bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural requirements for assembly of dimeric IgA probed by site-directed mutagenesis of J chain and a cysteine residue of the alpha-chain CH2 domain.
Authors: Krugmann S , Pleass R J , Atkin J D , Woof J M 
Published: December 2022

Abstract
The structural features of J chain required for interaction with IgA in IgA dimer assembly were investigated by coexpression of wild-type and mutant forms of J chain with IgA1 in CHO cells. With wild-type J chain, a mixture of J chain-containing dimers and monomers was secreted. Substitution of Cys14 of J chain with Ser resulted in expression of only monomer IgA covalently associated with J chain. Similarly, mutation of Cys68 to Ser also resulted in expression predominantly of a monomer IgA-J chain species. These results suggest that Cys14 and Cys68 play critical roles in formation of J chain-containing IgA dimers, with each forming a disulfide bridge to an IgA monomer. Substitution of Asn48 with Ala, to prevent attachment of N-linked carbohydrate to J chain, also resulted in markedly reduced dimer assembly, suggesting a requirement for the sugar moiety in J chain function. We also mutated Cys311 on the C alpha2 domain of the IgA heavy chain to Ser. When coexpressed with wild-type J chain, this mutant was still capable of forming dimers, indicating that this residue was not involved in dimerization. Taken together, our results are consistent with an arrangement in which IgA monomers are linked end-to-end with J chain interposed.
Isolation and characterization of 2'-fluoro-, 2'-amino-, and 2'-fluoro-/amino-modified RNA ligands to human IFN-gamma that inhibit receptor binding.
Authors: Kubik M F , Bell C , Fitzwater T , Watson S R , Tasset D M 
Published: December 2022

Abstract
CD4+ Th cells produce cytokines that play a pivotal role in the induction and regulation of cell-mediated and humoral immunity. Th1 cells, characterized by their secretion of IFN-gamma, induce macrophage cytotoxicity, delayed hypersensitivity, and enhanced cellular immunity. Secretion of IFN-gamma may even suppress Th2-enhanced humoral immunity. A counterproductive Th1 response and concomitant secretion of IFN-gamma may result in inflammatory and autoimmune diseases. IFN-gamma regulation of T cell function has potential for therapeutic intervention. To isolate high affinity oligonucleotide inhibitors of IFN-gamma activity, combinatorial libraries of RNA molecules modified at the 2' position of pyrimidine nucleotides with fluoro (F), amino (NH2), or a mixture of F and NH2 (2'-F/NH2) were screened using the SELEX (systematic evolution of ligands by exponential enrichment) combinatorial chemistry process. Each modified library of RNA molecules provides an expanded repertoire of molecules with increased structural diversity and unique binding properties. This added diversity increases the possibility of isolating molecules with the desired functional properties. These RNAs modified at the 2' position have also been shown to be nuclease resistant. High affinity ligands to human IFN-gamma from each modified library were isolated and characterized. The K(d)s of these ligands were determined and their secondary structures were predicted. The specificity of these ligands for IFN-gamma binding was confirmed, and their ability to inhibit binding of IFN-gamma to its receptor on A549 human lung carcinoma cells was determined. A 2'-NH2-modified ligand (2'-NH2-30) is described that binds IFN-gamma with high affinity and inhibits IFN-gamma-induced expression of MHC class I and ICAM-1 by human myeloid leukemia cells.
IL-12-deficient dendritic cells, generated in the presence of prostaglandin E2, promote type 2 cytokine production in maturing human naive T helper cells.
Authors: Kaliński P , Hilkens C M , Snijders A , Snijdewint F G , Kapsenberg M L 
Published: December 2022

Abstract
We studied to what extent the presence of an inflammatory mediator PGE2, during the development of dendritic cells (DC) affects their subsequent ability to induce Th1- and Th2-type cytokines in maturing naive Th cells. PGE2 (10(-9)-10(-6) M) did not alter the morphology or the expression of class II MHC and costimulatory molecules on DC obtained from monocytes in the presence of granulocyte-macrophage CSF and IL-4, although at concentrations above 10(-8) M, PGE2 prevented the acquisition of CD1a marker. Both control DC and DC maturing in the presence of PGE2 (PGE2-DC) were potent stimulators of naive Th cells. In contrast to control DC, which produced high amounts of IL-12 and trace amounts of IL-10, PGE2-DC produced no IL-12 and high amounts of IL-10 when stimulated in the absence of PGE2. This distinct cytokine profile of PGE2-DC was stable for at least 48 h of additional culture in the absence of PGE2. Control DC induced the development of Th0-like cells from superantigen-activated naive Th cells, whereas PGE2-DC promoted the development of Th cells that produced high amounts of IL-4 and IL-5. Experiments using IL-12-neutralizing Abs or rIL-12 indicated a crucial role of IL-12 deficiency in the induction of type 2 cytokine profiles. These findings suggest that elevated levels of PGE2 promote type 2 Th responses by stably impairing the ability of maturing DC to produce IL-12. Since type 2 Th responses are protective in several Th1-related autoimmune disorders, PGE2-DC may be considered for use in immunotherapy.
The intronic region of an incompletely spliced gp100 gene transcript encodes an epitope recognized by melanoma-reactive tumor-infiltrating lymphocytes.
Authors: Robbins P F , El-Gamil M , Li Y F , Fitzgerald E B , Kawakami Y , Rosenberg S A 
Published: December 2022

Abstract
Recent studies have characterized a number of the Ags that are recognized by melanoma-reactive T cells. Although the majority of tumor Ags appear to represent nonmutated gene products, a variety of epitopes have been shown to arise from either mutated or alternatively processed transcripts. Here, we report that the screening of a cDNA library with a HLA-A24-restricted melanoma-reactive T cell cloid derived from tumor infiltrating lymphocytes resulted in the isolation of a variant of the gp100 gene that had retained the entire fourth intron of this gene, termed gp100-in4. The gp100-in4 transcript could be detected by reverse transcriptase-PCR but could not be detected in Northern blots conducted with melanoma RNA, indicating that it represents a relatively rare transcript. Read-through of this transcript into the region corresponding to the fourth intron gave rise to an additional 35 amino acids not found in the normal gp100 glycoprotein, and a peptide within this region conforming to the HLA-A24 consensus motif (VYFFLPDHL) was shown to be recognized by the T cell cloid. The sequence of the intron was identical with that of a previously isolated genomic gp100 clone, and T cells that recognized the gp100-in4 gene product were found to recognize HLA-A24-matched allogeneic melanoma cell lines and melanocytes, demonstrating that this represents a nonmutated epitope. These results further extend the types of Ags that can be recognized by melanoma-reactive T cells to aberrant transcripts of melanosomal genes.
Eradication of murine bladder carcinoma by intratumor injection of a bicistronic adenoviral vector carrying cDNAs for the IL-12 heterodimer and its inhibition by the IL-12 p40 subunit homodimer.
Authors: Chen L , Chen D , Block E , O'Donnell M , Kufe D W , Clinton S K 
Published: December 2022

Abstract
IL-12 is a heterodimeric immunoregulatory cytokine composed of covalently linked p40 and p35 subunits and exhibits antitumor activity in a variety of laboratory models. The efficacy of systemically administered cytokines for cancer therapy is often limited by toxicity. The gene therapy approach provides a mechanism to achieve temporary and high local concentrations of cytokines within a tumor with less risk of systemic toxicity. We constructed replication-defective adenoviruses containing the murine IL-12 p40 subunit (Ad.mp40) or a bicistronic vector containing cDNAs for the p40 and p35 subunits (Ad.mIL-12). Murine MB49 bladder cancer cells infected with Ad.mIL-12 secrete high concentrations of biologically active IL-12, while those infected with Ad.mp40 produce the p40 homodimer. Tumors injected with Ad.mIL-12 show rapid increases in IL-12 and IFN-gamma expression over 2 to 5 days and a return to baseline by 7 to 14 days. Injection of tumors with Ad.mIL-12 (1 x 10(9) plaque-forming units) results in a complete tumor regression in all mice, while those treated with control adenovirus succumb to their tumor. Efficacy is reduced when studies are performed in mice depleted of CD4+ and CD8+ cells or in nude mice. Mice cured of their tumor by Ad.mIL-12 demonstrate specific protective immunity upon rechallenge. Ad.mp40 does not exhibit antitumor activity and may antagonize the activity of rIL-12 or Ad.mIL-12. In summary, gene therapy strategies for cancer using adenoviral vectors containing IL-12 are highly effective with no significant toxicity in mice.
IL-13 inhibits TNF production but potentiates that of IL-6 in vivo and ex vivo in mice.
Authors: Di Santo E , Meazza C , Sironi M , Fruscella P , Mantovani A , Sipe J D , Ghezzi P 
Published: December 2022

Abstract
IL-13 was reported to inhibit the synthesis of various cytokines in vitro, including that of TNF. It has divergent effects on IL-6 production, which is increased in endothelial cells and decreased in monocytes. We studied the effect of IL-13 administration on TNF and IL-6 production in vivo in mice. IL-13 (1 microg/mouse, i.v., 10 min to 6 h before LPS) decreased LPS (100 ng/mouse, i.v.)-induced serum TNF levels by 50%, while it increased the levels of IL-6 by fourfold. IL-13 potentiated IL-1beta (100 ng/mouse, i.v.)-induced serum IL-6 levels as well as IL-1- or LPS-induced serum amyloid A. When blood from IL-13-treated mice was stimulated with LPS in vitro, TNF production was decreased fivefold, and that of IL-6 was slightly decreased. We also cultured in vitro the aorta obtained from IL-13-pretreated mice and found that they produce more IL-6 (up to sevenfold) than aorta from control mice. Little or no TNF could be detected in these samples. Thus, IL-13 in vivo inhibits serum TNF but up-regulates serum IL-6. The differential regulation of IL-6 and TNF together with the results of ex vivo experiments could be explained by hypothesizing that the cellular origins of the two cytokines are different.
Cyclooxygenase-2-dependent delayed prostaglandin D2 generation is initiated by nerve growth factor in rat peritoneal mast cells: its augmentation by extracellular type II secretory phospholipase A2.
Authors: Murakami M , Tada K , Nakajima K , Kudo I 
Published: December 2022

Abstract
When rat serosal connective tissue mast cells (CTMC) were stimulated with nerve growth factor (NGF), the immediate prostaglandin D2 (PGD2) generation was followed by delayed PGD2 generation that occurred between 2 and 24 h, reaching levels as high as 50 ng and 260 ng/10(6) cells in the absence or presence of lysophosphatidylserine (lysoPS), respectively. This delayed PGD2 generation was accompanied by de novo induction of cyclooxygenase (COX)-2, with NGF and lysoPS acting as inducer and enhancer, respectively. COX-2 induction and the attendant delayed PGD2 generation in CTMC were modestly induced by c-kit ligand, but not by Fc epsilonRI cross-linking. This indicated that the stimulus specificity differed from that observed in the immediate phase, in which NGF, c-kit ligand, and Fc epsilonRI cross-linking, either in combination with each other or with lysoPS as a cofactor, elicited comparable levels of PGD2 generation within 10 min, reaching 10 to 20 ng/10(6) cells. Addition of type II secretory phospholipase A2 (sPLA2), a PLA2 isoform that is detected in microg/ml levels in inflammatory exudates, to NGF-stimulated CTMC significantly augmented delayed, but not immediate, PGD2 generation, and this augmentative effect was mediated in part by the enhancement of COX-2 expression by sPLA2. These results suggest that CTMC have the capacity to produce PGD2 over a prolonged period in the presence of tissue-derived cytokines and sPLA2 in a COX-2-dependent manner.
Recombinant histamine-releasing factor enhances IgE-dependent IL-4 and IL-13 secretion by human basophils.
Authors: Schroeder J T , Lichtenstein L M , MacDonald S M 
Published: December 2022

Abstract
Human recombinant histamine-releasing factor (HrHRF) is known to directly stimulate histamine release and IL-4 secretion from basophils of selected atopic donors in a reaction requiring the expression of a particular type of IgE, referred to as IgE+. In this study, HrHRF is shown to affect the IgE-mediated release of IL-4, IL-13, and histamine from basophils not normally releasing to this protein (i.e, those expressing IgE-). Priming with several different concentrations of HrHRF for 15 min enhanced basophil secretion of IL-4 and histamine after 4 h in a dose-dependent fashion following activation with anti-IgE Ab (10 ng/ml). This effect of HrHRF priming also occurred in cultures activated with 1 or 100 ng/ml of anti-IgE Ab. The secretion of IL-13 protein was enhanced similarly by HrHRF priming in cultures stimulated for 16 to 20 h with anti-IgE Ab. There were, however, no apparent changes in the secretion of histamine or cytokine by basophils primed with HrHRF and activated with the IgE-independent secretogogue, FMLP. These findings suggest that HrHRF modifies the response of basophils for IgE-dependent secretion by binding to a specific receptor, broadening the possible role of this protein in chronic allergic inflammation.
Identification of rat prostatic steroid-binding protein as a target antigen of experimental autoimmune prostatitis: implications for prostate cancer therapy.
Authors: Liu K J , Chatta G S , Twardzik D R , Vedvick T S , True L D , Spies A G , Cheever M A 
Published: December 2022

Abstract
The long term goal of this study is to develop autoimmune prostatitis as a therapy for prostate cancer. An immune attack capable of destroying normal prostate epithelial cells should also destroy malignant prostate tissue and provide therapeutic benefit in cancer patients. The current study was initiated to identify antigenic targets for experimental autoimmune prostatitis on the assumption that such proteins might also be suitable targets for immunotherapy of prostate cancer. Male Lewis rats were immunized with syngeneic prostate homogenates, and the immune sera were used to screen prostate proteins for immunoreactivity by Western blot analysis. The dominant protein recognized by the immune sera was purified by ion exchange chromatography and reverse phase HPLC. Microsequence analysis of two polypeptide components of this immunodominant protein demonstrated N-terminal sequences identical with two of the three component chains of rat prostatic steroid-binding protein (PSBP). T cell responses to PSBP were also detected in rats immunized with prostate homogenate. Immunizing male rats with purified PSBP induced vigorous Ab and T cell responses. Significant prostate inflammation was observed in some rats immunized with PSBP. Adoptive transfer of T cells immune to PSBP induced rapid and severe destructive autoimmune prostatitis. These results demonstrate that PSBP is a major target Ag of experimental autoimmune prostatitis in a rat model and may serve as a target Ag for vaccine and T cell therapy against prostate cancer.
Inactivation of lck and loss of TCR-mediated signaling upon persistent engagement with complexes of peptide:MHC molecules.
Authors: Lee J E , Cossoy M B , Chau L A , Singh B , Madrenas J 
Published: December 2022

Abstract
T cell activation follows recognition of specific peptide:MHC molecule complexes in the context of proper costimulation. The earliest detectable event in T cell activation, within seconds of TCR ligand recognition, is tyrosine phosphorylation of TCR subunits. This causes a cascade of events leading to up-regulation of gene transcription that will drive T cell proliferation and differentiation. Regulation of TCR-mediated signaling upon T cell commitment is unclear. Here, we report that persistent stimulation of T cells, beyond 10 min, correlated with a reversible decrease in tyrosine phosphorylation of T cell lysates that did not affect T cell commitment to proliferation. Loss of Ag-induced tyrosine phosphorylation was not due to lack of Ag presentation, loss of TCR expression, or T cell death, but, rather, it was associated with a lack of TCR subunit tyrosine phosphorylation. We termed this phenomenon TCR desensitization by analogy to the loss of signaling observed in other receptor systems upon persistent engagement with agonist ligands. TCR desensitization correlated with surface reexpression of TCR without concomitant reexpression of coreceptor molecules. Biochemically, TCR desensitization correlated with increased levels of serine-phosphorylated lck, loss of lck kinase activity, and reversible loss of cytosolic lck. Thus, TCR signaling is regulated by desensitization that may be due to serine phosphorylation of lck causing inactivation and loss of this src kinase. This may have important implications by preventing TCR signaling and activation-induced cell death once the T lymphocyte is committed to proliferate.
Antigen recognition and allogeneic tumor rejection in CD8+ TCR transgenic/RAG(-/-) mice.
Authors: Manning T C , Rund L A , Gruber M M , Fallarino F , Gajewski T F , Kranz D M 
Published: December 2022

Abstract
Three sources of help for the development of a CD8+ CTL response have been described: the CD4+ direct and indirect pathways and the CD8+ direct pathway. In an effort to understand the minimal requirements for the development of a CTL response in vivo, we have bred mice transgenic for the 2C TCR onto a RAG(-/-) background. The 2C T cells in this animal are exclusively CD8+ CTLs of a single specificity, and they exhibit altered thymic maturation compared with that of T cells from 2C TCR/RAG(+/+) mice. T cells from 2C TCR/RAG(-/-) mice can be activated to a high level in vivo by administration of a self-MHC-restricted antigenic peptide. The 2C TCR/RAG(-/-) mice are able to reject B7-negative allogeneic tumors bearing the appropriate peptide/MHC ligand p2C/Ld. These mice fail to reject syngeneic tumors, and their RAG(-/-) littermates lacking 2C T cells uniformly succumb to both allogeneic and syngeneic tumors. Moreover, blockade of B7 costimulatory molecules fails to prevent tumor rejection in the 2C TCR/RAG(-/-) mice, suggesting that allorejection is occurring independently of B7-mediated costimulation as well as in the absence of CD4+ T cells. CTLs isolated from the site of the tumor during the period of rejection express the activation marker CD25 and are able to mediate ex vivo cytolysis of tumor cells bearing the appropriate Ag. These results suggest that in this TCR transgenic model with a very high precursor frequency, CTL development can occur in the absence of B7:CD28 costimulation and without CD4+ help.
Transcriptional regulation of the junB gene in B lymphocytes: role of protein kinase A and a membrane Ig-regulated protein phosphatase.
Authors: Amato S F , Nakajima K , Hirano T , Chiles T C 
Published: December 2022

Abstract
We have examined herein whether membrane Ig (mIg) stimulates junB transcription through a protein kinase A (PKA)-dependent or PKA-independent pathway. PKA phosphotransferase activity was not increased following mIg cross-linking of Bal17 B cells. However, junB transcriptional activation was dependent upon PKA activity, as evidenced by inhibition of goat anti-mouse IgM-stimulated junB promoter-chloramphenicol acetyltransferase reporter gene activity in transfected Bal17 B cells treated with the PKA inhibitor H-89. mIg-stimulated junB promoter-chloramphenicol acetyltransferase activity was also blocked in B cells expressing a specific PKA inhibitor peptide, whereas in vivo expression of an inactive PKA inhibitor peptide variant was not inhibitory. Expression of a mutant cAMP response element binding protein (CREB) containing an inactivated kinase A phosphoacceptor site at Ser133 reduced mIg-stimulated junB transcription. Okadaic acid increased CREB1 phosphorylation at Ser133 and junB transcriptional activation, suggesting the action of protein phosphatase-1 (PP-1) or -2A (PP-2A). Extracts from unstimulated B cells exhibited phosphatase activity against an in vitro PKA-phosphorylated peptide containing the Ser133 phosphoacceptor site. The involvement of a phosphatase activity in regulating mIg-stimulated junB transcription is supported by our finding that extracts from goat anti-mouse IgM-stimulated B cells exhibited a significantly reduced level of Ser133 phosphatase activity. Hence, the level of CREB1 phosphorylation is governed by the balance between PKA and phosphatase activities. junB transcriptional activation results in part from mIg signals that negatively regulate a CREB1-targeted PP-1 or PP-2A activity.
IL-4 prevents insulitis and insulin-dependent diabetes mellitus in nonobese diabetic mice by potentiation of regulatory T helper-2 cell function.
Authors: Cameron M J , Arreaza G A , Zucker P , Chensue S W , Strieter R M , Chakrabarti S , Delovitch T L 
Published: December 2022

Abstract
Beginning at the time of insulitis, nonobese diabetic (NOD) mice demonstrate a thymocyte and peripheral T cell proliferative hyporesponsiveness induced by TCR cross-linking, which is associated with reduced IL-2 and IL-4 secretion. We previously reported that NOD CD4+ T cell hyporesponsiveness is reversed completely in vitro by exogenous IL-4, and that administration of IL-4 to NOD mice prevents the onset of insulin-dependent diabetes mellitus (IDDM). This result suggested that T cell-mediated destruction of pancreatic islet beta cells may result from a hyporesponsiveness in regulatory Th2 cells favoring a Th1 cell-mediated environment in the pancreas. In the present study, we tested this possibility by analysis of the mechanisms of protection from IDDM afforded by IL-4 treatment in NOD mice. We show that IL-4 protects NOD mice from insulitis and IDDM when administered i.p. three times a week for 10 wk beginning at 2 wk of age. This occurs by the modulation of the homing of autoreactive cells to inflammatory sites and the stabilization of a protective Th2-mediated environment in the thymus, spleen, and pancreatic islets. Thus, IL-4 treatment favors the expansion of regulatory CD4+ Th2 cells in vivo and prevents the onset of insulitis and IDDM mediated by autoreactive Th1 cells.