bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sepsis-induced apoptosis of the thymocytes in mice.
Authors: Wang S D , Huang K J , Lin Y S , Lei H Y 
Published: December 2022

Abstract
Intraperitoneal injection of Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) induces thymic atrophy in mice. The thymus weight, cell number, and viability began to decrease at 3 h, and reached their lowest level at 72 h. The thymocyte death was associated with DNA fragmentation of approximately 200 base pairs in ladder form. The kinetic study on histopathology revealed the process of thymocyte death and thymic atrophy. Flow-cytometric analysis showed that CD4+CD8+ thymocytes decreased predominantly. LPS caused thymocyte apoptosis, but only in LPS-responder mice, unlike Gram-negative bacteria that induced apoptosis in both LPS-responder (C3H/HeN) and LPS-nonresponder (C3H/HeJ). Gram-positive bacteria Streptococcus pneumoniae also caused apoptosis in LPS-nonresponder (C3H/HeJ) and LPS-responder mice (B6). The kinetics of serum TNF-alpha production after Gram-negative or Gram-positive bacteria injection was slightly different. E. coli induced serum TNF-alpha peak at 1 h in B6 mice, whereas S. pneumoniae induced a peak at 6 h in C3H/HeJ and at 9 h in B6 mice. Similarly, S. pneumoniae induced thymocyte apoptosis around 9 to 12 h, which was 6 to 9 h later than that observed with E. coli in B6 mice. Anti-TNF-alpha Ab completely blocked the E. coli-induced thymocyte apoptosis, but was only partially inhibitory on the S. pneumoniae-induced thymocyte apoptosis. Furthermore, thymocyte apoptosis induced by E. coli was inhibited by cycloheximide or actinomycin D. These data indicate that both Gram-negative and Gram-positive bacteria could induce thymus atrophy via apoptosis, and that TNF-alpha is a common denominator released and might be responsible for the thymocyte apoptosis.
Nitric oxide involvement in tumor-induced immunosuppression.
Authors: Lejeune P , Lagadec P , Onier N , Pinard D , Ohshima H , Jeannin J F 
Published: December 2022

Abstract
The mechanisms of immunosuppression induced by colon cancer in rats were investigated at the systemic and tumor levels. During tumor growth (after i.p. injection of rat colon adenocarcinoma cells in syngeneic BD IX rats), Con A-induced proliferation of splenic mononuclear cells decreased and nitric oxide (NO) production by splenic macrophages increased concomitantly. Incubating splenic mononuclear cells with an inhibitor of NO synthase, NG-monomethyl-L-arginine, restored lymphocyte proliferation. A low level of inducible NO synthase mRNA was detectable in tumors by Northern blotting, with a weak increase during tumor growth. The NO concentration measured in the tumor nodules increased weakly parallel to the tumor growth. Five and six weeks after tumor cell injection, tumor-infiltrating lymphocytes from disaggregated tumors did not proliferate in the presence of Con A. Addition of NG-monomethyl-L-arginine inhibited the production of NO in tumor dissociations and enhanced tumor-infiltrating lymphocyte proliferation. Glyceryl trinitrate (a NO-releasing compound) totally inhibited the lymphocyte proliferation in vitro while it slightly reduced the tumor cell proliferation. T lymphocytes were therefore more sensitive to NO than were tumor cells. Culture medium from tumor cells induced NO production by splenic macrophages, although the factor involved has not yet been identified. Furthermore, tumor cells could also play a part in NO production by tumors because the tumor cells were induced to produce NO by IFN-gamma plus IL-1. These results strongly suggest the participation of NO in the tumor-induced immunosuppression in rats.
Heightened intragraft CTL gene expression in acutely rejecting renal allografts.
Authors: Lipman M L , Stevens A C , Strom T B 
Published: December 2022

Abstract
The role of CTL in the immunopathogenesis of acute cellular rejection is controversial. To further define the relationship of activated CTLs to rejection, we analyzed gene expression of three CTL-derived effector molecules in renal allograft biopsies. CTLs are endowed with the ability to promote allograft damage through the elaboration of these highly cytopathic molecules. Intragraft gene transcript levels were determined for granzyme B, perforin, and TIA-1 and correlated with the immunologic status of the allograft as categorized by conventional clinical and histologic criteria. The categories were acute cellular rejection, chronic rejection, elements of both acute and chronic rejection, and no evidence of rejection. Biopsies were snap-frozen, total RNA extracted, and the mRNA converted to cDNA by reverse transcription. Levels were quantitated by competitive template PCR techniques. Intragraft granzyme B and perforin transcripts were highly restricted to biopsies in the acute cellular rejection category. TIA-1 expression was more ubiquitous but significantly higher transcript levels were found in the acute rejection category. The presence of these transcripts in acute cellular rejection samples implicates CTL in the pathogenesis. Moreover, intragraft CTL-specific transcript levels may serve as markers of rejection.
Engagement of the CD45 molecule induces homotypic adhesion of human thymocytes through a LFA-1/ICAM-3-dependent pathway.
Authors: Bernard G , Zoccola D , Ticchioni M , Breittmayer J P , Aussel C , Bernard A 
Published: December 2022

Abstract
Cell-cell interactions play a central role during differentiation and development of the immune system. T or B lymphocyte homotypic adhesions can be induced via several surface molecules which, in some cases, are known to trigger the LFA-1/ICAM-1 adhesion pathway. We show here that mAbs reacting with the CD45 common epitopes or restricted RO epitope lead to a strong and rapid aggregation of all human thymocytes, and of T cell lines with an immature phenotype, but not of peripheral T lymphocytes. Aggregation requires energy, a physiologic temperature, Mg2+ divalent cations, and an intact cytoskeleton. It is LFA-1 dependent because CD11a and CD18 mAbs inhibit homotypic aggregation, whereas CD11b and CD11c mAbs do not. Homotypic thymocyte adhesion, however, is not decreased by CD54 mAb (anti-ICAM-1) but is inhibited by CDw50 mAb (anti-ICAM-3). Soluble CD22 fails to induce thymocyte adhesion, suggesting that CD45-induced aggregation is triggered by another ligand. Finally, because inhibitions observed with mAbs against LFA-1 and ICAM-3 are only partial, it can be assumed that another adhesion pathway is involved in thymocyte adhesion. The adhesion event specific for thymocytes we describe here is likely to play an important role in T cell differentiation.
A minority subpopulation of CD4+ T cells directs the development of naive CD4+ T cells into IL-4-secreting cells.
Authors: Gollob K J , Coffman R L 
Published: December 2022

Abstract
The culture of CD4+ T cells with immobilized anti-CD3 and IL-2 generated a population of cells that produced both IL-4 and IFN-gamma on restimulation. In contrast, CD4+ T cells stimulated with immobilized anti-V beta 6 under otherwise identical culture conditions generated cells that produced IFN-gamma but not IL-4 on restimulation. This difference was likely a result of quantitative differences in the concentration of responding T cells in the two cultures rather than to qualitative differences between the two Abs. Anti-CD3 induced development of IL-4 secreting cells required IL-4 during the primary stimulation. This endogenous IL-4 in primary cultures was produced by cells with a Mel-14low, memory/activated phenotype but not by cells expressing the Mel-14high, naive phenotype. However, co-cultures of Mel-14high and Mel-14low populations marked with different Ly-5 allotypes demonstrated that nearly all of the IL-4-secreting cells that developed from primary cultures were generated from the Mel-14high population. Moreover, Mel-14high T cells could generate IL-4-secreting cells only in the presence of Mel-14low T cells or rIL-4. In addition, co-culture of CD4+, Mel-14low T cells from IL-4-deficient mice with CD4+, Mel-14high T cells from wild-type mice did not lead to the development of IL-4-secreting cells. Thus, IL-4, made by a minority population of previously differentiated CD4+ T cells, can induce the development of IL-4-secreting cells from the naive T cells but naive CD4+ T cells themselves do not develop into IL-4-secreting cells.
Costimulator dependence of lymphokine secretion by naive and activated CD4+ T lymphocytes from TCR transgenic mice.
Authors: McKnight A J , Perez V L , Shea C M , Gray G S , Abbas A K 
Published: December 2022

Abstract
The role of costimulation in Ag-induced responses of naive and differentiated IL-2 and IL-4-producing CD4+ T cells has been examined using cells from mice expressing a transgenic TCR specific for cytochrome c (81-104) + I-Ek. IL-2 secretion by naive and pre-activated T cells is dependent on costimulation, because it is not induced with chemically fixed APCs and is significantly inhibited by the B7 antagonist, CTLA4-Ig. In contrast, IL-4 secretion by in vitro differentiated Th2-like cells is relatively independent of costimulators. Thus, the requirement for costimulation is related more to lymphokine secretion profiles than to the previous activation status of CD4+ T lymphocytes.
Ligation of MHC class I and class II molecules can lead to heterologous desensitization of signal transduction pathways that regulate homotypic adhesion in human lymphocytes.
Authors: Wagner N , Engel P , Vega M , Tedder T F 
Published: December 2022

Abstract
Engagement of lymphocyte MHC class I and class II Ags activates an array of intracellular signal transduction pathways that up-regulates the activity of cell-surface adhesion receptors, resulting in homotypic cell-cell aggregation. In this study, engagement of MHC class I and class II molecules with specific mAbs was shown to also inhibit lymphocyte homotypic adhesion. Two mAbs reactive with class II Ag, homotypic adhesion blocking mAb (HAB)-2, and HAB-3, and one mAb reactive with class I Ag, HAB-4, were generated that inhibited homotypic adhesion of activated lymphocytes and B and T cell lines at concentrations as low as 0.1 microgram/ml. Binding of these mAbs resulted in heterologous desensitization of other surface signal transduction molecules as homotypic adhesion induced through class I, class II, CD19, CD20, CD39, CD40, Leu-13, and PMA was also inhibited. The spontaneous adhesion exhibited by some cell lines was also abrogated by binding of these mAbs. Abs that either induced, blocked, or had no effect on adhesion bound to distinct epitopes on class I, whereas the anti-class II mAbs recognized either distinct or overlapping epitopes. Thus, engagement of distinct epitopes on MHC molecules can result in homologous or heterologous desensitization of cell-surface signaling molecules. The induction or inhibition of homotypic adhesion through class I molecules did not require the presence of the cytoplasmic domain, as deletion of this portion of the class I molecule had no effect. In contrast, the transmembrane region was essential for signal transduction as the mAbs binding to a chimeric molecule in which the transmembrane and cytoplasmic domains of class I were exchanged with those of the HB15 molecule did not induce or inhibit homotypic adhesion. Although this report is the first demonstration that homotypic adhesion can be influenced in a negative manner through MHC molecules, these findings demonstrate a considerable level of cross-talk between MHC molecules and other cell-surface receptor systems and their signal transduction pathways, and suggests that MHC class I and class II molecules may serve important roles in the regulation of adhesive events during lymphocyte activation.
Critical binding site amino acids of anti-Z-DNA single chain Fv molecules. Role of heavy and light chain CDR3 and relationship to autoantibody activity.
Authors: Polymenis M , Stollar B D 
Published: December 2022

Abstract
Bacterial expression of single chain variable fragment (scFv) domains was used to assess Ag-binding contributions of specific regions and residues in a mouse mAb to Z-DNA (AbZ22). A variant scFv (Z3-3) that did not bind Z-DNA had the Z22 light chain but differed from the Z22 heavy chain at four complimentarity determining region 3 (CDR3), one FR4 and five VH segment residues. Gene segment swapping and site-directed mutagenesis indicated that the major contribution of the Z22 heavy chain is its CDR3. A scFv with the CDR3H-FR4H of Ab Z22 and the VH segment of Z3-3 had the same selective high affinity Z-DNA binding as Z22. Some Z-DNA binding was retained even when the CDR3H-FR4H of Ab Z22 was combined with a VH segment that shared only 44% sequence identity with Z22. Directed mutations indicated further that residues N99 and S98 in heavy chain CDR3 and F96 in light chain CDR3 were particularly important for Ag binding. Certain substitutions in CDR3H converted the highly selective Z22 Fv into a polyreactive Fv with autoantibody-like binding to B-DNA and denatured DNA. In a graphic molecular model, heavy chain N99 protrudes from the CDR3 loop at the base of the Ag-binding groove, and the light chain F96 is barely exposed on the base of this groove; the light chain F96 may be important in heavy chain-light chain association. Autoantibody and immunization-induced Ab to nucleic acid can be built on a very similar framework and differ by a small number of amino acid CDR3H residues.
A method for linking VL and VH region genes that allows bulk transfer between vectors for use in generating polyclonal IgG libraries.
Authors: Sarantopoulos S , Kao C Y , Den W , Sharon J 
Published: December 2022

Abstract
Libraries of Ab fragments have been produced by others from light and heavy chain cDNAs derived from populations of B lymphocytes and expressed in bacteria. However, such libraries have not been transferred to eukaryotic expression vectors to generate polyclonal libraries of intact glycosylated Abs that can mediate effector functions. We present a method for transferring pairs of linked VL-VH region genes between circular prokaryotic and eukaryotic vectors. The key feature of the transfer is that the VL and VH region genes are linked head to head (&lt;--&gt;) in opposite transcriptional orientations. To illustrate this method, a pair of VL and VH region cDNAs derived from an existing hybridoma cell line were linked head to head by PCR, transferred as a unit between vectors, and expressed as an IgG Ab with Ag binding activity. Although we tested the transfer of a single VL-VH region gene pair, this system is expected to allow the bulk transfer of physically linked VL-VH region gene combinations between different circular vectors and the expression of the same library as either Ab fragments or intact Abs.
Zymosan-induced IL-8 release from human neutrophils involves activation via the CD11b/CD18 receptor and endogenous platelet-activating factor as an autocrine modulator.
Authors: Au B T , Williams T J , Collins P D 
Published: December 2022

Abstract
We have investigated mechanisms that regulate the generation of IL-8 by human neutrophils on contact with zymosan particles in vitro. Zymosan stimulated IL-8 production, which increased with increasing particle numbers and was abolished by the protein synthesis inhibitor cycloheximide. IL-8 was detectable in culture supernatant at 8 h reaching a maximum at 24 h. In all further experiments IL-8 was measured at 24 h. mAbs to neutrophil CD18 (60.3 and 6.5E) caused a marked suppression of IL-8 generation, but only if added up to 2 h after zymosan stimulation. An anti-CD11b mAb (KIM 225) substantially inhibited zymosan-induced IL-8 release. We investigated whether other mediators generated during phagocytosis modulate IL-8 production. Two selective platelet-activating factor (PAF) receptor antagonists, WEB 2086 and UK 74505, produced a profound suppression of IL-8 generation, when added within 30 min to 1 h of zymosan stimulation. An IL-1R antagonist, a leukotriene B4 antagonist, and an anti-TNF-alpha Ab had no effect on IL-8 generation. FMLP, PAF, and a stable PAF agonist did not stimulate significant IL-8 production, however, a calcium ionophore (A23187) did induce IL-8 release and this was suppressed by UK 74505. We conclude that zymosan-induced IL-8 generation involves stimulation of the neutrophil via a CD11b/CD18 receptor resulting in beta 2-integrin mediated activation of signal transduction mechanisms that leads to cytokine synthesis. Furthermore, endogenously generated PAF, or a PAF, or a PAF-like molecule, appears to have an autocrine function in regulating this pathway of IL-8 production at an early stage after the interaction between the neutrophil and the particles.
Laminin peptides stimulate human neutrophil motility.
Authors: Harvath L , Brownson N E , Fields G B , Skubitz A P 
Published: December 2022

Abstract
Laminin, isolated from Engelbreth-Holm-Swarm tumor, and 10 chemically synthesized peptides, corresponding to various regions of the laminin A and B1 chains, were compared for their abilities to stimulate human peripheral blood polymorphonuclear leukocyte (PMN) chemotaxis and chemokinesis through polycarbonate membrane filters in a 48-well microchemotaxis assay. Peptides F-9, F-11, F-12, and F-13 were derived from the B1 chain of laminin at the intersection of the cross, and six peptides were derived from the laminin A chain: peptide TG-1 from the amino-terminal top globule; peptides GD-1, GD-3, GD-6, and GD-7 from the carboxyl-terminal globular domain; and peptide AG-1 from above the carboxyl-terminal globular domain. Laminin and the peptides were evaluated over a concentration range of 1 to 200 micrograms/ml in motility assays. Six of the peptides, F-9, F-12, GD-1, GD-3, GD-6, and TG-1, stimulated human PMN migration in the absence of a gradient (chemokinesis). A fluorescein conjugate of the most active laminin peptide, GD-1, exhibited nonspecific, nonsaturable binding to PMN. Intact laminin and the other peptides failed to stimulate human PMN migration. In contrast, intact Engelbreth-Holm-Swarm laminin stimulated rabbit peripheral blood PMN chemokinesis. These results demonstrate that rabbit and human peripheral blood PMNs have divergent migratory responses to intact laminin. These findings suggest that intact basement membrane laminin does not directly stimulate human blood PMN motility in vivo, but that selected laminin peptide sequences, which may be generated during proteolytic digestion of laminin, can activate human PMN migration.
Soluble recombinant complement receptor 1 inhibits inflammation and demyelination in antibody-mediated demyelinating experimental allergic encephalomyelitis.
Authors: Piddlesden S J , Storch M K , Hibbs M , Freeman A M , Lassmann H , Morgan B P 
Published: December 2022

Abstract
Activation of complement may contribute to tissue damage in many inflammatory diseases, including those that are clearly T cell driven. We have previously provided evidence that C is involved in tissue damage in multiple sclerosis and in the animal models of this disease, experimental allergic encephalomyelitis and Ab-mediated demyelinating experimental allergic encephalomyelitis, the latter being a model more closely resembling multiple sclerosis. The development of a soluble recombinant form of human complement receptor 1 (sCR1) with potent C-inhibiting activity both in vitro and in vivo provides a potential means of preventing C-mediated tissue damage in animal models and in human disease. Here, we describe the effects of this agent on clinical disease and pathology in Ab-mediated demyelinating experimental allergic encephalomyelitis in the rat. Daily i.p. injection of sCR1 (20 mg/kg) over 6 days completely suppressed serum C activity, reduced the severity of clinical disease (clinical score 1.33 vs 2.79 in untreated animals), inhibited central nervous system inflammation (inflammatory index 2.76 vs 6.55), and almost completely blocked demyelination (average 2.43% cord cross-section vs 8.81%). Deposition of C components C1, C3, and C9 was also markedly inhibited in sCR1-treated animals. This dramatic effect on a demyelinating disease, achieved using a well-tolerated biologic reagent, offers an exciting new prospect for therapy in multiple sclerosis.
Functional cytotoxic T cells are associated with focal lesions in the brains of SJL mice with experimental herpes simplex encephalitis.
Authors: Hudson S J , Streilein J W 
Published: December 2022

Abstract
Using a recently developed murine model of herpes simplex encephalitis in SJL mice, we isolated and characterized brain-infiltrating mononuclear cells to identify immune effectors that might contribute to pathology in this disease. Brain infiltrating mononuclear cells obtained from temporal area lesions were found to be predominantly T cells, with CD4+ and CD8+ T cell types present in equal numbers. The herpes simplex virus type 1 (HSV-1)-specific CTL that were present within the temporal area of HSV-1 infected SJL mice were fully activated (i.e., they did not require in vitro culture to acquire cytotoxic function). These cells were Thy-1.2+, CD8+ and exhibited the classical features of CTL activity: Ag specificity and MHC restriction. To our knowledge this is the first definitive demonstration of HSV-1-specific CTL activity directly ex vivo in mice. Freshly isolated spleen or lymph node cells from the same mice failed to exhibit CTL activity. The lytic capacity of infiltrating cells appeared to be mediated exclusively by CTL because treatment with Abs to Thy-1.2, or CD8, and C completely removed cytotoxic activity. NK cell activity was not detected in spleen, lymph node, or brain-infiltrating mononuclear cells from SJL mice with HSV encephalitis. Significantly, T cells were the prominent cell type in the temporal area of HSV-1-infected SJL mice just before the development of focal lesions, with CD8+ cells being present in equal or greater numbers than CD4+ cells (a CD4:CD8 ratio of 1 &lt; or = 1). Thus, the accumulation of functional CD8+ CTL in the temporal area of the brain correlated with the occurrence of focal entorhinal lesions.
Activation induces sensitivity toward APO-1 (CD95)-mediated apoptosis in human B cells.
Authors: Daniel P T , Krammer P H 
Published: December 2022

Abstract
We have previously described the APO-1 (CD95) cell surface molecule, a novel member of the nerve growth factor/TNF receptor superfamily, identical with the Fas Ag. Triggering of APO-1-induced apoptosis in APO-1+, apoptosis sensitive cells. The data in this study demonstrate that human peripheral blood B cells acquire sensitivity to APO-1-mediated apoptosis on PWM activation. To also study APO-1-mediated apoptosis in an Ag-specific human B cell response, we reconstituted severe combined immunodeficient (SCID) mice i.p. with human PBMC (SCID-hu mice). SCID-hu mice were then injected i.p. with soluble, adjuvant-free tetanus toxoid or diphtheria toxoid, respectively, directly after transfer of the PBMC (day 1) and received an Ag-booster injection on day 14. Two weeks after PBMC transfer human Abs were detected and shown to be Ag specific. SCID-hu mice co-injected with monoclonal anti-APO-1 Ab (IgG3,k) showed significantly suppressed anti-tetanus toxoid or anti-diphtheria toxoid titers, respectively. Sensitivity to anti-APO-1-mediated suppression was only observed in Ag-activated cells from day 0 to day 6 after Ag immunization. Suppression of Ab titers correlated with a decrease of Ag-specific Ig-secreting cells. Re-injection of syngeneic T cells and Ag did not reverse anti-APO-1-induced suppression. These data show a direct suppressive effect of anti-APO-1 on Ag-activated, "specific" B cells. Thus, APO-1-mediated apoptosis in Ag-activated B cells may contribute to the regulation of the humoral immune response.