bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural auto- and polyreactive antibodies differing from antigen-induced antibodies in the H chain CDR3.
Authors: Chen C , Stenzel-Poore M P , Rittenberg M B 
Published: December 2022

Abstract
We describe three sets of natural (preimmune) polyreactive antibodies and Ag-induced antibodies that share the same VH-VL combinations. The amino acid homology in the VH and VL segments averaged 92%. These sets were found among 49 neonatal and adult natural mAb that were compared with 35 Ag-induced monoclonals produced during the memory response to phosphocholine (PC)-keyhole limpet hemocyanin. Both groups of monoclonals had been selected on the basis of a restricted fine specificity pattern, namely the ability to recognize PC-protein and p-nitrophenyl phosphocholine but not PC. All of the antibodies were tested for reactivity against a panel of 15 self and foreign Ag. Despite their common fine specificity as the basis for selection, 33/49 natural antibodies were poly/auto reactive whereas 0/35 Ag-induced antibodies had such poly/auto reactive properties. The natural antibodies were encoded by genes representing nine different VH families and several V kappa and V lambda families. There were a few replacement substitutions distinguishing the Ag-induced antibodies from the natural antibodies in each set; however, the most noteworthy difference was the extreme variability of CDR3 in the natural antibodies that differed in both length and amino acid sequence from each other and from Ag-induced antibodies. The results suggest that CDR3 of the H chain may play a critical role in distinguishing poly- from monospecific combining sites in natural and Ag-induced antibodies.
Cytokine gene expression after in vivo primary immunization with goat antibody to mouse IgD antibody.
Authors: Svetić A , Finkelman F D , Jian Y C , Dieffenbach C W , Scott D E , McCarthy K F , Steinberg A D , Gause W C 
Published: December 2022

Abstract
Cytokines are important mediators of effector lymphoid cell function during an immune response, but their expression during an in vivo immune response has not been well documented. We analyzed the kinetics of cytokine gene expression during the course of an in vivo primary immune response to goat antibody to mouse IgD antibody. Total RNA was purified from spleens taken from freshly killed BALB/c mice 1 to 7 days after immunization. The reverse transcriptase polymerase chain reaction was used to evaluate the expression of seven cytokine genes, all of which encode cytokines that are secreted by T cells and are important in T and/or B cell activation and differentiation. These were IFN-gamma, IL-2, IL-4, IL-5, IL-6, IL-9, and IL-10. IL-2 and IL-9 exhibited an early elevated expression at days 2 to 3, and declined as the expression of IL-4, IL-6, IL-10, and IFN-gamma increased. In contrast, IL-5 gene expression showed little change, exhibiting a similar pattern to the housekeeping gene, hypoxanthine-guanine phosphoribosyl transferase. Cell sorting of CD4+ and CD4- cells at day 3 and day 5 after immunization revealed that CD4+ cells were the predominant source of the elevated cytokines (with the exception of IL-6). Our results demonstrate a specific and highly reproducible cytokine gene expression pattern during the course of a primary in vivo immune response that is marked by an absence of a clear-cut Th1/Th2 dichotomy.
Anti-IgM-mediated growth inhibition of a human B lymphoma cell line is independent of phosphatidylinositol turnover and protein kinase C activation and involves tyrosine phosphorylation.
Authors: Beckwith M , Urba W J , Ferris D K , Freter C E , Kuhns D B , Moratz C M , Longo D L 
Published: December 2022

Abstract
The RL cell line is an EBV-negative, surface IgM, IgD-positive B lymphoma line, which is significantly growth arrested in the presence of acrylamide-linked antibodies to the surface IgM receptor. We demonstrate here that activation of protein kinase C (PKC) with PMA abrogates anti-IgM-induced phosphoinositide turnover and Ca2+ mobilization; however, growth inhibition is not affected. In addition, inhibitors of PKC are unable to reverse the anti-IgM-mediated growth inhibition. Two-dimensional gel electrophoresis reveals a different pattern of protein phosphorylation after treatment of RL with PMA or anti-IgM. These data strongly suggest that anti-IgM-induced growth inhibition does not rely on phospholipase C-mediated phosphoinositide turnover, Ca2+ mobilization, or PKC activation. On the other hand, the phosphatase inhibitor orthovanadate results in an augmentation of proteins phosphorylated on tyrosine and the growth inhibition which follows anti-IgM treatment. Furthermore, protein tyrosine kinase inhibitors, genistein and herbimycin A, are able to reverse the anti-IgM-induced inhibition of growth. These data demonstrate that multiple signaling pathways are activated by the interaction of anti-IgM with its ligand, and suggest that tyrosine kinase activation is a critical component of the inhibitory response.
Predominant T cell receptor gene elements in TNP-specific cytotoxic T cells.
Authors: Kempkes B , Palmer E , Martin S , von Bonin A , Eichmann K , Ortmann B , Weltzien H U 
Published: December 2022

Abstract
H-2b class I-restricted, TNP-specific CTL clones were obtained by limiting dilution cloning of either short term polyclonal CTL lines or spleen cells of TNP-immunized mice directly ex vivo. Sequence analyses of mRNA coding for TCR alpha- and beta-chains of 11 clones derived from CTL lines from individual C57BL/6 mice revealed that all of them expressed unique but clearly nonrandom receptor structures. Five alpha-chains (45%) employed V alpha 10 gene elements, and four of those (36%) were associated with J beta 2.6-expressing beta-chains. The alpha-chains from these four TCR, moreover, contained an acidic amino acid in position 93 of their N or J region-determined sequences. Clones isolated directly from spleen cells carried these types of receptors at lower frequency, 27% V alpha 10 and 19% J beta 2.6, indicating that bulk in vitro cultivation on Ag leads to selection for these particular receptors. However, even in TNP-specific CTL cloned directly ex vivo, V alpha 10 usage was increased about fivefold over that in Ag-independently activated T cells in H-2b mice (4 to 5%). The selection for V alpha 10/J beta 2.6-expressing cells was obtained repeatedly in other TNP-specific CTL lines from C57BL/6 mice but not in FITC-specific CTL from the same strain or in TNP-specific CTL lines from B10.BR (H-2k) or B10.D2 (H-2d) mice. We conclude from this (a) that the selection for V alpha 10/J beta 2.6+ T cells is driven by the complementarity of these receptors to a combination of TNP and MHC epitopes and (b) that predominant receptor structures reflect the existence of a surprisingly limited number of "T cell-relevant" hapten determinants on the surface of covalently TNP-modified cells.
Differential regulation of surface Ig- and Lyb2-mediated B cell activation by cyclic AMP. I. Evidence for alternative regulation of signaling through two different receptors linked to phosphatidylinositol hydrolysis in murine B cells.
Authors: Muthusamy N , Baluyut A R , Subbarao B 
Published: December 2022

Abstract
The differential effect of cAMP on the regulation of early biochemical and cellular functions mediated through two different receptors on murine B cells are reported here. Surface IgM, the Ag receptor, and Lyb2, a 45-kDa differentiation Ag are concomitantly expressed on mature murine B lymphocytes. Triggering of B cells through these molecules, independently, resulted in inositol 1,4,5-triphosphate (IP3) generation, increase in intracellular Ca2+ levels, and cell enlargement associated with progression of cells from G0 to G1 ultimately resulting in DNA synthesis. Pretreatment of resting B cells with cholera toxin as well as other agents that raise the intracellular cAMP [(cAMP)i] such as forskolin, N6,2'-O-dibutyryl cyclic AMP, and 3-isobutyl-1 methyl xanthine inhibited the Ag receptor but not Lyb2-mediated DNA synthesis. The elevation of (cAMP)i inhibited the surface IgM but not Lyb2-mediated IP3 generation, Ca2+ response, and progression from G0 to G1 phase of the cell cycle. Failure of forskolin or N6,2'-O-dibutyryl cyclic AMP to inhibit Lyb2-mediated responses did not appear to be due to induction of cAMP-specific phosphodiesterase activity. Concentrations of H8 [N-(2-(methylamino)-ethyl)-5-isoquinoline sulfonamide, diHCl] inhibitory to cAMP dependent PKA prevented the inhibitory effect of forskolin on surface IgM-mediated Ca2+ response, suggesting that cAMP exerted its effects through PKA. These findings suggest that distinct PLC-coupled receptors, such as sIgM and Lyb2 molecules in B cells, may use either alternative mechanisms for phosphatidylinositol 4,5-bisphosphate hydrolysis or may use different intermediary transducer molecules that differ in their sensitivity to increased (cAMP)i levels. Thus "cross-talk" among cAMP and phosphatidylinositol signaling pathways was demonstrated for IgM but not Lyb2-mediated B cell activation.
Antigen-specific IGG2A production in response to prostaglandin E2, immune complexes, and IFN-gamma.
Authors: Stein S H , Phipps R P 
Published: December 2022

Abstract
Immune complexes (IC) can inhibit the differentiation of B lymphocytes into IgM secreting plasma cells in both Ag-specific and polyclonal systems. This report describes the ability of IC and IFN-gamma, or IFN-gamma and PGE2 to regulate the class of Ig produced in an Ag-specific system. In an in vitro model system using fluorescein (FL)-Brucella abortus as Ag, we previously showed that IC composed of an anti-FL antibody and FL-Ag inhibited the ability of FL-specific B cells to develop into IgM plaque-forming cells. In addition, PGE2 sensitized resting B cells to IC, whereas pretreatment with IL-4 alleviated the IC-mediated decrease in the IgM anti-FL response. In this manuscript, we demonstrate that IFN-gamma has antagonistic effects compared to IL-4, and potentiates the IC-induced decrease in the IgM antibody response. Interestingly, we discovered that the virtual ablation of the anti-FL IgM response exhibited by B cells treated with IC and IFN-gamma was accompanied by a dramatic increase in the anti-FL IgG2a response. Furthermore, resting B lymphocytes pulsed with IFN-gamma and PGE2, but not PGF2 alpha, exhibited augmented IgG2a production. This effect was also observed when IFN-gamma-pulsed B cells were stimulated with other agents, such as dibutyryl cAMP and cholera toxin, that elevate intracellular levels of cAMP. In addition, RpcAMP, the R-isomer of a sulfur-modified cAMP and a cAMP antagonist, inhibited anti-FL IgG2a responses. The ability of cAMP elevators such as PGE2 to promote IgG2a production, as well as to increase the frequency of IgG2a secreting cells, was demonstrated in B lymphocytes treated with IFN-gamma and polyclonally activated by LPS. Overall, our results demonstrate that IFN-gamma and PGE2-treated B lymphocytes challenged with antigen or LPS generate elevated levels of IgG2a via a cAMP-dependent pathway. These observations suggest that in vivo, PGE2 secreted by cells such as macrophages potentiates the ability of IFN-gamma to promote an IgG2a response, the predominant murine antiviral Ig.
Catecholamines stimulate the IFN-gamma-induced class II MHC expression on bovine brain capillary endothelial cells.
Authors: Coutinho G C , Durieu-Trautmann O , Strosberg A D , Couraud P O 
Published: December 2022

Abstract
The brain has been considered for a long time as an immunologically privileged site because of the lack of a true lymphatic system and the existence of several barriers that isolate it from the periphery. In the last few years, it became evident that cells in the central nervous system (astrocytes, microglial cells, and brain capillary endothelial cells) can be induced to express class II MHC and present Ag to T lymphocytes. The brain capillary endothelial cells, which are strategically located at the interface between blood and brain, could be involved in the initiation of immune responses within the brain parenchyma. We have previously characterized bovine brain capillary endothelial cells in culture and shown that they maintain in vitro a fully differentiated phenotype associated with the blood-brain barrier endothelium. In order to assess the role of these cells in the development of immune responses in the brain, we initiated the present study on the regulation of their class II MHC surface expression. Our data indicate that this expression on bovine brain capillary endothelial cells is inducible by IFN-gamma and further stimulated by catecholamines through activation of beta-adrenergic receptors. However, this latter effect is not mimicked by forskolin, theophylline, or dibutyryl-cAMP, suggesting the involvement of a cAMP-independent mechanism.
Thymic microenvironment induces HIV expression. Physiologic secretion of IL-6 by thymic epithelial cells up-regulates virus expression in chronically infected cells.
Authors: Schnittman S M , Singer K H , Greenhouse J J , Stanley S K , Whichard L P , Le P T , Haynes B F , Fauci A S 
Published: December 2022

Abstract
The hallmark of infection with HIV-1 is progressive depletion and qualitative dysfunction of the CD4+ Th cell population in infected individuals. Clinical trials of antiretroviral agents have shown that, despite suppression of virus replication, regeneration of the T cell pool does not occur. One proposed explanation for the defective regenerative capacity of the CD4+ T cell pool is infection of early T lymphocyte progenitors or stem cells. An additional explanation could be failure of cells of the intrathymic microenvironment (thymic epithelial (TE) cells) to carry out critical nurturing functions for developing thymocytes, i.e., secretion of thymocyte-trophic cytokines and expression of adhesion molecules. This study examines the effect of HIV on cultured TE cells and determines the role of TE cells in the regulation of viral expression in chronically HIV-infected cells. We found no evidence of infection of TE cells after exposure to HIV-1. However, normal human serum induced secretion of IL-6 by TE cells; induction of TE IL-6 was partially blocked by anti-IFN-gamma antibodies. Moreover, supernatants from TE cells maintained in normal human serum up-regulated HIV replication in chronically HIV-1-infected cells. Because intrathymic T cell precursors can be infected with HIV and T cell precursors come into close contact with TE cells in the thymus, IL-6 secreted by TE cells during normal intrathymic development may induce HIV expression in infected thymocytes in vivo and promote the intrathymic spread of HIV.
IL-1 receptor antagonist regulation of acute phase protein synthesis in human hepatoma cells.
Authors: Bevan S , Raynes J G 
Published: December 2022

Abstract
The hepatoma cell line HuH-7 has recently been shown to synthesize serum amyloid A (SAA) in response to IL-1. IL-1 receptor antagonist (IL-1Ra) was able to completely inhibit the response of SAA to IL-1 but not the increase seen in response to IL-6. IL-1Ra was equally effective at inhibiting IL-1 alpha or IL-1 beta. At a 10-fold molar excess of IL-1Ra over IL-1 there was complete inhibition of the SAA response. Removal of IL-1 at 24 h rapidly reduced the SAA secreted over the next 24 h. Addition of IL-1Ra to the cells at this time was as effective as removal of IL-1 at inhibiting the subsequent secretion of SAA. IL-1Ra was less effective at inhibition of IL-1-induced haptoglobin secretion. We would conclude that IL-1Ra may play an important role in the regulation of acute phase protein synthesis.
Murine T cell-stimulatory peptides from the 19-kDa antigen of Mycobacterium tuberculosis. Epitope-restricted homology with the 28-kDa protein of Mycobacterium leprae.
Authors: Harris D P , Vordermeier H M , Roman E , Lathigra R , Brett S J , Moreno C , Ivanyi J 
Published: December 2022

Abstract
Fifteen overlapping synthetic peptides, spanning the entire amino acid sequence of the Mycobacterium tuberculosis 19-kDa protein, were used to identify epitopes recognized by murine T cells. Five of the 15 peptides tested were able to elicit in vitro lymph node T cell proliferative responses in C57BL/10 mice primed by footpad inoculation with homologous peptide. Analysis in congenic strains of mice revealed H-2 restriction in the response to four peptides. However, one peptide, 19.7 (residues 61 to 80), induced T cell responses in all four haplotypes tested. This peptide was also unique in being able to stimulate lymph node cells from C57BL/10 mice immunized with recombinant 19-kDa protein, killed M. tuberculosis, or live bacillus Calmette Guerin infection. T cell lines specific for peptide 19.7 were of the CD4 phenotype. Significantly, sequence analysis revealed that residues 61 to 80 of the 19-kDa protein exhibited considerable homology with a single 20-amino acid sequence (residues 120 to 140), but not with any other region of the 28-kDa protein expressed in Mycobacterium leprae. This finding is the first evidence of epitope-restricted homology between otherwise structurally unrelated microbial Ag.
Distinct patterns of expression of MHC class I and beta 2-microglobulin transcripts at early stages of mouse development.
Authors: Jaffe L , Robertson E J , Bikoff E K 
Published: December 2022

Abstract
The class I surface Ag recognized during tissue graft rejection are composed of a 40- to 45-kDa H chain and a 12-kDa L chain, beta 2-microglobulin (beta 2m). Regulation of MHC gene expression during early development is thought to play an essential role in maternal tolerance of the fetal allograft. Here we used in situ hybridization techniques to characterize the temporal and spatial pattern of expression of MHC class I mRNA in the developing mouse embryo. MHC class I transcripts were initially detected at day 9.5 postcoitus in the primary and secondary trophoblast giant cell populations. At this stage, none of the remaining fetal components of the developing placenta expresses MHC class I mRNA. By contrast, the outer zone of trophoblast giant cells is the only trophectoderm-derived tissue in the developing placenta that does not express detectable levels of beta 2m mRNA. These findings indicate that the onset of MHC class I and beta 2m gene expression in early postimplantation stage embryos is not coordinately regulated. In addition, we made use of pluripotent embryonic stem (ES) cells to study developmental regulation of MHC class I and beta 2m gene expression in vitro. ES cells can be induced to form endoderm-like cells by the technique of suspension culture. In contrast to retinoic acid-treated F9 cells, the endoderm derived from ES cells expressed high levels of beta 2m mRNA, but no detectable MHC class I transcripts. These findings are consistent with results of our in situ hybridization experiments showing high levels of expression of beta 2m mRNA, and extremely weak expression of MHC class I transcripts in derivatives of the visceral endoderm in vivo.
Repertoire diversity of antibody response to bacterial antigens in aged mice. II. Phosphorylcholine-antibody in young and aged mice differ in both VH/VL gene repertoire and in specificity.
Authors: Nicoletti C , Borghesi-Nicoletti C , Yang X H , Schulze D H , Cerny J 
Published: December 2022

Abstract
Aging of mice is accompanied by both quantitative and qualitative changes in antibody responses to phosphorylcholine (PC), an immunodominant epitope of Streptococcus pneumoniae R36a strain (Pn). In order to study these changes at the molecular level, we generated PC-specific hybridomas from young (3 to 4 mo) and aged (20 to 24 mo) mice of different strains after primary immunization with S. pneumoniae R36a strain. These mAb were tested for Ig VH and VL gene family utilization, idiotopic repertoire, and cross-reactivity with unrelated Ag. Hybridomas from young mice (BALB/c, C57BL/6, and D1.LP) uniformly expressed the VH-S107 and V kappa-22 genes as well as most idiotopes of the T15 family, which were identified with different anti-T15 mAb. In contrast, the PC-reactive mAb from aged mice were quite heterogeneous: only 2 out of 13 utilized VHS107, 1 of 13 used VH7183, and 3 of 13 used VHJ558 gene family. Moreover, none of these mAb used L chain encoded by V kappa 22(0/13), but surprisingly they frequently expressed some of the T15 idiotope. In addition, the PC-binding mAb from aged mice showed broad cross-reactivity with various mouse and foreign proteins, whereas the mAb from young mice did not. These results demonstrate the genetic shift in antibody response of aging mice to PC, which is accompanied by a change in the antibody specificity. Interestingly, the qualitative repertoire change appears to be unrelated to the magnitude of antibody response, for the aged BALB/c mice maintain a very high reactivity to PC.
The murine Slp gene. Additional evidence that sex-limited protein has no biologic function.
Authors: Ogata R T , Zepf N E 
Published: December 2022

Abstract
Sex-limited protein (Slp) is a mouse serum protein of unknown function that has approximately 95% amino acid sequence identity with murine complement component C4 but is inactive in the complement pathway. The gene for Slp lies in the S region of the murine H-2 complex adjacent to the gene Cyp21 that encodes the Cytochrome P-450 enzyme steroid 21-hydroxylase. We report the sequence of a 26,307 bp long segment of the mouse genome that includes both the Slp and Cyp21 genes. The sequence reported was assembled from the sequences of three overlapping lambda phage genomic clones from mouse strain B10.WR, which carries four tandem pairs of Slp and Cyp21 genes. We also report the sequence of a fourth lambda clone, 12,539 bp in length, carrying parts of a distinct pair of Slp and Cyp21 genes from B10.WR mice. The Slp gene at 14.3 kb in length is about 1 kb shorter than the C4 gene; this difference is due primarily to absences of a simple repetitive sequence and a middle repetitive MT element in the corresponding introns 14 and 15, respectively. The gene sequence reveals an intron/exon organization identical to that of the murine C4 gene, and also that the 9 nucleotide deletion in exon 18, which appears to be directly responsible for the absence of complement activity, is unrelated to differences in intron sequences. Detailed comparisons of C4 and Slp gene sequences indicate that nucleotide substitutions in the Slp gene are occurring at approximately the same rate in both exons and introns. This implies that the murine Slp gene resembles a pseudogene and supports previously reported evidence that the Slp protein has no biologic function.