bluuebunny/crossref_metadata_2025_split huggingface dataset:
Longitudinal exposure of human T lymphocytes to weak oxidative stress suppresses transmembrane and nuclear signal transduction.
Authors: Flescher E , Ledbetter J A , Schieven G L , Vela-Roch N , Fossum D , Dang H , Ogawa N , Talal N 
Published: January 2023

Abstract
Products of polyamine oxidase activity, at micromolar levels and during a period of 2 to 3 days, down-regulate IL-2 mRNA levels and activity in human lymphocytes. We studied whether this suppression was associated with signal transduction abnormalities. We found that polyamine oxidase activity suppresses both anti-CD3-induced IL-2 production and protein tyrosine phosphorylation. Polyamine oxidase activity also caused a reduction in intracellular calcium mobilization after mitogenic stimulation. The most distal step of CD3-mediated signal transduction is dependent upon transcription factors that regulate a set of genes, including IL-2. We found that polyamine oxidase-treated cells exhibited very low DNA binding activity of two such factors: NFAT and NF-kappa B. On the other hand, AP-1 DNA binding activity was enhanced in polyamine oxidase-treated cells, suggesting a possible role for AP-1 in the human lymphocyte stress response. In accordance with the oxidation dependence of this suppressive mechanism, N-acetylcysteine (NAC; an antioxidant) significantly reversed the polyamine oxidase effects on lymphokine production and signal transduction. These results suggest that NAC contributes, under oxidizing conditions, to the preservation of immune function. In summary, our data suggest that chronic low-level oxidative stress, via suppression of mitogen-induced transmembrane signaling (protein-tyrosine phosphorylation and calcium mobilization), causes a decrease in the DNA binding activity of transcription factors that regulate the IL-2 gene. This results in decreased IL-2 production.
Activation of MAP2-kinase in B lymphocytes by calcium ionophores.
Authors: Franklin R A , Tordai A , Mazer B , Terada N , Lucas J J , Gelfand E W 
Published: January 2023

Abstract
The role of increases in intracellular calcium levels on tyrosine phosphorylation in human B lymphocytes was studied. Stimulation of normal, resting B lymphocytes or B lymphoblastoid cells with the calcium ionophores ionomycin or A23187 induced the tyrosine phosphorylation and the enzymatic activation of microtubule-associated protein-2 kinase (MAP2-K). Treatment of these cells with PMA induced tyrosine phosphorylation of a protein with the identical mobility, as well as the enzymatic activation of MAP2-K. Stimulation of these cells with ionomycin also resulted in increased ribosomal S6 kinase activity. Activation of MAP2-K in B lymphocytes by calcium ionophore was rapid (detectable within 1 min), transient (returning to background levels by 45 min), and dependent on extracellular calcium. These results demonstrate that transmembrane calcium flux induced by calcium ionophore results in the tyrosine phosphorylation and enzymatic activation of MAP2-K in human B cells.
Active induction of unresponsiveness (tolerance) to DNFB by in vivo ultraviolet-exposed epidermal cells is dependent upon infiltrating class II MHC+ CD11bbright monocytic/macrophagic cells.
Authors: Hammerberg C , Duraiswamy N , Cooper K D 
Published: January 2023

Abstract
Contact sensitizers, tumor Ags, and microbial pathogens presented through UV-exposed skin result in T cell-mediated immune tolerance (inhibition of acquisition of responsiveness) to these normally potent immunogens. The APC in UV-exposed skin that delivers the signals inducing tolerance remains highly controversial and is the subject of this study. Application of the contact sensitizer, 2,4-dinitro-1-fluorobenzene (DNFB), to C3H/HeN mice immediately after a single dose of 72 mJ/cm2 UVB (138 mJ/cm2 total UVB) resulted in unresponsiveness to an initial DNFB ear challenge, but failed to block the development of responsiveness after a second sensitization on previously unexposed skin (no tolerance). A state of tolerance could only be achieved if a delay of 72 h was allowed to elapse between the UV exposure and the initial sensitization. Epidermal cell suspensions (EC) were prepared from the skin of normal controls and from skin exposed to the same UV dose 3 days before (UV-EC). Three days after in vivo UV exposure, Langerhans cells (CD11blow Ia+) were depleted, and CD11bbright Ia+ macrophages had appeared in the epidermis along with GR-1+ neutrophils. Intracutaneous injection of 2,4 dinitrobenzenesulfonic acid (DNBSO3)-haptenated UV-EC, but not normal controls, resulted in the induction of locally inducible Ag-specific tolerance to DNFB, indicating the presence and dominance of tolerogenic signal within in vivo-irradiated epidermis. Removal of CD11b+ and class II MHC+ cells within UV-EC showed that a CD11b+ class II MHC+ population was indeed critical for tolerance induction. In addition, tolerance induction by UV-EC was not a result of surviving, UV-exposed Langerhans cells, because haptenated 3-day cultured EC from epidermis removed 5 h after UV exposure (before leukocytic infiltration) failed to induce a tolerogenic state. In conclusion, the ability of UV-exposed skin to induce peripheral adult tolerance to a normally potent immunogen is critically dependent on inflammatory class II MHC+, CD11bbright monocytic/macrophagic cells that infiltrate UV-irradiated skin at the same time the ability to tolerize is acquired.
Expression of recombinase-activating genes (RAG-1 and 2) in human decidual mononuclear cells.
Authors: Hayakawa S , Saito S , Nemoto N , Chishima F , Akiyama K , Shiraishi H , Hayakawa J , Karasaki-Suzuki M , Fujii K T , Ichijo M 
Published: January 2023

Abstract
Recombinase-activating genes (RAG-1 and RAG-2) are expressed in immature T or B lymphocytes and possess activity to induce V(D)J rearrangement in TCR and Ig genes. We examined their expression in human decidual and non-pregnant endometrial samples using a highly sensitive RT-PCR technique. Expression of RAG-1 and 2 was noted in all (13/13) pregnant decidual tissues obtained at different gestational stages. After anti-human Ig treatment to rule out the possibility of RAG-1,2 expression from decidual B-cells, strong expression of RAGs was still noted in B cell depleted decidual cells in contrast to lymph nodes and PBMC that lost RAG mRNA expression after this treatment. After FACS mediated cell sorting, strong expression of RAG-1,2 was noted in CD16-CD56bright cells and weak expression in CD3+ cells. Although CD16-CD56bright cells lack surface CD3, they express CD3 epsilon mRNA only detectable by RT-PCR. Our results suggest the nature of decidual CD16-CD56bright cells as a progenitor of extrathymic T cells that possess RAG-1 and 2 mRNA as markers of their immaturity, and possibly differentiate into CD3+ extrathymic T-cells in the decidua under the influence of trophoblastic cells. We propose the human decidua as a new site of extrathymic T-cells differentiation and propose possible roles of trophoblastic cells to attract progenitor lymphocytes of bone marrow origin and trigger their TCR rearrangement as thymic epithelial cells.
Expression of CD43 on murine and human pluripotent hematopoietic stem cells.
Authors: Moore T , Huang S , Terstappen L W , Bennett M , Kumar V 
Published: January 2023

Abstract
To understand regulation of hemopoiesis, it would be helpful to identify physiologically relevant function-associated molecules on stem cells. Here, we report the detailed examination of CD43 expression on murine and human pluripotent hemopoietic stem cells. Mouse stem cells were found within the Ly6+Lin-CD43high subpopulation of bone marrow. These cells, upon transfer into SCID mice, caused rapid repopulation of thymus, spleen, and bone marrow. Retransfer of bone marrow cells from primary SCID recipients of Ly6+Lin-CD43high cells into secondary recipients resulted in repopulation of lymphohemopoietic cells. All Ly6+Lin-CD43high cells were found to express high levels of c-kit. In contrast, Ly6+Lin-CD43-/low cells caused limited and variable thymic and splenic repopulation. These cells failed to repopulate the marrow cavity and did not contain retransplantable stem cells. These data indicate that murine pluripotent stem cells express high levels of CD43. Examination of human fetal bone marrow cells revealed a population of CD34+CD38-CD43+ cells. When single sorted cells with this phenotype were cultured in vitro, they were able to produce colonies with a dispersed growth pattern. Cells with this growth pattern have previously been shown to have myeloid and lymphoid growth potentials and extensive self-renewal capacity. Furthermore, CD34+CD38-HLA-DR+ cells, recently shown to be highly enriched in stem cell activity, expressed relatively high levels of CD43. Because CD43 has recently been shown to bind to intercellular adhesion molecule-1, these data suggest a possible role for CD43 in the regulation of hemopoiesis.
The mechanism of autoantibody production in an autoimmune MRL/lpr mouse.
Authors: Shan H , Shlomchik M J , Marshak-Rothstein A , Pisetsky D S , Litwin S , Weigert M G 
Published: January 2023

Abstract
Rheumatoid factors (RF) and anti-DNA Abs from MRL/lpr mice have features similar to Abs directed toward foreign Ags, indicating a role of specific activation by Ags during disease. But our previous studies and analogous studies from others concentrated on a limited subset of hybridomas selected on the basis of Ag binding to well characterized target autoantigens. Thus, it has been unclear to what extent clonal expansion is restricted to identifiable autospecificities. To obtain a more complete picture of disease-associated autoantibody production, we designed the following experiment. A large number of B cell hybridomas were generated from the spleen of an MRL/lpr mouse and then analyzed for self-specificity, sequence, and clonal relationship. Surprisingly, we found that clonal expansion was limited to only a few autospecificities, implying a unique property of this response. In addition, we used Southern blotting with heavy and L chain constant region probes to screen both RF and non-RF hybridomas for membership in clones, one of which was first identified among RF hybridomas. We found no non-RF members of this clone. The size and number of mutations of this clone were sufficient for us to conclude that nonspecific (i.e., non-RF) mutant members are rapidly lost. Had an Ag other than IgG2a been driving clonal expansion, we should have seen mutants that retained spectificity for that Ag but that lost specificity for IgG2a. This observation, along with the restriction of clonal expansion to a few autospecificities, provides strong evidence that normal autoantigens themselves drive autoantibody clonal expansion.
Proteolytic activity of an antibody light chain.
Authors: Sun M , Gao Q S , Li L , Paul S 
Published: January 2023

Abstract
The light chain (L chain) of a mAb raised against unactivated vasoactive intestinal peptide (VIP) hydrolyzed this peptide, whereas the heavy chain (H chain) and an irrelevant L chain were without activity. The reaction kinetics were consistent with efficient substrate recognition by the anti-VIP L chain compared with conventional proteases. The L chain cleaved four peptide bonds clustered between residues 16 and 21 in VIP. Mixtures of the L chain with its H chain partner displayed reduced hydrolytic activity compared with the free L chain, suggesting that the H chain is a modulator of the catalytic activity. These observations suggest: 1) the immune system can generate catalytic sites in the L chain subunit of Abs found in response to polypeptide Ags, and 2) free L chains found in vivo could display an Ag-specific catalytic function.
Abnormal signal transduction by T cells of mice with parental tumors is not seen in mice bearing IL-2-secreting tumors.
Authors: Salvadori S , Gansbacher B , Pizzimenti A M , Zier K S 
Published: January 2023

Abstract
There is considerable evidence to demonstrate that immune function is abnormal in tumor-bearing mice, perhaps accounting, at least in part, for progressive tumor growth. In an attempt to generate an antitumor response, we used retroviral vectors to express IL-2 cDNA in CMS5, a murine fibrosarcoma. Mice inoculated with unmodified tumor cells suffered progressive tumor growth, whereas tumors secreting IL-2 were rejected or grew slowly. Animals bearing unmodified but not IL-2-secreting tumors also were immunosuppressed. On the basis of these observations, we were interested in how IL-2 secretion by the tumor cells prevented the onset of hyporesponsiveness. To identify biochemical differences between T cells of mice with parental vs slowly growing IL-2-secreting tumors, we examined signal transduction after activation through the CD3/TCR complex. Protein tyrosine phosphorylation was altered and calcium flux was reduced in cells of mice with parental tumors compared with animals with slowly growing IL-2-secreting tumors. In addition, levels of protein for the tyrosine kinases p56lck and p59fyn, as well as the TCR-zeta-chain, were reduced. These differences in signal transduction were observed for T cells of mice with parental and IL-2-secreting tumors of the same size, demonstrating that differences in tumor size alone could not explain our findings. Thus, IL-2 secretion by tumors seems to be able to prevent immunosuppression by maintaining normal signal transduction in T cells, facilitating the generation of antitumor responses.
Protective cytotoxic T lymphocytes are induced during murine infection with Chlamydia trachomatis.
Authors: Starnbach M N , Bevan M J , Lampe M F 
Published: January 2023

Abstract
T cell responses are often an important component in immunity to organisms that replicate intracellularly. Cytotoxic T lymphocyte (CTL) recognition of peptide Ag in the context of MHC class I molecules results in lysis of infected cells and the release of cytokines including IFN-gamma. Members of the genus Chlamydia are obligate intracellular pathogens that cause blindness and sexually transmitted disease worldwide. Even though it replicates within a membrane-bound vacuole, Chlamydia trachomatis may elicit a CTL response if Chlamydia Ags are present in the cytoplasmic compartment where they can be processed for presentation and bound by MHC class I. In this study, we characterized a CTL line derived from mice infected with C. trachomatis. This CTL line is specific for, and able to lyse, Chlamydia-infected cells. The peptide epitope recognized by this CTL line is present on infected cells, and is presented to the CTL by the classical MHC class I molecule H-2 Ld. Adoptive transfer of this CTL line into an infected mouse affords protection, and this protection requires the activity of IFN-gamma.
Acyclic analogue of lipid A stimulates TNF-alpha and arachidonate release via a unique LPS-signaling pathway.
Authors: Fagan M A , Liu Y , Stütz P , Vyplel H , Golenbock D T 
Published: January 2023

Abstract
LPS has been implicated in the pathogenesis of Gram-negative bacterial sepsis. Despite intensive efforts to define the LPS-signal transduction pathway, CD14 is the sole molecule clearly demonstrated to possess signaling capabilities. However, it remains unclear whether CD14 is the only LPS-signaling molecule expressed in phagocytes and how CD14-mediated signaling occurs. Compound SDZ 280.961 is a synthetic triacylated amino acid that structurally resembles the reducing sugar moiety of lipid A. SDZ 280.961 effectively stimulated TNF-alpha release from human PBMC. Co-incubation of PBMC with the specific LPS inhibitor Rhodobacter sphaeroides lipid A inhibited SDZ 280.961-mediated stimulation of TNF-alpha release, indicating that this analogue signals mononuclear cells via a LPS-activated signaling pathway. Induction of TNF-alpha release from mononuclear cells by SDZ 280.961 was strongly dependent on the presence of serum and was enabled by the presence of purified LPS-binding protein, characteristics of CD14-mediated signaling. In contrast, SDZ 280.961-mediated signaling was not inhibited by blocking anti-CD14 mAbs. A Chinese hamster ovary fibroblast line transfected with human CD14, which responds to LPS in a manner qualitatively similar to that of macrophage cell lines, failed to respond to SDZ 280.961. Taken together, these data suggest that the lipid A analogue SDZ 280.961 activates monocytes via a unique LPS-signal transduction pathway that appears to be independent of CD14.
CD11b+ macrophages that infiltrate human epidermis after in vivo ultraviolet exposure potently produce IL-10 and represent the major secretory source of epidermal IL-10 protein.
Authors: Kang K , Hammerberg C , Meunier L , Cooper K D 
Published: January 2023

Abstract
Because activated human macrophages can be potent sources of IL-10, and because immunosuppressive tolerance-inducing macrophages populate the skin after UV exposure, we determined whether IL-10 is induced after UV exposure of human skin and whether it is related to the immigrating macrophages. Keratomes were obtained from control skin or from skin obtained 72 h after a single exposure to four minimal erythemal doses of UVB. Quantitative reverse-transcriptase PCR on total RNA extracted immediately from skin keratomes showed that IL-10 mRNA was elevated in UV-exposed skin. Epidermal cell suspensions from non-UV-exposed keratomes (C-EC) and UV-exposed keratomes (UV-EC) were fractionated by sequential immunobead selection. IL-10 mRNA was reproducibly 200- to 400-fold higher in CD11b+ UV-EC (macrophages) relative to CD11b- UV-EC (keratinocytes). IL-10 mRNA was not detected in C-EC that contained the CD1a+ population (Langerhans cells) nor in CD1a- C-EC keratinocytes from normal skin. As determined by ELISA, CD11b+ UV-EC IL-10 cell-associated protein was fivefold higher than that of CD11b- UV-EC; this was confirmed by flow cytometric visualization of IL-10 protein in permeabilized cells. CD11b+ UV-EC macrophages secreted IL-10 protein into the supernatant at a level of 333 +/- 51 pg/10(6) cells, whereas UV-EC keratinocytes did not secrete detectable levels of IL-10 (n = 3), although UV did induce low levels of IL-10 mRNA and cell-associated protein in keratinocytes. Therefore, although human keratinocytes accumulate intracellular IL-10 after in vivo UV exposure, the most potent production and secretion of IL-10 in the epidermis seems to be that of UV-induced macrophages. Skin-infiltrating macrophage secretion of such a potent immunoregulatory cytokine may account for the delayed immunosuppressive environment of sunburned skin and the altered APC activity of the infiltrating macrophages.
Differential responses of fibroblasts from wild-type and TNF-R55-deficient mice to mouse and human TNF-alpha activation.
Authors: Mackay F , Rothe J , Bluethmann H , Loetscher H , Lesslauer W 
Published: January 2023

Abstract
The role of the two TNF receptor types, TNF-R55 and TNF-R75, was studied on mouse fibroblasts, taking advantage of TNF-R55-deficient mice generated by gene targeting (Tnfr1 degree-mice), and selectivity of human TNF-alpha for mouse TNF-R55. Radioligand binding assays showed that both TNF receptors were expressed on wild-type mouse fibroblasts, whereas normal levels of TNF-R75 were expressed on mouse fibroblasts isolated from Tnfr1 degree-mice. It was found that TNF-R55 controlled four major TNF-induced fibroblast functions: (1) adhesion to leukocyte cell lines as well as ICAM-1, VCAM-1, CD44, and MHC class I up-regulation; (2) secretion of other cytokines as demonstrated by stimulated IL-6 and granulocyte-macrophage-CSF releases; (3) cell proliferation; and (4) NF-kappa B activation. Stimulation through TNF-R75, in TNF-R55-deficient fibroblasts, did not have any effect in these functions. In general, mouse TNF-alpha (recognizing both mouse TNF receptors) had a higher sp. act. than human TNF-alpha (recognizing only mouse TNF-R55) in wild-type fibroblasts, whereas both mouse and human TNF-alpha had similar cytotoxic activities in WEHI 164 cells.
Interactions of human complement component C3 with factor B and with complement receptors type 1 (CR1, CD35) and type 3 (CR3, CD11b/CD18) involve an acidic sequence at the N-terminus of C3 alpha'-chain.
Authors: Taniguchi-Sidle A , Isenman D E 
Published: January 2023

Abstract
Complement component C3 is a multifunctional protein that interacts with many different ligands and receptors. Several experimental approaches involving blocking Abs, proteolytic fragmentation, and synthetic peptides have been used to predict which regions in C3 are required for its various functions. We have used site-directed mutagenesis to alter specific residues in the C3 segments 730-739 and 933-942 that have been proposed to be required for the binding of factor B by C3, and have examined, within the context of the intact C3b molecule, the effect of these substitutions on the C3b-factor B interaction. Because it has been suggested that factor H and complement receptors type 1, 2, and 3 may recognize sites in C3 that partially or completely overlap those of factor B, the relevant proteolytic fragment of each mutant C3 was tested for its ability to interact with these molecules. This study clearly demonstrates that a segment near the N-terminus of the alpha'-chain, which contains the negatively charged residues 730DE and 736EE, is involved in the interactions of C3 proteolytic fragments with factor B and complement receptors type 1 and 3, but not type 2. Factor H cofactor activity was also partially affected by these mutations. In contrast, mutation of the 937KED triplet in the C3 933-942 segment had little or no effect on any of these activities.
C1q binding properties of monomer and polymer forms of mouse IgM mu-chain variants. Pro544Gly and Pro434Ala.
Authors: Taylor B , Wright J F , Arya S , Isenman D E , Shulman M J , Painter R H 
Published: January 2023

Abstract
The effect of replacing proline with alanine at position 434 in the C mu 3 domain (P434A) and with glycine at position 544 in the C mu 4 domain (P544G) of the mu-chain of mouse IgM has been studied. The P434A substitution results in the loss of measurable complement-mediated cytolytic activity (CML) and a decrease in the association rate constant at low ionic strength (mu = 0.06), that results in a diminished Ka for C1q binding to P434A IgM bound to haptenated cells (0.4 x 10(9) M-1). Binding of C1(qr2s2) could not be detected. In contrast, replacement of proline at 544 had no measurable effect on the cytolytic or C1q/C1 binding properties of the polymeric molecule, supporting the view that the C mu 3 domain is important in C1q binding and CML. The secreted monomeric subunit of P544G was not able to mediate CML. Also, whereas hapten-bound P544G polymer bound C1q with a functional affinity of 1.5 x 10(9) M-1 at low ionic strength (mu = 0.06), similar to that observed with wild-type polymer (1.7 x 10(9) M-1) and wild-type IgG monomer (4.7 x 10(9) M-1), no C1q binding was detected with the P544G IgM monomer. This could not be attributed to differences in glycosylation. Inasmuch as the P544G mutation per se had no effect on the C1q binding properties of the polymer, we conclude that unlike IgG, aggregation does not sufficiently enhance the avidity of IgM monomer to enable it to activate complement. Augmentation of the site must occur during polymerization or when the IgM binds to Ag.