bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-15 functions as a potent autocrine regulator of macrophage proinflammatory cytokine production: evidence for differential receptor subunit utilization associated with stimulation or inhibition.
Authors: Alleva D G , Kaser S B , Monroy M A , Fenton M J , Beller D I 
Published: December 2022

Abstract
The cytokine IL-15 appears to mimic the stimulatory activity of IL-2 on lymphocytes by utilizing part of the IL-2R complex. Although effects of IL-15 on Mphi activities have not previously been reported, its derivation from activated Mphi suggested a possible autocrine role in regulating Mphi functions and prompted us to determine whether IL-15 modulated LPS-activated Mphi cytokine production. Whereas high IL-15 concentrations enhanced proinflammatory (i.e., TNF-alpha, IL-1, and IL-6) and anti-inflammatory (i.e., IL-10) cytokine production by two- to sixfold, extremely low IL-15 concentrations (picomolar to attomolar range) markedly and selectively suppressed Mphi proinflammatory, but not anti-inflammatory, cytokine production by two- to fourfold. The stimulation (but not the suppression) of TNF-alpha production by IL-15 required the (IL-2/IL-15) receptor beta chain, as demonstrated by receptor subunit-blocking studies and lack of stimulation of Mphi from IL-2Rbeta-deficient mice. Conversely, suppression most likely involved the alpha receptor (IL-15R alpha) because this high affinity receptor would be engaged by low concentrations of IL-15, and its inducible expression correlated with the degree of suppression in both a time- and LPS dose-dependent fashion. Moreover, Ab-mediated neutralization studies revealed that endogenous IL-15 activity regulated Mphi activation with kinetics similar to that seen in response to exogenously added IL-15: suppressor activity increased over time in correlation with IL-15R alpha gene expression. This study demonstrates a novel dose-dependent and autocrine activity of IL-15 in Mphi regulation.
IL-7 overexpression in transgenic mouse keratinocytes causes a lymphoproliferative skin disease dominated by intermediate TCR cells: evidence for a hierarchy in IL-7 responsiveness among cutaneous T cells.
Authors: Williams I R , Rawson E A , Manning L , Karaoli T , Rich B E , Kupper T S 
Published: December 2022

Abstract
IL-7 is a keratinocyte-derived lymphocyte growth factor critical for the development of gammadelta T cells including murine dendritic epidermal T cells (DETC). We derived transgenic mice that overexpress IL-7 in basal keratinocytes under the control of the human K14 promoter. These K14/IL-7 mice develop dermal and epidermal T cell infiltrates associated with alopecia. This lymphoproliferative skin disease is substantially more severe in mice homozygous for the K14/IL-7 transgene. Conventional DETC expressing a Vgamma5 Vdelta1 TCR are rare or absent among the cutaneous T cells in these mice. The T cells in the skin infiltrates of young K14/IL-7 mice are predominantly gammadelta T cells that express intermediate levels of TCR, are negative for E-cadherin, often lack expression of CD2, and include cells that coexpress NK1.1. T cells expressing intermediate levels of a TCR-alphabeta are also present in transgenic skin, and progressively increase in number as the mice age. Phenotypically similar intermediate gammadelta and alphabeta T cell subsets also constitute the major lymphocyte populations recovered from organ culture of normal mouse skin in the presence of IL-7, suggesting that the T cells that accumulate in the epidermis of K14/IL-7 mice are derived from precursors normally resident in skin. We conclude that intermediate TCR cells, some of which coexpress NK1.1, can be selectively expanded in skin under the influence of IL-7 produced locally. Our results also suggest that features of the epidermal microenvironment besides keratinocyte-derived IL-7 account for the normal predominance of Vgamma5 Vdelta1 DETC in mouse epidermis.
Fas- and FasL-deficient mice are resistant to induction of autoimmune encephalomyelitis.
Authors: Waldner H , Sobel R A , Howard E , Kuchroo V K 
Published: December 2022

Abstract
Experimental autoimmune encephalomyelitis (EAE) is an organ-specific autoimmune disease inducible in susceptible animals by myelin Ag-specific CD4+ Th1 cells. The mechanisms by which these cells induce inflammation and demyelination in the central nervous system (CNS) are incompletely understood. To determine the roles of Fas and FasL in the involvement of CNS autoimmune injury, we determined susceptibility to EAE of Fas-or FasL-deficient mice. Compared with wild-type mice, mice expressing lpr (Fas) and gld (FasL) mutations were relatively resistant to the development of clinical EAE, and this correlated with fewer inflammatory infiltrates and cells undergoing apoptosis in the CNS of the mutant mice. The gld and lpr mice, however, developed significant T cell responses with production of Th1 cytokines in response to the encephalitogenic myelin peptide. These results suggest that the Fas/FasL pathway plays a critical role in the development of EAE probably by mediating apoptosis within the target tissue.
Induction of tissue-specific autoimmune prostatitis with prostatic acid phosphatase immunization: implications for immunotherapy of prostate cancer.
Authors: Fong L , Ruegg C L , Brockstedt D , Engleman E G , Laus R 
Published: December 2022

Abstract
Prostatic acid phosphatase (PAP) is uniquely expressed in prostatic tissue and prostate cancer. In this study, the immunogenicity of PAP was investigated in a male rat model. We show that immunization with recombinant rat or human PAP in CFA leads to a significant Ab response, but does not generate CTL or result in autoimmune prostatitis. In contrast, immunization with recombinant vaccinia expressing human PAP, but not rat PAP, generates a CTL response and tissue-specific prostatitis in the absence of detectable PAP-specific Abs. These findings suggest that a cellular immune response to PAP, rather than Abs, mediates destructive autoimmune prostatitis. Thus, xenogeneic forms of PAP are a new tool for the induction of prostate-specific immunity and may prove useful for the immunotherapy of prostate cancer.
B cells genetically deficient in the c-Rel transactivation domain have selective defects in germline CH transcription and Ig class switching.
Authors: Zelazowski P , Carrasco D , Rosas F R , Moorman M A , Bravo R , Snapper C M 
Published: December 2022

Abstract
The Ig heavy chain locus contains a number of binding sites for the transcriptional activator, c-Rel. In this study, we evaluated the capacity of B cells from mice made genetically deficient in the C-terminal, transactivation domain of the c-Rel protein (delta c-Rel) to undergo Ig class switching. Flow-cytometric and digestion circularization PCR analyses revealed that delta c-Rel B cells failed to switch to IgG3 in response to LPS alone, or to IgG1 or IgE in response to LPS + IL-4. This failure to switch to IgG3 or IgG1 was associated with a corresponding loss of germline CH gamma 3 or CH gamma 1 RNA. However, the defective switching to IgE in delta c-Rel B cells was associated with normal levels of germline CH epsilon RNA relative to control B cells. The ability of delta c-Rel B cells to switch to IgG1, in response to LPS + IL-4, could be restored through the action(s) of additional stimuli, and this was associated with induction of normal levels of germline CH gamma 1 RNA relative to controls. In contrast, LPS-activated B cells from delta c-Rel mice underwent normal switching to IgA in the presence of TGF-beta, relative to control B cells. This was associated with equivalent steady state levels of germline CH alpha RNA between the two B cell populations. These data are the first to demonstrate a key and selective role for c-Rel in the regulation of Ig class switching. Furthermore, distinct differences are revealed in the Ig isotype induction profiles of B cells lacking c-Rel activity vs those deficient in p50/nuclear factor-kappa B.
CTL generation in the presence of IL-4 is inhibited by free p40: evidence for early and late IL-12 function.
Authors: Abdi K , Herrmann S H 
Published: December 2022

Abstract
The cytokine requirements for the generation of a CTL response were examined using thymocyte responders stimulated with Con A. In agreement with previous reports, IL-4 alone can generate a strong CTL response. To determine whether IL-12 was required for this response, we added either a neutralizing Ab against IL-12 or an antagonist of IL-12 function, p40. Both anti-IL-12 and p40 were found to inhibit the generation of CTL in the presence of IL-4. Consistent with these data, exogenous IL-12 was found to synergize with IL-4, particularly, when IL-4 was added at levels unable to generate a CTL response alone. This synergistic response was observed whether IL-12 was added at the beginning of culture along with IL-4 or after the first day to cultures initiated with IL-4. Likewise, the combination of IL-2 plus IL-12 evoked a strong synergistic response when cultures were initiated with IL-2 and IL-12 was added initially or after the first day of culture. Addition of either IL-2 or IL-12 alone did not generate a response. In contrast to these data showing that IL-12 was able to signal late in culture, p40 inhibited CTL generation in response to IL-4 only when added at the beginning of culture. These results imply that CTL induction involves a crucial early IL-12 signal, which once delivered permits cells to respond to a later IL-12 signal. These data are consistent with the idea that free circulating p40 could inhibit the generation of CTL by antagonizing the early IL-12 "differentiation" signal.
Differential requirement of protein tyrosine kinases and protein kinase C in the regulation of T cell locomotion in three-dimensional collagen matrices.
Authors: Entschladen F , Niggemann B , Zänker K S , Friedl P 
Published: December 2022

Abstract
Locomotion of T lymphocytes within three-dimensional collagen matrices is regulated via different signaling states of the cells. Purified human CD4+ and CD8+ T cells developed a spontaneously locomoting subpopulation of about 25% of the whole population immediately after incorporation into a three-dimensional collagen matrix analyzed by time-lapse videomicroscopy. This spontaneous locomotion was accompanied by enhanced tyrosine phosphorylation of the focal adhesion kinase (FAK). Inhibition of protein tyrosine kinase (PTK) activity using genistein significantly reduced the spontaneous locomotory activity. This reduction was overcome by subsequent activation of protein kinase C (PKC) using PMA, which led to a persistent increase of locomotory activity to more than 60% of the cells. Thus, the PKC-driven type of locomotion was independent of PTK activity, whereas spontaneous locomotion was not altered by inhibition of PKC activity using calphostin C or inhibition of the serine/ threonine phosphatases pp1 and pp2A using okadaic acid. We presume that PTK activity, especially tyrosine phosphorylation of FAK, is decisively involved in the regulation of spontaneous T lymphocyte locomotion, which is independent of PKC activity. In contrast, PKC-driven locomotion is independent of tyrosine phosphorylation events, indicating that T lymphocyte locomotion is regulated by more than one signal transduction pathway. Furthermore, confocal microscopy analysis of phosphotyrosine residues, FAK, and PKC revealed an exclusive cellular distribution of these components, suggesting a regulation of T lymphocyte locomotion different from migration models developed for other cell types, which refer to a colocalization of FAK and PKC in focal adhesions.
The processing routes determined by negatively charged residues in DR1-restricted T cell determinants.
Authors: Robadey C , Ammerlaan W , Muller C , Cloutier I , Sékaly R P , Haefliger J A , Demotz S 
Published: December 2022

Abstract
The presentation pathways followed by DR1-restricted determinants from the fusion protein of measles virus were studied. By assessing the capacity of various APC preparations to stimulate fusion protein-specific T cells, it was shown that the determinant contained within the fusion protein sequence 254-268 (F254) relies on newly synthesized DR1 protein for its presentation. By contrast, the determinant contained within the fusion protein sequence 314-328 (F314) is captured by DR1 protein recycled from the plasma membrane. In vitro binding analyses showed that the F254 and F314 peptides optimally bind to DR1 at pH 4 and pH 5, respectively. In addition, it was found that binding of the F254 peptide to DR1 is much poorer at pH 7 than at pH 4, while binding of the F314 peptide was decreased only moderately at pH 7 as compared with pH 5. Substitution of the glutamic acid 261 for an alanine in the F254 peptide resulted in an analogue with an improved capacity of binding to DR1 at neutral pH. By contrast, replacement of the valine 319 by a glutamic acid in the F314 peptide generated an analogue with a decreased binding capacity at pH 7. These findings indicated that determinants that do not bear acidic residues are captured efficiently by DR1 molecules over a broader range of pH than determinants containing acidic residues. Binding analyses between DR1 and four additional peptides further supported this conclusion. Altogether, these results suggested that acidic residues, by tuning the optimal pH for the assembly of peptide-DR1 complexes, determine the processing pathway followed by the determinants.
Human endothelial cell costimulation of T cell IFN-gamma production.
Authors: Briscoe D M , Henault L E , Geehan C , Alexander S I , Lichtman A H 
Published: December 2022

Abstract
In this report, we show that human endothelial cells (EC) provide costimulatory signals to mitogen-activated CD4+ T cells to augment IFN-gamma production. We also show that EC can enhance responsiveness of the T cells to IL-12. While IL-12 has no effect on IFN-gamma production by cultured CD4+ T cells in the absence of EC, addition of IL-12 to T cell-EC cocultures augments IFN-gamma production by as much as fivefold. Separation of T cells from EC by a semipermeable membrane inhibits the effect of EC and IL-12 on IFN-gamma production. Anti-LFA-3 Abs, in the absence or presence of IL-12, inhibit EC costimulation of IFN-gamma production by up to 50%, while Abs to intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), LFA-1, and very late antigen-4 (VLA-4) have relatively little effect. Pretreatment of T cells with conditioned medium from T cell-EC cocultures, or with IL-2 or IL-1 alpha similarly primes CD4+ T cells for the costimulatory effect of IL-12 on IFN-gamma production. EC costimulation of IFN-gamma production is inhibited by cyclosporine. However, in the presence of IL-12 there is a marked resistance to this inhibitory effect, suggesting that the IL-12-induced costimulatory pathway is distinct from the costimulatory pathway activated by endothelium alone. Our data are consistent with the hypothesis that, as a consequence of interactions with endothelium, T cells that migrate into an inflammatory site are primed to have enhanced responses to Ag and cytokine(s), such as IL-12, that influence T cell-cytokine production.
Identification of a novel MHC class I gene, Mamu-AG, expressed in the placenta of a primate with an inactivated G locus.
Authors: Boyson J E , Iwanaga K K , Golos T G , Watkins D I 
Published: December 2022

Abstract
Maternal tolerance of the fetal allograft remains poorly understood. In humans, expression of the highly polymorphic classical HLA-A and HLA-B loci is suppressed, while expression of the nonclassical HLA-G locus is up-regulated at the maternal-fetal interface. Like other nonclassical MHC class I molecules, HLA-G exhibits limited diversity, but certain characteristics of HLA-G distinguish it from other nonclassical MHC class I molecules: it has a truncated cytoplasmic domain, it is the product of alternatively spliced mRNAs, and it is expressed primarily in the placenta. We have examined MHC class I expression in the placenta of the rhesus monkey to determine whether this animal is a suitable model in which to study the function of HLA-G. Although the rhesus monkey possesses orthologs of many MHC class I and II loci found in humans, the HLA-G ortholog is a pseudogene in this nonhuman primate species. In this study, we report the identification of a novel nonclassical MHC class I locus expressed in the placenta of the rhesus monkey, Mamu-AG (Macaca mulatta-AG). Although unrelated to HLA-G, Mamu-AG encodes glycoproteins with all of the characteristics of HLA-G. These Mamu-AG glycoproteins are limited in their diversity, possess truncated cytoplasmic domains, are the products of alternatively spliced mRNAs, and their expression is restricted to the placenta. Taken together, these data suggest that convergent evolution may have resulted in the expression of a unique nonclassical MHC class I molecule in the rhesus monkey placenta, and that the common structural features of Mamu-AG and HLA-G may be functionally significant.
Domain-switched mouse IgM/IgG2b hybrids indicate individual roles for C mu 2, C mu 3, and C mu 4 domains in the regulation of the interaction of IgM with complement C1q.
Authors: Chen F H , Arya S K , Rinfret A , Isenman D E , Shulman M J , Painter R H 
Published: December 2022

Abstract
Although polymeric IgM and monomeric IgG are potent activators of the classical complement pathway, previous studies have indicated that monomeric IgM is inactive. To understand this and to examine the roles of the individual mu domains in complement activation, we created a set of IgM/IgG2b mouse chimeric Abs in which homologous domains of both Abs have been interchanged, either singly or together with adjacent domains. The monomer subunits (H2L2) of the resulting chimeras were analyzed for their capacities to bind C1q and to initiate complement-mediated lysis (CML) of haptenated erythrocytes. When C gamma 2 was flanked by C mu 4, the inherent C1q-binding activity of the C gamma 2 domain was lost. This demonstrates that C mu 4 can suppress the C1q-binding activity of the adjacent C gamma 2 domain, and suggests that C mu 4 may exert a similar effect on the C mu 3 domain in the IgM monomer subunit. When C mu 3 was located in an IgG2b background and potentially freed from the constraints imposed by the IgM background, the monomer was not able to bind C1q or initiate CML. This suggests that these activities are not expressed inherently in the C mu 3 domain. The transplantation of C mu 3 together with C mu 4 into the IgG background permitted polymer formation. This polymer was able to bind C1q, although neither the monomer nor the polymer forms were active in CML; conversely, all IgM polymers with a transplanted C gamma 2 domain were active in both C1q binding and CML, and demonstrated apparent Kd values similar to that of wild-type IgM.
Flexibility of human IgG subclasses.
Authors: Roux K H , Strelets L , Michaelsen T E 
Published: December 2022

Abstract
A variable region (Id)-matched set of genetically engineered human IgG1, -2, -3, and -4 subclass molecules was analyzed by electron microscopy for hinge-mediated differences in flexibility. The hinge-mediated bending was studied, as was the ability of the subclasses to form immune complexes with two anti-Id mAbs. The data show that the rank order (most to least flexible) of the IgG subclasses for hinge-folding mode of flexibility between Fab arms is IgG3 &gt; IgG1 &gt; IgG4 &gt; IgG2. The mean Fab-Fab angles for the subclasses are IgG3, 136 degrees; IgG4, 128 degrees; IgG2, 127 degrees; and IgG1, 117 degrees. Fab-Fc angles were similarly analyzed. By sampling of equimolar mixtures of Id-bearing IgGs and each of two anti-Id mAb after incubation over time (1.5 min to 3.5 h), different kinetic profiles of immune complex formation of defined geometry were documented. Both anti-Id mAbs displayed unique kinetic profiles when complexed with the four IgG subclass molecules but also shared important features. Most notable was the higher propensity to form closed bivalent ring Id-anti-Id dimers with IgG3 than with IgG2 and IgG4. IgG1 was intermediate in its ability to form such dimers.
TNF initiates E-selectin transcription in human endothelial cells through parallel TRAF-NF-kappa B and TRAF-RAC/CDC42-JNK-c-Jun/ATF2 pathways.
Authors: Min W , Pober J S 
Published: December 2022

Abstract
TNF acts on the E-selectin gene promoter at three kappa B elements and at a variant cAMP-responsive element that binds ATF2/c-Jun. In human endothelial cells, TNF rapidly induces N-terminal domain phosphorylation of both c-Jun and ATF2. Transient overexpression of N-terminal truncated c-Jun or catalytically inactive Jun N-terminal kinase (JNK) 1 and 2 inhibits TNF-induced transcription of an E-selectin but not a kappa B promoter-reporter gene. Transient overexpression of the TRAF2 adaptor protein can activate NF-kappaB and endogenous JNK, whereas N-terminal truncated TRAF2 protein blocks TNF-induced NF-kappa B and JNK activation as well as E-selectin promoter-reporter gene transcription. Transient overexpression of RAC1 or CDC42, but not RAS, constitutively activates JNK and augments TNF-induced E-selectin transcription. Finally, transient overexpression of catalytically inactive JNK or truncated TRAF2 partially inhibits endogenous E-selectin protein expression in human endothelial cells. These data suggest that TNF activates parallel TRAF-NF-kappa B and TRAF-RAC/CDC42-JNK-c-Jun/ATF2 pathways to initiate E-selectin transcription.
Dual effects of LPS antibodies on cellular uptake of LPS and LPS-induced proinflammatory functions.
Authors: Pollack M , Ohl C A , Golenbock D T , Di Padova F , Wahl L M , Koles N L , Guelde G , Monks B G 
Published: December 2022

Abstract
Human phagocytes recognize bacterial LPS (endotoxin) through membrane CD14 (mCD14), a proinflammatory LPS receptor. This study tested the hypothesis that anti-LPS Abs neutralize endotoxin by blocking cellular uptake through mCD14. Ab-associated changes in the uptake and cellular distribution of FITC-LPS were assessed by flow cytometry and laser scanning confocal microscopy in human CD14-transfected Chinese hamster ovary fibroblasts (CHO-CD14 cells) and human peripheral blood monocytes. LPS core- and O-side chain-specific mAbs inhibited mCD14-mediated LPS uptake by both cell types in the presence of serum. O-side chain-specific mAb concurrently enhanced complement-dependent LPS uptake by monocytes through complement receptor-1 (CR1) and uptake by CHO-CD14 cells involving another heat-labile serum factor(s) and cell-associated recognition molecule(s). Core-specific mAb inhibited mCD14-mediated uptake of homologous and heterologous LPS, while producing less concurrent enhancement of non-mCD14-mediated LPS uptake. The modulation by anti-LPS mAbs of mCD14-mediated LPS uptake was associated with inhibition of LPS-induced nuclear factor-kappaB (NF-kappaB) translocation and TNF-alpha secretion in CHO-CD14 cells and monocytes, respectively, while mAb enhancement of non-mCD14-mediated LPS uptake stimulated these activities. LPS-specific Abs thus mediate anti-inflammatory and proinflammatory functions, respectively, by preventing target cell uptake of LPS through mCD14 and augmenting uptake through CR1 or other cell receptors.