bluuebunny/crossref_metadata_2025_split huggingface dataset:
A monoclonal antibody to the NH2-terminal segment of human IFN-gamma selectively interferes with the antiproliferative activity of the lymphokine.
Authors: Caruso A , Tiberio L , De Rango C , Bonfanti C , Flamminio G , Gribaudo G , Monti E , Viani E , Manca N , Garotta G 
Published: December 2022

Abstract
To gain more information about the relationship between the structure of IFN-gamma and its activity, a peptide corresponding to a hydrophilic peak between amino acids 4 and 16 was used to immunize mice and generate mAb. mAb IGMB-15 reacts to both native and rIFN-gamma and neutralizes the antiproliferative activity of IFN-gamma without affecting its antiviral activity or its ability to up-regulate HLA-DR Ag expression. Moreover, we observed that mAb IGMB-15 was unable to inhibit the binding of radiolabeled IFN-gamma to its cellular receptor. These findings show that the NH2-terminal region may somehow be involved in the biologic activity of IFN-gamma. Besides, the capability of mAb IGMB-15 to inhibit the antiproliferative but not the antiviral activity of IFN-gamma in the same cell (HEp-2) suggests the presence of different elements involved in signal transduction, which may account for the multiple activities of the lymphokine.
In vitro selection of RNA epitopes using autoimmune patient serum.
Authors: Tsai D E , Keene J D 
Published: December 2022

Abstract
Nucleotide-specific autoimmune epitopes have not been precisely defined despite the fact that certain kinds of DNA and RNA species are known to bind autoantibodies. Our laboratory has used nucleic acid epitope libraries, consisting of randomized RNA pools, to select specific RNA conformers recognized by antibodies, including a peptide-specific antibody. In the present study, serum from a patient with systemic lupus erythematosus was used to select ligands from an RNA epitope library. The selected RNA contained sequences that were found to be similar to regions within the U1 small nuclear RNA, previously shown to react with autoantibodies. Furthermore, the selected RNA epitopes were able to inhibit autoantibody reactivity with specific regions of U1 RNA, thus demonstrating their immunologic cross-reactivity with the natural RNA epitope. Although the origins of nucleic acid-binding autoantibodies are not understood, the identification of these defined U1 RNA epitopes, in regions of the RNA where cell proteins are not known to bind, is most compatible with models of immunologic cross-reactivity or with direct presentation to the immune system rather than with anti-Id models. These experiments demonstrate that RNA epitope libraries may be used to reveal the fine specificity of autoimmune recognition and provide a useful approach to study RNA-protein interactions.
Biased T cell receptor usage by Ld-restricted, tum- peptide-specific cytotoxic T lymphocyte clones.
Authors: Solheim J C , Alexander-Miller M A , Martinko J M , Connolly J M 
Published: December 2022

Abstract
We have investigated the TCR gene usage in a panel of H-2Ld-restricted, tum- peptide-specific CTL clones. These clones possess identical MHC restriction and peptide specificity, yet they vary dramatically in the amount of peptide required to sensitize targets for recognition. We previously demonstrated a precise quantitative correlation between the determinant density requirement of a given clone and the CD8 dependency. In this study we sequenced polymerase chain reaction copies of the TCR mRNA used by these clones, not only to correlate TCR structure with recognition of a specific class I/peptide complex, but also to determine if the functional affinity differences between these clones is reflected in the TCR gene products used. The number of TCR V beta, V alpha, and J alpha region gene segments expressed by these clones is very limited. Twelve of 17 clones express V beta 8 at comparable levels on the cell surface. Using PCR amplification of cDNA templates, cloning, and dideoxy sequencing, we have obtained the nucleotide sequence of the TCR V-(D)-J regions in seven of the V beta 8+ clones. Two of the clones use V beta 8.2 and identical J alpha gene segments. Three of the five V beta 8.3+ clones express identical V alpha and J alpha gene products and the other two use similar V alpha chains and J alpha chains with a shared motif in the predicted CDR3 region. Although no clear correlation between TCR gene usage and CD8 dependency was seen, the range of TCR gene usage in the tum- peptide-specific, Ld-restricted immune response is strikingly narrow and suggests a coselection of the alpha- and beta- chains for recognition of the class I/peptide complex.
Enhancement of natural killer activity by an antibody to CD44.
Authors: Tan P H , Santos E B , Rossbach H C , Sandmaier B M 
Published: December 2022

Abstract
In this study, we examined the in vitro effect of an anti-CD44 mAb, S5, on NK function using canine PBMC as effectors. S5 enhanced NK activity in a dose-dependent and rapid fashion as did IM7, another anti-CD44 mAb that recognizes a common epitope(s) on CD44. Other anti-CD44 mAb (Hermes-1 and S3) that recognize epitopes distinct from S5 and IM7 had a variable effect on NK activity. The activation of increased killing by S5 only occurred when NK-sensitive targets were used, suggesting that lymphokine-activated killer cells were not being induced. Antibody-dependent cell cytotoxicity was not the mechanism involved in the augmentation of NK activity, nor was it Fc receptor-dependent, inasmuch as S5 F(ab')2 was able to increase NK activity. F(ab') fragments of S5 were equivalent to intact S5 in their ability to stimulate NK activity, demonstrating that cross-linking of CD44 was not a necessary component of stimulation, and that nonspecific agglutination of target and effector cells was not occurring via the two F(ab) arms. The enhancement of NK function was monocyte-independent and mediated by radioresistant cells, indicating that the antibody enhanced NK cells directly. This finding would suggest that CD44 can direct a transmembrane signal for NK cell activation.
Simultaneous ligation of CD5 and CD28 on resting T lymphocytes induces T cell activation in the absence of T cell receptor/CD3 occupancy.
Authors: Verwilghen J , Vandenberghe P , Wallays G , de Boer M , Anthony N , Panayi G S , Ceuppens J L 
Published: December 2022

Abstract
The T cell surface molecules CD5 and CD28 have been shown to be receptors for accessory signals in T cell activation. We here demonstrate that in the absence of any other activating stimulus, simultaneous ligation of CD5 and CD28 by mAb induces polyclonal T cell activation. Immobilization of the anti-CD28 and anti-CD5 mAb was an essential requirement for T cell stimulation. This was done either through coating of the culture plates with goat anti-mouse Ig, or by coculture with mitomycin C-treated Fc gamma R-bearing P815 mouse mastocytoma cells. Most importantly, T cells could also be stimulated with B7, the natural ligand of CD28, and anti-CD5 presented on irradiated 3T6 mouse fibroblasts co-transfected with human Fc gamma RII and with B7. Neither immobilized mAb 9.3 (anti-CD28) nor any of four different anti-CD5 mAb were mitogenic as a sole stimulus. Immobilized mAb identifying CD4, CD7, or LFA-1 were not co-mitogenic with either mAb 9.3 or one of the anti-CD5 mAb. The T cell proliferation induced by cross-linking of CD5 and CD28 is IL-2-dependent, as was demonstrated by the cell-surface expression of the p55 chain of the IL-2R, the production of IL-2, and inhibition of the proliferative response by the anti-IL-2R mAb anti-Tac. CD5/CD28 ligation induced production of TNF-alpha, but not of IL-4, and did not induce modulation of the TCR/CD3 complex. Expression of IL-2R (p55) and of CD69 preferentially occurred on CD29-low naive cells, and indicated that about 50% of the cultured cells were activated. Cell proliferation was not increased by adding monocytes to the cultures and it was inhibited by PKC inhibitors (H7 and staurosporine) and by cyclosporine A. In conclusion, our data provide evidence for a pathway of Ag-independent T cell activation via CD5 and CD28, which preferentially stimulates native T cells.
Multiple changes in VLA protein glycosylation, expression, and function occur during mouse T cell ontogeny.
Authors: Wadsworth S , Halvorson M J , Chang A C , Coligan J E 
Published: December 2022

Abstract
VLA molecules (beta 1 integrins) are cell-surface alpha beta heterodimers that bind to extracellular matrix (ECM) proteins such as fibronectin, laminin, and collagen. We analyzed the expression, structure, and function of VLAs on mouse thymocytes, as a first step toward understanding their role in T cell development. Two major forms of beta 1 were detected, which differed in their extent of N-glycosylation and sialylation. No evidence for alternative splicing of beta 1 mRNA was obtained by PCR analyses. The larger (135 kDa, nonreduced) more basic beta 1 was the only form on nonmature (J11d+) adult thymocytes, with 135 kDa and larger beta 1-chains expressed on fetal thymocytes from day 14 of gestation through birth. The smaller (120 kDa, nonreduced), more acidic beta-chain was found exclusively on mature (J11d-) thymocytes and peripheral lymphocytes. VLA alpha-chain expression was also analyzed. Virtually all thymocytes were VLA-alpha 4+, -alpha 6+. VLA-alpha 5 was detected in both J11d+ and J11d- thymocytes by immunoprecipitation, but could not be analyzed in detail because of the lack of an appropriate mAb for flow cytometry. VLA-alpha 1 and -alpha 2 were immunoprecipitated only from cells within the J11d- population. Only J11d+ thymocytes (12 to 15%) bound to fibronectin (via VLA-4 and VLA-5) and binding to laminin (via VLA-6) was two to fourfold higher in J11d+ compared with J11d- thymocytes (60 to 80% vs 20 to 30%). The high percentage of J11d+ thymocytes adhering to laminin suggests that VLA-6 exists in an activated state on most thymocytes, in contrast to resting peripheral T cells. These data show that major changes in VLA glycosylation, expression, and ECM-binding capacity occur as thymocytes mature, supporting the hypothesis that VLA-ECM interactions play a role in T cell ontogeny.
Function associated with IL-2 receptor-beta on human neutrophils. Mechanism of activation of antifungal activity against Candida albicans by IL-2.
Authors: Djeu J Y , Liu J H , Wei S , Rui H , Pearson C A , Leonard W J , Blanchard D K 
Published: December 2022

Abstract
Polymorphonuclear neutrophils (PMN) are essential components of the host defense system against a wide variety of pathogens. We report here the novel finding that freshly isolated human PMN constitutively express detectable surface levels of IL-2R beta, but not IL-2R alpha, as analyzed by flow cytometry. Northern blot analysis confirmed the constitutive expression of mRNA for IL-2R beta in PMN. Scatchard analysis using 125I-labeled IL-2 demonstrated the presence of approximately 600 intermediate binding IL-2R per PMN, with a dissociation constant of 1.1 x 10(-9) M, similar to that of IL-2 binding to YT-1 tumor cells that specifically express IL-2R beta. More importantly, PMN were able to respond functionally to IL-2 by enhanced growth-inhibitory activity against an opportunistic fungal pathogen, Candida albicans. IL-2 activation of antifungal activity was dose-dependent, with some functional activation detected at 1 U/ml of rIL-2 and maximal activation at 1000 U/ml. The action of IL-2 was rapid, with maximal PMN activation after 30-min incubation with IL-2. The IL-2 enhancement of antifungal activity could be blocked by a specific antibody against IL-2R beta, but not by anti-IL-2R alpha. Analysis of the mechanism of IL-2 activation of PMN indicated that oxidative metabolism, as measured by superoxide anion production, was not involved. Instead, PMN release of lactoferrin appeared to be responsible for the heightened activity against C. albicans in IL-2-treated PMN. Not only was lactoferrin detected in the supernatants of IL-2-treated PMN, but also the antifungal activity of PMN activated by IL-2 could be blocked in the presence of antilactoferrin. These results, taken together, indicate that normal PMN are capable of functionally responding to IL-2 via expression of the IL-2R beta chain.
Serologic analysis of a murine chemokine, TCA3.
Authors: Luo Y , Laning J , Dorf M E 
Published: December 2022

Abstract
The TCA3 gene encodes a proinflammatory cytokine related to IL-8 and MCP-1 (JE). TCA3 mRNA is produced by T cells in response to stimulation with Ag or Con A. Glycosylated and nonglycosylated forms of rTCA3 produced by transfected Chinese hamster ovary cells were purified. rTCA3 was used to immunize hamsters and produce mAb. Four mAb were characterized; each was specific for TCA3, failing to react with the closely related molecule MCP-1 (JE). Western blotting also demonstrated that all four mAb specifically recognize rTCA3, native TCA3 produced by activated mouse T cells, and the nonglycosylated TCA3 core protein. A sensitive and specific capture ELISA for TCA3 quantitation was developed, allowing measurement of TCA3 levels in the supernatants from activated murine splenocytes and T cell clones. In addition, two mAb demonstrated dose-dependent neutralization of TCA3 inflammatory activity. Thus, the results directly demonstrate that TCA3 is expressed in an activation-specific manner by mouse T cells. The data also provide characterization of mAb reagents specific for this new cytokine.
IL-1 and tumor necrosis factor-alpha each up-regulate both the expression of IFN-gamma receptors and enhance IFN-gamma-induced HLA-DR expression on human monocytes and a human monocytic cell line (THP-1).
Authors: Krakauer T , Oppenheim J J 
Published: December 2022

Abstract
Stimulation of human blood monocytes (adherent mononuclear cells) and the monocytic cell line, THP-1, by IL-1 or TNF-alpha leads to the up-regulation of IFN-gamma receptors. Scatchard analysis using 125I-IFN-gamma revealed a twofold increase in the number of IFN-gamma receptors on THP-1 cells without an alteration in the affinity of the receptor. The potential functional significance of this induction of IFN-gamma receptors on monocytes and THP-1 cells was investigated by examining the effect of IFN-gamma on MHC class II Ag expression by these cells. Both IL-1 and TNF-alpha enhanced the IFN-gamma-induced HLA-DR expression (&gt; twofold) and this effect was inhibited by antibody to IFN-gamma. In the case of human monocytes, IL-1 or TNF-alpha, each by themselves also increased HLA-DR expression, which was also abrogated by antibody to IFN-gamma. The data suggest that the immunopotentiating effects of IL-1 and TNF-alpha are mediated in part by enhancing IFN-gamma receptor expression on monocytes and macrophages. This presumably would increase the capacity of IFN-gamma to activate macrophages, enabling them to express HLA-DR and present Ag more effectively.
Primary in vivo responses to ovalbumin. Probing the predictive value of the Kb binding motif.
Authors: Lipford G B , Hoffman M , Wagner H , Heeg K 
Published: December 2022

Abstract
CD8+ cytolytic T cells recognize Ag presented by MHC class I molecules on the surface of target cells. It is known that presenting cells process nascent protein into peptides of approximately eight to nine amino acids which bind to the peptide groove of MHC class I and are transported to the cell surface. Recently, several laboratories have postulated that each MHC class I haplotype has a binding motif of at least two amino acids nested within the peptide. One such motif is XXXXF/YXXL which binds to the mouse MHC class I molecule, H2-Kb, and can be found in the known antigenic peptide from OVA at amino acids 257-264. By using the motif to scan OVA five peptides were found that fit this pattern, OVA 11-18, OVA 55-62, OVA 107-114, OVA 176-183, and OVA 257-264. Binding studies revealed that three out of the five peptides (OVA 55-62, OVA 176-183, and OVA 257-264) bind to MHC class I. To test the natural antigenicity of the predicted peptides, C57BL/6 mice were immunized with OVA containing immunostimulating complexes to elicit a MHC class I-driven response to naturally processed OVA. The cytolytic potential of the responding T cell population was tested in vitro by using EL-4 cells preincubated with the predicted synthetic peptides as targets. The known antigenic peptide OVA 257-264 elicited a strong response; however, OVA 176-183 was also recognized while the remaining three were not recognized. The CTL response did not strictly correlate with the ability of the selected peptides to bind Kb, for example, OVA 55-62 was able to bind Kb efficiently, yet elicited no cytolytic response. In addition, the plasticity of the peptide-binding motif was probed by making amino acid substitutions, and as a result the motif proved to be more flexible than previously suspected. This represents the first report of a Kb-associated CTL epitope within OVA other than OVA 257-264. It also demonstrates the predictive quality of the Kb-binding motif; however, not all predicted peptides were recognized by primary OVA-induced CTL, implying more rules of processing and binding are needed.
Recombinase activating gene expression in thymic subpopulations. A transitional cell type has lost RAG-2 but not RAG-1.
Authors: Campbell J J , Hashimoto Y 
Published: December 2022

Abstract
We have used a highly sensitive Northern blot probing technique to examine RAG-1 and RAG-2 mRNA expression in unmanipulated murine thymocytes of various developmental phenotypes sorted by flow cytometry. We have found that neither RAG-1 nor RAG-2 are down-regulated until thymocytes reach the TCRhi stage. TCRhi, CD8+CD4+ cells have lost RAG-2 mRNA but continue to express significant levels of RAG-1 mRNA, providing molecular evidence that this cell type is transitional between the TCRlo, CD4+CD8+ and the TCRhi, CD4+CD8-, or CD4-CD8+ phenotypes.
Molecular analysis of double isotype expression in IgA switching.
Authors: Kunimoto D Y , Sneller M C , Claflin L , Mushinski J F , Strober W 
Published: December 2022

Abstract
In this and previous studies we have shown that during the course of B cell isotype differentiation occurring in the CH12.LX B cell line, small numbers of cells appear that bear both membrane (m)IgM and membrane IgA. We have cloned relatively stable populations of such dual-bearing cells and have performed studies to determine their molecular status. In the study of one such subclone (CH12.LX.7.10), we show by primer extension that both mu and alpha mRNA contain identical VHDJH gene segments. In complementary studies of another such subclone (CH12.LX.7.13), we show using DNA restriction fragment analysis, that the C mu gene segment, but not the C alpha gene segment, is associated with the JH gene segment. Additionally, Northern blot analysis of productive message of this clone shows that both mu and alpha mRNA cohybridize to the same VH region-specific probe. Taken together, these data suggest that CH12.LX mIgM/mIgA dual-bearing cells occur in the absence of C mu gene segment deletion and that the mu and alpha mRNA transcripts are derived using an alternative mechanism such as transplicing or alternative splicing of a long RNA transcript. On the assumption that these clones are representative of mIgM/mIgA dual-bearing cells appearing during CH12.LX IgM to IgA isotype differentiation, these data support the idea that B cells simultaneously produce mu and alpha mRNA transcripts during one stage of IgA isotype switching.
Cytokine production in BALB/c mice immunized with radiation attenuated third stage larvae of the filarial nematode, Brugia pahangi.
Authors: Bancroft A J , Grencis R K , Else K J , Devaney E 
Published: December 2022

Abstract
BALB/c mice immunized with radiation attenuated third stage larvae of the filarial nematode Brugia pahangi are strongly immune to challenge infection. Investigation of the profile of cytokines secreted by spleen cells from immune mice stimulated in vitro with either parasite Ag or with Con A revealed high levels of IL-5 and IL-9 and moderate levels of IL-4. In contrast, secretion of IFN-gamma by spleen cells from immune animals was negligible. Spleen cells from control mice secreted low levels of all cytokines assayed. Levels of parasite-specific IgE were significantly elevated in immune animals and a peripheral blood eosinophilia was observed, which exhibited a biphasic distribution. Our results are consistent with the preferential expansion of Th2 cells in immune animals and provide the basis for dissecting the means by which radiation attenuated larvae of filarial nematodes stimulate immunity.
Modulation of human basophil histamine release by insulin-like growth factors.
Authors: Hirai K , Miyamasu M , Yamaguchi M , Nakajima K , Ohtoshi T , Koshino T , Takaishi T , Morita Y , Ito K 
Published: December 2022

Abstract
Several lines of evidence indicate that basophils play an active pathogenic role in the late-phase reaction. Inasmuch as various cytokines are produced locally by activated cells of the immune system during late-phase reaction, "priming" of basophils by cytokines has become an area of active study over the last few years. We studied the effect of insulin-like growth factor (IGF)-I, shown to be active on immature and mature hemopoietic cells, on histamine release from human basophils. IGF-I enhanced histamine release initiated by anti-IgE, calcium ionophore A23187, and phorbol ester in a dose-dependent fashion (ED50: 300-600 pM), although IGF-I had little or no effect on the release caused by FMLP and C5a. The priming effect of IGF-I took place rapidly and reached plateau levels in 15 min. IGF-II and insulin, both of which have high amino acid sequence homology with IGF-I, also primed basophils. The order of enhancing potencies was IGF-I &gt; IGF-II &gt; insulin; IGF-I was 10-fold more potent than IGF-II and 250-fold more potent than insulin. Although specific receptors for each factor have been identified, blocking experiments using a mAb against IGF-I receptor showed almost complete abolishment of the enhancing effect of these factors, indicating that the enhancing effect is exhibited via the IGF-I receptor. Inasmuch as IGF-I has been shown to be produced by alveolar macrophages, fibroblasts, and nasal polyps, these results indicate that IGF may regulate allergic reactions in vivo by enhancing histamine release from basophils.
IL-8 induces the locomotion of human IL-2-activated natural killer cells. Involvement of a guanine nucleotide binding (Go) protein.
Authors: Sebok K , Woodside D , al-Aoukaty A , Ho A D , Gluck S , Maghazachi A A 
Published: December 2022

Abstract
The effect of IL-8 on the in vitro locomotion of human IL-2-activated natural killer (IANK) cells was studied. It was observed that IL-8 induces chemokinesis in these cells, as determined by their migration in modified Boyden chambers. Bacterial toxins such as cholera toxin or pertussis toxin inhibited IL-8-induced chemokinetic activity, suggesting the involvement of guanine nucleotide-binding (G) proteins in IL-8 signal transduction in these cells. Pertussis toxin ADP-ribosylates a 39-kDa protein, whereas cholera toxin ADP-ribosylates a 43- to 45-kDa protein. Pretreatment of IANK cell membranes with 0.01 or 0.1 ng/ml of IL-8 and/or 5 microM GTP-gamma S did not affect pertussis toxin- or cholera toxin-dependent ADP-ribosylation. Western blot analysis showed that IANK cell membranes possess one Gi (39 kDa), two Gs (43 kDa and 45 kDa), and one Go (39 kDa). Pretreatment of IANK cell membranes with concentrations between 0.001 to 1.0 ng/ml of IL-8 resulted in the disappearance of the 39 kDa Go, but not Gi or Gs protein(s), suggesting that IL-8 receptors expressed on IANK cells are coupled to Go. Various concentrations of IL-8 enhanced the binding of GTP-gamma 35 S to IANK cell membranes, which further indicates the coupling of G proteins to IL-8 receptors in IANK cells.