bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of D, JH, and junctional diversity in the fetal, adult, and aged B cell repertoires.
Authors: Bangs L A , Sanz I E , Teale J M 
Published: December 2022

Abstract
Polymerase chain reaction-amplified cDNA libraries of the IgH genes of fetal, young adult, and aged BALB/c mice were sequenced so that the complimentarity determining region 3 (CDR3) in each could be analyzed. The results show extensive diversity in the CDR3 region in all three libraries examined. A prominent feature of the fetal repertoire is the lack of nucleotide region additions and shorter germline-derived D segments compared with the adult repertoires. Also of interest were distinct differences in D family and JH usage in the three libraries representing different stages of ontogeny. The absence of DFL16.2 in the fetal sequences analyzed was of particular note. Also of note was a substantial underutilization of the largest D family, DSP2, in the aged repertoire. The study provides further evidence that the Ig repertoire is developmentally regulated. In addition, the results indicate that several aspects of the recombination process are different in adult and fetal B lineage cells, suggesting that B cells present early in ontogeny are distinct from those present in the adult.
T cell recognition of transforming proteins encoded by mutated ras proto-oncogenes.
Authors: Peace D J , Chen W , Nelson H , Cheever M A 
Published: December 2022

Abstract
Activated ras proto-oncogenes contribute to the pathogenesis of many animal and human malignancies. ras proto-oncogenes are generally activated by point mutations within codons 12 or 61, which result in the expression of ras protein (p21) bearing characteristic single amino acid substitutions at the corresponding residues. The purpose of the current study was to determine whether the presence of single transforming amino acid substitutions can render normal ras protein immunogenic and, thus, a possible target for T cell-mediated tumor therapy. In initial experiments, C57BL/6 mice were immunized with a synthetic peptide corresponding to residues 5 through 16 of p21 containing the transforming substitution of arginine for normal glycine at residue 12. The results demonstrated that class II MHC-restricted T cells which were specific for the peptide could be elicited, and that the peptide-induced T cells could specifically recognize the corresponding intact p21 ras protein. Recognition of p21 ras protein by peptide-specific T cells implies that C57BL/6 APC can process the activated ras protein in a fashion that allows presentation of digested protein by class II MHC molecules in a configuration similar to the configuration with synthetic peptide. Evaluation of the immunogenicity of peptides containing alternative transforming amino acid substitutions of ras protein demonstrated that some, but not all, were immunogenic in individual strains of mice. Therefore, although ras protein-specific T cells can be elicited by immunization with synthetic peptides, not all of the potential ras mutations commonly associated with malignancy may be recognizable by T cells from all individuals.
Substance P acts directly upon cloned B lymphoma cells to enhance IgA and IgM production.
Authors: Pascual D W , Xu-Amano J C , Kiyono H , McGhee J R , Bost K L 
Published: December 2022

Abstract
The IgA producing murine B lymphoma, CH12.LX.C4.4F10 (4F10) and the IgM producing murine lymphoma, CH12.LX.C4.5F5 (5F5) were found to express substantial numbers of substance P (SP) receptors having dissociation constants equal to 0.69 nM. Binding of SP by these B lymphoma cells was via the tachykinin-specific C-terminus sequence, Phe-X-Gly-Leu-Met-NH2, because SP, SP antagonist (D-Pro2-D-Phe7-D-Trp9-SP), eledoisin, and substance K could effectively inhibit radiolabeled SP binding, whereas the SP N-terminus fragment, SP (1-4), could not. The functionality of these receptors could be demonstrated by the ability of subnanomolar concentrations of SP to induce Ig secretion in a dose-dependent fashion. However, the presence of a second stimulus in these cultures was required to obtain maximal increases. IgA secretion by 4F10 cells was elevated only 25 to 37%, and IgM secretion by 5F5 cells was not significantly increased in cultures in which nanomolar concentrations of SP were present. Conversely, coculturing 5F5 cells with a suboptimal concentration of LPS (50 ng/ml) and 10(-10)M SP resulted in an approximate threefold increase in supernatant IgM when compared to control cultures stimulated with LPS alone. While not as dramatic, 10(-10) M SP also enhanced IgA secretion of LPS-stimulated 4F10 cells by approximately 45%. This enhancement of Ig secretion was SP-specific, as evidenced by the ability of 1000-fold excess of SP antagonist to block SP-induced, but not LPS-induced, Ig production. Clearly, SP could act synergistically with LPS to enhance Ig secretion; therefore, we questioned whether this augmentation was also reflected at the level of H chain mRNA expression. 10(-9)M SP induced modest increases (50 to 60%) in mu-chain mRNA expression by LPS-stimulated 5F5 cells when compared with cells stimulated with LPS alone. The 4F10 cells did not display this magnitude of difference for alpha-chain mRNA expression. Thus, although SP-induced increases of mu-chain mRNA by 5F5 cells may contribute to the increased Ig secretion observed by these LPS-activated lymphocytes, it is unlikely that increased mRNA expression can totally account for the threefold increases in secretion that were observed.
Cyclic AMP directly inhibits IL-2 receptor expression in human T cells: expression of both p55 and p75 subunits is affected.
Authors: Krause D S , Deutsch C 
Published: December 2022

Abstract
Using purified human T lymphocytes stimulated in serum-free media with adhered anti-CD3 + exogenous IL-2, we have shown that elevated [cAMP]i (mimicked by CPT-cAMP or induced by the physiological agonist PGE2) directly inhibits mitogen-induced 1) [3H]thymidine incorporation by PBMC, purified T cells, and isolated CD4+ and CD8+ T cell subpopulations; 2) expression of both high- and low-affinity IL-2 receptors; 3) plasma membrane expression of both p55 and p75 subunits of the IL-2 receptor; and 4) expression of p55 mRNA, but not p75 mRNA. The decrease in p55 mRNA is not due to enhanced mRNA metabolism. We conclude that elevated [cAMP]i, acting directly on T cells, inhibits mitogenesis by decreasing IL-2 receptor expression. We discuss the possible physiological relevance for the multiple stages of T cell activation that are sensitive to elevated [cAMP]i.
The ability of cultured Langerhans cells to process and present protein antigens is MHC-dependent.
Authors: Aiba S , Katz S I 
Published: December 2022

Abstract
There is controversy regarding the ability of short term (2 to 3 days) cultured epidermal Langerhans cells (cLC) to process and present intact protein Ag to primed T cells. Some studies have shown that cLC are potent APC for both haptens and intact protein Ag, whereas in others cLC have been unable to process and present intact protein Ag. In an attempt to resolve this controversy, we tested the ability of Langerhans cells from several strains of mice to process and present intact protein Ag to T cell clones and T cell hybridomas. We found that both cLC and freshly prepared Langerhans cells from various Iak mice, including BALB.k mice, process and present intact protein antigens (i.e., hen egg lysozyme, cytochrome c, and OVA) to T cells. These functions are retained in cLC cultured for 7 days. In contrast, cLC from Iad mice do not process intact protein Ag, such as hen egg lysozyme and myoglobin, although they can present relevant peptides to specific T cells and are potent stimulators of allogeneic responses. Furthermore, cLC from (Iak x Iad)F1 mice process and present intact protein Ag to Iak-restricted T cells, but not to Iad-restricted T cells. Although cLC that processed and presented intact protein Ag to T cells exhibited enhanced class II MHC expression, they were, on a per cell basis, somewhat less efficient than were fresh Langerhans cells. Finally, we found that if Iad Langerhans cells are pulsed with intact protein Ag and then cultured for 3 days, they are then fully capable of inducing Ag- and MHC-specific T cell proliferation.
Regulation of expression of CD27, a T cell-specific member of a novel family of membrane receptors.
Authors: de Jong R , Loenen W A , Brouwer M , van Emmerik L , de Vries E F , Borst J , van Lier R A 
Published: December 2022

Abstract
CD27 belongs to a newly defined family of transmembrane R, including the nerve growth factor R, two distinct TNF R and CD40. The function of CD27 is unknown, but on the basis of structural and functional properties, we postulate that it plays a role in the events subsequent to T cell activation, possibly as a cytokine R. We have analyzed the mechanisms underlying the regulation of CD27 protein expression. Membrane expression of CD27 strongly increases after T cell activation via the TCR/CD3 complex or the CD2 molecule. In contrast, direct stimulation of protein kinase C by phorbol esters markedly down-regulates CD27 surface expression. This down-regulation most likely does not result from CD27 phosphorylation, because both anti-CD3 mAb and PMA induce hyperphosphorylation of CD27 on serine residues. Rather, membrane expression seems to be regulated primarily at the RNA level. Stimulation of T cells with anti-CD3 mAb strongly increases steady state CD27 mRNA levels, whereas PMA treatment greatly reduces these transcript levels. Dissection of the TCR/CD3-induced signaling pathways showed that cytoplasmic cAMP as well as Ca2+ concentrations contribute to the increase of CD27 expression. These data indicate that upon Ag-specific T cell stimulation, membrane expression of CD27 is regulated at the RNA level through the joint action of distinct TCR/CD3-associated signaling pathways.
Reconstitution of an active surface CD2 by DNA transfer in CD2-CD3+ Jurkat cells facilitates CD3-T cell receptor-mediated IL-2 production.
Authors: Makni H , Malter J S , Reed J C , Nobuhiko S , Lang G , Kioussis D , Trinchieri G , Kamoun M 
Published: December 2022

Abstract
To investigate the requirements for CD2 expression in the activation of T lymphocytes via the CD3-TCR complex, we produced and characterized a series of CD2-variants of the IL-2 producing Jurkat leukemia cell line, J32 (surface phenotype, CD2+, CD3+, CD28+). These mutants were derived by radiation and immunoselection, and were cloned under limiting dilution conditions. A total of 3 out of 30 of these mutants selectively lost the expression of both CD2 surface molecules and CD2 mRNA, and retained the expression of the CD3-TCR complex and the CD28 molecule. A mitogenic combination of anti-CD2 antibodies (9.6 + 9-1) failed to stimulate activation of these variants as measured by mobilization of intracellular Ca2+ and by IL-2 production. The CD2- mutants stimulated with anti-CD3 or anti-TCR mAb revealed an 8- to 32-fold decrease in IL-2 production and IL-2 mRNA accumulation as compared with the parental cells. No alteration of CD3-TCR-induced mobilization of intracellular Ca2+ was observed in the CD2- mutants. Reconstitution of CD2 expression by gene transfer in two J32 CD2- mutants restored IL-2 production and IL-2 mRNA accumulation in responses to both anti-CD2 and anti-CD3-TCR mAb. These results are the first direct demonstration of the requirement for CD2 molecules in optimizing IL-2 response in human T cells stimulated via CD3-TCR complex.
Aspirin-like drugs prime human T cells. Modulation of intracellular calcium concentrations.
Authors: Flescher E , Fossum D , Gray P J , Fernandes G , Harper M J , Talal N 
Published: December 2022

Abstract
Aspirin-like drugs (ALD) enhance T cell proliferation by suppressing PG production in monocytes. Normal human T cells do not produce any eicosanoids. Therefore we studied whether ALD would affect purified T cells directly. We found that ALD enhanced the proliferation and IL-2 production of T cells in the absence of monocytes. This effect did not depend on arachidonic acid metabolism as no lipoxygenase products and only nonsuppressive levels of cyclooxygenase products were detected in T cell cultures. Several possible mechanisms of the ALD effect were ruled out including 1) enhanced mitogen binding, 2) induction of activation markers (IL-2R, transferrin receptor, HLA-DR) on the cell surface, 3) down-regulation of suppressor cells. ALD caused a rise in [Ca2+]i which appeared to reflect an influx of Ca2+ from the extracellular milieu and was more pronounced in CD4+ cells. The rise in intracellular levels of Ca2+, that is considered a necessary second messenger for T cell activation, may prime these cells for an enhanced response to mitogens. In addition, ALD increased T cell membrane fluidity but only at higher concentrations than those found to enhance proliferation. The pharmacologic effect of ALD on T cells presents a possible new immunoenhancing potential of these drugs and may have therapeutic use in immunosuppressed individuals.
Effects of transforming growth factor-beta and IL-1 alpha on prostaglandin synthesis in serum-deprived osteoblastic cells.
Authors: Marusić A , Kalinowski J F , Harrison J R , Centrella M , Raisz L G , Lorenzo J A 
Published: December 2022

Abstract
We investigated the effects that the combination of IL-1 alpha and transforming growth factor-beta (TGF-beta) had on PGE2 production in a murine clonal osteoblastic cell line MC3T3-E1 and primary rat calvarial osteoblast-like cells. In serum-supplemented medium, IL-1 alpha was a potent stimulator of PGE2 production in MC3T3-E1 cells (50-fold increase with 0.1 ng/ml). TGF-beta (10 ng/ml) had only a small effect alone and no additional effect on IL-1 alpha-induced responses. In serum-deprived MC3T3-E1 cells, PGE2 responses to IL-1 alpha were either absent or markedly reduced. TGF-beta alone had small effects. However, simultaneous addition of TGF-beta with IL-1 alpha to MC3T3-E1 cells partially restored the ability of IL-1 alpha to generate a PGE2 response (10-fold increase in PGE2 with 0.1 ng/ml of both IL-1 alpha and TGF-beta). As with MC3T3-E1 cells, serum-deprived primary fetal rat calvarial osteoblastic cells also did not respond to IL-1 alpha, unless TGF-beta was present in the medium (sixfold increase in PGE2 with 0.1 ng/ml IL-1 alpha and 10 ng/ml TGF-beta). The synergistic effect of TGF-beta and IL-1 alpha was specific for PGE2 responses, because these factors did not synergistically affect cell proliferation, collagen and noncollagen protein synthesis, or alkaline phosphatase activity. The observed synergy was not associated with changes in the steady state cyclooxygenase (PGH synthase) mRNA levels. However, it did correlate with increased release of [3H]arachidonic acid from prelabeled serum-depleted MC3T3-E1 cells. Hence, the synergistic interactions of IL-1 alpha and TGF-beta on PGE2 appear to occur through an increase in the release of arachidonic acid substrate from phospholipid pools. These effects may be important for both normal bone turnover and the responses of bone to inflammatory and immune stimuli.
Recombinant human granulocyte colony-stimulating factor improves the compromised state of recipient mice without affecting the induction of specific tolerance in the cyclophosphamide-induced tolerance system.
Authors: Nishimura Y , Mayumi H , Tomita Y , Eto M , Maeda T , Nomoto K 
Published: December 2022

Abstract
The effects of recombinant human granulocyte CSF (rhG-CSF) on cyclophosphamide (CP)-induced tolerance was studied. In the recipient C57BL/10 Sn Slc (B10) mice given 1 x 10(8) B10.BR Sg Sn Slc (B10.BR) spleen cells (SC) on day -2 followed by 200 mg/kg CP on day 0, the number of leukocytes and neutrophils in the periphery declined to their minimum levels on day 4. When rhG-CSF in a dose of 200 micrograms/kg was given daily for 5 days to the B10 mice, which had been treated with B10.BR SC and CP, starting one day after the administration of CP, the leukocyte and neutrophil counts declined to the same levels as those in the B10 mice treated with B10.BR SC and CP alone on day 2. On day 4, however, the counts recovered to their normal levels. The nucleated cell count of the spleen in the B10 mice given B10.BR SC and CP followed by rhG-CSF decreased less and recovered faster than that in the B10 mice given B10.BR SC and CP. The case was found to be the same in bone marrow, and the difference did not reach statistical significance. When the recipient mice were inoculated i.p. with 4 x 10(4) Pseudomonas aeruginosa (GNB-139) on day 4, the survival of the B10 mice treated with B10.BR SC and CP was markedly improved by rhG-CSF administration. The administration of rhG-CSF did not affect either the prolongation or the specificity of skin allograft survival, as shown in an H-2 mis-matched combination of B10.BR----B10 and in an H-2 identical combination of AKR/J Sea(AKR)----C3H/HeN Crj (C3H). The tolerant state, which was demonstrated by various immune responses, such as CTL, delayed footpad reaction, and antibody, was also not affected by rhG-CSF. Furthermore, the basic mechanisms for inducing a long-lasting skin allograft tolerance in this system--namely, the specific destruction of Ag-stimulated and then proliferating mature T cells in the periphery, the establishment of mixed chimerism, and the intrathymic clonal deletion of immature T cells--were preserved even when rhG-CSF was given to C3H mice previously made tolerant of AKR.
Epitopes of the p70 and p80 (Ku) lupus autoantigens.
Authors: Reeves W H , Pierani A , Chou C H , Ng T , Nicastri C , Roeder R G , Sthoeger Z M 
Published: December 2022

Abstract
High titer autoantibodies to the Ku Ag, a DNA-protein complex containing 70- and approximately 80-kDa protein subunits (p70 and p80, respectively), are found in sera of certain patients with systemic lupus erythematosus and related disorders. Autoepitopes of the Ku Ag were identified and partially characterized by expressing fragments of the p70 and p80 cDNA as fusion proteins in bacteria. Systemic lupus erythematosus sera reacted on immunoblots with at least three epitopes of p70 (amino acids 560-609, 506-535, and 115-467), and three epitopes of p80 (amino acids 682-732, 558-681, and 1-374). These six antigenic regions had distinct amino acid sequences, and were also immunologically distinct, as determined by using immunoaffinity-purified auto-antibodies to particular epitopes. Detailed mapping of the strongly antigenic region near the C terminus of p70 revealed a complex conformational or discontinuous epitope, the antigenicity of which was abolished by deleting either amino acids 560-571 or 601-609. The C terminus of p80 may also contain a discontinuous or conformational epitope(s). Although only some sera reacted with p70 or p80 on immunoblots, all sera that immunoprecipitated the native Ku complex reacted with native Ku by ELISA, and inhibited the binding of mAb directed at epitopes of native Ku. Taken together, these studies indicate that anti-Ku autoantibodies target a diversity of independent epitopes located on p70, p80, and the intact Ku complex, and that a significant portion of the autoantibodies in most patients' sera is directed against conformational/discontinuous epitopes.
Mechanisms of host defense against Candida species. I. Phagocytosis by monocytes and monocyte-derived macrophages.
Authors: Maródi L , Korchak H M , Johnston R B 
Published: December 2022

Abstract
We studied the biochemical basis of phagocytosis of Candida albicans, a serious pathogen, and Candida parapsilosis, which is rarely pathogenic, by human monocytes (Mo) and monocyte-derived macrophages (MDM). Optimal phagocytosis of both species by Mo required the presence of extracellular Ca2+ and opsonization through both the classic and alternative complement pathways. Serum-opsonized Candida were ingested equally by Mo and MDM; unopsonized Candida were phagocytosed only by macrophages, and uptake began slowly. This opsonin-independent phagocytosis required Ca2+ and could be blocked by yeast mannan or mannose-BSA conjugate, suggesting a role for the mannose receptor. Opsonized Candida elicited a vigorous increase in the concentration of [Ca2+]i in Mo and MDM, but no Ca2+ transient was detected in MDM stimulated with unopsonized Candida. Pretreatment of MDM with ionomycin to increase [Ca2+]i had no effect on phagocytosis of unopsonized Candida. Addition of 5 mM EGTA completely inhibited changes in [Ca2+]i in Mo and MDM, suggesting that the Ca2+ transient induced by opsonized Candida is due to an influx of extracellular Ca2+. Differences in pathogenicity between the two Candida species could not be explained by differences in any aspect of phagocytosis. Uptake mediated by the macrophage mannose receptor could play a role in clearance of Candida under opsonin-poor conditions.
Probing VH gene-family utilization in human peripheral B cells by in situ hybridization.
Authors: Zouali M , Theze J 
Published: December 2022

Abstract
Recent studies on the genomic organization of the human Ig VH locus have revealed the presence of an important proportion of VH pseudogenes and a high degree of interspersion among VH gene-family members. The mechanisms of selection of VH genes expressed by differentiating B cells remain to be elucidated. We have made use of RNA-RNA in situ hybridization to probe the repertoire of VH gene-families assembled in peripheral B cells of normal adults. Cells were in vitro activated with mitogens and then hybridized to [35S]-labeled anti-sense RNA probes specific for C mu and C gamma genes, and for the six known human VH gene-families. We found that the numbers of cells expressing C mu and C gamma mRNA were similar to the total numbers of cells expressing members of the six VH gene-families. Therefore, the six known VH gene-families represent essentially the human VH locus. We also found that expression of VH gene-families does not closely correlate with their relative genomic complexity. This apparently biased expression may suggest that in some VH gene-families the ratio of pseudogenes/functional genes is particularly high, and/or that regulatory mechanisms play a major role in shaping the available VH gene repertoire in differentiating B cells.
Anti-C-reactive protein inhibits the calcium-dependent stage of natural killer cell activation.
Authors: Hamoudi W H , Baum L L 
Published: December 2022

Abstract
The studies described in this publication were designed to determine which stage of the NK lytic mechanism is inhibited by anti-C-reactive protein (CRP). Although anti-CRP prevents target cell lysis, it does not block E:T cell conjugate formation. In parallel experiments, the number of conjugates observed in the presence of anti-CRP was normal, whereas the number of target cells killed by this same group of effector cells was greatly inhibited. Since an early stage of NK-mediated lysis requires calcium, conjugates can be synchronized by incubating effector and target cells in the absence of calcium. When conjugates were formed in the absence of calcium, and anti-CRP and calcium were then added to cultures at the same time, anti-CRP inhibited maximally. Anti-CRP continued to inhibit somewhat throughout the calcium-dependent stage but did not block lysis when added after the completion of calcium requiring events. Events that are blocked by anti-CRP must be required for the generation of NK cytotoxic factor because anti-CRP blocks the production of this factor. Once generated, however, anti-CRP does not block the activity of NK cytotoxic factor. This evidence indicates that anti-CRP blocks NK-mediated lysis at the calcium dependent stage of lysis. Events that follow this stage in the lytic process are also inhibited.