Role of nuclear factor-kappa B in the activation of alveolar macrophages by fungal beta-glucans.
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Animals↗
Biomedical subjects
C Huntoon
Publications and source records attributed to C Huntoon.
Mechanism responsible for T-cell antigen receptor- and CD28- or interleukin 1 (IL-1) receptor-initiated regulation of IL-2 gene expression by NF-kappaB.
Initiation of the T-helper lymphocyte activation program is regulated through the T-cell receptor (TCR) and costimulatory receptors. Analysis of TCR and either anti-CD28- or interleukin 1 (IL-1)-mediated activation of the IL-2 promoter shows that costimulatory signals augment promoter activity through NF-kappaB sites. This study comparatively evaluates the mechanisms whereby signals initiated from the TCR and these two costimulatory receptors converge to synergistically increase NF-kappaB transcriptional activity. IL-1 alone stimulates an acute but transient NF-kappaB nuclear localization and a suboptimal NF-kappaB transcriptional response. In contrast, anti-CD3-anti-CD28 or anti-CD3-IL-1 synergistically stimulate prolonged NF-kappaB nuclear localization and NF-kappaB-mediated transcription. Both TCR- and costimulatory receptor-initiated synergistic NF-kappaB responses result from prolonging high rates of cytosolic IkappaB degradation during the second phase of the biphasic NF-kappaB nuclear localization. However, in contrast to previous reports, prolonged nuclear localization of NF-kappaB complexes is not necessarily associated with long-term depletion of IkappaBbeta. In response to either costimulus, c-Rel selectively translocated to the nucleus as a result of induced c-Rel expression and the continued production of c-Rel-IkappaBalpha complexes, which turn over rapidly due to the high rate of IkappaBalpha degradation in the cytosol during the second phase of the response. In contrast, IkappaBbeta is nearly completely degraded during the acute response to either IL-1 or anti-CD3-IL-1 while anti-CD3-anti-CD28 stimulates only a partial reduction (35 to 40%) in cytosolic IkappaBbeta. Cyclosporine (CsA), which inhibits stimulus-induced NF-kappaB transcriptional activity, selectively inhibits the stimulus-induced c-Rel nuclear localization and the rapid formation and degradation of c-Rel-IkappaBalpha complexes in the cytosol. CsA also inhibits both the prolonged, high rate of IkappaBalpha degradation and the lower level of IkappaBbeta turnover during the second phase of the activation response. Together, these results suggest a mechanism by which signals from the T-cell antigen receptor and either CD28 or IL-1 synergistically regulate IL-2 gene transcription by modulating NF-kappaB nuclear translocation.
Animals↗
Dual signal transduction through delta opioid receptors in a transfected human T-cell line.
Opiates are known to function as immunomodulators, in part by effects on T cells. However, the signal transduction pathways mediating the effects of opiates on T cells are largely undefined. To determine whether pathways that regulate free intracellular calcium ([Ca2+]i) and/or cAMP are affected by opiates acting through delta-type opioid receptors (DORs), a cDNA encoding the neuronal DOR was expressed in a stably transfected Jurkat T-cell line. The DOR agonists, deltorphin and [D-Ala2, D-Leu5]-enkephalin (DADLE), elevated [Ca2+]i, measured by flow cytofluorometry using the calcium-sensitive dye, Fluo-3. At concentrations from 10(-11)-10(-7) M, both agonists increased [Ca2+]i from 60 nM to peak concentrations of 400 nM in a dose-dependent manner within 30 sec (ED50 of approximately 5 x 10(-9) M). Naltrindole, a selective DOR antagonist, abolished the increase in [Ca2+]i, and pretreatment with pertussis toxin was also effective. To assess the role of extracellular calcium, cells were pretreated with EGTA, which reduced the initial deltorphin-induced elevation of [Ca2+]i by more than 50% and eliminated the second phase of calcium mobilization. Additionally, the effect of DADLE on forskolin-stimulated cAMP production was determined. DADLE reduced cAMP production by 70% (IC50 of approximately equal to 10(-11) M), and pertussis toxin inhibited the action of DADLE. Thus, the DOR expressed by a transfected Jurkat T-cell line is positively coupled to pathways leading to calcium mobilization and negatively coupled to adenylate cyclase. These studies identify two pertussis toxin-sensitive, G protein-mediated signaling pathways through which DOR agonists regulate the levels of intracellular messengers that modulate T-cell activation.
Adenylate Cyclase Toxin↗
IL-1 receptor and TCR signals synergize to activate NF-kappa B-mediated gene transcription.
Previous studies have demonstrated that IL-1 receptor (IL-1R)- and TCR-initiated signals can interact synergistically to increase the rate of transcription of several lymphokine and lymphokine receptor genes during the competence phase of the activation program in T helper lymphocytes. In this report we describe how signals initiated through the type I IL-1R interact with signals from the antigen receptor to synergistically augment the transactivating properties of NF-kappa B. The synergistic antigen receptor initiated signals are mediated through protein kinase C because they can be mimicked by the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, but not with calcium ionophores; and are staurosporine sensitive but cyclosporine resistant. Gel shift analyses demonstrate that NF-kappa B nuclear translocation is stimulated primarily by IL-1 rather than by antigen receptor signals. Western blot and phosphorylation analyses demonstrate that the synergistic effect on NF-kappa B functional activity is independent of I kappa B alpha (MAD3)-NF-kappa B dissociation in the cytosol and is not associated with I kappa B nuclear translocation. The IL-1-induced NF-kappa B DNA nuclear localization is transient and can be prolonged either by an antigen receptor-initiated signal or by inhibiting protein synthesis. These results suggest that IL-1 induces both NF-kappa B nuclear translocation and the synthesis of a protein(s) responsible for terminating NF-kappa B-DNA interaction in the nucleus. Antigen receptor signals prolong NF-kappa B-DNA interaction, probably by functionally antagonizing the IL-1-induced synthesis of a protein(s) responsible for the transient NF-kappa B-DNA interaction and consequently synergistically enhance IL-1-induced NF-kappa B-dependent gene transcription.
Alkaloids↗
Ligand-induced desensitization of interleukin 1 receptor-initiated intracellular signaling events in T helper lymphocytes.
Although interleukin 1 (IL-1) receptor signaling events in T helper lymphocytes are incompletely characterized, events associated with translocation of the transcription factor NF-kappa B are receptor-proximal assays of ligand-initiated responses. In this report we demonstrate that the transient nature of IL-1-induced NF-kappa B nuclear translocation occurs as a consequence of ligand-induced receptor desensitization. Other receptor-initiated events including induction of I kappa B alpha phosphorylation, expression of c-jun and junB mRNA, and costimulatory effects on IL-2 synthesis also are altered by IL-1 receptor desensitization. IL-1 receptor desensitization is not initiated by tumor necrosis factor, which also stimulates NF-kappa B translocation, and is not a consequence of alterations in either IL-1 receptor expression or binding affinity. In the absence of IL-1, the effects of desensitization are completely reversed within 18 h. Since IL-1 desensitization is initiated under conditions of low receptor occupancy, it is likely that receptor desensitization results from alterations to a receptor-proximal transducer, rather than from direct modification of the IL-1 receptor. These results suggest that the cyclic nature of the events in the T helper lymphocyte activation program can be controlled, in part, by the reversible desensitization of cell surface IL-1 receptors.
Animals↗
Substitution of class II alpha chain polymorphic residues defines location of A alpha k serologic epitopes and alters association between alpha beta and Ii polypeptides.
Structure-function studies of the MHC class II alpha chain have been performed by constructing a panel of A alpha k cDNA genes with one or more d allele substitutions at each polymorphic residue of the alpha 1 domain. The altered genes (A alpha k*) were transfected into a B lymphoma cell line (BKO), which is deficient in A alpha mRNA but retains constitutive wild-type A beta k mRNA expression. Cytofluorometric analysis of cell surface A alpha k* Ak beta molecules was used to map the polymorphic alpha chain residues comprising four serologic epitopes. A alpha k-reactive mAbs 1E9, 2A2, and 3F12 recognize an epitope that includes the polymorphic residue 44 of the A alpha k polypeptide, and the A alpha k-reactive antibody, K24-199, recognizes a conformationally determined epitope influenced by residues from all three polymorphic regions. In addition, we confirmed previous studies demonstrating that la.19 and la.2 mAbs bind to epitopes adjacent to residue 75 in A alpha k. A cell surface negative expression variant also was identified in the panel of mutant cell lines and biochemically characterized. Substitution of six d allele polymorphic residues at positions 11, 14, 28, 69, 70, and 75 in the A alpha k polypeptide (T.EG A alpha k* A beta k*) results in an A alpha k* polypeptide that associates with the A alpha k polypeptide but does not associate with the li polypeptide. This defect in li-A alpha k A beta k interaction is associated with a conformational change in the alpha 1 beta 1 domain that was identified by altered reactivity of the T.EG complex with conformationally dependent anti-alpha and anti-beta mAbs.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
Heteroconjugate antibody-directed killing of autologous human renal carcinoma cells by in vitro-activated lymphocytes.
Tumor cell lysis can be enhanced significantly in vitro when heteroconjugate (HC) antibodies (anti-CD3 x anti-tumor mAb) are used to specifically direct lymphocyte effector cells to the tumor cell target. In order to effectively utilize HC antibodies in an immunotherapy protocol, methods must be identified for the optimum expansion, activation, and retargeting of lymphocyte-effector populations from cancer patients. In this study, we have compared the proliferative responses of different normal and renal cell carcinoma (RCC) patient lymphocyte preparations (PBL, tumor-infiltrating lymphocytes) stimulated in vitro for periods up to 12 days with a variety of growth factor combinations (anti-CD3, rIL-2, rIL-4). These activated lymphocyte preparations were then tested in vitro for their ability to kill RCC tumor cells and tumor cell lines in the presence of HC preparations (anti-CD3 mAb covalently linked to mAb reactive to different RCC tumor-associated Ag). RCC patient PBL cultured with anti-CD3 plus rIL-2 for 12 days resulted in a 3- to 160-fold expansion of effector cells. These cells, as well as tumor infiltrating lymphocytes, when retargeted with appropriate HC antibodies were capable of mediating high levels of killing of autologous tumor cells. No constitutive autologous anti-tumor cell response was detected in the absence of added HC antibodies. Of the five anti-RCC mAb tested (A6H, K29, K20, UR07, and URO 3), HC containing URO 3 x anti-CD3 and K20 x anti-CD3 elicited the highest level of tumor cell lysis by the activated lymphocyte effector cells. Together these results demonstrate that HC antibodies may be a useful imunotherapeutic reagent for directing the killing of RCC tumor cells by autologous lymphocytes.
Antibodies, Neoplasm↗
Assessing applicants to the NASA flight program for their renal stone-forming potential.
Spaceflight could provoke formation of kidney stones, in part by causing hypercalciuria and hyperphosphaturia. Applicants for spaceflight who have metabolic or environmental derangements to begin with might be particularly susceptible to stone formation in space. We, therefore, analyzed 24-h urine samples for stone-forming risk factors in 104 male applicants before their selection into the astronaut-mission specialist corps. The urinary environment was abnormally supersaturated with calcium oxalate in 25.0% of applicants, brushite in 36.5%, and monosodium urate in 66.3%, predisposing these applicants to crystallization of stone-forming calcium salts. This high level of supersaturation was caused by both "metabolic" and environmental disturbances. Thus, hypercalciuria was found in 11.5% of applicants, hyperoxaluria in 2.9%, hyperuricosuria in 18.3% and hypocitraturia in 5.8%. Environmental derangements were generally more prominent, as indicated by low urine volume of less than 2 L.d-1 in 84.6%, high urinary phosphate in 24.4%, and high urinary sodium in 10.6% of applicants. The results suggest that most of the abnormal stone risk factors disclosed among applicants for spaceflight programs were environmental in origin.
Adult↗
Effect of potassium depletion in normal males: an Apollo 15 simulation.
In the course of Apollo 15, physiologic abnormalities, manifested by ectopic activity on the ECG and unusual alterations in excerise tolerance, occurred in the crew of the Lunar Excursion Module. These were associated with decreases in total body potassium, measured by 42K, of 10% and 15%. The possibility of inadequate potassium (K plus) intake existed. A simulation study was performed prior to Apollo 16, corresponding in duration to Apollo 15. Subjects endured the same sleep aberrations and caloric expenditure as the Apollo 15 astronauts. Subjects consumed a diet containing only 15 mEq/d of K plus during the entire 12 d of absolute bedrest. ECG was continuously monitored, body fluid compartments and total body K plus were measured at intervals by radionuclide methods, electrolyte balance was determined daily, and excercise and orthostatic tolerances were determined prior to and after bedrest. In spite of decreases in total body K plus measured by 42K of 14.5% and 10.5%, and by potassium balances of 3.3% and 6.5%, respectively, neither of the two subjects developed symptomatic hypokalemia. Minor ECG abnormalities were noted in one subject. Orthostatic and exercise tolerance showed only those changes expected as a result of bedrest. Muscle strength was unaffected. Study implications and reasons for discrepancies between K plus loss measured by balance techniques and 42K are reviewed.
Adult↗
Bone and body mass changes during space flight.
Body mass, calcium and skeletal changes occur in humans who have worked in microgravity. Physiologic changes are seen as early as one week and are still occurring 312 days into space flight. The physiologic changes in bone and mineral metabolism may be among those which limits long duration space flight if an adequate countermeasure is not developed. The purpose of this paper is to summarize what is known about calcium dynamics and bone mineral changes as well as associated changes of body mass induced by space flight. The data reported is from a variety of studies conducted in both actual and simulated space flight.
Aerospace Medicine↗
On the correlation between individual biochemical parameters of human blood serum following space flight and their basal values.
The article presents data concerning the osmolality and concentration of electrolytes and hormones regulating their balance for blood serum of 223 cosmonauts and astronauts. The obtained results allow us to judge the constancy of physicochemical parameters for the blood serum of healthy individuals and how they react to extreme conditions of space flight. The parameters used for evaluation included not just absolute values for the examined indices, but also how they responded to space flight, the dependence on baseline values and the interrelationship between ions. These data are important to predict the effect of exposure to extreme conditions and point to what extent the effect depends on the characteristics of the individual.
Aerospace Medicine↗