Self Antigen Independently. A Theoretical Alternative to the Modified Self Concept. With 3 Figures.- F: T-Cell-Mediated Autoreactivity.- Introductory Remarks.- T-Cell Reactivity to Polymorphic MHC Determinants. I. MHC-Guided T-Cell Reactivity.- T-Cell Reactivity to Polymorphic MHC Determinants. II. Self-Reactive and Self-Restricted T Cells. With 6 Figures.- T-Cell Reactivity to Polymorphic MHC Determinants. III. Alloreactive and Allorestricted T Cells. With 9 Figures.- Appearance of New Specificities in Lectin-Induced T-Cell Clones Obtained from Limiting Dilution T-Cell Cultures. With 2 Figures.- Syngeneic Cytotoxicity and Veto Activity in Thymic Lymphoid Colonies and Their Expanded Progeny. With 4 Figures.- Functional Analysis of a Self-I-A Reactive T-Cell Clone Which Preferentially Stimulates Activated B Cells.- Indexed in Current Contents.
... 1). (Published with permission from Biochem. J. 239, p. 764 ~ 1986 The Biochemical Society, L... more ... 1). (Published with permission from Biochem. J. 239, p. 764 ~ 1986 The Biochemical Society, London.) References Edith Sire 1 sire, E. and Cross, 53 (1986) 8iochem. ... (1987)Nature 328, 626-629 23 Fazekas de St Groth, B., Gallagher, PF and Miller, JFAP (1986) Proc. ...
Antigen recognition by T lymphocytes initiates a series of events that ultimately lead to express... more Antigen recognition by T lymphocytes initiates a series of events that ultimately lead to expression of functional activities, e.g., lymphokine secretion in helper T cells or delivery of the lethal hit in CTL. The earliest changes detectable after TCR triggering are a rise in the concentration ofpolyphosphoinositide breakdown products, inositoltrisphosphate (IP3) and diacylglycerol (DAG) (1). IP3 appears to cause a rise in cytosolic Ca 2+ concentration by release of Cat + from intracellular stores (2), and DAG is an activator of PKC (3). These consequences ofantigen recognition can be artificially induced by mAbs against the TCR or against the TCRassociated CD3 molecules. In addition, mAbs directed to other surface molecules that define "alternative" activation pathways such as CD2 (4) induce the same events (5). The interaction ofmAbs with most ofthese molecules leads to their transient removal from the cell surface, a process termed modulation. Modulation of CD2 (6) or Tp44 (7, 8) leads to unresponsiveness to the respective mAb but has no influence on other pathways. In contrast, modulation of the TCR/CD3 complex that is also a consequence of antigen-specific triggering results in a transient state of refractoriness to any signal given via a surface molecule (6, 8). The mechanism leading to this general unresponsiveness is not known. Recently it has been shown that in TCR/CD3modulated Jurkat leukemia cells the early metabolic steps, i.e., formation of IP3 and increase in Ca 2+ concentration do not take place (9). In this report, we demonstrate that a TCRassociated GTP-binding protein is functionally inactivated by TCR modulation. Volume 168 August 1988 817-822 Materials and Methods Brief Definitive Report Cells. Human CD8+ CTL clones or lines were obtained as described (10) and propagated in growth medium consisting of RPMI-1640 with 5% AB serum and 20 U/ml rIL-2. Reagents. All chemicals were obtained from Sigma Chemical Co., Munich, FRG. Anti-CD3 or anti-CD8 mAbs were purified from the supernatant of OKT3 or OKT8 hybridoma cell lines. The anti-CD8 mAb BMA081 (IgG2a) and the anti-CD3 mAb BMA030 (IgG2a) were a gift from Dr. R. Kurrle, Behring Werke AG, Marburg. Purified goat anti-mouse IgG antibodies were obtained from Tago Inc ., Burlingame, CA. a toxin from Staphylococcus aureus
Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Sahara... more Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Saharan Africa. In Madagascar, the endemicity of tick-borne rickettsiae and their vectors has been incompletely studied. The first part of the present study was conducted in 2011 and 2012 to identify potential anthropophilic tick vectors for SFG rickettsiae on cattle from seven Malagasy regions, and to detect and characterize rickettsiae in these ticks. Amblyomma variegatum was the only anthropophilic tick species found on 262 cattle. Using a novel ompB-specific qPCR, screening for rickettsial DNA was performed on 111 A. variegatum ticks. Rickettsial DNA was detected in 96 of 111 ticks studied (86.5%). Rickettsia africae was identified as the only infecting rickettsia using phylogenetic analysis of ompA and ompB gene sequences and three variable intergenic spacers from 11 ticks. The second part of the study was a cross-sectional survey for antibodies against SFG rickettsiae in plasma samples taken from healthy, pregnant women at six locations in Madagascar, two at sea level and four between 450 and 1300 m altitude. An indirect fluorescent antibody test with Rickettsia conorii as surrogate SFG rickettsial antigen was used. We found R. conorii-seropositives at all altitudes with prevalences between 0.5% and 3.1%. Our results suggest that A. variegatum ticks highly infected with R. africae are the most prevalent cattle-associated tick vectors for SFG rickettsiosis in Madagascar. Transmission of SFG rickettsiosis to humans occurs at different altitudes in Madagascar and should be considered as a relevant cause of febrile diseases.
This study addresses the role of a bacterial superantigen as a potential virulence factor during ... more This study addresses the role of a bacterial superantigen as a potential virulence factor during an acute systemic infection. BALB/c mice were intravenously infected with a recombinant Staphylococcus aureus strain capable of producing plasmid-encoded staphylococcal enterotoxin B (SEB) or with the SEB plasmid-deficient parental strain. Infection with SEB-producing bacteria resulted in an initial expansion and subsequent decrease of circulating V beta 8+ T lymphocytes. This numeric decrease was accompanied by a SEB-specific state of hyporesponsiveness of splenic T cells. In parallel with SEB-triggered unresponsiveness of a large proportion of T lymphocytes, a weakening of the overall T cell responsiveness towards the invading bacteria was found. Furthermore, the production of SEB altered the kinetics of bacterial clearance: Animals infected with the SEB-producing variant showed a significantly elevated bacterial burden and could less efficiently clear the bacteria. However, the overall effect of SEB production on the course of bacterial infection was surprisingly weak, suggesting that the superantigen was only a minor virulence factor for the bacterium.
Predominance of Thl-type T cells in synovial fluid of patients with Yersinia-induced reactive art... more Predominance of Thl-type T cells in synovial fluid of patients with Yersinia-induced reactive arthritis* The pathogenetic mechanisms underlying the development of reactive arthritis and the functional capacities of synovial T cells specific for Yersinia enterocolitica are still unclear. In this study we have determined the cytokine secretion patterns of 24 CD4+ synovial fluid (SF)-derived Tcell clones from 2 patients with Yersinia-induced reactive arthritis, 16 clones specific for different Yersinia antigens and 8 clones as controls. The clones specific for Yersinia antigens predominantly belong to the T helper cell 1 (Thl) subset with production of interferon (1FN)-y and interleukin (1L)-2, but no IL-4, whereas SF T cells not reactive withyersinia antigens produce IL-2, IL-4 and IFN-y and thus belonged to the Tho subset. Moreover, short-term Tcell lincs established from SF and peripheral blood showed the same pattern. To further analyze the functional relevance of these data we investigated the influence of IFN-y and IL-4 on the intracellular killing of Yersinia in a human glioblastoma cell line. Our data show that theTh1 cytokine IFNy promotes intracellular killing of Yersinia,whereas this effect is antagonized by the Th2 cytokine IL-4. Furthermore, the Th2 cytokine IL-10 inhibited the antigen-specific proliferative response and IFN-y and IL-2 production by the T h l cells. These results provide insight into the antibacterial mechanisms at work in reactive arthritis after infection with Yersinia enterocolitica and, for the first time, reveal the cross-regulatory properties of cytokines derived from Thl and Th2 cells in a human immune response to bacterial antigens.
The idiopathic hypereosinophilic syndrome (HES) comprises a heterogeneous group of disorders with... more The idiopathic hypereosinophilic syndrome (HES) comprises a heterogeneous group of disorders with unknown pathogenesis characterized by persistent peripheral blood and bone marrow eosinophilia and eosinophilic infiltrates of multiple organs leading to severe organ dysfunction. In the present study, T lymphocyte clones were randomly established from the blood of a patient with HES and propagated in culture with mitogen and interleukin 2. Whereas 28 of 29 clones were able to stimulate myeloid colony formation when co-cultured with normal bone marrow cells in a double-layer micro-agar culture system, one third of these clones preferentially stimulated pure eosinophil colonies (up to 98% of all colonies). This pattern differed markedly (p less than 0.001) from the pattern of release of hemopoietic factors by 126 T cell clones established from four other individuals. Eosinophil colony stimulation was due to the release of a lineage-specific eosinophilic colony-stimulating factor (Eo-CSF) by these clones after appropriate stimulation. Production of Eo-CSF in vitro was inhibited by hydrocortisone or cyclosporin A. All Eo-CSF-producing clones had the T4+8-phenotype and were capable of producing in addition interleukin 2 and interferon-gamma. Southern blot analysis of the T cell receptor beta-chain rearrangement of the Eo-CSF-producing clones showed a different rearrangement pattern for each clone. These studies suggest a reactive T cell-mediated eosinophilia as the pathogenetic mechanism in this case of HES and, for the first time, point to a biologic relevance of a lymphokine-induced stimulation of hemopoiesis.
Herpes virus saimiri (HVS) immortalizes T lymphocytes from a variety of primates and causes acute... more Herpes virus saimiri (HVS) immortalizes T lymphocytes from a variety of primates and causes acute T cell lymphomas and leukemias in nonnatural primate hosts. Here we have analyzed the requirements for growth of three HVS-transformed human T cell lines. The cells expressed the phenotype of activated T cells: two were CD4 + , and one was CD8 +. All three cells responded to all allogeneic human cell lines tested with enhanced proliferation, production of interleukin 2 (Ib2), and increased expression of the I1:2 receptor. Binding of CD2 to its ligand CD58 was the critical event mediating stimulation because: (a) monoclonal antibodies (mAbs) to CD2 and to CD58, but not to a variety of other surface structures, blocked induced and spontaneous proliferation and Ib2 production; (b) only anti-CD2 mAbs were stimulatory if crosslinked; (c) a nonstimulatory cell was rendered stimulatory by CD58 transfection; and (d) the cells responded specifically to CD58 on sheep red blood cells. Growth of the cells required activation because cyclosporin A and FK506 blocked stimulator cell-induced II:2 production and proliferation as well as the spontaneous growth of the lines. Antibodies to the I1:2 receptor reduced proliferation of the cells and blocked 11:2 utilization. Taken together, these results show that HVS-transformed T cells proliferate in response to CD2-mediated contact with stimulator cells or with each other in an I1:2-dependent fashion. They suggest that HVS transforms human T cells to an activationdependent autocrine growth.
analysis and cytokine release of liverinfiltrating and peripheral blood T lymphocytes from patien... more analysis and cytokine release of liverinfiltrating and peripheral blood T lymphocytes from patients with chronic hepatitis of different etiology.
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